What would cause a gas fireplace not to ignite?

Check Your Thermocouple and IgnitorThe spark igniter and thermocouple may be malfunctioning if there is no blockage in the tubing and gas is flowing out. Check to see if anything has gotten stuck between the two. Changing the igniter if the pilot light starts but doesn’t stay lit is a possibility.

Silky Terrier Dog Breed Playing Aro... Silky Terrier Dog Breed Playing Around

How much does it cost to replace a thermocouple in a gas fireplace?

You can expect to pay between $150 and $250 for a professional to replace a thermocouple or thermopile.

How do you fix a thermocouple on a gas fireplace?

Replacement of a ThermocoupleThe gas supply to the gas valve must be disconnected. Unscrew the thermocouple connector from the gas valve, then remove the thermocouple probe from its clip and remove the thermocouple assembly from the gas valve. Purchase a new thermocouple from your local hardware store.