Find Out How a Furnace Works

November 16, 2012

If your home is heated by a furnace, it’s important to know how your heating system works. It will allow you to make better decisions about the maintenance of your furnace and can even help you extend the lifespan of your equipment. Find out how a furnace works from the heating experts at Rick’s Heating & Cooling. We have provided the homeowners of the Cincinnati, Ohio area with exceptional heating services and advice since 1986. We can help you understand your home heating system so when it comes time for maintenance, you’ll understand what your furnace needs.

How a Furnace Works: A Complete Heating Cycle

Before we get into the explanation of how a furnace works through a complete heating cycle, let’s define what a furnace is: it is a type of forced-air central heating that heats the air in your air through the combustion of a fuel. The process your furnace uses to regulate the temperature is a series of steps that are repeated until the air reaches the temperature set on the thermostat.

Here’s how a furnace works:

  1. When the thermostat determines the temperature in the room has dropped below the temperature set on the thermostat, the heating cycle can begin.
  2. The inducer fan in your furnace will start, pulling enough air into the unit to establish combustion airflow.
  3. Once proper airflow is established, the gas valve opens to permit gas to flow through the burners to be ignited by a spark or heat from the igniter. (In older models, there is a “standing pilot” light which is a small flame that burns constantly to ignite the gas.) The spark or igniter will go out immediately after the flame has been lit.
  4. The flame will heat up the heat exchanger for approximately two minutes before the blower turns on. This allows the metal walls or tubing in your heat exchanger to absorb the heat from the flame so that it can later be transferred into the air in your home. Another important step that occurs in your heat exchanger throughout this process is the release of toxic gases that are a byproduct of the fuel combustion. As carbon monoxide is collected in your heat exchanger, it is safely expelled through an exhaust vent out of the house.
  5. After the heat exchanger has reached an acceptable temperature, the blower fan will engage, drawing air from the house through the return ducts and blowing over the heat exchanger, where it will absorb the heat energy stored there.
  6. The warmed air is pushed on by the blower into the supply ductwork to be redistributed back into your home.

This process will repeat multiple times until the desired temperature set on the thermostat is achieved. Understanding how a furnace works is very important for any homeowner, so if you have any questions about your heating system, contact Rick’s Heating & Cooling today. Or if your furnace isn’t functioning properly as you know it should be, we can provide exceptional furnace maintenance or furnace repair in Lebanon, Morrow, Cincinnati, and the surrounding Ohio areas. Contact us today to schedule an estimate.