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Common Furnace Problems

Below are 10 most common Furnace problems and advice on how to prevent them from occurring.

When cold weather arrives hundreds of homeowners call DeMark Home Ontario because of furnace problems and services needed. If you of possible furnace issues then you can take proactive actions to prevent them and save yourself from service calls.

Common Furnace ProblemsDirty Filters – the most common furnace problem comes from dirty filters. When filter gets clogged the airflow is reduces causing furnace to work harder to circulate. In some cases clogged filter can cause damage to the limit switch that controls the fan.

Lack of Maintenance – Heating system requires regular maintenance to prevent any future furnace problems. If you fail to perform regular maintenance you can come across breakdowns and equipment failure. Scheduled maintenance helps your equipment to work more efficiently and reliably.

Furnace makes Noise – If your heating system is making very loud noise and you constantly hear bangs, squeaking and cracks it is a sign of possible furnace problems. These may be a sign of mechanical problem, clogged burner or an airflow reduction.

Furnace not heating enough – If your furnace is undersized it may not produce enough heat as needed for the square footage of your home.

Thermostat Issues – A faulty thermostat or a dead thermostat battery can create heating problems in your home. Thermostat sends signal to your furnace to heat your home to a desired temperature. If t-stat is faulty it can lead to problems with the fan and comfort of your home.

Wear and tear – Furnaces have a lifespan of 15-20 years. Normal wear and tear will cause problems and comfort issues in your home and even overheating.

Blower runs continuously – Blower running continuously can be a sign of limit switch problem and you will be required to call a licensed technician to fix your furnace problems.

Frequent Cycling – when your furnace constantly cycles On and OFF this may indicate a clogged furnace or improper airflow or failed thermostat settings.

Ignition or pilot control problem – If there is an issue with pilot light or ignition it will create problems heating your home or commercial area. Problems with thermocouple and clogs in the appliance may cause unlit pilot light.

Furnace doesn’t heat at all – If your furnace doesn’t turn on at all there can be few reasons for this including thermostat settings, power, pilot light or gas. If you’ve tried all the steps and your furnace still not heating it is time to call an expert.

Demark Home Ontario advices to take below steps for Repairs

  • Check thermostat – If your furnace stopped working the first thing you should do it check your thermostat. Faulty thermostats and dead batteries are the most common furnace problems cause. Thermostat settings should be set on “Auto” or “Heat”. In the “On” position set to “High”, “Medium” or “Low” modes the fan will run continuously. Check temperature on the thermostat and if it still doesn’t help you may need to purchase a new thermostat.
  • Change furnace filter – Furnace filters need to be changed every 30-90 days. Dirty filters can lead to multiple furnace problems. Furnace technicians can show you how to change your filter if you are not sure where to start.
  • Maintenance – Have technician perform annual maintenance on your heating system before the season starts. Experts can determine problems at an early stage and fix them saving you hundreds or thousands of dollars on repairs and unit replacement.
  • Check breaker– If your furnace stopped working check if your furnace breaker tripped or a fuse blew off.
  • Mechanical Issues – If you have not received technical training and you are not a gas technician you should not try to fix mechanical furnace issues on your own otherwise you may void the warranty or accidentally damage you heating system.


If you need to replace your furnace or schedule annual maintenance call Demark Home Ontario heating and cooling expert. Our team of knowledgeable and highly trained technicians will examine your furnace issues and suggest the best solution to bring comfort back to your home. Call us today at 647-847-2998 or submit your request online.

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