Gas Hot Water Pilot Won't Stay Lit: DIY Checks Before You Call
A gas hot water pilot that won't stay lit is almost always one of three faults. Here's the order we check them in.
1. Thermocouple
This is the pencil-thin sensor in the pilot flame. When it heats up, it tells the gas valve to stay open. Thermocouples fail every 5–8 years in Brisbane's humidity. Replacement: $180–$260.
2. Blocked Pilot Orifice
Spiders in Brisbane love the warmth of a pilot assembly and build webs in the orifice. Symptom: weak yellow pilot flame instead of a crisp blue one.
3. Faulty Gas Valve
If thermocouple tests OK and the pilot is clean, the gas valve itself is failing to hold. Depending on unit age, either replace the valve ($320–$480) or the whole heater.
Safety Warning
Never bypass or disable the thermocouple. It's the only thing stopping raw gas from flowing when the flame is out.
Frequently Asked Questions
Can I relight the pilot myself?
Yes — instructions are on the unit. If it lights and immediately goes out when you release the button, the thermocouple is the culprit.