What Causes a Gas Fireplace to Shut Off?

Pilot Light

• If a fireplace's pilot light extinguishes, the fireplace might shut off. Like other gas appliances, many gas fireplaces use pilot lights as an ignition device. Pilot lights are essentially a small, open flame. The pilot light sits between the main gas supply and gas fireplace hearth. When you open your gas fireplace's gas supply, the pilot light provides the spark that ignites the primary flame. Pilot light flames are small and fragile. Drafts, blowing debris and dust easily extinguish pilot lights. If your pilot light frequently blows out, check for nearby sources of drafts.

Thermocouple

• A thermocouple is a safety device that senses temperature. Applied to gas fireplaces, thermocouples monitor the temperature of a pilot light. If the pilot light extinguishes, the thermocouple cuts off fuel supply to the pilot light and prevents gas from entering the home. A defective or broken thermocouple might cause a gas fireplace to suddenly shut-off.

Gas Supply

• Inadequate gas supply is an often overlooked cause of sudden shutoff. If you have a finite supply of gas, such as a propane tank, you should immediately check your tank's level after the fireplace extinguishes. If you receive gas from a utility provider, you should check your shut-off valve and gas meter and call the utility provider to check for outages. Alternatively, if you use the same gas supply line for several appliances, such as a clothes dryer and oven, make sure that you aren't operating all the appliances at once. Concurrent operation might restrict gas flow to the fireplace.

Thermostat

• Thermostat and control settings can cause gas fireplaces to suddenly extinguish. Many fireplaces connect to a remote thermostat. The thermostat's temperature setting determines when the fireplace activates and shuts off. When the fireplace reaches the thermostat's setting, the fireplace extinguishes and might appear to suddenly "shut off." If your fireplace has a thermostat, check its settings to determine if the shut-off is due to a low temperature setting.