Proper Sequence for Furnace Operation

During the winter months, everyone takes for granted that their furnace will keep them comfortable but how does a furnace do that?

How a Furnace Works

When the room temperature drops below the set point on the thermostat, it sends an electric signal to the furnace. at that point, the inducer motor starts (to make sure that there are no obstructions in the flue pipe). Then the ignition system gets a signal to ignite the pilot assembly. Once the pilot or glow plug is lit, the flame sensor tells the gas valve to open and ignite the burners.

After a few minutes, the furnace blower kicks on and starts blowing warm air through the duct system. Simultaneously, the cooler air from within the home is pulled back to the furnace via the return air ducts. This process continues until the thermostat is satisfied.

Most people call for service if the furnace doesn’t work. However, you should always call for service if you have any of the following:

  • Short cycling
  • It takes multiple attempts to ignite the burners
  • Any unusual odors, like a burning smell
  • Any unusual noises, either from the metal work or one of the motors

Fortunately, many issues can be avoided by having regular preventative HVAC maintenance.

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