Troubleshooting
Water Heater Pilot Light Won't Stay Lit?
If your gas water heater's pilot lights but goes out when you release the control knob, the most likely culprit is a bad or misaligned thermocouple (or thermopile on newer units) that isn't sensing the flame and signaling the gas valve to stay open. Other causes are a dirty pilot orifice, a tripped flammable-vapor sensor, or a drafty or blocked flue. A pilot that won't stay lit means no hot water until it's resolved.
What to do right now
- Relight following the label instructions exactly, holding the knob a full 30-60 seconds before you let go
- If it dies again, smell for gas. If you smell gas, leave and call from outside, don't keep relighting
- Check that the pilot flame (when lit) is blue and wraps the thermocouple tip, not yellow or lifting away.
Likely causes
- Failed thermocouple or thermopile not generating enough millivolts to hold the gas valve open
- Dirty or partially clogged pilot orifice producing a weak, drifting flame
- Tripped flammable-vapor lockout on newer sealed-combustion heaters
- Downdraft or blocked flue, more common in northern AZ high-country installs and windy conditions
When to call a pro
If the quick fixes do not solve it, this is usually a water heater repair & replacement job. Liberty dispatches 24/7 with upfront pricing.
Water Heater Pilot Light Won't Stay Lit?, FAQ
- How much does a thermocouple cost to replace?
- The part itself is cheap, often under $30, but it has to be the correct type and positioned right in the flame. A lot of no-hot-water calls come down to this one part.
- Why does my pilot only go out on windy days?
- That points to a flue draft or combustion-air problem rather than the thermocouple. Wind pushing down the vent can blow out or starve the pilot, especially at higher elevations.
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