Gas Pilot Won't Light: What You Can Check, and Where You Must Stop
Three checks a homeowner can make safely, the component that usually turns out to be the cause, and the clear line where this stops being a homeowner task.
A pilot that will not light or will not stay lit has a small number of likely causes, and one or two of them are genuinely within a homeowner's reach. The rest are licensed gas work. We would rather be explicit about which is which than have you find the line by crossing it.
01Stop immediately if you smell gas
If there is a gas odour, do not continue troubleshooting. Leave, and call the gas utility from outside. This is not a hedge — it is the one instruction on this page that overrides everything else on it.
Everything below assumes no gas odour is present.
02The three checks you can safely make
Confirm the gas supply valve is actually open — it gets closed for other work and not reopened more often than you would expect. Confirm any wall switch or remote has power and working batteries, since many failures are a dead battery rather than an appliance fault. And read the lighting instructions on the plate inside the unit, because the sequence differs between models and a wrong sequence produces exactly this symptom.
Those three resolve a meaningful fraction of calls before anyone is dispatched.
03The component that is usually responsible
The thermocouple or thermopile — the sensor that detects the pilot flame and holds the gas valve open. As it ages its output falls, and below a threshold the valve closes even though the pilot is visibly lit. The classic symptom is a pilot that lights, burns while you hold the knob, and drops the moment you release it.
It is a consumable component with a finite life. Diagnosis is a millivolt measurement, not a guess, and that measurement is what separates replacing the right part from replacing parts in sequence.
04Where it stops being a homeowner task
Anything involving the valve, the gas connection, the burner assembly or the ignition system is licensed work in Texas and ends with a leak test. That is not us protecting a market — it is the point at which an error has consequences that are not recoverable.
It is also worth stating that a gas appliance venting into a chimney depends on that chimney being sound. A pilot problem and a venting problem can present together, and the venting side needs its own verification.
Check the supply valve, the batteries and the lighting sequence. If the pilot lights and drops on release, expect a thermocouple or thermopile and have it measured rather than guessed. Beyond that, hand it over — and if you smell gas, leave first and call from outside.
Every recommendation here starts from one place: a graded, photographed chimney inspection done to one standard, with a paper trail you keep.
The Chimney Standard Team
This article was written and reviewed by the CSIA-certified crew at Chimney Standard. Every recommendation reflects NFPA 211 and CSIA trade standards and the same documented, photographed approach we hold every job to.
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