Besides the DIY maintenance tasks that any interested homeowner can perform, central furnaces require professional servicing. Do no underestimate maintenance. Furnaces are like vehicles: maintenance is of paramount importance for energy improvements, efficiency and home safety.
Have a professional to inspect and service your gas furnace at least once every 2 to 4 years.
DIY Gas Furnace Maintenance
Cleaning the filters (or replacing them) is especially important for energy savings, and a typically DIY task.
Regular DIY maintenance is also important to prevent safety hazards. If you're up to it, here are some simple tips on tasks that you can tackle yourself.
Changing or cleaning the air filter
Changing (or cleaning) dirty furnace air filters is easy, cheap, and can save you hundreds of dollars in energy savings.
If the filters are disposable, just replace them with new ones. Replaceable filters will cost you some few dollars and can be bought in improvement and hardware stores.
Washable air filters (often plastic filters) can be washed with soap and warm water; something that can be done in a bathtub or outdoors, using a common hose. Take into account the owner’s manual for details and tips on cleaning your furnace air filters.
Look at the owner’s manual for help and tips, and do not forget to clean out the area around the filter with a vacuum or a wet rag, before reinstalling the air filters.
If the pilot light doesn't work or isn't deep blue, pay attention. That's a warning sign. Call a professional to fix the problem.
Check for gas leaks
Be attentive to gas leaks. You may use a CO2 detector for an accurate measurement, though most leaks are easily detectable by smell or from gas build up. Though simple do detect, leaks should be fixed by a professional.
Most gas furnace motors are sealed and do not require any lubrication, but some do. Oil may be needed. See recommendations and tips in the owner’s furnace manual.
Tension belt Tips
If your gas furnace is running more loudly than usual, inspect the tension belt. Damaged belts are a common cause of noise. Call a professional to fix the problem.
Check the venting regularly
Check the exhaust stack connected to your furnace and look for leaks, gaps, rust, blockages and debris. Venting system parts can deteriorate over time. Damaged systems can pose a variety of health hazards.
Thermostat DIY Tips
If you are having temperature control problems, take a look at the thermostat. If it isn't working properly, the gas furnace will not function properly either. Confirm all the furnace cycles using your thermostat (through start-up to shut-down). Also check the supply and return air temperature.
Gas Furnace Service Inspections
The heating professional will inspect the gas furnace burners, the heat exchanger, the safety controls, the combustion chamber (looking for cracks) and the CO levels...
He will look for rust (in the burner and in the manifold area), soot and leaks (in the heat exchanger and venting system), misalignments, debris, dust (in the burner) or obstructions and blockages in the venting system. Checking the gas input as well as the flame/pilot is also important for adjustments.
Sealing possible leaks in the chimney and vent connectors is very important. Replacing the vent pipe or even the heat exchanger may be necessary. Looking for cracks, pipe separation, and other deterioration signs in the venting system is also part of a regular professional maintenance.
Heat exchanger, Blower cleaning and oiling
The service technician should inspect the heat exchanger passages and the burners, looking for signs of corrosion. Any leaks involving the heat exchanger should be fixed. In some models the heat exchanger should be removed for inspection. Oiling the blower and cleaning it – removing dirt, soot and corrosion - is also crucial. Problems with the blower should be fixed by cleaning it, and by adjusting the gas input and by solving the causes of possible high CO levels and soot (often caused by leaks in the venting system).
Settings, temperatures, and CO levels should be tested and adjusted. High carbon monoxide levels (more than 100 ppm) should be fixed.
Cracks and leaks should be conveniently air sealed. The professional technician should pay special attention to possible chimney cracks and to the connections between the main ducts and the furnace.
The motor, the blower wheel, the air filters or the flame sensor (on electronic ignition units) of any gas furnace should be cleaned on a regular basis by the homeowner or... by a professional technician.