Thermal Zone Furnace Parts — Browse All Models

Troubleshooting tips to fix your Thermal Zone furnace when it won't heat

• Check for power. Reset the house circuit breaker for the furnace to make sure the unit has electrical power.
• Some Thermal Zone furnaces have a power switch beside the unit that shuts off power to the furnace during the summer when the furnace isn't being used. Make sure that switch is turned on.
• Check the gas supply. Make sure the gas valve to the furnace is fully open.
• Check the air filter. If it's too dirty, it will block air flow and the burner won't light if the unit senses low air flow.
• Check the pilot light to see if it's lit. Without the pilot light, the main burners won't ignite.
• Clean the flame sensor if necessary. If the flame sensor is dirty, it may shut off gas to the pilot/primary burners as a safety precaution.
• Check the thermostat settings. Make sure the thermostat is set to "Heat" and not "Fan" as running it on "Fan" mode will not engage the burners.

Common replacement parts for Thermal Zone furnaces

• Blower fan. The blower fan circulates air through the heat exchanger to heat your home.
• Flame sensor. The flame sensor is a safety device that detects the burner flame when the gas valve is open. If the flame sensor is dirty or damaged, it may not detect a flame properly, which will cause the furnace to shut down so heat doesn't continue to flow.
• Burner igniter. The burner igniter is a module that uses an electric spark to ignite the gas coming out of the burner manifold.
• Gas valve. The gas valve regulates the flow of gas to burner. If the gas valve is stuck closed, the burner won't light.
• Vent blower. The vent blower is part of the furnace's exhaust system and is responsible for moving dangerous gases out of the furnace through the chimney.