These error codes indicate the indoor and outdoor units of the system cannot successfully communicate.

<h2 id="isPasted"><u>Introduction</u></h2><p>The &#x201C;E1&#x201D;, &#x201C;EL 01&#x201D;, or &#x201C;EL01&#x201D; error codes indicate the indoor and outdoor units of the system cannot successfully communicate. This article is for discontinued Quantum series systems (WYS, CYB, RYB, UYB, and FYB).&#xA0;</p><h2 id="prerequisites"><u>Prerequisites</u></h2><p id="isPasted">Recommended parts to prepare:</p><ul><li style="font-size: 16px;">Indoor printed circuit board (PCB)</li><li style="font-size: 16px;">Outdoor printed circuit board (PCB)</li><li style="font-size: 16px;">Short-circuited component</li></ul><h2 id="troubleshooting"><u>Troubleshooting</u></h2><p><strong id="isPasted">Note</strong>: An HVAC professional may be required for assistance.</p><h3 id="isPasted"><span style="font-size: 16px;">The troubleshooting recommendations for new or recently installed units include:</span></h3><ul><li style="font-size: 16px;">Check each of the communication cables. Tug on each wire to ensure they&#x2019;re fastened securely. There are 8 wire ends in total &#x2013; 4 on the indoor terminal block and 4 on the outdoor terminal block.</li><li style="font-size: 16px;">Cut off the terminated spade head and attach bare copper.&#xA0;</li><li style="font-size: 16px;">Check if the copper is making solid contact with the connector spades or lugs.</li></ul><h3 id="the-troubleshooting-recommendations-for-used-units-include"><span style="font-size: 16px;">The troubleshooting recommendations for used units include:</span></h3><ul><li style="font-size: 16px;">Power off the unit and restart it after 2 minutes. If the problem continues, check the wiring connection between the indoor and outdoor units.</li><li style="font-size: 16px;">If the wiring connection between the indoor and outdoor units are fine, test the DC voltage between N/L2 and S by using a multimeter. The red pin of the multimeter connects with 2 port (S or L2 port), while the black in is for 3 port (N or S port). <strong>Note</strong>: When an AC is running properly, the voltage is moving alternately as positive and negative values.<ul style="font-size: initial;"><li style="font-size: 16px;">If the value is alternative from negative to positive, replace the indoor PCB.</li><li style="font-size: 16px;">If the value is fixed and close to 0, check the wiring connection from the indoor terminal to the indoor PCB.</li><li style="font-size: 16px;">If the value is always positive, turn on the unit and check if W and 1 (L) are connected. <strong>Note</strong>: If the voltage displays a positive value, the outdoor unit has a malfunction. If the voltage holds a specific value, the indoor unit has a malfunction.</li><li style="font-size: 16px;">If the wiring connection between the indoor and outdoor units is incorrect, adjust the connection or change the wires.</li></ul></li><li style="font-size: 16px;">Check the wiring connection from the outdoor terminal to the outdoor PCB. If there is more than 1 PCB, check the wiring between the PCBs.</li></ul><h3 id="isPasted"><span style="font-size: 16px;">The troubleshooting recommendations for units with only 1 PCB include:</span></h3><ul><li style="font-size: 16px;">Check if the power LED is on.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If on, replace the outdoor PCB. <strong id="isPasted">Note</strong>: For certain models, the outdoor PCB cannot be removed separately. In this case, the whole outdoor electric control box should be replaced.</li><li style="font-size: 16px;">If not, unplug all the high voltage components connected to the main PCB to check its resistance. High-voltage components include 4-way valves, heaters, and AC fans. &#xA0;</li></ul></li><li style="font-size: 16px;">Check if there are any component short circuits.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If there is a component short circuit, replace the short-circuited component and outdoor PCB.&#xA0;</li><li style="font-size: 16px;">If there is not a component short circuit, unplug the electronic expansion valve.</li></ul></li><li style="font-size: 16px;">Check if power LED is on after unplugging the electronic expansion valve.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If on, replace the coil of the electronic expansion valve.</li></ul></li></ul><h3 id="isPasted"><span style="font-size: 16px;">The troubleshooting recommendations for used units with main PCB and IPM boards include:</span></h3><ul><li style="font-size: 16px;">Check the AC voltage of the L, N output to the IPM board. &#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If the AC voltage is the same as the power input, unplug all the high-voltage components connected to the main PCB to check its resistance.</li><li style="font-size: 16px;">If the AC voltage is not the same as the power input, replace the main PCB.</li></ul></li><li style="font-size: 16px;">Check if there are any component short circuits.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If there is a component short circuit, replace the short-circuited component and main PCB.&#xA0;</li><li style="font-size: 16px;">If there is not a component short circuit, check the DC 5V, 12V from the IPM board to the main PCB. &#xA0;</li></ul></li><li style="font-size: 16px;">Check the DC 5V, 12V from the IPM board to the main PCB.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If they appear normal, replace the main PCB.&#xA0;</li><li style="font-size: 16px;">If not, unplug the electronic expansion valve and check if the DC 5V, 12V to the main PCB are functioning.</li></ul></li><li style="font-size: 16px;">Check if the DC 5V, 12V to the main PCB are functioning.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, replace the coil of the electronic expansion valve.&#xA0;</li><li style="font-size: 16px;">If not, replace the IPM board.</li></ul></li></ul><h2 id="troubleshooting-diagram"><u>Troubleshooting Diagram</u></h2><p><u><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052717-ed55b7f7-e3d6-43fb-8cb7-8316e2b5b20c-849f4d33-b0b9-40dc-8e7a-77cf3ba90c1a.png" id="isPasted" class="fr-fic fr-dib fr-bordered"></u></p><p><u><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052717-dd0d0d8d-2d03-4976-a62d-c425d1ff7b02-32af5c3c-c3dd-4546-9ba1-a08c1d6f5a4f.png" id="isPasted" class="fr-fic fr-dib fr-bordered"></u></p><h2 id="isPasted"><u>Scope of Models Covered</u></h2><table style="width: 100%;"><tbody><tr><td style="width: 48.1263%; background-color: rgb(41, 105, 176);" class="fr-thick"><div style="text-align: center;"><strong><span style="color: rgb(255, 255, 255);">Single-Zone Mini Split Systems</span></strong></div></td><td style="width: 51.7294%; background-color: rgb(41, 105, 176);" class="fr-thick"><div style="text-align: center;"><strong><span style="color: rgb(255, 255, 255);">Multi-Zone and Light Commercial Mini Split Systems</span></strong></div></td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009AMFI20RPD / WS009AMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN020GMFI22M2E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009GMFI20RPD / WS009GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN030GMFI22M3E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN012AMFI20RPD / WS012AMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN040GMFI22M4E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN012GMFI20RPD / WS012GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN050GMFI22M5E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN018GMFI20RPD / WS018GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">CB009GMFILCFHD / CB012GMFILCFHD / CB018GMFILCFHD / CB024GMFILCFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN024GMFI20RPD / WS024GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">RB009GMFILDFHD / RB012GMFILDFHD /&#xA0;<br>RB018GMFILDFHD / RB024GMFILDFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN030GMFI20RPD / WS030GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">FB012GMFILDFHE / UB018GMFILCFHD / UB024GMFILCFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN036GMFI20RPD / WS036GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">WS009GMFI22HLE / WS012GMFI22HLE / WS018GMFI22HLE / WS024GMFI22HLE</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009AMFI22RPE / WS009AMFI22HLE<br>YN012AMFI22RPE / WS012AMFI22HLE</td><td style="width: 51.7294%;" class="fr-thick">YN009GMFI22RPE / YN012GMFI22RPE / YN018GMFI22RPE / YN024GMFI22RPE</td></tr></tbody></table>

E1, EL 01, or EL01 Error Codes

These error codes indicate the speed of the indoor or outdoor fan is operating outside of its normal range.

<h2 id="introduction"><u>Introduction</u></h2><p>The &quot;E3&quot;, &quot;EH 03&quot;, &quot;F5&quot;, or &quot;EC 07&quot; error codes indicate the speed of the indoor or outdoor fan is operating outside of its normal range. The &quot;E3&quot; and &quot;EH 03&quot; error codes indicate the indoor fan is operating outside of its normal range, while the &quot;F5&quot; and &quot;EC 07&quot; errors codes indicate the outdoor fan. This article is for discontinued Quantum series systems (WYS, CYB, RYB, UYB, and FYB).&#xA0;</p><p>If the speed of the indoor or outdoor fan remains too low or high for a certain time, the LED display will show the failure code, resulting in the system to turn off.</p><h2 id="prerequisites"><u>Prerequisites</u></h2><p>Recommended parts to prepare:</p><ul><li style="font-size: 16px;">Connection wires</li><li style="font-size: 16px;">Fan assembly</li><li style="font-size: 16px;">Fan motor</li><li style="font-size: 16px;">Printed circuit board (PCB)</li></ul><h2 id="troubleshooting"><u>Troubleshooting</u></h2><p><strong id="isPasted">Note</strong>: An HVAC professional may be required for assistance.</p><p>The troubleshooting recommendations include:&#xA0;</p><ul><li style="font-size: 16px;">Power off the unit and restart it after 2 minutes. If the problem continues, shut off the power supply and rotate the unit&apos;s fan by hand.&#xA0;</li><li style="font-size: 16px;">Check if the unit&apos;s fan is turning easily. If the fan is turning easily, check the wiring of the fan motor.</li><li style="font-size: 16px;">Ensure that the fan motor is properly connected and wired.&#xA0;</li><li style="font-size: 16px;">Measure the voltage for the fan motor from the PCB. <strong>Note</strong>: Refer to the Measuring Fan Motor Voltage<strong id="isPasted">&#xA0;</strong>section for information on measuring fan motor voltage.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If the voltage is within the normal parameters, replace the fan motor.&#xA0;</li><li style="font-size: 16px;">If not, replace the main PCB. <strong>Note</strong>: For certain models, the outdoor PCB cannot be removed separately. In this case, the whole outdoor electric control box should be replaced.</li></ul></li></ul><h2 id="measuring-fan-motor-voltage"><u>Measuring Fan Motor Voltage</u></h2><ul><li style="font-size: 16px;"><strong>Indoor or Outdoor DC Fan Motor (Control Chip in Fan Motor)</strong>: Power on the unit and wait until it is in standby mode. Measure the voltage of pin1-pin3 and pin4-pin3 in the fan motor connector. If the value of the voltage is not within the range displaying in the tables below, the PCB has faulted and needs replacing.&#xA0;<ul style="font-size: initial;"><li>DC motor voltage input and output (voltage: 220-240V~):<table style="width: 100%;"><thead><tr><th style="background-color: rgb(41, 105, 176);"><div style="text-align: center;" id="isPasted"><span style="color: rgb(255, 255, 255);">No.</span></div></th><th style="background-color: rgb(41, 105, 176);"><div style="text-align: center;" id="isPasted"><span style="color: rgb(255, 255, 255);">Color</span></div></th><th style="background-color: rgb(41, 105, 176);"><div style="text-align: center;" id="isPasted"><span style="color: rgb(255, 255, 255);">Signal</span></div></th><th style="background-color: rgb(41, 105, 176);"><div style="text-align: center;" id="isPasted"><span style="color: rgb(255, 255, 255);">Voltage</span></div></th></tr></thead><tbody><tr><td style="width: 25%; background-color: rgb(255, 255, 255);" class="fr-thick"><div style="text-align: center;">1</div></td><td style="width: 25%; background-color: rgb(255, 255, 255);" class="fr-thick"><div style="text-align: center;">Red</div></td><td style="width: 25%; background-color: rgb(255, 255, 255);" class="fr-thick"><div style="text-align: center;">Vs/Vm</div></td><td style="width: 25%; background-color: rgb(255, 255, 255);" class="fr-thick"><div style="text-align: center;">280V</div></td></tr><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">2</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">---</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">---</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">---</div></td></tr><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">3</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Black</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">GND</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">0V</div></td></tr><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">4</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">White</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Vcc</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">14-17.5V</div></td></tr><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">5</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Yellow</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Vsp</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">0~5.6V</div></td></tr><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">6</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Blue</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">FG</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">14-17.5V</div></td></tr></tbody></table></li><li><span style="font-size: 16px;">DC motor voltage input and output (voltage: 115V~)</span>:<table style="width: 100%;"><thead><tr><th style="background-color: rgb(41, 105, 176);"><div style="text-align: center;"><span style="color: rgb(255, 255, 255);">No.&#xA0;</span></div></th><th style="background-color: rgb(41, 105, 176);"><div style="text-align: center;"><span style="color: rgb(255, 255, 255);">Color</span></div></th><th style="background-color: rgb(41, 105, 176);"><div style="text-align: center;"><span style="color: rgb(255, 255, 255);">Signal</span></div></th><th style="background-color: rgb(41, 105, 176);"><div style="text-align: center;"><span style="color: rgb(255, 255, 255);">Voltage</span></div></th></tr></thead><tbody><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">1</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Red</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Vs/Vm</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">140V~190V</div></td></tr><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">2</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">---</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">---</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">---</div></td></tr><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">3</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Black</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">GND</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">0V</div></td></tr><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">4</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">White</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Vcc</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">14-17.5V</div></td></tr><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">5</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Yellow</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Vsp</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">0~5.6V</div></td></tr><tr><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">6</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">Blue</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;">FG</div></td><td style="width: 25.0000%;" class="fr-thick"><div style="text-align: center;" id="isPasted">14-17.5V</div></td></tr></tbody></table><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052115-2a7167a3-efca-4b85-96a1-25c69a2d154e-quantumseries_errorcode_e3_dcmotorvoltageinputoutput_diagram.png" style="width: 300px;" class="fr-fic fr-dib"></li></ul></li><li><strong><span style="font-size: 16px;">Outdoor DC Fan Motor (Control Chip is in Outdoor PCB)</span></strong><span style="font-size: 16px;">: Release the UVW connector. Measure the resistance of U-V, U-W, and V-W. If the resistance isn&apos;t equal to each other, the fan motor has faulted and needs replacing. Otherwise, the PCB has faulted and needs replacing.</span><span style="font-size: 12px;"><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052115-1e5b37a7-6f12-46c4-a600-443e2aabd705-quantumseries_errorcode_e3_outdoordcfanmotor_controlchip_diagram.png" style="width: 300px;" class="fr-fic fr-dib">&#xA0;</span></li><li><strong><span style="font-size: 16px;">Indoor DC Fan Motor</span></strong><span style="font-size: 16px;">: Power on the unit and set it to run in Fan mode at high fan speed. After letting the unit run for 15 seconds, measure the voltage of pin1 and pin2. If the value of the voltage is less than 100V (208~240V power supply) or 50V (115V power supply), the PCB has faulted and needs replacing.</span><span style="font-size: 12px;"><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052115-324d568c-7155-44eb-a623-ebad461d7676-quantumseries_errorcode_e3_indoordcfanmotor_diagram.png" style="width: 300px;" class="fr-fic fr-dib">&#xA0;</span></li></ul><h2 id="troubleshooting-diagram"><u>Troubleshooting Diagram</u><span style="font-size: 18px;"><u><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052115-4f159445-8c7d-4d69-b017-a93cf85d7f3c-quantumseries_errorcode_e3.png" style="width: 600px;" class="fr-fic fr-dib fr-bordered"></u></span></h2>

E3, EH 03, F5, or EC 07 Error Codes

These error codes indicate the system detects refrigerant leakage.

<div data-block="true" data-editor="br7aq" data-offset-key="fkhs8-0-0" id="isPasted"><h2 id="isPasted"><u>Introduction</u></h2><p>The &#x201C;EC&#x201D; or &#x201C;EL 0C&#x201D; error codes indicate the system detects refrigerant leakage. This article is for discontinued Quantum series systems (WYS, CYB, RYB, UYB, and FYB).&#xA0;</p><h2 id="prerequisites"><u>Prerequisites</u></h2><p>Recommended parts to prepare:</p><ul><li style="font-size: 16px;">T2 sensor</li><li style="font-size: 16px;">Indoor printed circuit board (PCB)</li><li style="font-size: 16px;">Additional refrigerant</li></ul><h2 id="troubleshooting"><u>Troubleshooting</u></h2><p><strong>Note</strong>: An HVAC professional may be required for assistance.</p><h3 id="the-troubleshooting-recommendations-for-new-or-recently-installed-units-include"><span style="font-size: 16px;">The troubleshooting recommendations for new or recently installed units include:</span></h3><ul><li style="font-size: 16px;">Open the valves on the outdoor unit fully. The valves release the refrigerant from the outdoor unit into the circuit.</li><li style="font-size: 16px;">Ensure that the length of the piping used for the indoor unit does not exceed the pre-charge refrigerant length. (25 ft. pre-charge per zone)</li><li style="font-size: 16px;">Inspect the unit for a potential leak. Check the following:<ul style="font-size: initial;"><li style="font-size: 16px;">Oil stains or residue around the unit&#x2019;s fittings and connections.</li><li style="font-size: 16px;">Hissing or bubbling sounds near the unit when it&#x2019;s running.</li><li style="font-size: 16px;">Reduced cooling or heating performance.</li></ul></li><li style="font-size: 16px;">Check the pressure PSI for the unit and verify it&#x2019;s within the appropriate range. Use r410a-compaible gauges while the system is on and running to check the pressure PSI. Use the manual button on the indoor unit to force the compressor to turn on. <strong>Note</strong>: Use the <a href="https://www.pdhvac.com/site/downloads/Temperature-Pressure-Chart.pdf" target="_blank" rel="noopener noreferrer">Refrigerant Pressure-Temperature chart</a> for reference when checking the pressure PSI.&#xA0;</li></ul><h3 id="the-troubleshooting-recommendations-for-used-units-include"><span style="font-size: 16px;">The troubleshooting recommendations for used units include:</span></h3><ul><li style="font-size: 16px;">Power off the unit and restart it after 2 minutes. If the problem continues, put your hands in front of the indoor air outlet.</li><li style="font-size: 16px;">Check if there is cool air blowing out from the indoor air outlet.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, check the T2 sensor.&#xA0;</li><li style="font-size: 16px;">If no, check the system for leakages.</li></ul></li><li style="font-size: 16px;">If the T2 sensor is securely attached, replace the indoor PCB.</li><li style="font-size: 16px;">Repair any leakages and recharge the refrigerant. If there are no leakages present, clear potential blockages in the unit.</li></ul><h3 id="the-troubleshooting-recommendations-for-units-with-excessive-exhaust-temperatures-include"><span style="font-size: 16px;">The troubleshooting recommendations for units with excessive exhaust temperatures include:</span></h3><ul><li style="font-size: 16px;">Power off the unit and restart it after 15 minutes. If the problem continues, put your hands in front of the indoor air outlet.</li><li style="font-size: 16px;">Check if there is cool air blowing out from the indoor air outlet.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, check the T2 sensor.&#xA0;</li><li style="font-size: 16px;">If no, check the system for leakages.</li></ul></li><li style="font-size: 16px;">Check if the T2 sensor is loose.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, ensure that the T2 sensor is properly connected.&#xA0;</li><li style="font-size: 16px;">If no, check if the T1 sensor is too close to the evaporator.</li></ul></li><li style="font-size: 16px;">Check if the T1 sensor is too close to the evaporator.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, re-install the T1 sensor correctly.&#xA0;</li><li style="font-size: 16px;">If no, replace the indoor PCB.</li></ul></li><li style="font-size: 16px;">Repair any leakages and recharge the refrigerant. If there are no leakages present, charge the refrigerant appropriately, which is about 10% of the nameplate charge. <strong>Note</strong>: Refer to the Methods for Checking Leaks section for information on how to find leaks in the system.</li></ul><h2 id="methods-for-checking-leaks"><u>Methods for Checking Leaks</u></h2><ul><li style="font-size: 16px;">Check for leaks by combining water with a small amount of dish soap or liquid detergent. Apply the soapy water solution to the fittings, connections, and tubing of the indoor and outdoor units while the system is turned on. The particular spot where the bubbles form indicates the location of the refrigerant leak.</li><li style="font-size: 16px;">Leak detector tools can detect refrigerant leaks through electronic sensors along the piping and around the unit coils.</li><li style="font-size: 16px;">Nitrogen pressure testing is commonly used by leak detection techs.</li></ul><p><strong>Note</strong>: Warranty coverage requires a confirmation of the location or origin of the leak.</p><h2 id="troubleshooting-diagrams"><u>Troubleshooting Diagrams</u><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052718-38389b22-a3d2-4ecd-b56f-269f8a3b5d9c-ebd216c5-5ded-4932-bd7f-7e3d18d254b8.png" style="box-sizing: border-box; -webkit-font-smoothing: antialiased; border-style: none; max-width: 100%; width: 692px; cursor: default;" class="fr-fic fr-dib fr-bordered"></h2><hr><p><br></p></div><div style="box-sizing: border-box; -webkit-font-smoothing: antialiased; color: rgb(27, 28, 29); font-family: Inter, &quot;Helvetica Neue&quot;, Arial, Helvetica, sans-serif; font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052718-58d089a9-e24a-4a47-8c1c-f29437c79e16-0557c194-d654-4a5d-a444-acf4c9abf917.png" style="box-sizing: border-box; -webkit-font-smoothing: antialiased; border-style: none; max-width: 100%; width: 692px; cursor: default;" class="fr-fic fr-dib"></div><p><br></p>

EC or EL 0C Error Codes

These error codes indicate the indoor or outdoor PCB main chip is not receiving feedback from the EEPROM chip.

<div data-block="true" data-editor="8h0ar" data-offset-key="3g900-0-0" id="isPasted"><h2 id="isPasted"><u>Introduction</u></h2><p>The &#x201C;F4&#x201D; or &#x201C;EC51&#x201D; error codes indicate the indoor or outdoor PCB main chip is not receiving feedback from the EEPROM chip. This article is for discontinued Quantum series systems (WYS, CYB, RYB, UYB, and FYB).&#xA0;</p><h2 id="prerequisites"><u>Prerequisites</u></h2><p>Recommended parts to prepare:</p><ul><li style="font-size: 16px;">Indoor printed circuit board (PCB)</li><li style="font-size: 16px;">Outdoor printed circuit board (PCB)</li></ul><h2 id="troubleshooting"><u>Troubleshooting</u></h2><p><strong id="isPasted">Note</strong>: An HVAC professional may be required for assistance.</p><p>The troubleshooting recommendations include:</p><ul><li style="font-size: 16px;">Power off the unit and restart it after 2 minutes.&#xA0;</li><li style="font-size: 16px;">Check if the error code is still displaying.</li><li style="font-size: 16px;">Replace the outdoor mainboard if the error is still displaying.</li></ul><p><strong>Note</strong>: Contact our Parts and Warranty department for any replacement components. Call 1-800-919-0150; Option #4.</p><h2 id="troubleshooting-diagram"><u>Troubleshooting Diagram</u></h2></div><div data-block="true" data-editor="8h0ar" data-offset-key="23bnm-0-0" style="box-sizing: border-box; -webkit-font-smoothing: antialiased; color: rgb(34, 34, 34); font-family: Inter, &quot;Helvetica Neue&quot;, Arial, Helvetica, sans-serif; font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><p><span data-offset-key="23bnm-0-0" style="box-sizing: border-box; -webkit-font-smoothing: antialiased;"><span data-text="true" style="box-sizing: border-box; -webkit-font-smoothing: antialiased;"><img src="https://attachments.gorgias.help/aalb/hc/qb0/ec%2051-49f384ad-edc8-4dd4-bb7f-42ffe7cf1de5.png" style="width: 545px;" class="fr-fic fr-dib fr-bordered"></span></span></p></div>

F4 or EC51 Error Codes

This article explains how to interpret light commercial AC (LCAC) error codes without an onboard LED readout.

<h2 id="isPasted"><u>Introduction</u></h2><p><span style="font-size: 16px;">This article explains how to interpret light commercial AC (LCAC) error codes <span style="font-size: 16px;" id="isPasted">without an onboard LED readout. This article is</span> for discontinued Quantum series systems (WYS, CYB, RYB, UYB, and RYB).&#xA0;</span></p><p><span style="font-size: 16px;">Some Quantum series systems do not possess an onboard LED display on the indoor unit.</span></p><p><span style="font-size: 16px;">Systems without LED displays use various light indicators to convey operations. For error codes, the light indicators will flash in certain sequences to convey the type of error.&#xA0;</span></p><p><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025022815-8787f5de-2e31-4832-a5e5-3c2d0bd36b89-lcac.png" style="width: 692px;" class="fr-fic fr-dib fr-bordered"></p><p><span style="font-size: 16px;">Use this table to interpret sequences:</span></p><table style="width: 93%; margin-right: calc(7%);"><tbody><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(41, 105, 176);" class="fr-thick"><strong><span style="color: rgb(255, 255, 255);">Operation Lamp</span></strong></td><td style="width: 14.4411%; text-align: center; background-color: rgb(41, 105, 176);" class="fr-thick"><strong><span style="color: rgb(255, 255, 255);">Timer Lamp</span></strong></td><td style="width: 20.0309%; text-align: center; background-color: rgb(41, 105, 176);" class="fr-thick "><strong><span style="color: rgb(255, 255, 255);">Error Code Interpretation</span></strong></td><td style="width: 43.9536%; text-align: center; background-color: rgb(41, 105, 176);" class="fr-thick"><strong><span style="color: rgb(255, 255, 255);">Meaning of Error</span></strong></td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">&#x2606; 1 time</td><td style="width: 14.4411%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">OFF</td><td style="width: 20.0309%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">E0</td><td style="width: 43.9536%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">Indoor unit EEPROM parameter error</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">&#x2606; 2 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">OFF</td><td style="width: 20.0309%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">E1</td><td style="width: 43.9536%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">Communication malfunction between indoor and outdoor units</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">&#x2606; 4 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">OFF</td><td style="width: 20.0309%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">E3</td><td style="width: 43.9536%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">Indoor fan speed out of control</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">&#x2606; 5 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">OFF</td><td style="width: 20.0309%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">E4</td><td style="width: 43.9536%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick ">Indoor room temperature sensor (T1) malfunction</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">&#x2606; 6 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">OFF</td><td style="width: 20.0309%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">E5</td><td style="width: 43.9536%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">Evaporator coil temperature sensor (T2) malfunction</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">&#x2606; 7 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">OFF</td><td style="width: 20.0309%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">EC</td><td style="width: 43.9536%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">Refrigerant leakage detection</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">&#x2606; 8 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">OFF</td><td style="width: 20.0309%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">EE</td><td style="width: 43.9536%; text-align: center; background-color: rgb(239, 239, 239);" class="fr-thick">Water-level alarm malfunction</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">&#x2606; 1 time</td><td style="width: 14.4411%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">SOLID</td><td style="width: 20.0309%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">F0</td><td style="width: 43.9536%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">Current overload protection</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">&#x2606; 2 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">SOLID</td><td style="width: 20.0309%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">F1</td><td style="width: 43.9536%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">Outdoor ambient temperature sensor (T4) malfunction</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">&#x2606; 3 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">SOLID</td><td style="width: 20.0309%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">F2</td><td style="width: 43.9536%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">Condenser coil temperature sensor (T3) malfunction</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">&#x2606; 4 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">SOLID</td><td style="width: 20.0309%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">F3</td><td style="width: 43.9536%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">Compressor discharge temperature sensor (T5) malfunction</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">&#x2606; 5 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">SOLID</td><td style="width: 20.0309%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">F4</td><td style="width: 43.9536%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">Outdoor unit EEPROM parameter error</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">&#x2606; 6 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">SOLID</td><td style="width: 20.0309%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">F5</td><td style="width: 43.9536%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">Outdoor fan speed has been out of control</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">&#x2606; 7 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">SOLID</td><td style="width: 20.0309%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">F6</td><td style="width: 43.9536%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">Indoor coil outlet pipe sensor (Located on outdoor unit low pressure valve)</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">&#x2606; 8 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">SOLID</td><td style="width: 20.0309%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">F7</td><td style="width: 43.9536%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">Communication malfunction between Cassette optional lift panel and the unit</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">&#x2606; 9 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">SOLID</td><td style="width: 20.0309%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">F8</td><td style="width: 43.9536%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">Cassette optional lift panel malfunction</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">&#x2606; 10 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">SOLID</td><td style="width: 20.0309%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">F9</td><td style="width: 43.9536%; text-align: center; background-color: rgb(203, 245, 214);" class="fr-thick">Cassette optional lift panel not closed</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">&#x2606; 1 time</td><td style="width: 14.4411%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">FLASHING</td><td style="width: 20.0309%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">P0</td><td style="width: 43.9536%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">Inverter module (IPM) malfunction</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">&#x2606; 2 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">FLASHING</td><td style="width: 20.0309%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">P1</td><td style="width: 43.9536%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">Over-voltage or under-voltage protection</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">&#x2606; 3 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">FLASHING</td><td style="width: 20.0309%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">P2</td><td style="width: 43.9536%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">Compressor top high temperature protection (OLP)</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">&#x2606; 4 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">FLASHING</td><td style="width: 20.0309%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">P3</td><td style="width: 43.9536%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">Low ambient temperature cut off in heating</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">&#x2606; 5 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">FLASHING</td><td style="width: 20.0309%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">P4</td><td style="width: 43.9536%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">Compressor drive malfunction</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">&#x2606; 6 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">FLASHING</td><td style="width: 20.0309%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">P5</td><td style="width: 43.9536%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">Indoor units mode conflict</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">&#x2606; 7 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">FLASHING</td><td style="width: 20.0309%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">P6</td><td style="width: 43.9536%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">Low pressure protection</td></tr><tr><td style="width: 21.4286%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">&#x2606; 8 times</td><td style="width: 14.4411%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">FLASHING</td><td style="width: 20.0309%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">P7</td><td style="width: 43.9536%; text-align: center; background-color: rgb(245, 241, 203);" class="fr-thick">Outdoor IPM temperature sensor error</td></tr></tbody></table><p><br></p><h2 id="examples"><u>Examples</u></h2><p>Below is an example of a CYB air handler flashing an error code pattern.&#xA0;</p><p><span class="fr-video fr-deletable fr-rv fr-fvc fr-dvb fr-draggable" contenteditable="false" draggable="true"><iframe width="100%" src="https://player.vimeo.com/video/1061294244?h=79dbbccbec&amp;autoplay=1" frameborder="0" allowfullscreen class="fr-draggable"><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span></iframe></span></p><p id="isPasted"><span style="font-size: 16px;">As we can observe, the sequence is:</span></p><ul><li style="font-size: 16px;">Timer Light -&gt; FLASHING &#x2605;</li><li style="font-size: 16px;">Operation Light -&gt; 7x Flashes &#x2605;</li></ul><p>Therefore, the code is P6 for Low Pressure (Low Refrigerant/Leak) Detection Protection.</p><hr><p><span style="font-size: 16px;">Here is another example of an error code for CYB systems:</span></p><p><span class="fr-video fr-deletable fr-rv fr-fvc fr-dvb fr-draggable" contenteditable="false" draggable="true"><iframe width="100%" src="https://player.vimeo.com/video/1061310885?h=30e2951287" frameborder="0" allowfullscreen class="fr-draggable"><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span><span class="fr-mk" style="display: none;">&#xA0;</span></iframe></span></p><p id="isPasted">As we can observe, the sequence is:</p><ul><li style="font-size: 16px;">Timer Light &gt; FLASHING &#x2605;</li><li style="font-size: 16px;">Operation Light &gt; 6x Flashes &#x2605;</li></ul><p>Therefore, the code is P5 for Indoor Units Mode Conflict.&#xA0;</p><p>This usually occurs on a multi-zone setup where one indoor unit is calling for heat and another is calling for cooling. For multi-split systems, all indoor units must be working in the same mode of either <strong>all cool</strong> or <strong>all heat</strong>. The code can be eliminated by changing all units to the same mode or turning off the conflicting unit. Using Auto mode can sometimes result in this error as well.</p>

Light Commercial AC Error Codes

These error codes indicate an inverter drive error is present.

<h2 id="isPasted"><u>Introduction</u></h2><p>The &quot;P0&#x201D; or &#x201C;PC00&#x201D; error codes indicate an inverter drive error is present. The inverter drive error can either be the compressor or outdoor board failing. This article is for discontinued Quantum series systems (WYS, CYB, RYB, UYB, and FYB).&#xA0;</p><h2 id="prerequisites"><u>Prerequisites</u></h2><p>Recommended parts to prepare:</p><ul><li style="font-size: 16px;">Compressor</li><li style="font-size: 16px;">Connection wires</li><li style="font-size: 16px;">IPM module board</li><li style="font-size: 16px;">Outdoor fan assembly</li><li style="font-size: 16px;">Outdoor printed circuit board (PCB)</li></ul><h2 id="video-tutorial"><u>Video Tutorial</u></h2><p><span style="font-size: 16px;">Watch this video tutorial to learn how to troubleshoot the &quot;P0&quot; or &quot;PC00&quot; error codes:</span></p><p><span style="font-size: 16px;" id="isPasted"><a href="https://www.youtube.com/watch?v=BbWekj6Uoyk&amp;t=4s&amp;ab_channel=PioneerMiniSplitStore" target="_blank" rel="noopener noreferrer">P0 and P4 Error Codes Service and Diagnostic</a></span></p><p><span style="font-size: 16px;">Video length: 4:19</span></p><h2 id="troubleshooting"><u>Troubleshooting</u></h2><p><strong>Note</strong>: An HVAC professional may be required for assistance.</p><h3 id="the-troubleshooting-recommendations-for-new-or-recently-installed-units-include"><span style="font-size: 16px;">The troubleshooting recommendations for new or recently installed units include:</span></h3><ul><li style="font-size: 16px;">Ensure that the outdoor refrigerant valves are backed out all the way counterclockwise to the open position by ohming &#x3A9; out the compressor with a multimeter.<img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025053012-cc38fbd2-c3a4-44b9-9359-3cf6a89d2c5f-outdoor_refrigerant_valves.png" style="width: 300px;" class="fr-fic fr-dib"></li><li style="font-size: 16px;">Remove the top and front panels of the unit to see the compressor.</li><li style="font-size: 16px;">Pull out the sound insulation blanket wrapped around the compressor.</li><li style="font-size: 16px;">Ohm &#x3A9; out three compressor lead pairs on the large white Molex plug between the compressor and the board. The plug usually has red, blue, and white (or black) wires, meaning you will test each pin against each other.</li><li style="font-size: 16px;">Test each wire individually against the ground using the metal casing of the unit or a ground screw. The wires should not have any reading against the ground. The compressor should not be grounded. The multimeter should read &#x201C;0&#x201D; or &#x201C;Open Line.&#x201D;</li><li style="font-size: 16px;">If the compressor operates properly, replace the outdoor inverter power module (IPM) board.</li></ul><h3 id="the-troubleshooting-recommendations-for-used-units-include"><span style="font-size: 16px;">The troubleshooting recommendations for used units include:</span></h3><ul><li style="font-size: 16px;">Check the wiring between the PCB and compressor.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If there is an error, ensure the proper connections or replace the wires and connectors.&#xA0;</li><li style="font-size: 16px;">If there is not an error, check if the IPM is installed correctly.</li></ul></li><li style="font-size: 16px;">Check if the IPM is installed correctly.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If the IPM is installed correctly, conduct an IPM continuity check.</li><li style="font-size: 16px;">If the IPM is not installed correctly, fix the installation, tighten the screws, and apply silicon grease.&#xA0;</li></ul></li><li style="font-size: 16px;">Check if the IPM terminal resistance is uniform.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If it is, check the outdoor fan and outdoor unit ventilation.</li><li style="font-size: 16px;">If it&#x2019;s not uniform, replace the IPM board or outdoor PCB.&#xA0;</li></ul></li><li style="font-size: 16px;">Check if the outdoor fan and outdoor unit ventilation are operating properly.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, check the compressor resistance valves.</li><li style="font-size: 16px;">If no, refer to the solution of the &#x201C;Fan speed is operating outside of the normal range&#x201D; malfunction.&#xA0;</li></ul></li><li style="font-size: 16px;">Ensure that the compressor resistance valves are uniform.&#xA0;<ul style="font-size: initial;"><li style="font-size: 16px;">If the valves are uniform, replace the outdoor PCB. <strong id="isPasted">Note</strong>: For certain models, the outdoor PCB cannot be removed separately. In this case, the whole outdoor electric control box should be replaced.&#xA0;</li><li style="font-size: 16px;">If the valves are not uniform, replace the compressor.</li></ul></li></ul><p><strong>Note</strong>: Contact our Parts and Warranty department for any replacement components. Call 1-800-919-0150; Option #4.</p><h2 id="troubleshooting-diagram"><u>Troubleshooting Diagram</u></h2><p><u><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052720-8d2e41fd-e66e-4ec1-8309-b840750f981f-f345428b-584b-4f1a-ae8f-472a2e2ed59b.png" id="isPasted" class="fr-fic fr-dib fr-bordered"></u></p><h2 id="isPasted"><u>Scope of Models Covered</u></h2><div data-block="true" data-editor="e2pdf" data-offset-key="bgrm2-0-0" id="isPasted" style="box-sizing: border-box; -webkit-font-smoothing: antialiased; color: rgb(34, 34, 34); font-family: Inter, &quot;Helvetica Neue&quot;, Arial, Helvetica, sans-serif; font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><table id="isPasted" style="width: 100%;"><tbody><tr><td style="width: 48.1263%; background-color: rgb(41, 105, 176);" class="fr-thick"><div style="text-align: center;"><strong><span style="color: rgb(255, 255, 255);">Single-Zone Mini Split Systems</span></strong></div></td><td style="width: 51.7294%; background-color: rgb(41, 105, 176);" class="fr-thick"><div style="text-align: center;"><strong><span style="color: rgb(255, 255, 255);">Multi-Zone and Light Commercial Mini Split Systems</span></strong></div></td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009AMFI20RPD / WS009AMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick ">YN020GMFI22M2E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009GMFI20RPD / WS009GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN030GMFI22M3E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN012AMFI20RPD / WS012AMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN040GMFI22M4E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN012GMFI20RPD / WS012GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN050GMFI22M5E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN018GMFI20RPD / WS018GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">CB009GMFILCFHD / CB012GMFILCFHD / CB018GMFILCFHD / CB024GMFILCFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN024GMFI20RPD / WS024GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">RB009GMFILDFHD / RB012GMFILDFHD /&#xA0;<br>RB018GMFILDFHD / RB024GMFILDFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN030GMFI20RPD / WS030GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">FB012GMFILDFHE / UB018GMFILCFHD / UB024GMFILCFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN036GMFI20RPD / WS036GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">WS009GMFI22HLE / WS012GMFI22HLE / WS018GMFI22HLE / WS024GMFI22HLE</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009AMFI22RPE / WS009AMFI22HLE<br>YN012AMFI22RPE / WS012AMFI22HLE</td><td style="width: 51.7294%;" class="fr-thick">YN009GMFI22RPE / YN012GMFI22RPE / YN018GMFI22RPE / YN024GMFI22RPE</td></tr></tbody></table><div data-offset-key="bgrm2-0-0" style="box-sizing: border-box; -webkit-font-smoothing: antialiased; position: relative; white-space: pre-wrap; direction: ltr; text-align: left;"><br></div></div>

P0 or PC00 Error Codes

These error codes indicate a voltage error is present.

<h2 id="isPasted"><u>Introduction</u></h2><p>The &quot;P1&#x201D; or &#x201C;PC01&#x201D; error codes indicate a voltage error is present. This article is for discontinued Quantum series systems (WYS, CYB, RYB, UYB, and FYB).&#xA0;</p><h2 id="prerequisites"><u>Prerequisites</u></h2><p>Recommended parts to prepare:</p><ul><li id="isPasted" style="font-size: 16px;">Power supply wires</li><li style="font-size: 16px;">IPM module board</li><li style="font-size: 16px;">Printed circuit board (PCB)</li><li style="font-size: 16px;">Reactor</li></ul><h2 id="video-tutorial"><u>Video Tutorial</u></h2><p id="isPasted">Watch this video tutorial to learn how to troubleshoot the &quot;P1&quot; or &quot;PC01&quot; error codes:</p><p><span style="font-size: 16px;"><a href="https://www.youtube.com/watch?v=aWEmJCp7bXA&amp;t=2s" target="_blank" rel="noopener noreferrer">P1 Error Codes Service and Diagnostic</a></span></p><p>Video length: 2:10</p><h2 id="troubleshooting"><u>Troubleshooting</u></h2><p id="isPasted"><strong>Note</strong>: An HVAC professional may be required for assistance.</p><p><strong><span style="font-size: 16px;">The troubleshooting recommendations include:</span></strong></p><ul><li style="font-size: 16px;">Ensure that the unit has the proper breaker. The Quantum series systems require a standard single (110V) or double (220V) pole breaker. The unit will not work with a tandem-double pole or GFCI/AFCI breaker. <strong>Note</strong>: You can send photos to our Technical Support team to confirm the proper breaker.</li><li style="font-size: 16px;">Ensure that the indoor and outdoor model numbers match in series, BTU sizing, voltage, and compatible SEER levels.</li><li style="font-size: 16px;">Check if the wiring terminations are correct. The 1, 2, 3 configuration has to match in color sequence outside and inside.</li><li style="font-size: 16px;">Confirm the communication wiring is a solid run, containing no splices.</li><li style="font-size: 16px;">Check for any physical damage along the wiring. You can run spare wire to confirm.</li><li style="font-size: 16px;">If the wiring is correct, check the outdoor unit voltages. The outdoor unit voltages should read 220V or 110V.<ul style="font-size: initial;"><li style="font-size: 16px;">Check the AC voltage across terminals 1 + 2 on the indoor unit.</li><li style="font-size: 16px;">Check the AC voltage across terminals 1 + 2 on the outdoor unit.</li><li style="font-size: 16px;">Check the AC voltage across terminals L + N (or L1 + L2) on the indoor unit.</li></ul></li><li style="font-size: 16px;">If the outdoor unit voltages are correct, check the compressor. <strong>Note</strong>: Checking the compressor requires turning the unit&#x2019;s power completely off.<ul style="font-size: initial;"><li style="font-size: 16px;">Remove the top and front panels of the unit.</li><li style="font-size: 16px;">Ohm &#x3A9; out the compressor lead pairs on the Molex plug between the compressor and board. The three pairs of leads on the compressor side of the plug should match and all be between 1-3.</li><li style="font-size: 16px;">Test each wire individually against the ground using the metal casing of the unit or a ground screw. The wires should not have any reading against the ground. The compressor should not be grounded. The multimeter should read &#x201C;0&#x201D; or &#x201C;Open Line.&#x201D;</li></ul></li><li><span style="font-size: 16px;">If the compressor operates properly, check the unit&#x2019;s reactor. <strong>Note</strong>: Not all unit&#x2019;s have reactors.</span>&#xA0;<img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025053012-353533c3-981e-433c-a155-b3b74978100f-unit_reactor.png" style="width: 300px;" class="fr-fic fr-dib"><ul><li style="font-size: 16px;">Unplug the two leads.</li><li style="font-size: 16px;">Test the two leads. The two leads should read between 0-to-1-ohm &#x3A9;.</li></ul></li><li style="font-size: 16px;">If the unit&#x2019;s reactor operates properly, the outdoor mainboard needs replacing. If the unit&#x2019;s reactor is not functioning properly, replace the reactor.</li></ul><p><strong>Note</strong>: Contact our Parts and Warranty department for any replacement components. Call 1-800-919-0150; Option #4.</p><p>If you need to see the correct wiring of the compressor, see the Related Resources section at the bottom of the article.</p><p>If you need information on how to open the outdoor condenser unit, see the Related Resources section.</p><div data-block="true" data-editor="c82a9" data-offset-key="692pa-0-0" style="box-sizing: border-box; -webkit-font-smoothing: antialiased; orphans: 2; text-align: start; text-indent: 0px; widows: 2; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><div data-block="true" data-editor="e2pdf" data-offset-key="9te0u-0-0" style="box-sizing: border-box; -webkit-font-smoothing: antialiased; orphans: 2; text-align: start; text-indent: 0px; widows: 2; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><h2 id="troubleshooting-diagram"><u>Troubleshooting Diagram</u></h2><p style="color: rgb(34, 34, 34); font-family: Inter, &quot;Helvetica Neue&quot;, Arial, Helvetica, sans-serif; font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-transform: none; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap;"><img src="https://attachments.gorgias.help/aalb/hc/qb0/pc01%20edit-36fdbf89-c69b-40fd-9bd3-c54b360d2957.png" style="width: 501px;" class="fr-fic fr-dib fr-bordered"></p><h2 id="isPasted"><u>Scope of Models Covered</u></h2></div></div><div data-block="true" data-editor="c82a9" data-offset-key="7g7s-0-0" style="box-sizing: border-box; -webkit-font-smoothing: antialiased; color: rgb(34, 34, 34); font-family: Inter, &quot;Helvetica Neue&quot;, Arial, Helvetica, sans-serif; font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><table style="width: 100%;"><tbody><tr><td style="width: 48.1263%; background-color: rgb(41, 105, 176);" class="fr-thick"><div style="text-align: center;"><strong><span style="color: rgb(255, 255, 255);">Single-Zone Mini Split Systems</span></strong></div></td><td style="width: 51.7294%; background-color: rgb(41, 105, 176);" class="fr-thick"><div style="text-align: center;"><strong><span style="color: rgb(255, 255, 255);">Multi-Zone and Light Commercial Mini Split Systems</span></strong></div></td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009AMFI20RPD / WS009AMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN020GMFI22M2E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009GMFI20RPD / WS009GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN030GMFI22M3E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN012AMFI20RPD / WS012AMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN040GMFI22M4E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN012GMFI20RPD / WS012GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN050GMFI22M5E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN018GMFI20RPD / WS018GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">CB009GMFILCFHD / CB012GMFILCFHD / CB018GMFILCFHD / CB024GMFILCFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN024GMFI20RPD / WS024GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">RB009GMFILDFHD / RB012GMFILDFHD /&#xA0;<br>RB018GMFILDFHD / RB024GMFILDFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN030GMFI20RPD / WS030GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">FB012GMFILDFHE / UB018GMFILCFHD / UB024GMFILCFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN036GMFI20RPD / WS036GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">WS009GMFI22HLE / WS012GMFI22HLE / WS018GMFI22HLE / WS024GMFI22HLE</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009AMFI22RPE / WS009AMFI22HLE<br>YN012AMFI22RPE / WS012AMFI22HLE</td><td style="width: 51.7294%;" class="fr-thick">YN009GMFI22RPE / YN012GMFI22RPE / YN018GMFI22RPE / YN024GMFI22RPE</td></tr></tbody></table></div><h2 id><br></h2><h2 id="related-resources"><u>Related Resources</u></h2><ul><li style="font-size: 16px;">For information on the correct wiring for the compressor, see page 21 in this manual: <a href="https://www.pdhvac.com/site/downloads/WYS_SM.pdf" target="_blank" rel="noopener noreferrer">Quantum Inverter Series Service &amp; Troubleshooting manual</a></li><li style="font-size: 16px;">See page 90 in this manual to learn how to open the outdoor condenser unit: <a href="https://www.pdhvac.com/site/downloads/WYS_SM.pdf" id="isPasted" target="_blank" rel="noopener noreferrer">Quantum Inverter Series Service &amp; Troubleshooting manual</a></li></ul>

P1 or PC01 Error Codes

These error codes indicate high-temperature or high-pressure protection of the IPM.

<h2 id="isPasted"><u>Introduction</u></h2><p>The &quot;P2&#x201D; or &#x201C;PC02&#x201D; error codes indicate high-temperature or high-pressure protection of the inverter power module (IPM). This article is for discontinued Quantum series systems (WYS, CYB, RYB, UYB, and FYB).&#xA0;</p><h2 id="isPasted"><u>Troubleshooting</u></h2><p><strong>Note</strong>: An HVAC professional may be required for assistance.</p><h3 id="the-troubleshooting-recommendations-include"><span style="font-size: 16px;">The troubleshooting recommendations include:</span></h3><ul id="isPasted"><li style="font-size: 16px;">Check if an obstruction is present in the airflow system of the indoor and outdoor units.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, clear the air inlet and outlet of the indoor and outdoor units. Clear the heat exchanger of the indoor and outdoor units too.</li><li style="font-size: 16px;">If no obstruction is found in the airflow system of the indoor and outdoor units, power off the system and restart it after 10 minutes.</li></ul></li><li style="font-size: 16px;">Check if the temperature of the compressor top is more than 194&#xB0;F (90&#xB0;C).<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, check if the refrigerant system is functioning properly.</li><li style="font-size: 16px;">If no, check all the connections for the unit. Specifically check the connection of the overload protector (OLP) sensor.</li></ul></li><li style="font-size: 16px;">Check if the refrigerant system is functioning properly.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, replace the outdoor control printed circuit board (PCB).</li><li style="font-size: 16px;">If no, repair the refrigerant system.</li></ul></li><li style="font-size: 16px;">Check all the connections for the unit. Specifically check the connection of the OLP sensor.<ul style="font-size: initial;"><li style="font-size: 16px;">If the connections are fine, measure the resistance between the two ports of the OLP.</li><li style="font-size: 16px;">If the connections are not fine, correct the connections for the unit.</li></ul></li><li style="font-size: 16px;">Measure the resistance between the two ports of the OLP sensor. Check if the resistance reads &#x201C;0&#x201D;.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, replace the outdoor control PCB.</li><li style="font-size: 16px;">If no, replace the OLP sensor. &#xA0;</li></ul></li></ul><p><strong>Note</strong>: Contact our Parts and Warranty department for any replacement components. Call 1-800-919-0150; Option #4.</p><h2 id="troubleshooting-diagram"><u>Troubleshooting Diagram</u></h2><p><img src="https://attachments.gorgias.help/aalb/hc/qb0/screenshot%202024-02-05%20at%203.23.37%E2%80%AFpm-b32d111e-8dd1-4c21-b222-2d1d1345d089.png" style="width: 632px;" class="fr-fic fr-dib fr-fil fr-bordered"></p><p><br></p>

P2 or PC02 Error Codes

These error codes indicate the internal refrigerant levels are imbalanced.

<h2 id="isPasted"><u>Introduction</u></h2><p>The &quot;PC 03&#x201D; or &#x201C;PC03&#x201D; error codes indicate the internal refrigerant levels are imbalanced. This article is for discontinued Quantum series systems (WYS, CYB, RYB, UYB, and FYB).&#xA0;</p><h2 id="prerequisites"><u>Prerequisites</u></h2><p>Recommended parts to prepare:</p><ul type="disc"><li style="font-size: 16px;">Connection wires</li><li style="font-size: 16px;">Pressure switch</li><li style="font-size: 16px;">Refrigerant</li><li style="font-size: 16px;">Outdoor fan</li><li style="font-size: 16px;">Outdoor printed circuit board (PCB)</li></ul><h2 id="troubleshooting"><u>Troubleshooting</u></h2><p id="isPasted"><strong>Note</strong>: An HVAC professional may be required for assistance.</p><p><strong><span style="font-size: 16px;">The troubleshooting recommendations for new or recently installed units include:</span></strong></p><ul><li style="font-size: 16px;">Confirm the outdoor refrigerant valves are backed out all the way counterclockwise to the open position by ohming &#x3A9; out the compressor with a multimeter.<img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025053012-8405812b-0521-43f0-86cd-46e4b7b49b29-outdoor_refrigerant_valves.png" style="width: 300px;" class="fr-fic fr-dib"></li><li style="font-size: 16px;">Ensure that the lineset being used is at least 10 feet (3 m) in length. If the lineset is not at least 10 feet (3 m) in length, the system may be factory overcharged.</li><li style="font-size: 16px;">Check if any major leaks are present at the connection point of the lineset. Fix any found leaks and recharge the lineset to spec. <strong>Note</strong>: Refer to the Methods for Checking Leaks section for information on how to find leaks in the system.&#xA0;</li><li style="font-size: 16px;">Check if any minor leaks are present at the four separate connection points of the lineset. If the unit was operating for a few weeks and now displays the error code, a minor leak is likely present, allowing refrigerant to leak over time. Fix any found leaks and re-charge the lineset to spec.</li></ul><p><strong id="isPasted">Note</strong>: If you need to reference the Refrigerant Pressure vs. Temperature chart for Pioneer Split systems, visit the <strong>Related Resources</strong> section at the bottom of the article.</p><p><strong>The troubleshooting recommendations for low-pressure protection include:</strong></p><ul><li style="font-size: 16px;">Confirm the low-pressure protector and main control board are wired properly.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, check if the low-pressure protector is broken.</li><li style="font-size: 16px;">If no, reconnect the low-pressure protector and main control board.</li></ul></li><li style="font-size: 16px;">Check if the low-pressure protector is broken by disconnecting the plug and measuring the resistance of the protector. The resistance value of the low-pressure protector should be &#x201C;0&#x201D;.<ul style="font-size: initial;"><li style="font-size: 16px;">If the value is &#x201C;0&#x201D;, check if the outdoor-ambient temperature is too low.</li><li style="font-size: 16px;">If the value is not &#x201C;0&#x201D;, replace the low-pressure protector.</li></ul></li><li style="font-size: 16px;">Check if the outdoor ambient temperature is too low.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, stop the unit.</li><li style="font-size: 16px;">If no, check if the valve core of the high-pressure valve is open fully.</li></ul></li><li style="font-size: 16px;">Check if the valve core of the high-pressure valve is open fully.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, check if the indoor fan is running properly in Cooling mode.</li><li style="font-size: 16px;">If no, open the valve core of the high-pressure valve.</li></ul></li><li style="font-size: 16px;">Confirm the indoor fan is running properly in Cooling mode.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, replace the outdoor main board.</li><li style="font-size: 16px;">If no, refer to the solution of the &#x201C;Fan speed is operating outside of the normal range&#x201D; malfunction.</li></ul></li><li style="font-size: 16px;">Replace the outdoor main board. Confirm if the problem still occurs. <strong>Note</strong>: For certain models, the outdoor PCB cannot be removed separately. In this case, the whole outdoor electric control box should be replaced.&#xA0;</li><li style="font-size: 16px;">If the problem does not occur, check if the system functions properly after adding more refrigerant.</li><li style="font-size: 16px;">If the system does not operate properly after adding more refrigerant, check if the refrigerant system is functioning properly.</li></ul><p><strong><span style="font-size: 16px;">The troubleshooting recommendations for high-pressure protection include:</span></strong></p><ul><li style="font-size: 16px;">Confirm the high-pressure switch and main control board are wired properly.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, check if the high-pressure protector is broken.</li><li style="font-size: 16px;">If no, reconnect the high-pressure switch and main control board.</li></ul></li><li style="font-size: 16px;">Check if the high-pressure protector is broken by disconnecting the plug and measuring the resistance of the protector. The resistance value of the high-pressure protector should be &#x201C;0&#x201D;.<ul style="font-size: initial;"><li style="font-size: 16px;">If the value is &#x201C;0&#x201D;, check if the outdoor-ambient temperature is higher than 122&#xB0;F (50&#xB0;C).</li><li style="font-size: 16px;">If the value is not &#x201C;0&#x201D;, replace the high-pressure protector.</li></ul></li><li style="font-size: 16px;">Check if the outdoor ambient temperature is higher than 122&#xB0;F (50&#xB0;C).<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, stop the unit.</li><li style="font-size: 16px;">If no, check if the outdoor unit ventilation is operating well.</li></ul></li><li style="font-size: 16px;">Check if the outdoor ventilation is operating well.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, check if the outdoor fan is running properly.</li><li style="font-size: 16px;">If no, ensure that the outdoor unit ventilation is functioning properly.</li></ul></li><li style="font-size: 16px;">Confirm the outdoor fan is running properly.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, check if the heat exchanger is dirty.</li><li style="font-size: 16px;">If no, refer to the solution of the &#x201C;Fan speed is operating outside of the normal range&#x201D; malfunction.</li></ul></li><li style="font-size: 16px;">Check if the heat exchanger is dirty.<ul style="font-size: initial;"><li style="font-size: 16px;">If yes, clean the heat exchanger.</li><li style="font-size: 16px;">If no, replace the outdoor main board.</li></ul></li><li style="font-size: 16px;">Replace the outdoor main board. Confirm if the problem still occurs. <strong>Note</strong>: For certain models, the outdoor PCB cannot be removed separately. In this case, the whole outdoor electric control box should be replaced.&#xA0;</li><li style="font-size: 16px;">If the problem does not occur, check if the refrigerant system is functioning properly.</li></ul><p><strong>Note</strong>: Contact our Parts and Warranty department for any replacement components. Call 1-800-919-0150; Option #4.</p><h2 id="isPasted"><u>Methods for Checking Leaks</u></h2><ul><li style="font-size: 16px;">Check for leaks by combining water with a small amount of dish soap or liquid detergent. Apply the soapy water solution to the fittings, connections, and tubing of the indoor and outdoor units while the system is turned on. The particular spot where the bubbles form indicates the location of the refrigerant leak.</li><li style="font-size: 16px;">Leak detector tools can detect refrigerant leaks through electronic sensors along the piping and around the unit coils.</li><li style="font-size: 16px;">Nitrogen pressure testing is commonly used by leak detection techs.</li></ul><h2 id="troubleshooting-diagram"><u>Troubleshooting Diagram</u></h2><p><u><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052814-f47c0f5b-3d76-4316-8654-07a2fbdcff00-57a0fce4-8730-4c50-988a-8fb3f2d2c886.png" id="isPasted" class="fr-fic fr-dii fr-bordered" style="width: 682px;"></u><br></p><p><u><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052814-7bc05e56-76d0-45a1-b4fa-da54ef160308-8ff3f3a0-0b61-42ea-93f8-4a42a9249309.png" id="isPasted" class="fr-fic fr-dib fr-bordered"></u></p><p><u><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025052814-1c902960-75e6-4a1b-bb89-d461240189bd-d7cdc21b-caf3-46e6-9f39-2b79a86f7bfa.png" id="isPasted" class="fr-fic fr-dib fr-bordered"></u></p><h2 id="scope-of-models-covered"><u>Scope of Models Covered</u></h2><table style="width: 100%;"><tbody><tr><td style="width: 48.1263%; background-color: rgb(41, 105, 176);" class="fr-thick"><div style="text-align: center;"><strong><span style="color: rgb(255, 255, 255);">Single-Zone Mini Split Systems</span></strong></div></td><td style="width: 51.7294%; background-color: rgb(41, 105, 176);" class="fr-thick"><div style="text-align: center;"><strong><span style="color: rgb(255, 255, 255);">Multi-Zone and Light Commercial Mini Split Systems</span></strong></div></td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009AMFI20RPD / WS009AMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN020GMFI22M2E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009GMFI20RPD / WS009GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN030GMFI22M3E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN012AMFI20RPD / WS012AMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN040GMFI22M4E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN012GMFI20RPD / WS012GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">YN050GMFI22M5E</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN018GMFI20RPD / WS018GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">CB009GMFILCFHD / CB012GMFILCFHD / CB018GMFILCFHD / CB024GMFILCFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN024GMFI20RPD / WS024GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick ">RB009GMFILDFHD / RB012GMFILDFHD /&#xA0;<br>RB018GMFILDFHD / RB024GMFILDFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN030GMFI20RPD / WS030GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">FB012GMFILDFHE / UB018GMFILCFHD / UB024GMFILCFHD</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN036GMFI20RPD / WS036GMFI20HLD</td><td style="width: 51.7294%;" class="fr-thick">WS009GMFI22HLE / WS012GMFI22HLE / WS018GMFI22HLE / WS024GMFI22HLE</td></tr><tr><td style="width: 48.1263%;" class="fr-thick">YN009AMFI22RPE / WS009AMFI22HLE<br>YN012AMFI22RPE / WS012AMFI22HLE</td><td style="width: 51.7294%;" class="fr-thick">YN009GMFI22RPE / YN012GMFI22RPE / YN018GMFI22RPE / YN024GMFI22RPE</td></tr></tbody></table><p><br></p><h2 id="related-resources"><u>Related Resources</u></h2><ul><li style="font-size: 16px;">Click this link to reference the Refrigerant Pressure vs. Temperature chart for Pioneer Split systems: <a data-fr-linked="true" href="https://www.pdhvac.com/site/downloads/Temperature-Pressure-Chart.pdf" id="isPasted" target="_blank" rel="noopener noreferrer">Refrigerant Pressure vs. Temperature chart</a></li></ul>

PC 03 or PC03 Error Codes

<div data-block="true" data-editor="dhgg" data-offset-key="cv8g8-0-0" id="isPasted"><h2 id="isPasted"><u>Introduction</u></h2><p>The &quot;P4&#x201D;, &#x201C;PC 04&#x201D;, or &#x201C;PC04&#x201D; error codes indicate an inverter drive error is present. The error codes may display if the compressor or outdoor board is failing. This article is for discontinued Quantum series systems (WYS, CYB, RYB, UYB, and FYB).&#xA0;</p><h2 id="isPasted"><u>Video Tutorial</u></h2><p>Watch this video tutorial to learn how to troubleshoot the &quot;P4&#x201D;, &#x201C;PC 04&#x201D;, or &#x201C;PC04&#x201D; error codes:</p><p><a href="https://www.youtube.com/watch?v=BbWekj6Uoyk&amp;t=4s&amp;ab_channel=PioneerMiniSplitStore" target="_blank" rel="noopener noreferrer">P0 and P4 Error Codes Service and Diagnostic</a></p><p>Video length: 4:19</p><h2 id="isPasted"><u>Troubleshooting</u></h2><p><strong>Note</strong>: An HVAC professional may be required for assistance.</p><h3 id="the-troubleshooting-recommendations-include"><span style="font-size: 16px;">The troubleshooting recommendations include:</span></h3><ul><li style="font-size: 16px;">Ensure that the outdoor refrigerant valves are backed out all the way counterclockwise to the open position by ohming &#x3A9; out the compressor with a multimeter.<img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025053012-9c894fc4-50df-477d-8cb0-2dc820746c17-outdoor_refrigerant_valves.png" style="width: 300px;" class="fr-fic fr-dib"></li><li style="font-size: 16px;">Remove the top and front panels of the unit to see the compressor.</li><li style="font-size: 16px;">Pull out the sound insulation blanket wrapped around the compressor.</li><li><span style="font-size: 16px;">Ohm &#x3A9; out three compressor lead pairs on the large white Molex plug between the compressor and the board. The plug usually has red, blue, and white (or black) wires, meaning you will test each pin against each other.</span><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2025053012-1c66c916-5bd8-4a6c-ab49-f9279af6e2ca-molex_plug.png" style="width: 300px;" class="fr-fic fr-dib"></li><li style="font-size: 16px;">Test each wire individually against the ground using the metal casing of the unit or a ground screw. The wires should not have any reading against the ground. The compressor should not be grounded. The multimeter should read &#x201C;0&#x201D; or &#x201C;Open Line.&#x201D;</li><li style="font-size: 16px;">If the compressor operates properly, replace the outdoor inverter power module (IPM) board.</li></ul><p><strong>Note</strong>: Contact our Parts and Warranty department for any replacement components. Call 1-800-919-0150; Option #4.</p><h2 id="isPasted"><u>Related Resources</u></h2><ul><li style="font-size: 16px;">Click this link for a general parts diagram of the WYS wall mount. The diagram displays the compressor in the outdoor unit: <a href="https://www.pdhvac.com/site/downloads/wys22_Exploded_Parts_Diagram.pdf">WYS Wall Mount Parts Diagram</a>&#xA0;</li><li style="font-size: 16px;">See page 90 in this manual to learn how to open the outdoor condenser unit: <a href="https://www.pdhvac.com/site/downloads/WYS_SM.pdf" target="_blank" rel="noopener noreferrer" id="isPasted">Quantum Inverter Series Service &amp; Troubleshooting Manual</a></li></ul></div><div data-block="true" data-editor="dhgg" data-offset-key="e6av4-0-0" style="box-sizing: border-box; -webkit-font-smoothing: antialiased; color: rgb(34, 34, 34); font-family: Inter, &quot;Helvetica Neue&quot;, Arial, Helvetica, sans-serif; font-size: 14px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: pre-wrap; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><br></div>

P4, PC 04, or PC04 Error Codes

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Use these troubleshooting guides to resolve errors for Quantum WYS, CYB, RYB, UYB, and FYB systems.

Quantum Systems

Troubleshooting

Discontinued Products

Pioneer Offers Hyper-Heat Units

Pioneer Systems Offer Both Heating & Cooling Functions

Understand the Difference Between 115V & 230V Systems

Understand the Refrigerants Used for Each Model

How to Choose a System

Mini Splits are Capable of Using Fewer Indoor Units than the Outdoor Unit’s Zonal Capacity

Pioneer Mini Splits Function as Dehumidifiers

Pioneer Offers Different Lineset Lengths

Pioneer Offers Pre-Charged Linesets

Pioneer Offers Pre-Flared Linesets

Pioneer Systems Include Factory Pre-Charged Refrigerant

Single-Zone Mini Splits Cannot be Used with Multiple Indoor Units

Understand how Mini Splits are Powered

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Understand the Meaning of “Multi-Zone”

Mini-Split Basics

Determine the Unit Size Needed for Your Space

Match the Lineset Diameter to Your Pioneer Indoor Unit

Understand Why Short Cycling Occurs When Sizing Systems

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Diamante Essenza High-Wall (WYT-17) Overview

Diamante Pro High-Wall (WYT-20) Overview

Quantum Fresh High-Wall (WYT-FA) Overview

Quantum Hyperformance High-Wall (WYT-25) Overview

Quantum Ultra Ceiling Cassette (CYT-24) Overview

Quantum Ultra Ducted Ceiling Concealed (RYT-24) Overview

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Quantum Ultra Multi-Zone Overview

Vertex Ducted Central Split (DYC-18) Overview

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ECOasis 50 Ductless Wall-Mounted Single-Room Energy Recovery Ventilator (ERV) Overview

ECOasis 150 Ductless Wall-Mounted Single-Room Energy Recovery Ventilator (ERV) Overview

Energy Recovery Ventilators

QHD070 Whole-House Ducted Dehumidifier (QHD) Overview

High Performance Dehumidifier

Full Inverter Rooftop RV Air Conditioner Heat Pump (PYZ) Overview

Under-Bench RV Inverter Packaged Heat Pump Air Conditioner (PYR) Overview

Recreational Vehicle Systems

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First-Time Setup

Connect the Refrigerant Piping to the Indoor Unit

Cassette Units

Ducted Units

Flex Units

Wall-Mounted Units

Indoor Units

Angle Linesets Upward

Complete the Safety Checks & Test Run

Find Out if a Wall-Mounted Indoor Unit can be Set onto Ceilings

Find Out if the Indoor Unit Requires Anything Extra in Order to be Wall-Mounted

Find Out the Ideal Height for Mounting Indoor Units

Leakage Inspection & Vacuuming for Refrigerant Lines

Learn the Gauge of Wire Used for Ductless System Connections

Open the Service Valve

Set Up the Lineset to Exit from the Side of the Indoor Unit

Understand the 6-Foot Plastic Whips & 4-Lead Mini Split Connection Wire

Understand how to Properly Uncoil the Lineset

Understand the Drilling Details to Accommodate Drain & Refrigerant Lines

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Understand the Torque Wrench Size for Installing Your System

Installation Requirements

Understand the Allowable Zone Combinations for Multi-Zone Systems

Multi-Zone Units

Install Outdoor Units: Getting Started

Air Evacuation & Bleed the Circuit for Outdoor Units

Connect the Electrical Wiring for Outdoor Units

Connect the Refrigerant Piping to the Outdoor Unit

Mount the Outdoor Unit

Select the Installation Location for Outdoor Units

Select the Installation Location for Ducted Central Split Outdoor Units

Set Up the Condensate Water Drainage for Outdoor Units

Understand How to Install Ducted Central Split Outdoor Units on Support Pads

Outdoor Units

Ductless & Ducted Systems

Install ECOasis 50 Energy Recovery Ventilators

Install ECOasis 150 Energy Recover Ventilators

Energy Recovery Ventilator

Connect the Drain Fitting for QHD070 Whole-House Ducted Dehumidifiers

High Performance Dehumidifiers

Install Rooftop RV Systems: Getting Started

Create the Roof Opening for Rooftop RV Systems

Install the Air Duct & Top Mounting Plate for Rooftop RV Systems

Mount the Panel for Rooftop RV Systems

Place the Unit onto the Roof for Rooftop RV Systems

Setup the Electrical Wiring for Rooftop RV Systems

Setup the System Connections for Rooftop RV Systems

Understand the Installation Requirements for Rooftop RV Systems

Rooftop RV Inverter

Install Under-Bench RV Systems: Getting Started

Connect & Power Up Under-Bench RV Systems

Create the Floor Openings for Under-Bench RV Systems

Create the Recirculation Air Opening for Under-Bench RV Systems

Fasten the Under-Bench RV System into Place

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Under-Bench RV Inverter

Installation & Setup

Understand the DIP Switches for Vertex Ducted Central Split Systems

DIP Switch Layouts

Turn the LED Display On or Off

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Understand the Master Unit Display for ECOasis 50 Energy Recovery Ventilators

Understand the Onboard Controller & Terminal Block Layout for QHD070 Whole-House Ducted Dehumidifiers