The thermocouple on your Heatilator fireplace senses when the pilot light is on and feed it gas. If the pilot is off, the thermocouple closes the gas valve to prevent a gas leak. After years of use, the thermocouple on a Heatilator fireplace can go bad, not allowing gas to flow to your fireplace, even if the pilot is on. Replace the thermocouple to get your fireplace working again.
Turn off the gas to your Heatilator fireplace. Wait about one-half hour for things to cool down.
Open the maintenance hatch below or to the side of your fireplace.
Locate the pilot light inside the hatch. The long metal stick next to the pilot is the thermocouple.
Disconnect the thermocouple line from the gas line with a wrench.
Remove the old thermocouple and secure the new one in its place.
Close the maintenance hatch, turn on the gas and turn on the fireplace.