Diagnosing and Resolving Water Heater Temperature Sensor Failure

water heater temperature sensor failure


The temperature sensor in your water heater acts as a crucial signal switch, directing the gas control valve to release or cut off the gas flow based on the water temperature. However, like any mechanical component, the temperature sensor can malfunction, leading to issues such as overheating, cold water, or insufficient hot water. Here’s a comprehensive guide on how to troubleshoot and address water heater temperature sensor failure.

Diagnosing Water Heater Temperature Sensor Failure:

1. Measure Resistance:

Utilize a multimeter to measure the temperature sensor’s resistance. Compare the measured resistance to the expected values based on the manufacturer’s provided table for sensor resistance at different temperatures. If the resistance value falls outside the recommended range, it indicates a faulty sensor.

Addressing Water Heater Problems:

Troubleshooting Common Water Heater Issues:

1. Water Temperature Problems:

In cases of water being too hot, too cold, or a lack of hot water, potential causes include inadequate power, a malfunctioning temperature sensor, damaged heating elements, or incorrect connections of hot and cold lines.

2. Leakage:

Leakage issues may arise from a faulty T&P relief valve, overheating, or insufficient water pressure.

3. Discolored Water:

Discoloration could be a result of anode rod corrosion.

4. Unusual Noises:

Deposits accumulated during water heater operation can lead to strange noises. Regular maintenance helps address these issues.

Checking the Water Heater Temperature Sensor:

1. Disassembly:

Disassemble the gas valve with the attached temperature sensor from the water heater’s back plate.

2. Multimeter Test:

Switch the multimeter to ohms mode and connect it to pin probes. Insert the pin probes into the sensor’s holes to measure resistance. Compare the measured resistance with the expected values at different temperatures from the manufacturer’s chart.

3. Replacement:

If the temperature sensor readings are incorrect, replace the sensor. If the issue persists, consider replacing the gas valve.

Water Heater Maintenance Tips:

1. Insulating the Water Heater:

Insulating an electric water heater can reduce standby heat loss and lower water heating costs. Follow local regulations and manufacturer guidelines to ensure safety.

2. Pipe Insulation:

Insulate hot water pipes to reduce heat loss and conserve water by eliminating the need to wait for hot water.

3. Sediment Removal:

Periodically drain the water tank to wash away sediment, improving efficiency and preventing overheating.

4. Anode Rod Check:

Check the anode rod regularly to prevent tank rusting and reduce sediment buildup.

5. Regular Maintenance:

Regular inspections and maintenance, including checking the T&P valve, temperature controls, and other components, contribute to operational efficiency.

By following these troubleshooting steps and maintenance tips, you can diagnose and resolve water heater temperature sensor issues, ensuring a reliable and efficient hot water supply in your home. Regular attention to your water heater’s condition enhances its longevity and performance.

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About the author


I am Ben , a seasoned HVAC specialist with over 6 of experience in the HVAC industry. I holds HVAC Certification and has a proven track record in providing expert advice on HVAC systems.