Error code E1/EL 01/EL01Updated a month ago

Introduction

The “E1”, “EL 01”, or “EL01” error codes indicate the indoor and outdoor units of your Quantum Series system cannot successfully communicate.

Prerequisites

Recommended parts to prepare:

• Indoor Printed Circuit Board (PCB)
• Outdoor Printed Circuit Board (PCB)
• Short-circuited component

Troubleshooting

Note: You may require an HVAC professional for assistance.

The troubleshooting recommendations for new or recently installed units include:

• Check each of the communication cables. Tug on each wire to ensure they’re fastened securely. There are 8 wire ends in total – 4 on the indoor terminal block and 4 on the outdoor terminal block.
• Cut off the terminated spade head and attach bare copper. 
• Check if the copper is making solid contact with the connector spades or lugs.

The troubleshooting recommendations for used units include:

• Power Off the unit and restart it after 2 minutes. If the problem continues, check the wiring connection between the indoor and outdoor units.
• 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). Note: When an AC is running properly, the voltage is moving alternately as positive and negative values.
  • If the value is alternative from negative to positive, replace the indoor PCB.
  • If the value is fixed and close to 0, check the wiring connection from the indoor terminal to the indoor PCB.
  • If the value is always positive, turn On the unit and check if W and 1 (L) are connected. Note: 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.
  • If the wiring connection between the indoor and outdoor units is incorrect, adjust the connection or change the wires.
• 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.

The troubleshooting recommendations for units with only 1 PCB include:

• Check if the power LED is On. 
  • If On, replace the outdoor PCB. Note: For certain models, the outdoor PCB cannot be removed separately. In this case, the whole outdoor electric control box should be replaced.
  • 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.  
• Check if there are any component short circuits. 
  • If there is a component short circuit, replace the short-circuited component and outdoor PCB. 
  • If there is not a component short circuit, unplug the electronic expansion valve.
• Check if power LED is On after unplugging the electronic expansion valve. 
  • If On, replace the coil of the electronic expansion valve.

The troubleshooting recommendations for used units with main PCB and IPM boards include:

• Check the AC voltage of the L, N output to the IPM board.  
  • 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.
  • If the AC voltage is not the same as the power input, replace the main PCB.
• Check if there are any component short circuits. 
  • If there is a component short circuit, replace the short-circuited component and main PCB. 
  • If there is not a component short circuit, check the DC 5V, 12V from the IPM board to the main PCB.  
• Check the DC 5V, 12V from the IPM board to the main PCB. 
  • If they appear normal, replace the main PCB. 
  • If not, unplug the electronic expansion valve and check if the DC 5V, 12V to the main PCB are functioning.
• Check if the DC 5V, 12V to the main PCB are functioning. 
  • If yes, replace the coil of the electronic expansion valve. 
  • If not, replace the IPM board.

Troubleshooting Diagram

Scope of Models Covered