Gas Fireplace Pilot Light Won't Stay Lit
You hold the knob down, the pilot lights, you release — and it goes right out. Here's what's actually wrong, and why this one needs a licensed gas tech (not a YouTube video).
Don't keep relighting it
The safety shut-off is doing exactly what it's designed to do — preventing unburned gas from flowing into your home. Repeated relighting attempts can flood the firebox with gas. Stop, and book a tech.
What's actually happening
When the pilot is on, the flame is supposed to heat a small metal probe called a thermocouple (or thermopile on newer units). When hot, that probe generates a tiny voltage — around 25 to 30 millivolts — that tells the gas valve "the pilot is on, it's safe to keep gas flowing."
When you release the knob and the pilot dies, it means the valve isn't seeing enough voltage from that probe. That can mean one of five things:
The 5 likely causes
Worn-out thermocouple or thermopile
Most common cause, especially in Florida humidity. Voltage output has dropped below the valve's threshold. Fix: $185–$285 part swap.
Pilot flame not properly enveloping the probe
Dust, spider webs (real problem in Florida), or a clogged pilot orifice cause a weak or misaligned flame. The probe never gets hot enough.
Loose or corroded thermocouple connection at the valve
The connection at the gas valve has corroded — common on coastal homes. Voltage is generated but doesn't make it to the valve.
Failing gas valve
The valve's safety magnet has weakened. Even adequate voltage won't hold it open. Less common, but happens on 15+ year-old units.
Low gas pressure
Especially on LP systems with cold tanks or partial blockages. Pilot lights weakly, doesn't generate enough heat.
Why this one isn't a DIY fix
- Diagnosing requires a millivolt meter, under load, with proper probes
- Thermocouple replacement requires breaking a gas joint — must be leak-tested with a manometer
- If it's actually the valve, that's a sealed gas component requiring a licensed gas tech in Florida
- Wrong-part replacement is the #1 reason customers call us after trying themselves
Book a tech — same day in most of Florida
$69 diagnostic visit. We bring thermocouples, thermopiles, and the common pilot assemblies for every major brand on the truck. Most pilot issues are fixed in one visit.