Rheem Water Heater Error Code 31: How to Fix It

Q: What causes a Rheem water heater inlet thermistor to fail?

Inlet thermistors typically fail due to age, mineral buildup from hard water, electrical surges, or exposure to excessive heat. Normal wear over 5-8 years of operation is the most common cause.

Q: Can I bypass the inlet thermistor temporarily?

No, you should never bypass the inlet thermistor as it's a critical safety component that prevents overheating and ensures proper temperature regulation. Operating without it can damage the water heater and void your warranty.

Q: How much does it cost to replace a Rheem inlet thermistor?

A replacement inlet thermistor typically costs between $25-60 for the part. Professional installation adds $100-200 in labor costs, making total repair costs range from $125-260.

Q: Will error code 31 prevent my water heater from heating water?

Yes, error code 31 will prevent the water heater from operating normally. The unit's safety systems will shut down heating elements until the faulty thermistor is replaced and the error is cleared.

Q: How long do Rheem water heater thermistors typically last?

Rheem water heater thermistors typically last 5-8 years under normal operating conditions. Factors like water quality, usage patterns, and electrical fluctuations can affect their lifespan.

Abstract

Error code 31 on your Rheem water heater indicates a problem with the inlet thermistor, which is the sensor that monitors cold water temperature entering the unit. This sensor may be open (disconnected) or shorted (electrically damaged), preventing the water heater from properly regulating heating cycles.