Gas Water Heater: Pilot won't stay lit

If your pilot light will not stay lit, it is important that you take steps to fix it immediately. Several problems can shut off the pilot-a failed gas supply, lack of combustion air due to a clogged vent or a vent draft that blows out the pilot. A missing, crooked or blocked vent draft hood can cause a vent draft. Also, if the vent pipe cap on the top of the vent pipe on the roof is blocked or missing, wind can go down the pipe and blow the pilot out.

Another common problem causing the pilot to go out or not stay lit is a failed thermocouple (pilot generator). The thermocouple in your water heater keeps the pilot lit by sending a low current electrical signal to keep the gas valve open. If the thermocouple fails, it doesn't send the signal to the gas valve and the gas valve shuts off, extinguishing the pilot.

When lighting the pilot, you press and hold the pilot button to supply gas to the pilot until the pilot heats up enough to generate the signal to keep the gas valve open on its own. If the pilot light goes out when you release the button, you'll likely need to replace the thermocouple because it isn't sending the signal to the gas valve to keep the gas valve open.

gas water heater

These repairs may help solve your gas water heater problem

Replace the water heater thermocouple

Replace the water heater thermocouple

The thermocouple monitors the pilot light. It detects whether your pilot light is lit by generating a small electrical current powered by the heat of the pilot flame. The gas valve won't open if it doesn't sense the small electrical current produced by the thermocouple because it assumes the pilot light is off. Replace the thermocouple if it doesn't detect the pilot flame.

Symptoms common to all water heaters

Choose a symptom to see related water heater repairs.

Main causes: water supply needs chlorine treatment, anode rod too reactive
Main causes: thermostat temperature set too high, thermostats need adjustment, faulty thermostat, shorted heating element
Main causes: thermostats need adjustment, water heater capacity too low, bad heating element, thermostat failure, excessive tank sediment
Main causes: lack of power, no gas supply, thermostat limit switch tripped, bad element, bad thermostat, gas valve failure, bad thermocouple
Main causes: faulty pressure relief valve, water is overheating
Main causes: broken heating element, thermostat failure, excessive tank sediment, tank size too small, burner valve assembly failure
Main causes: loose water pipe fittings, leaky drain valve, bad temperature-pressure relief valve, leaky heating element, cracked tank

Articles and videos common to all water heaters

Use the advice and tips in these articles and videos to get the most out of your water heater.

September 26, 2019

Keeping your smart appliances secure from hackers

By Lyle Weischwill

Find out how to protect your smart appliances from malevolent invasions by hackers.

November 1, 2018

How to read a wiring schematic video

By Sears PartsDirect staff

Learn how to decipher symbols so you can buy the right part for your problem.

August 1, 2015

Water heater common questions

By Sears PartsDirect staff

These common questions and answers can help you make the most of your water heater.