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Furnace maintenance

Having your natural gas heating system regularly inspected and maintained is the best way to keep it working safely and efficiently and to ensure good air quality in your home.

Call a professional

Schedule regular inspections, cleaning and maintenance with a licensed gas contractor. Refer to your owner’s manual for directions on how often you should have your equipment serviced (usually at least once a year), and what it should involve. Typically, a furnace service should include, but is not limited to:

  • checking operation of safety limit controls, temperature set points, thermostat, blower, pressure switches, pilot light, gas piping and C02 levels
  • lubricating blower and motor bearings
  • burner and blower inspection

If you have a natural gas boiler, service should include, but is not limited to:

  • checking operation of safety limit controls, pressure relief valve, water pressure and temperature set points and radiant floor temperature control device
  • lubricating circulating pump

After the service, ask your gas contractor for a copy of their completed checklist. For more details, see the Technical Safety BCs complete service checklist.

Regular maintenance

Safety tip: When inspecting or changing filters or fan belts, shut off the electricity at the furnace switch and at the circuit breaker panel first.

  • Filters are very important for maintaining healthy air quality. Change or clean furnace filters at least every three months and keep the fan compartment door tightly closed. Filters are located at or near the blower compartment of the furnace and may be held in place by a clip.
  • If your furnace has a fan belt, inspect it for cracks or signs of wear (and have it replaced if necessary) at the same time you change the furnace filters.
  • Keep vents and air returns clear of obstructions like furniture, lint, dust or pet hair.
  • Keep the area around the furnace clear. Don't store items against the furnace or keep flammable items in the furnace room.
  • Check the chimney and appliance vent system at least once a year to ensure the pipe is connected securely, there are no signs of corrosion or damage and nothing has fallen into the base of the chimney or into the flue.
  • If your furnace motor has oiling points, apply one or two drops of SAE 20 non-detergent oil every heating season. Avoid over-oiling!

Watch for warning signs

There are almost always warning signs a furnace isn't working properly:

  • frequent pilot light outages (not all furnaces have standing pilot lights — check your manual)
  • delayed ignition (mid- and high-efficiency furnaces have an intentional delay — check your manual)
  • a yellow or wavering flame
  • excessive soot or corrosion on the appliance or vent system (white, brown or black streaks)
  • too much or too little heat
  • any continuous or intermittent odour — either the "rotten egg" or sulphur smell of the odourant in natural gas or a sharp odour that may cause eyes to sting
  • symptoms of the presence of carbon monoxide: nausea, headaches, lethargy or other flu-like symptoms
  • indications that the flame has 'rolled-out' of the furnace — scorch marks by the door or other opening

If your pilot light goes out

Most natural gas appliances with pilot lights are designed to shut off automatically if the pilot goes out. To relight the pilot, follow the manufacturer's instructions (usually located on a metal plate near the furnace burner or gas controls). If it fails to relight, turn off the manual valve in the natural gas supply to the furnace and call a licensed gas contractor.

Note: many newer gas furnaces do not have a standing pilot light. Check your owner's manual.

Learn more

Find out more about choosing and maintaining different types of natural gas space heating systems.