Gas fireplace won't light

Q: Gas fireplace won't light

In Canada, when a gas fireplace won't light, the most common cause on a standing-pilot unit is simply that the pilot has gone out — relight it by following the label sequence printed on the unit. On remote- or switch-controlled fireplaces, dead batteries in the receiver or handset (or a switch left off) are the next thing to rule out, followed by a gas shutoff that's been turned to closed. If the pilot lights but won't stay lit, a worn thermocouple or thermopile is the usual culprit — that, and any work on the gas valve or module, is licensed gas work. If you smell gas at any point, stop, leave, and call your gas utility from outside.

A fireplace that won't light is usually a small, cheap fix — a pilot that blew out, dead remote batteries, or a shutoff someone nudged closed — not a broken appliance.

tuneWhat are you noticing?

Select anything that matches and the checklist below reorders to fit. Not sure? Skip it.

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Start here

In Canada, check the pilot first on a standing-pilot fireplace. Look through the glass or the lower access for the small standing flame; if it's out, relight it by following the label sequence printed on the unit — usually turn the knob to PILOT, hold it in while you press the igniter, keep holding about 30 seconds, then release. Free, and the most common fix by far. If it won't catch or you smell gas, stop and call your gas utility.

Ranked from real-world failure data. The order updates as you select what you’re noticing above.

Likely causes, in the order to check them

Showing the typical order

Beginner-friendly Doable, with care Safety-critical Call a pro

handymanHow to fix it

Relight the standing pilot by following the label sequence printed on the fireplace — turn the control to PILOT, hold it in while you press the igniter, keep holding about 30 seconds so the flame sensor warms, then release and switch to ON.

Find the printed lighting instructions on the fireplace — usually on the inside of the lower door, behind the louvre, or on a label near the control knob — and follow that exact sequence; it overrides these generic steps.
Turn the gas control knob to PILOT, press it in, and hold it down while you press the igniter button (or hold a long lighter to the pilot) until the pilot flame catches.
Keep the knob held in for about 30 seconds after the pilot lights so the flame sensor warms, then slowly release. If the pilot goes out when you let go, the thermocouple is the next suspect.
With the pilot holding, turn the knob to ON and call for flame with the switch or remote. If you ever smell gas or the pilot won't catch after a couple of tries, stop, wait, and call your gas utility or a gas-fitter.

schedule10 min savingsusually free

verifiedWhy this one goes to a pro

Clearing a pilot orifice, servicing an igniter, or diagnosing a gas control valve or ignition module means live gas work and a leak-tight, correctly tuned reassembly. In every province this is work for a licensed gas-fitter — the cost of the visit is small next to the cost of getting gas or combustion wrong.

Your notes travel with the request — what you saw, what you ruled out, when it started — so the pro arrives with a head start instead of a mystery.

visibilityHow to check

report Gas safety before you testYou'll have the pilot lit and gas flowing to test the sensors, and the millivolt test means working around the burner. Work in a ventilated space, keep the area clear, and if you smell more than the faint whiff of relighting, stop and leave. Servicing a gas fireplace's controls is licensed gas work in much of Canada — if any of this is outside your comfort, a sensor swap is a fast, inexpensive job for a licensed gas-fitter.

Relight the pilot per the unit's printed instructions and watch it: if it dies within a minute of releasing the knob, a weak thermocouple is the prime suspect.
Look at the sensor tips — they should sit right in the pilot flame. A tip that's corroded, white-chalky, or bent out of the flame points to failure.
To confirm, a multimeter on millivolts across the thermopile should read in the hundreds of mV (typically ~325–750 mV) with the pilot lit; a reading well below the unit's spec confirms replacement.

buildmultimeter schedule20 min

handymanHow to fix it

Shut off the gas, let it cool, remove the sensor(s) from the pilot bracket, fit a matching thermocouple/thermopile (match length and connector type), reseat the tip in the pilot flame, and leak-test every joint with soapy water before leaving it running. Where local rules reserve this to a licensed gas-fitter, book the pro.

Turn the gas control to OFF, close the gas shutoff valve at the fireplace (handle a quarter-turn, crosswise to the pipe), and let the pilot area cool completely.
Note how the sensor sits, then disconnect it at the control valve and free the tip from the pilot bracket.
Fit a new thermocouple or thermopile of the same length and connector; hand-thread the nut, then snug about a quarter-turn — the metal is soft, do not overtighten. Set the tip so the pilot flame wraps its top.
Reopen the gas, relight, and brush a 50/50 dish-soap/water mix on every joint. Growing bubbles mean a leak: shut off and re-seat. No bubbles, confirm the pilot holds and the burner lights, and you're done.

schedule45 min savings$20–45

Gas fireplace thermocouple / thermopileMatch thermocouple vs thermopile, the length, and the connector type to the old sensor and your unit's valve

gavel Check your province first AB: homeowner may do this · BC: homeowner may do this · ON: homeowner may do this · PE: homeowner may do this · QC: licensed professionals only
Relighting, battery changes, and checking the shutoff position are owner tasks everywhere; owner replacement of a flame sensor sits in a grey area — gas-fitting on the valve/module is licensed-only. Confirm the provincial rule before publishing this as DIY.

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Why the list is in this order

We don’t sort by likelihood alone. We sort the way a good, honest tradesperson thinks: rule out the free, safe, common causes first. That’s why the cheap checks outrank the expensive repairs — and why anything dangerous gets a hard stop instead of a pep talk. The order exists to save you money, not to sell you anything.