Polar Bear Air Conditioning & Heating Inc Blog : Posts Tagged ‘Gas Furnace’

How Electric Ignition Works on a Gas Furnace

Tuesday, February 25th, 2014

If you installed a gas furnace for your heating in Washington, DC, instead of an electric one, it was probably because of the savings you receive using natural gas, a more economical power source than electricity. However, if you have a modern gas furnace, it still needs a small amount of electricity to run. The key electrical system in a gas furnace is the electric ignition, which we’ll examine in detail.

The two types of electronic ignition systems

Gas furnaces originally used standing pilot lights to ignite gas burners (and you’ll still find older models that use pilot lights). However, because standing pilot lights consume extra power to stay lit, they reduce furnace efficiency. The new electric ignition systems require only a small amount of electricity and do run continually. This is one of the reasons that new furnaces have higher efficiency ratings.

There are two types of electric ignition systems in gas furnaces:

  1. Furnace intermittent pilots – This system does use a pilot light; however, the pilot light comes on only when needed and an electric spark activates it. When the thermostat calls for heat, high voltage sent through the igniter causes a spark that ignites the pilot, and it supplies sufficient heat to turn on the burners. The pilot light shuts off when the burners do.
  2. Hot surface igniters  This is the more common system, and requires no pilot light at all because the ignition generates enough heat to ignite the burners. They are made from silicon nitride or silicon carbide and operate similar to light bulbs: current passes through them and causes their surface to turn hot. A sensor detects this heat, and then opens the gas valve to send natural gas to the burners. The heat from the igniter activates the gas jets. These igniters are durable and dependable, although they will need replacement at some point during the furnace’s lifetime. Make sure you have regular maintenance for your gas furnace so your technician will know when to change the igniter.

Maintenance Is Key

Gas furnaces are safer today than ever before, and it is partially thanks to electric igniters. But don’t let your furnace go without yearly maintenance: keeping those igniters working their best is how you know your furnace is working its best. Contact Polar Bear Air Conditioning & Heating Inc. to sign up for our maintenance program for your heating in Washington, DC.

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