Why Your Pilot Light Won't Stay Lit (And How to Fix It)

You light the pilot, hold the knob, watch the flame flicker to life — and then the moment you release the button, it goes right back out. Or maybe it stays lit for a few minutes, then dies on its own. Either way, a pilot light that won't stay lit is one of the most frustrating gas fireplace problems homeowners face.

The good news: the cause is almost always one of a handful of well-understood issues. Here's how to diagnose what's happening and what you can do about it.

Before diving into causes, a quick explanation of how the pilot system is supposed to work:

When you press and hold the pilot knob, you're manually opening the gas valve to the pilot. The small flame that results heats a component called the thermocouple (or thermopile in newer systems). Once the thermocouple gets hot enough, it generates a small electrical signal that tells the gas valve it's safe to stay open. When you release the knob, the thermocouple's signal is what keeps the gas flowing to the pilot.

If anything interrupts this process — a weak thermocouple, a dirty pilot orifice, a draft — the pilot goes out.

This is the most common cause of a pilot that won't stay lit. The thermocouple is a small metal probe that sits in the pilot flame. Over time (typically 5–10 years), it wears out and can no longer generate enough voltage to hold the gas valve open.

Signs this is your problem:

• Pilot lights but goes out immediately when you release the knob
• Fireplace is several years old and has never had the thermocouple replaced
• Pilot flame looks normal but won't hold

What to do: Thermocouple replacement is a straightforward repair for a licensed technician — typically 30–45 minutes of labor. It's not a DIY job because it involves working with gas components. Call Ohio Gas Fireplace at 216-282-1995.

Even a perfectly good thermocouple won't work if it's not sitting in the pilot flame. The tip of the thermocouple needs to be directly in the hottest part of the flame — the inner blue cone — to generate adequate voltage.

Signs this is your problem:

• Pilot recently serviced or the fireplace was moved
• Thermocouple tip looks clean and undamaged
• Pilot flame seems to miss the thermocouple tip

What to do: A technician can bend the thermocouple bracket slightly to reposition the tip into the flame. This is a quick fix during a service call.

The pilot orifice is a tiny opening that meters the gas flow to the pilot flame. If it becomes clogged with dust, debris, or spider webs (a surprisingly common problem in fireplaces that sit unused for months), the flame will be too small and weak to adequately heat the thermocouple.

Signs this is your problem:

• Pilot flame is small, yellow, or flickering rather than a steady blue
• Fireplace hasn't been used in several months
• Problem started at the beginning of the heating season

What to do: With the gas off and the fireplace cool, a technician can clean the pilot orifice with compressed air or a fine wire. This is often done as part of an annual maintenance visit.

A strong draft can blow out the pilot flame before the thermocouple has a chance to heat up — or extinguish it during operation. This is more common in:

• Older homes with drafty fireplaces
• Fireplaces near exterior doors or windows
• Homes with powerful exhaust fans (range hoods, bathroom fans) that create negative pressure

Signs this is your problem:

• Pilot goes out on windy days or when doors/windows are opened
• Problem is intermittent and weather-related
• You can see the pilot flame flickering or bending

What to do: Check that the glass doors are properly sealed. Have a technician inspect the venting system for any issues that might be allowing drafts to reach the pilot assembly.

If the gas pressure at the fireplace is too low, the pilot flame will be weak and may not generate enough heat to keep the thermocouple satisfied. This can happen due to:

• Issues with the gas regulator
• Partially closed shutoff valve
• Problems with the gas utility supply

Signs this is your problem:

• Other gas appliances also seem to be running weakly
• Problem started after utility work in your area
• Gas shutoff valve is not fully open

What to do: Check that the shutoff valve is fully open (handle parallel to the pipe). If other appliances are also affected, contact your gas utility. If only the fireplace is affected, have a technician check the gas pressure at the manifold.

In some cases, the gas valve itself is failing and not staying open even when the thermocouple is sending the correct signal. This is less common than thermocouple failure but does occur, especially in older fireplaces.

Signs this is your problem:

• Thermocouple has been replaced but problem persists
• Fireplace is 15+ years old
• Technician has ruled out all other causes

What to do: Gas valve replacement is a job for a licensed technician. Depending on the fireplace model, a new valve may cost $150–$400 in parts plus labor.

If your pilot light won't stay lit, don't keep fighting it on your own. A service call from Ohio Gas Fireplace will diagnose the exact cause and fix it right the first time. We serve all of Northeast Ohio and offer same-day appointments for fireplace issues.

Call 216-282-1995 or schedule online. Most pilot light repairs are completed in a single visit.