7 Furnace Parts That Usually Break


Sometimes referred to as a heater or boiler in the British vernacular, a furnace is a heating unit that is designed to heat an entire building. They are used as the major component in a central heating system, and typically have an average lifespan of 15 to 20 years – depending on the type of furnace. There are several different kinds of furnaces, including gas, oil, electric, and modulating furnaces.

Living in Canada, a furnace is a valuable household appliance that undergoes a lot of use – particularly in those bitterly cold winter months. Much like any other appliance, furnaces can break down, need replacement parts, and even may need yearly inspections. If you have any questions or concerns about what type of furnace you have, need furnace repairs, or need a furnace inspection, then SmileHVAC.ca can help.

Furnaces are made up of several different parts, meaning that there are a variety of places that they can break down or need replacement parts. The seven main parts of your furnace are also the parts that will likely need to be repaired or replaced are:

  1. Thermostat;
  2. Gas valve;
  3. Burners
  4. Blower;
  5. Heat exchange;
  6. Ducts;
  7. Ventilation system.

Your furnace’s thermostat is important, as it gives your furnace the signal to turn itself on. To make certain that your furnace’s thermostat is working, check that the display is on and lit – if not, then the batteries for your thermostat might be dead and need replacing or a fuse may have blown in your electrical panel. If neither of those is the case, then turn the breaker for the thermostat off, remove the cover safely, and then check inside for any dirt build-up that will need to be removed. Lastly, make certain that if your thermostat is on and working, make certain that the date and time it displays are correct, as it may be programmed.

If your furnace is not turning on, then check to see if your furnace’s pilot light is blue – if it is, there should be a blue light. When your furnace’s thermostat signals to turn the furnace on the gas valve opens and the burners ignite. If the pilot light on your furnace is yellow, turn off the power and gas, then clean with a vacuum cleaner to remove any dirt and debris that might have accumulated. Now, if your pilot light is not on, then there could be an issue with the thermocouple, a safety device that keeps the gas valve from sending gas into your furnace.

The most common reasons as to why your furnace’s heat exchanger might not be working are dirt and debris build-up and insufficient water flow. With debris build-up, the solution is to run what is known as a CIP cycle to clear it out – if that does not solve the issue, then it will likely need to be cleaned manually. If the problem is not due to dirt and debris build-up, check the pressure and flow rate, which can also cause issues with your furnace’s productivity.

When checking your furnace’s blower, make sure that your thermostat is working and that it’s set to both the correct temperature (not too low, or it will not work) and the right mode – as a furnace set to cool air mode will not be blowing warm air. If there is no issue with your thermostat settings and the furnace is still not blowing warm air, then check the circuit breakers on your furnace and that the furnace itself is turned on. If those both check out fine and functional, then the fan is likely the problem. To check on your furnace’s fan, look for the inspection window to see if there has been a build-up of dirt and debris that will need to be cleaned out and ensure that there is a flashing green light – if instead, the light is flashing red, then you will need to call a service technician to diagnose and fix the problem.

When checking your furnace over – or even when you go to turn it on for the colder months – check the ventilation system. Your furnace is equipped with an air filter that should be checked regularly. Replacing the filter is something that you should do at the start of every cold season and as required. If your air filter is clean and new and you are still experiencing problems with your furnace, then you may need to check to ensure that your ventilation duct seams are intact and not leaking air and that there is no furniture or debris blocking your furnace’s vents.

For those in doubt or concerned about their furnace’s well-being and functionality, then call a furnace technician. Having a furnace service technician come in and examine your furnace at least once a year, to ensure that it is functioning and to catch any issues that may arise is important. Regular servicing can help extend the lifespan of your furnace, meaning that you will not need to have to replace it, which would be incredibly expensive.

Having a service technician in regularly for your furnace is not the only way that you can help extend the lifespan of your furnace. There are other ways that you can ensure its long life, which includes changes your furnace’s air filters regularly and keeping your furnace operating efficiently and on a consistent schedule.