Why Won’t My Gas Fireplace Pilot Light Stay Lit?
Why Won't My Gas Fireplace Pilot Light Stay Lit?
You light the pilot, hold the knob, let go, and it goes out. It's one of the most common gas fireplace problems we see, and it usually comes down to one of a handful of causes.
How the pilot is supposed to work
Most gas fireplaces use a small, constant pilot flame to light the main burner. Sitting in that flame is a safety sensor called a thermocouple (or a thermopile on many millivolt fireplaces). When it heats up, it produces a tiny electrical current that tells the gas valve it's safe to keep the gas flowing. If the sensor doesn't get hot enough, the valve shuts the gas off. That's a safety feature doing its job, and it's why the pilot goes out when you let go of the knob.
So when a pilot won't stay lit, the question is usually: why isn't the sensor getting enough heat, or why isn't the valve reading it?
The most common causes
1. A dirty pilot assembly
Dust, lint and spider webs collect around the pilot. That makes the flame weak, small or blue-tipped in the wrong direction, so it doesn't wrap around the thermocouple properly. This is the number one cause, and it's exactly what an annual cleaning prevents.
2. A worn-out thermocouple or thermopile
These sensors wear out over time. A weak one may hold the pilot for a while and then let it drop, or not hold it at all. Replacement is routine for a technician.
3. A loose or corroded connection
The sensor connects to the gas valve, and a loose or dirty connection can stop the signal getting through even when the sensor itself is fine.
4. Drafts
A strong downdraft through the vent, especially on windy days, can blow the pilot out. If it only happens in bad weather, that's a clue worth mentioning to your technician.
5. Gas supply problems
Low gas pressure or a partly closed shut-off valve can starve the pilot. If other gas appliances in your home are acting up too, call your gas utility.
What you can safely check yourself
- Make sure the fireplace's gas shut-off valve (usually behind the lower grille) is fully open, with the handle in line with the pipe.
- Follow the lighting instructions on the label inside your fireplace exactly, including how long to hold the knob. Many units need 30 to 60 seconds for the sensor to heat up.
- If your unit uses a remote or wall switch, replace the batteries in the remote and the receiver.
- Look at the pilot flame. A healthy one is steady, mostly blue and wraps around the sensor. A small, yellow or flickering flame points to cleaning or a part.
That's where homeowner troubleshooting should stop. Cleaning the pilot assembly, replacing the thermocouple or thermopile and adjusting gas pressure are jobs for a licensed gas technician.
Natural gas has an added odour that smells like rotten eggs or sulphur. If you smell it, don't touch light switches, phones or the fireplace controls. Get everyone outside, then call Enbridge Gas's emergency line at 1-866-763-5427 or 911 from outside the home.
Frequently asked questions
Why does my gas fireplace pilot go out when I let go of the knob?
Usually the thermocouple or thermopile isn't getting hot enough, often because the pilot is dirty or the sensor is worn. The gas valve shuts off as a safety measure.
Is it safe to keep relighting the pilot?
A couple of attempts following the manufacturer's instructions is fine. If it won't stay lit after that, or you smell gas, stop and call a licensed technician.
How much does it cost to fix a pilot that won't stay lit?
Often it's solved with cleaning during a regular service. If a thermocouple or thermopile needs replacing, your technician will quote the part before doing the work.