A gas fireplace that will not light is almost always one of a handful of problems: no power to the ignition system, a pilot that will not stay lit, a dirty or worn safety sensor, or a gas supply issue. The trick is knowing which is which, and which ones are safe to look at yourself.
Below are the most common reasons we find on fireplace repair calls, roughly in the order we check them.
Start with the batteries and the switch
Many modern fireplaces use a remote, a wall switch and a battery powered receiver or backup pack near the valve. If any of those batteries are low, the fireplace may click weakly or do nothing at all. Replacing every battery in the system is the first thing to try.
Also confirm the wall switch is on and that the valve knob is not set to Off. It sounds obvious, but a bumped knob after cleaning is a surprisingly common call.
The pilot lights but will not stay lit
On standing pilot fireplaces, a small flame heats a thermocouple, which proves to the gas valve that it is safe to stay open. If the thermocouple is dirty, bent away from the flame or worn out, the valve closes as soon as you release the knob.
The thermopile works the same way but generates the small voltage that runs the main burner. A weak thermopile often lets the pilot burn while the main flame refuses to come on. Both parts are tested with a meter and replaced in a single visit.
Clicking with no flame
Electronic ignition systems spark repeatedly while gas flows to the pilot. If you hear clicking but see no flame, the pilot orifice may be blocked by dust or spider webs, the spark gap may be off, or gas may not be reaching the pilot.
If you smell gas after a few attempts, stop. Turn the valve off, open a window, and let the smell clear. If it does not clear quickly, leave and call your gas utility from outside.
Call (289) 801-7262Weak, yellow or sooty flames
A fireplace that lights but burns small, yellow and leaves soot on the glass usually has misplaced logs, a dirty burner or the wrong gas pressure. Logs that block burner ports change how the gas mixes with air.
Soot is a sign of incomplete combustion and should not be ignored. Cleaning, correct log placement and a pressure check usually fix it.
Not sure it's a DIY fix?
Describe the symptom over the phone and a HeatNest technician will tell you what it likely is and what a repair involves.
Call (289) 801-7262What a technician checks
On a repair visit we follow the gas path from the shut off valve to the burner so nothing gets guessed at.
- Inlet and manifold gas pressure.
- Thermocouple and thermopile output.
- Pilot assembly, orifice and spark gap.
- Valve operation and receiver/control board.
- Venting, glass gasket and carbon monoxide readings.
Preventing the next no start
Most ignition problems come from dust, spider webs and parts that slowly drift out of spec. An annual cleaning and safety check before the cold season keeps the pilot assembly clean and catches a weakening thermopile before it fails on a holiday weekend.
Common questions
+Can I relight my gas fireplace pilot myself?
Yes, if your model has a manual pilot and you follow the lighting instructions on the label inside the lower panel. If it will not stay lit after two or three tries, call a technician.
+How much does a thermocouple replacement cost?
It depends on the model and parts availability. We confirm the price after testing and before doing any work.
+Why does my fireplace shut off after a few minutes?
Common causes are a weak thermopile, an overheating safety switch, or a venting problem that the safety system detects.
+How often should a gas fireplace be serviced?
Once a year, before the season you use it most.
+Is soot on the glass dangerous?
It indicates incomplete combustion. Stop using the fireplace and have it cleaned and checked.