MRCOOL Air Conditioner Error Codes


MRCOOL was created after seeing a huge market gap. There was a time when heating and cooling appliances came in a single size, so regardless of the space you had to make do with one size fits all. There was no way to control heating or cooling, or even a chance to enjoy any feature. Fortunately, MRCOOL saw the gap in the market and started working on a more consumer-friendly product line.

Even to date, MRCOOL offers cutting-edge heating and cooling solutions that fit our modern lifestyle. Offering you appliances that are not only state-of-the-art but offer an advanced design and system that matches all your needs. Offering you a wide range of heating and cooling solutions that work best for your needs.

There is a time in your life when the most reliable appliance you have starts to show an error. While it might be a dark day, fortunately for you there is a simple solution for most error codes. To help you out we have accumulated a complete list of the MRCOOL air conditioner error codes. Offering you a chance to find out exactly what is wrong with your appliance, so you can finally make a decision. Rather than fighting with the appliance, or spending endless money on the repair, we suggest you first find the problem and then look for a solution.

Overview: Fault Display on the Dual 8 Numeral Tube of Outdoor Mainboard




Error CodesMeaning
E1Actuation of high pressure switch
E3Actuation of low pressure switch
E4Air discharge high temperature protection of compressor
F2Malfunction of condenser temperature thermistor
F3Malfunction of outdoor ambient temperature thermistor
F4Malfunction of Exhaust Temp. Sensor
oNNormal operation
H1Defrost operation

How to Fix?

Error Code: E1

Trouble Case: Actuation of high pressure switch

Origin of Trouble Signal: High pressure switch

Measure: Abnormality is detected when the contact of the high pressure switch opens for 3 sec. The system will be shut down. The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.

Error Code: E3

Trouble Case: Actuation of low pressure switch

Origin of Trouble Signal: Low pressure switch

Measure: When the unit runs more than 4 minutes or does not run, the low pressure switch opens for more than 3sec and the system will be shut down. The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.

Error Code: E4

Trouble Case: Air discharge high temperature protection of compressor




Origin of Trouble Signal: Exhaust over temperature protection

Measure: The exhaust temperature is higher than 125°C for more than 5sec, the system will be shut down. After stopping the compressor for 3 mins, if the exhaust temperature is lower than 90°C for more than 5 sec, the compressor will re-start. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.

Error Code: F2

Trouble Case: Malfunction of condenser temperature thermistor

Origin of Trouble Signal: Condenser temperature thermistor

Measure: Malfunction of condenser temperature thermistor is detected when there is a short circuit or an open circuit in the condenser temperature thermistor for more than 5 sec. The system will be shut down. The reset for the malfunction of condenser temperature thermistor is automatic.

Error Code: F3

Trouble Case: Malfunction of outdoor ambient temperature thermistor

Origin of Trouble Signal: Outdoor ambient temperature thermistor

Measure: Malfunction outdoor ambient temperature thermistor is detected when there is a short circuit or an open circuit in the outdoor ambient temperature thermistor for more than 5 sec. The system will be shut down. The reset for the malfunction of condenser temperature thermistor is automatic.

Error Code: F4

Trouble Case: Malfunction of Exhaust Temp. Sensor

Origin of Trouble Signal: Exhaust temperature sensor

Measure: If the exhaust temperature sensor is detected of open circuit 5 seconds successively after the compressor is started for 2 minutes or short circuit 5 seconds successively at any time .The system will be shut down. After the fault is eliminated, the system can automatically resume to operation.

Error Code: oN



Trouble Case: Normal operation

Origin of Trouble Signal: Unit operating normally or in standby mode.

Error Code: H1

Trouble Case: Defrost operation

Origin of Trouble Signal: Unit operating in defrost

Error Analysis

Trouble Case: Power problem

Measure:

  1. Check control transformer power (24V).
  2. If power is available to demand control board and LED(s) do not light, replace control board.

Trouble Case: Actuation of high pressure switch

Measure: Abnormality is detected when the contact of the high pressure switch opens for 3 sec. The system will be shut down. The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.

Trouble Case: Actuation of low pressure switch

Measure: When the unit runs more than 4 minutes or does not run, the low pressure switch opens for more than3sec and the system will be shut down..The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.

Trouble Case: Air discharge high- temperature protection of compressor

Measure: The exhaust temperature is higher than 125°C for more than 5s, the system will be shut down. After stopping the compressor for 3 mins, if the exhaust temperature is lower than 90°C for more than 5s, the compressor will re-start. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.

Trouble Case: Malfunction of exhaust Temp. Sensor

Measure: If the exhaust temperature sensor is detected of open circuit 5 seconds successively after the compressor is started for 3 minutes or short circuit 5 seconds successively at any time The system will be shut down. After the fault is eliminated, the system can automatically resume to operation.

For 13 SEER R410A Unitary Ducted Split AC & Heat Pump

Olympus Series Mid-Static Duct Air Handler

Fault CodesSolutions
E0Indoor EEPROM error
E1Communication malfunction between indoor and outdoor units
E3Indoor fan speed malfunction
E4Indoor room temperature sensor open circuit or short circuit
E5Evaporator coil temperature sensor open circuit or short circuit
ECRefrigerant leakage detection malfunction
EEWater-level alarm malfunction
E8Communication malfunction between two indoor units (for twins model)
E9Other malfunction of twins model
F0Current overload protection
F1Outdoor room temperature sensor open circuit or short circuit
F2Outdoor condenser pipe temperature sensor error
F3Discharging air temperature sensor error
F4Outdoor EEPROM error
F5Outdoor fan speed malfunction (Only for DC fan motor)
F6T2b sensor error
P0Inverter module IPM protection
P1High/Low voltage protection
P2High temperature protection of compressor top
P3Outdoor low temp. protection
P4Compressor drive error
P5Mode conflict

MRCOOL Split AC Manual PDF




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24 thoughts on “MRCOOL Air Conditioner Error Codes”

  1. I have the latest diy 36k Mrcool 4 zone. I only have 2 units hooked up. One of the zones will work for a while and then all of a sudden close up and display “- -” . It will still make some noises. I turn it off and back on and then it starts working again. What is the issue and how do I fix it?

    Reply
  2. i have a gen 3 36000 BTU split system that has a p6 code. We have made contact with the Tech. and he said that it was a valve that wasn’t open at the top.There is no valve at the top.There is two at the compressor that lead to the evaporator and that is it.I bought this for my church and those that installed it are the elders.We are a little perplexed,the manual,that we have, say,s it a sensor and the tech say;s a valve.We need some clarification on what are recourse is.I am thinking of hiring a local contractor to see what is going on. Please respond

    Reply
    • DF is DeFrost. When in HEAT mode, the outside coil frosts if the outside temperature is below about 37°F. The fans shut off, then the unit reverses cycle to COOL, without running the interior fan, to cause the outside coil to heat to melt the frost away. Then the cycle reversing valve switches back to HEAT and normal operation.

      Reply
    • Hi, thanks for asking.

      Error Code: E3
      Trouble Case: Actuation of low pressure switch
      Origin of Trouble Signal: Low pressure switch
      Measure: When the unit runs more than 4 minutes or does not run, the low pressure switch opens for more than 3sec and the system will be shut down. The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.

      Reply
  3. I have a 2nd gen 9000k Mr Cool the indoor unit blinks 88 with the little “data sent” icon blining as well. Can anyone answer my ?

    Reply
  4. I have a 2nd gen 12K Mr Cool DIY. the indoorunit blinks 88 with the little “data sent” icon blinking as well.

    Does anyone have any idea why or what this is telling me?

    Thank You

    Reply
  5. This is nice I see no information on the error codes anywhere in the documentation that came with my unit nor on their website.

    However, I am getting a P4 code. Any idea what this is for?

    Reply

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