Daikin Error Code C4
Heat exchanger sensor fault
Error Code Summary
| Brand | Daikin |
| Error Code | C4 |
| Meaning | Heat exchanger sensor fault |
| Cause | Indoor coil thermistor open/short |
| Recommended Action | Check thermistor resistance, replace if out of spec |
How to Fix Daikin Error C4
- 1
Power Cycle the Unit
Turn off the unit at the breaker, wait 5 minutes, then restore power. Some errors auto-clear after a restart.
- 2
Identify the Issue
Error C4 means: Heat exchanger sensor fault. The most common cause is: Indoor coil thermistor open/short.
- 3
Take Corrective Action
Check thermistor resistance, replace if out of spec
- 4
Test the System
After completing repairs, run the system and monitor for the error code. If it recurs, the issue may require professional diagnosis.
Safety Notice
Always disconnect power before performing any electrical work. If you're not a certified HVAC technician, contact a qualified professional for repairs involving refrigerant, electrical components, or compressor work.
Frequently Asked Questions
What does Daikin error code C4 mean?
Daikin error code C4 indicates: Heat exchanger sensor fault. This is typically caused by: Indoor coil thermistor open/short.
How do I fix Daikin error code C4?
To fix Daikin error code C4: Check thermistor resistance, replace if out of spec. If the error persists after these steps, contact a qualified HVAC technician.
Is Daikin error code C4 serious?
Error code C4 (Heat exchanger sensor fault) should be addressed promptly to prevent further damage to your Daikin system. Always turn off the unit if you notice unusual sounds, smells, or continued malfunction.