MRCOOL / DIY 5th Generation
EH 02 error code
The indoor PCB does not receive zero-crossing signal feedback for 4 minutes or the zero-crossing signal interval is abnormal.
- Severity
- technician
- Verified
- Jul 18, 2026
What triggers it
The indoor PCB does not receive zero-crossing signal feedback for 4 minutes or the zero-crossing signal interval is abnormal.
What to do
- Check the wiring connections and the power supply.
- If wiring or power supply is not normal, correct the connections and turn the unit on when the power supply is good.
- If wiring and power supply are normal, replace the indoor main PCB.
Which systems show it
- Units with an AC fan motor; the manual says this error is invalid for other models.
Related codes
Technician scope
Indoor PCB
Source
- Document
- data/sources/mrcool-diy5-service.pdf
- Section
- 4.7 TS03: Zero crossing signal detection error diagnosis and solution
- Page
- 58