Daikin Mini Split Error Code C4: How to Fix It

Q: What causes Daikin error code C4?

Error code C4 is caused by a defective indoor heat exchanger thermistor (R2T sensor). This can happen due to sensor aging, moisture damage, physical damage to the sensor, or loose electrical connections.

Q: Can I still use my Daikin mini split with error C4?

While the unit may continue to run, it cannot properly control temperature without a functioning thermistor. This can lead to poor efficiency, inadequate cooling or heating, and potential damage to the compressor from improper cycling.

Q: How much does it cost to fix Daikin error C4?

A replacement thermistor typically costs $20-50. Professional repair including labor usually ranges from $150-300 depending on your location and the technician's rates.

Q: How long do Daikin thermistors typically last?

Thermistors in mini split systems typically last 8-15 years. Factors like humidity, dust accumulation, and electrical surges can affect their lifespan.

Q: Will error C4 damage my Daikin mini split?

The error itself won't cause immediate damage, but running the system without proper temperature sensing can lead to inefficient operation and potential compressor issues over time. It's best to address the error promptly.

Abstract

Daikin mini split error code C4 indicates a defective indoor heat exchanger thermistor (R2T sensor). This temperature sensor monitors the evaporator coil and when it fails, your system cannot properly regulate cooling or heating cycles, potentially causing poor performance or system shutdown.