Just over 50 percent of American homes now heat with natural gas-fired furnaces. The heart of the furnace is the gas valve that regulates the flow of natural gas to the burner. A standard valve includes a rotating control dial, as well as a pilot light reset button. In addition to regulating burner gas, the valve supplies gas to the pilot light as well as connects to the thermocouple that automatically shuts off the gas if the pilot goes out. High-efficiency furnaces that utilize an electronic igniter instead of a standing pilot light do not incorporate a manual lighting procedure, and the gas valve typically provides only a basic on/off control.
Adding Fuel to the Flame
On standard or electronic units, when the valve control dial setting is “Off,” gas to the burner is shut off. On a conventional pilot light furnace, rotating the dial to the center “Pilot” setting and depressing the pilot reset button allows the pilot light to be manually lit. When the dial is rotated to “On,” the valve supplies gas to the furnace burner when the thermostat signals for heat. If the furnace utilizes an electronic igniter, an ignition control module receives the thermostat signal, energizes the igniter, then automatically opens the valve and gas flows to the burner.
- Photo Credit BernardaSv/iStock/Getty Images
Common Gas Furnace Problems
Gas furnaces use either natural gas or propane to heat an enclosed area. A significant advantage of this method of temperature control...
How Does a Natural Gas Valve Work?
A natural gas valve is a component of a gas furnace. It connects the natural gas line of the house to the...
Instructions for Replacing the Gas Valve on a Furnace
A malfunctioning gas valve will not supply the furnace's burners with the proper amount of fuel. Gas valves locked in the closed...
How to Unlock a Gas Valve
A gas valve is a safety feature on a heating systems. The gas valve shuts off or turns on the flow of...
What Is a Modulating Furnace?
Furnaces need to cycle on and off depending on the heating needs of the home. This cycling on and off can waste...
How to Repair a Furnace Gas Valve
replacing a furnace gas valve doesn't have to cost an arm and a leg in expensive repair bills. Repair a furnace gas...
How Does a Gas Heater Work?
A gas heater works by a gas valve allowing a certain amount of gas to fuel a flame, and the amount of...