How Does My Gas Furnace Work?

Have you ever wondered how does my gas furnace work?  Although today’s furnaces can generate heat using a variety of fuels, natural gas is one of the most popular. Natural gas furnaces typically use a combination of methane and other carbon-based gases.  We, at JMAC Plumbing and Air Conditioning want you to understand how your furnace works so you can spot any potential problems.

The Thermostat

Although you could argue your gas furnace begins the house-heating process when you turn on your heating, ventilation, and air conditioning (HVAC) system, the reality is that in most homes, the thermostat really runs the show.

A thermostat is a temperature-activated switch that communicates your home’s temperature to the gas furnace’s control board. Once you program your thermostat to a particular temperature, your HVAC system will cycle on and off to keep your home near that set level.

The Ignitor 

When your thermostat sends a signal to your gas furnace to turn on your heating system, your ignitor starts. Although some older gas furnaces use a pilot light, modern gas furnaces have a safer electronic starter.

The old-fashioned pilot light used to operate by having a regulator supply a tiny bit of gas to keep a small flame burning, which would then ignite the furnace when a Nevada homeowner turned it on. If the pilot light went out, you would run the risk of dangerous gas leaking into your home.

The modern electronic starter uses an element a lot like a light bulb filament to ignite the gas burner instead. When your thermostat reaches a preset temperature, the starter sends an electric current over the filament, igniting the natural gas.

The Combustion Chamber 

The gas furnace’s ignitor lights the fuel in the combustion chamber, which is where the natural gas and oxygen mix. Your home’s furnace uses a draft hood or vent system to take in oxygen to generate clean and efficient combustion.

This same vent system releases the combustion by-products through a flue to the outside air. Typically, standard-efficiency flues are made from galvanized steel and high-efficiency units employ polypropylene venting, which is easy to install and maintain.

It’s important the combustion chamber is properly maintained, so you can ensure your indoor air quality is safe and healthy. You want to be sure all the natural gas is completely consumed inside the combustion chamber.

The Heat Exchanger 

Above the combustion chamber, you’ll see the heat exchanger, which takes the heat that rises above the chamber to generate the warm air for your home. Heat exchangers usually use a series of metal tubes, which are heated by burners when gas is consumed inside the combustion chamber.

The hot tubes transfer radiant heat to the air that blows through the exchanger. Once it arrives at the proper temperature, the furnace’s motor will turn on and blow that air throughout your air duct system. When the cooler air returns to the furnace, the entire cycle begins again and continues until the thermostat is triggered to turn off.

Blower fans direct the air coming from your home’s return ducts into the hot heat exchanger for further heating. When you install your gas furnace, you program some furnaces with a multispeed blower.

High-efficiency-model furnaces usually have a variable speed blower that can self-modulate fan speeds. According to the American Council for an Energy Efficient Economy, variable-speed motors are more energy efficient than conventional systems.

Some high-efficiency gas furnaces may also contain several heat exchangers with curved surfaces. This design slows down the airflow over more surface area so you can generate more heat with less fuel.

It’s important your heat exchanger is in good condition because a faulty one could allow dangerous leaks into your home.

Contact Us for All Your Furnace Needs

Whether you’re in need of a new gas furnace, a repair to an existing system, or regular maintenance, turn to JMAC Plumbing and Air Conditioning in Las Vegas, NV, for help. Our trained experts provide high-quality workmanship to be sure your gas furnace is operating optimally. Call 702-227-5622 or request service online today.