Gas Fireplace Won't Turn On — Complete Troubleshooting Guide

By GasFireplaceFixer.com · Gas Fireplace Repair Guide

⚠ Safety First: Always shut off the gas supply valve before performing any hands-on maintenance. If you smell gas at any time, evacuate immediately and call your gas utility. These guides are for informational purposes — if you are unsure at any point, stop and contact a certified technician.

A gas fireplace that won't turn on can have a surprisingly wide range of causes. This guide works through every possibility in order from simplest to most complex so you can find and fix the issue efficiently.

Check the Basics First

Before diagnosing anything technical, confirm: the gas supply valve behind or beside the fireplace is fully open (handle parallel to the pipe), the wall switch or thermostat is set correctly, and the circuit breaker for the fireplace hasn't tripped. These simple checks resolve about 20% of 'won't turn on' calls.

Is the Pilot Light On?

Look through the glass at the pilot burner area. If you don't see a small standing flame, the pilot is out. Relight it following the procedure printed on your gas valve label. If the pilot won't stay lit after relighting, see our guide on fixing a pilot light that won't stay lit.

Remote Control or Wall Switch Issues

If the pilot is lit but the main burner won't fire, the problem is often the remote control or receiver. Replace the remote batteries first — this solves the issue more often than you'd expect. If that doesn't work, locate the receiver module near the valve compartment and try manually jumping the TH/TP terminals with a small wire. If the burner fires when jumped, the receiver or remote has failed.

Check the Thermopile Output

The thermopile generates the millivoltage that powers the gas valve. Test it with a multimeter set to DC millivolts across the TP and TH/TP terminals on the valve. A reading below 300 mV when the pilot has been burning for several minutes indicates a weak thermopile that needs replacement.

Inspect the Gas Valve

If all sensors test within spec but the main burner still won't fire, the gas valve itself may have failed. Gas valve failures are not DIY repairs — the valve must be replaced by a licensed technician. Signs of a failed valve include correct millivolt readings but no response from the main burner, or a valve that gets hot to the touch.

Error Codes and Control Board Issues

If your fireplace has an IPI (intermittent pilot ignition) system with a status light, check for blink codes before doing anything else. The code will point you directly to the fault. See our guide on gas fireplace status light blink codes for a full breakdown.

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