Understanding how your gas furnace operates can help you understand the potential cause when problems strike. If your gas furnace suddenly becomes less efficient or stops heating, there are a few key parts that could be behind the problem. Due to the presence of gas, carbon monoxide, and electricity, you always want to leave the fix in the hands of a trained heating repair services technician.

Here are three key parts that keep your gas furnace operating correctly and how problems with these parts can interfere with your system's output.

Draft Inducer Fan

The draft inducer fan, or draft inducer motor, is a powered fan that is an integral part of the ignition portion of the furnace system. The motor intakes air from the room around the furnace or from outside, via a vent pipe, and pushes that air inwards towards the burner system. The air helps regulate the burner system and then pushes toxic gases that form out the vent pipe for safe disposal.

A problem with the draft inducer will often stop the ignition process before combustion can even take place. The lack of fan power will trigger a safety switch, or a series of safety switches, that will prevent gas from entering the combustion chamber so that no toxic fumes form when there's no way to vent the fumes.

Hot Surface Ignitor

When you change the settings on your thermostat to ask for hot air, the thermostat sends a signal to the hot surface ignitor in the furnace. The ignitor heats up and glows red so that the burner assembly knows that it is time to start igniting the gas and heating the air.

Hot surface ignitors have a limited lifespan that averages around five years so make sure you have recently replaced this part or do so now. If the ignitor breaks and isn't replaced, your burner won't start up and you won't have any hot air coming out of your vents.

You can perform a quick check to see if the ignitor is broken by locating the part, using your owner's manual for a guide if necessary, and conducting a visual inspection. Does the ignitor have any obvious cracks or white marks that indicate burns? Call an HVAC tech to replace the part.

Blower Fan Motor

The draft inducer isn't the only motorized fan inside a gas furnace. The blower fan motor circulates cold air from inside your home, passes the air through the heated furnace, and then pushes that air back out your vents to provide you with warm air.

Problems with the fan speed or the motor can leave you with inadequate supplies of hot air or no hot air at all. A non-functioning blower fan can make it seem like the whole unit isn't working when it's really just that one part.

For more info about issues you may be seeing with your furnace, contact a company like Chappel's Heating & Cooling.