If your water heater pilot light keeps going out, it’s usually a sign that something is preventing your gas hot water system from operating properly. In some cases, the problem may be as simple as a temporary interruption to the gas supply or a pilot light that needs relighting. In other situations, faulty components inside the unit may require professional repairs.
Understanding why the pilot light won’t stay lit can help you determine whether it’s safe to carry out some basic checks or whether it’s time to contact a licensed gas fitter.
In this guide, we’ll explain what a pilot light does, the most common reasons it keeps going out, what you can safely check yourself, and when professional assistance is needed.
A pilot light is a small flame found on many older gas storage hot water systems. Its job is to ignite the main burner whenever the water inside the tank needs heating.
If the pilot light goes out, the main burner cannot ignite, meaning your hot water system won’t heat the water.
It’s worth noting that not every hot water system has a pilot light. Many newer gas continuous flow systems use electronic ignition instead, while electric, heat pump and solar hot water systems don’t use pilot lights at all.
There are several reasons why a pilot light may repeatedly extinguish. Some are relatively straightforward, while others involve components that should only be repaired by a licensed gas fitter.
A faulty thermocouple is one of the most common causes of pilot light problems.
The thermocouple is a safety device that detects whether the pilot flame is burning. If it doesn’t sense enough heat, it automatically shuts off the gas supply to prevent gas from escaping.
Over time, thermocouples can wear out or become misaligned, causing them to shut off the gas even though the pilot has been lit correctly.
Common signs include:
Replacing a thermocouple should be carried out by a licensed gas fitter.
If the gas supply is interrupted, the pilot light won’t receive enough fuel to remain lit.
Before assuming there’s a fault with the hot water system, check whether:
If none of your gas appliances are working, the issue may be related to your gas supply rather than the hot water system itself.
Outdoor gas hot water systems can occasionally experience pilot light outages during strong winds.
Wind entering the burner area may extinguish the small flame, particularly if the unit’s protective cover has become loose or damaged.
If this only happens during severe weather, it may simply require relighting once conditions improve. However, frequent wind-related outages should be inspected by a professional.
Dust, insects and debris can gradually build up around the pilot assembly.
This may reduce the size of the flame or prevent it from burning consistently.
A weak pilot flame often appears:
Cleaning gas components should only be carried out by someone qualified to work on gas appliances.
The gas control valve regulates the flow of gas to both the pilot light and the main burner.
If it begins to fail, it may interrupt the gas supply intermittently, causing the pilot light to go out without warning.
Gas valves are safety-critical components and should only be diagnosed or replaced by a licensed gas fitter.
If your manufacturer’s instructions allow it, you may be able to safely relight the pilot light yourself.
While instructions vary between models, the general process usually involves:
Always follow the instructions provided by your hot water system manufacturer.
If the pilot light immediately goes out again, avoid repeatedly attempting to relight it. This usually indicates an underlying fault that requires professional attention.
Some pilot light issues are simple, but others involve gas components that should never be repaired yourself.
Arrange professional assistance if:
When dealing with gas hot water systems, avoid taking unnecessary risks.
Don’t:
If you ever smell gas, turn off the gas supply if it’s safe to do so, leave the area, and seek professional assistance immediately.
While some faults occur naturally as components wear out, regular maintenance can help reduce unexpected breakdowns.
Some good habits include:
Routine servicing allows worn components to be identified before they fail completely.
This commonly indicates a faulty thermocouple, although other gas supply issues may also be responsible. A licensed gas fitter can diagnose the exact cause.
Yes. Outdoor gas hot water systems can occasionally have their pilot light extinguished during strong winds, particularly if the burner area is exposed or the cover is damaged.
A healthy pilot flame is usually blue. A yellow or orange flame may indicate dirt, poor combustion, or another fault that should be inspected by a licensed gas fitter.
Many manufacturers provide instructions for safely relighting the pilot. Always follow the instructions for your specific model. If the pilot won’t stay lit or you’re unsure how to proceed, contact a licensed gas fitter.
No. Many modern gas continuous flow systems use electronic ignition instead of a continuously burning pilot light. Electric, heat pump and solar hot water systems also don’t have pilot lights.
A water heater pilot light that keeps going out is often a sign that something isn’t functioning correctly within your gas hot water system. While temporary issues such as a brief gas interruption or strong winds may occasionally extinguish the pilot, repeated outages often indicate a faulty thermocouple, gas control valve, or another component that requires professional attention.
If your pilot light won’t stay lit or you’re experiencing ongoing hot water problems, it’s best to have the system inspected by a licensed gas fitter.
At Melbourne Gas Plumber, we provide professional gas hot water repairs, gas leak detection, appliance servicing and gas fitting services across Melbourne. Contact our experienced team to diagnose the problem and restore your hot water safely.
Every week, we share practical insights based on the combined knowledge and real-world experience of our team. Our articles cover gas fitting, gas safety, appliance installation, hot water systems, maintenance and everyday plumbing issues, so you can make well-informed decisions about your gas plumbing needs.
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