The short answer
If a gas storage hot water pilot lights but won’t stay lit, the usual causes are a failing thermocouple (the sensor that holds the gas valve open), wind or draught hitting an outdoor unit, a dirty or weak pilot flame, or a faulty gas control. Relight only by the instructions on the unit — and stop if it keeps going out, you smell gas, or the flame looks yellow and unstable. McDermott Plumbing does licensed plumbing and gas fitting for gas hot water: call (08) 6187 3999 or text 0406 882 648. If you smell gas through the house, leave and call ATCO on 13 13 52 first.
What usually kills a pilot that won’t stay lit
On many outdoor gas storage units (including common Rheem-style pilots), a small standing pilot heats a thermocouple. That thermocouple generates a tiny current that keeps the safety gas valve open. When the thermocouple is worn, loose, or the flame no longer envelopes it properly, the valve closes and the pilot goes out — again and again.
Wind is the other classic outdoor-unit problem. A strong southerly or a unit sitting in a wind tunnel between walls can blow the pilot around or snuff it. Manufacturers have used pilot shields on some models for exactly that reason. Shielding and correct flame shape are adjustments for a licensed gas fitter, not a backyard “fix” with foil or cardboard.
- Thermocouple worn, dirty, or not sitting in the pilot flame
- Wind or draught on an outdoor unit (or a missing/damaged pilot shield)
- Pilot orifice dirty — weak, yellow or lazy flame
- Gas control or thermoelectric safety valve failing
- Low gas pressure or a supply issue (check whether other gas appliances still work)
Safe DIY — and the stop-DIY line
- Confirm other gas appliances still work and the gas meter or bottle valve is on.
- Follow only the lighting instructions on the rating label or access cover. Wait the full cool-down time the label requires if the flame goes out mid-light.
- On units with a pilot indicator (needle in a red/green window), use that to confirm the pilot is holding — don’t guess.
- Stop after a couple of failed attempts. Repeated lighting without finding the fault wastes gas and can leave unburnt gas around the burner.
- Do not dismantle the gas control, swap thermocouples, or bypass safety parts yourself. In WA that work is licensed gas fitting.
- If you smell gas, hear hissing, or feel dizzy near the unit, leave the area and treat it as a gas emergency — ATCO 13 13 52 for natural gas, then call us once it’s safe.
What we do on a pilot / thermocouple call
We check the pilot flame, thermocouple output, gas control, burner condition and whether wind or a damaged shield is part of the story. Often the fix is a thermocouple and a clean, correctly adjusted pilot. Sometimes the gas control itself has failed, or the unit is old enough that repair isn’t the sensible path — we’ll say so straight.
We’ll also look at why you called: no hot water, lukewarm showers, or a unit that works for a day then dies. Continuous-flow (instantaneous) gas units don’t use a standing pilot the same way — those are a different fault path (power, error codes, ignition). See our no-hot-water page if you’re not sure which system you have.
What to tell us when you call
- Brand and model from the side sticker (Rheem and similar outdoor storage units are common) — a photo to 0406 882 648 helps.
- Whether the pilot lights at all, holds briefly, or won’t light.
- Indoor or outdoor unit, and whether it’s in a windy corner.
- Natural gas or LPG bottles.
- Your suburb.
Common questions
- Why does my gas hot water pilot light keep going out?
- Most often a worn thermocouple, wind on an outdoor unit, a dirty pilot, or a failing gas control. Relight per the label once or twice; if it won’t hold, call a licensed gas fitter. McDermott Plumbing: (08) 6187 3999 or text 0406 882 648.
- Can I replace a hot water thermocouple myself?
- No. Thermocouple and gas-control work on a gas hot water system is licensed gas fitting in WA. Safe DIY stops at following the lighting instructions on the unit.
- Does wind put out an outdoor Rheem pilot?
- It can. Outdoor storage units in exposed or windy spots sometimes need a proper pilot shield and a healthy flame. Don’t improvise covers that block combustion air — call a licensed gas fitter.
- My pilot stays lit but I still have no hot water — why?
- Then the problem may be elsewhere: main burner, thermostat, tempering valve, or a different system type. See our no-hot-water checks, or call us with the model sticker.
- Is a pilot that won’t stay lit a gas emergency?
- Not by itself if there’s no smell of gas and the unit is cold. If you smell gas, leave and call ATCO on 13 13 52 for natural gas emergencies first, then a licensed gas fitter.
Related pages
Official sources
Last updated 2 October 2026. General information only. Every property is different, so call us to talk about yours.