These codes indicate a high-pressure or low-pressure switch failure. This article applies to Quantum multi-zone systems.

<p><strong>H1 Error Code: Outdoor Unit High-Pressure Switch Error</strong></p><p>The high-pressure switch is installed on the discharge pipe. When the pressure on the high-pressure side of the system exceeds the preset protection value, the protection activates and the system displays error code &quot;H1.&quot;</p><p><strong>H2 Error Code: Outdoor Unit Low-Pressure Switch Error</strong></p><p>The low-pressure switch is installed on the suction pipe. When the pressure on the low-pressure side of the system falls below the preset protection value, the protection activates and the system displays error code &quot;H2.&quot;&#xA0;</p><p><img src="https://attachments.gorgias.help/Q9r0k7BYaV2vg13y/hc/9JWjXVxG8m6DvMqm/2026101317-3cdafa88-0510-4d8d-a4d4-829144ba51f5-h1_h2_code.png" style="width: 600px;" class="fr-fic fr-dib fr-bordered"></p>

H1 or H2 Error Codes

This code indicates a mode conflict between indoor units, such as one unit set to Cooling and another set to Heating. This article applies to Quantum multi-zone systems.

<p><strong>PA Error Code: Top Flow Unit Communication Failure or Preset Mode Conflict</strong></p><h2 id="causes"><u>Causes</u></h2><ol><li style="font-size: 16px;">If the first indoor unit to turn on operates in Cooling or Dehumidification mode, the other indoor units can operate only in Cooling, Dehumidification, or Air Supply mode. An indoor unit set to any other mode reports a mode conflict fault and does not start. This fault does not affect indoor units that are already running.</li><li style="font-size: 16px;">If the first indoor unit to turn on operates in Heating mode, the other indoor units can operate only in Heating mode. An indoor unit set to any other mode reports a mode conflict fault and does not start. This fault does not affect indoor units that are already running.</li></ol><h2 id="solution"><u>Solution</u></h2><p>Set all the indoor units to the same mode.&#xA0;</p><h2 id="note"><u>Note</u></h2><p>Avoid running the units on Auto mode, as it could cause this error.</p>

PA Error Code

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