Top 10 Gas Water Heater Pilot Light Problems! Won't Light, Won't Stay Lit!

Introduction

This tutorial provides step-by-step guidance on troubleshooting common pilot light problems with gas water heaters. Understanding how the thermocouple, solenoid, and pilot flame work is essential for effective maintenance and repair. This guide will help you identify and resolve issues that prevent your water heater pilot light from igniting or staying lit.

Step 1: Understand the Components

• Thermocouple: This device senses the pilot flame and generates a small electrical voltage (30mV) that keeps the gas valve open.
• Solenoid: This is an electromagnetic valve that controls the flow of gas to the pilot light and burner.

Step 2: Verify the Pilot Light Ignition

1. Ensure the gas supply to the water heater is turned on.
2. Use a spark ignitor or lighter to attempt to ignite the pilot light.
3. If the pilot light fails to ignite, proceed to check for specific issues.

Step 3: Check Common Problems

Problem 1: Spark Ignitor Not Working

• Inspect the ignitor for any visible damage.
• Test the ignitor circuit with a multimeter to confirm it's functioning properly.

Problem 2: Gas Supply Issues

• Check if the gas is turned off or if there’s low inlet pressure.
• Confirm that the gas line is not obstructed.

Problem 3: Pilot Flame Size

• Inspect the size of the pilot flame. It should be a steady blue flame.
• If the flame is too small, adjust the pilot gas valve to increase the flow.

Problem 4: Pilot Flame Position

• Ensure that the pilot flame is properly enveloping the thermocouple.
• If the flame is bent or misdirected, adjust the pilot assembly.

Problem 5: Incorrect Thermocouple Position

• Check the alignment of the thermocouple. It must be positioned correctly to detect the flame.
• If misaligned, reposition it so it is enveloped by the pilot flame.

Problem 6: Dirty Thermocouple

• A dirty thermocouple can fail to generate enough voltage.
• Clean the thermocouple using steel wool or a dollar bill to remove any carbon build-up.

Problem 7: Testing the Thermocouple

1. Disconnect the thermocouple from the gas valve.
2. Use a multimeter to measure the millivolts generated.
3. A functioning thermocouple should produce around 30mV. If it's lower, it may need replacement.

Problem 8: Thermal Limit Switch Failure

• Test the thermal limit switch for continuity.
• If faulty, it will need to be replaced to restore proper function.

Problem 9: Wind Issues

• Ensure that the water heater is not located in a drafty area.
• If wind is blowing into the pilot assembly, consider installing a shield.

Problem 10: Bad Solenoid

• Check the solenoid for functionality.
• Use a multimeter to test for proper operation. Replace it if necessary.

Conclusion

By following these steps, you can troubleshoot and resolve common pilot light issues with gas water heaters. Regular maintenance, including cleaning components and checking gas supply, can prevent many of these problems from occurring. If issues persist or if you feel uncomfortable performing these tasks, consult a licensed HVAC technician for assistance.