Derby AC Error Codes – Meaning and How to Fix Them

Derby is a UK-based corporation that came into being in 1985. Since its inception, the company has seen a great deal of growth in terms of numbers. UK’s independent refrigerator and air conditioning parts wholesalers have taken Europe by storm. They are currently regarded as one of the best appliance manufacturers in the UK and offer top-of-the-line refrigeration rolls and air conditioners in the UK. The company has headquarters in Nottingham, and offers services all around the mainland and nationwide in the UK. in addition, they have paired with a few retailers that offer its products all around the world.

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 Derby 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.

Codes Table

Error CodesLed Status
E0EEPROM parameter error
E1Indoor / outdoor units communication protection
E2Zero-crossing signal error
E3Fan speed out of control
E5Open or short circuit of outdoor temperature sensor (T4)
E6Open or short circuit of room (T1) or evaporator temperature sensor (T2)
P0Outdoor PCB protection
P1Over voltage or too low voltage protection
P2Temperature protection of compressor top.
P4Inverter compressor drive error

Note: E4 & P3: Reserved function

Diagnosis and Solution

E0 (EEPROM parameter error) error diagnosis and solution

Circuit or software error on indoor PCB ⇒ Replace indoor PCB

E1 (indoor / outdoor units communication protection) error diagnosis and solution

E2 (zero-crossing signal error) diagnosis and solution

E3 (indoor fan speed out of control) diagnosis and solution


*Unit does not star:

  • Power cut. Wait for power to be restored.
  • Unit may have become unplugged. Check that plug is securely in wall receptacle.
  • Fuse may have blown. Replace the fuse.
  • Battery in Remote controller may have been exhausted. Replace the battery.
  • The time you have set with timer is incorrect. Wait or cancel timer setting.

*Unit not cooling or heating (Cooling/ heating models only) room very well while air flowing out from the air condtioner:

  • Inappropriate temperature setting. Set temperature correctly.
  • Air filter is blocked. Clean the air filter.
  • Doors or Windows are open. Close the doors or windows.
  • Air inlet or outlet of indoor or outdoor unit has been blocked. Clear obstructions away first, then restart the unit.
  • Compressor 3 minutes protection has been activated. Wait.

If the trouble has not been corrected, please contact a local dealer or the nearest customer service center. Be sure to inform them of the detailed malfunctions and unit model.

Failure Indications

Derby AC Self Diagnostic Failure Indications
Derby AC Self Diagnostic Failure Indications


Derby Air Conditioner Manual PDF-1

Derby Air Conditioner Manual PDF-2

Derby Air Conditioner Manual PDF-3

*If you can't find the code you're looking for on our site, please let us know, and we'll update our database as soon as possible.

23 thoughts on “Derby AC Error Codes – Meaning and How to Fix Them”

  1. I have a ducted system it’s show e4 error from what I have come up with it’s apparently in defrost mode???? How can I speed this process up or is it something else? we are currently on day 1 of a heat wave


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