MRCOOL / DIY 5th Generation
EH C1 error code
The refrigerant sensor detects leakage concentration at or above the manual's LFL thresholds.
- Severity
- safety
- Verified
- Jul 18, 2026
What triggers it
The refrigerant sensor detects leakage concentration at or above the manual's LFL thresholds.
What to do
- Power off, then restart the unit 2 minutes later.
- If the problem remains, check the system for refrigerant leakage.
- If leakage is present, repair the leak and recharge refrigerant.
- If no leakage is found, check the refrigerant system for blockages and clear any blockage.
Reset procedure
Power off, then restart the unit 2 minutes later. For multi-zone leakage alarm, the manual says the buzzer alarm can be eliminated by pressing any key on the remote, wired controller, or app.
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
Refrigerant sensor, leak repair
Source
- Document
- data/sources/mrcool-diy5-service.pdf
- Section
- 4.7 TS06-N10: Refrigerant sensor detects leakage diagnosis and solution
- Page
- 69