MRCOOL / DIY 5th Generation
PC 11 error code
Outdoor main control board DC bus high voltage protection from the voltage detection circuit.
- Severity
- technician
- Verified
- Jul 18, 2026
What triggers it
Outdoor main control board DC bus high voltage protection from the voltage detection circuit.
What to do
- Check the power supply; if it is not working, turn off the unit.
- Check power-supply connections and wires; correct connections or replace wires if needed.
- Power on and measure P-N voltage where applicable.
- Replace the IPM board if P-N voltage is abnormal.
- Check the reactor; replace the reactor if it is not normal, otherwise replace the outdoor PCB.
Which systems show it
- MRCOOL DIY 5th Generation single-zone 9k, 12k, 18k, 24k, and 36k D25 indoor/outdoor models listed in manual section 1.1.
Related codes
Technician scope
Technician-tier outdoor auxiliary board diagnostic; see service manual section 4.3
Source
- Document
- data/sources/mrcool-diy5-service.pdf
- Section
- 4.3 Error Display; 4.7 TS10-S
- Page
- 37, 71