Gas Fireplace Not Lighting? Causes and Repair Costs

A gas fireplace that clicks but will not light, or lights and goes out, is almost always one of five issues. All of them are common, and all of them are fixable.

1. Pilot will not stay lit

The thermocouple or thermopile is weak. These generate the millivolts that hold the gas valve open — as they age, output drops below spec and the pilot drops out seconds after you release the knob. Replacement runs $220–$380.

2. Clicking but no ignition

The igniter electrode is out of position, cracked, or fouled. Spider webs in the pilot assembly are a genuinely common cause in seasonal units — insects are attracted to mercaptan, the odourant in natural gas.

3. Fireplace lights, then shuts off

Usually a dirty pilot assembly restricting flame contact with the sensor, or a blocked flue. Blocked venting is the one to take seriously — it is a carbon monoxide risk, not just an inconvenience.

4. Remote or wall switch does nothing

Dead receiver batteries, a failed wall switch, or a receiver that has lost pairing. Cheap to fix once diagnosed, and often mistaken for a dead fireplace.

5. Glass fogging, soot, or a yellow flame

Yellow, lazy flames and soot mean incomplete combustion — wrong air shutter setting, dirty burner ports, or logs placed incorrectly after a cleaning. Log placement matters more than people expect and directly changes combustion quality.

What annual service includes

Full disassembly and cleaning of the burner and pilot assembly, glass gasket inspection, venting check, gas pressure test, carbon monoxide test at the appliance, and a combustion report. Budget $180–$300.

Safety first

Gas appliances in Ontario must be serviced by a licensed technician. If you smell gas, do not operate switches — leave and call the gas emergency line.

Book service

See gas fireplace repair costs and the fireplace service page. To book, call us or request a free quote — TSSA-licensed, insured, written report every visit.