What is an E1 Error Code? - MRCOOL DIY Ductless Mini Split

If an E1 error code shows up in your air handler, that means there is a communication error either with the indoor unit or the outdoor unit. The causes for this could be a wiring mistake, or a faulty control board with the indoor unit or the outdoor unit.

Troubleshooting An E1 Error Code

One thing you can do to try and troubleshoot the E1 error code is power off the MRCOOL DIY mini split then wait two minutes and restart it. If the E1 error code displays again, however, you may want to measure the unit's voltage. If you are not comfortable working with electricity, you may want to call MrCool tech support at 270-366-0457.

For the outdoor unit, take off the side wiring cover with a screw driver. Then, using a multi-meter, test the voltage. For a unit running off of 120 volts, touch the ends to L1 and Ground. For a unit running off of 240 volts, you will want to touch the ends to L1 and L2.

For the indoor unit, you will want to place the ends of the multi-meter on 1 and 2 to make sure the unit is getting voltage. For a 120 volt unit, you will want to go between 1 and Ground. Doing these things will help you determine if the unit is wired correctly. If it is not a wiring issue, it is possible your control board may need to be replaced in either the indoor unit or the outdoor unit.

This is when it is important to call the MRCOOL Warranty Department so they can help you determine the reason for the E1 error code.

Other MrCool DIY Error Codes

  • E0 - Indoor unit EEPROM parameter error
  • E1 - Indoor / outdoor units communication error
  • E2 - Zero-crossing signal detection error
  • E3 - Indoor fan speed has been out of control
  • E4 - Indoor room temperature sensor T1 open circuit or short circuit
  • E5 - Evaporator coil temperature sensor T2 open circuit or short circuit EC - Refrigerant leakage detection
  • F0 - Overload current protection
  • F1 - Outdoor ambient temperature sensor T4 open circuit or short circuit
  • F2 - Condenser coil temperature sensor T3 open circuit or short circuit
  • F3 - Compressor discharge temperature sensor TP open circuit or short circuit
  • F4 - Outdoor unit EEPROM parameter error
  • F5 - Outdoor fan speed has been out of control
  • P0 - IPM malfunction or IGBT over-strong current protection
  • P1 - Over voltage or over low voltage protection
  • P2 - High temperature protection of IPM module or compressor top
  • P3 - Outdoor ambient temperature too low
  • P4 - Inverter compressor drive error
  • P5 - Indoor units mode conflict (multi-zone ONLY)
  • P6 - Low pressure protection(Only for 36K)
2 comments (view/add)
  • David Bonzell
    David Bonzell
    Posted on 7/30/2019

    I have a DA2421-H21 24,000 btu Ductless Air unit. Once a week I notice error code P4 at the Display window and a hissing of R410A inside the evap unit coils. This continues for 15 seconds, and the code and hissing clears. Can you reply on the cause?

  • Steven
    Steven from Ingrams
    Posted on 7/31/2019

    We don't sell the DuctlessAire line of mini-splits, so we wouldn't know for sure what the issue may be. However, if it were the MrCool DIY line of mini-splits, this video may help: https://iwae.com/resources/videos/p1-p4-error-code-mrcool-diy-ductless-mini-split.html

* All fields required.

Your email address will not be published. Comments will display after being approved by our moderators. Comments may be edited for clarity.