If you have a Cooper & Hunter mini split that gives a P3 error code, the outdoor ambient temperature is usually too low for heating.
The unit has shut down and given the error to protect the compressor from damage.
What is a Mini Split P3 Error Code?
A P3 Error Code is an “Outdoor ambient temperature too low” protection on Cooper & Hunter mini splits.
Keep in mind P3 can mean something else on other brands or firmware, so match the code to your model manual.
If In heating mode the outdoor temperature is lower than -25°C (about -13°F) for 1 hour, the LED will display a P3 failure.
If the outdoor temperature is higher than -22°C (about -8°F) for 10 minutes and the compressor stops for 1 hour, or outdoor temperature is higher than -5°C (about 23°F) for 10 minutes, then the unit will return to work.
Also, on many Cooper & Hunter and Gree-platform units, overload current protection is F0, not P3.
Possible Causes
- Outdoor ambient temperature too low
- Faulty outdoor ambient temperature sensor (T4)
- Wiring
- Faulty Outdoor PCB
Possible Fixes
- If outdoor temperature is below about -25°C (-13°F) in heating mode, the P3 code is likely normal protection.
- Power off the unit, wait a few minutes, and power it back on.
- If it is not that cold outside, check the outdoor ambient temperature sensor (T4) wiring and resistance.
- Check outdoor terminal connections are normal.
- If the sensor and wiring check out, the outdoor main PCB may be faulty.
Summary
A P3 Error Code on a Cooper & Hunter mini split is an “Outdoor ambient temperature too low” fault.
If the weather is very harsh and cold, this may be normal; otherwise, there is likely a problem with the outdoor ambient sensor or its reading.
Be sure to check the outdoor ambient temperature sensor (T4) wiring and resistance if it is not that cold outside.
A common problem is the wiring is wrong or faulty with a loose or bad connection.
The outside unit main PCB bard may also be bad and need to be tested.
Have you had issues with a Cooper & Hunter mini split with a P3 Error Code? Let us know your fix below.