How to Fix a Furnace

For those who own a home, they know hoe frustrating it can be when the furnace breaks down. Although fixing a furnace should be left to a professional, there are few simple things one can do to fix a furnace.

The following is a simple guide on how to fix a furnace:

1. The first question is whether you would like to fix a gas furnace or oil furnace.
A gas furnace typically needs repair of three parts: thermocoupler, pilot light, or some electrical component. Be cautious if you smell gas in the house. If you do, do not turn any lights on or off, leave the house, and leave the door open and phone the gas company immediately.

2. The pilot light, reset button and thermocoupler are most likely located in close proximity. Find the panel door that will give you access to these. If the furnace isn't running, the solution may be a blown fuse, pilot light is out, the blower switch is off, or the gas valve to the furnace is closed. Check the fuses/circuit breakers, light the pilot, ensure the blower switch is on, or ensure that the valve is fully open.

3. If the problem is that there is not enough heat, you may need to replace the filter. You may also try raising the temperature on the thermostat, make sure the registers are clean and not clogged, the blower may be clogged or a blower belt may be loose.

4. If the pilot won't light, check that the gas valve is open, and clean the pilot opening.
If the pilot won't stay lit, you may need to clean or replace the thermocouple. You might also adjust the pilot flame; it should be about 5 cm.

5. If the furnace turns on and off repeatedly, it may be a dirty filter, or the motor and/or blower may require lubricating.

6. If the furnace is noisy, the panels may need tightening. Other solutions may be to lubricate the blower and motor, check that belts are tight, or replace the belts if they appear worn.

7. An oil furnace typically can be repaired by the homeowner when it involves the filters, blower, motor belts, switches and thermostat. Any other repairs require professional service.

8. The air filter and blower are usually located beneath a panel on one side of the furnace. You should check that the blower is clean, and also clean soot from the stack. Lubricating the blower motor is another maintenance item that can be performed by the homeowner. If the furnace isn't running, check the power switch, fuses or circuit breaker. Make sure there is oil in the tank, and that the oil filter and oil pump strainer are clean.

9. If the burner won't fire, press the reset button on the stack control, and make sure the stack control is clean. If there is not enough heat, raise the thermostat a few degrees, clean the air filter, make sure registers are open and not obstructed, clean the blower assembly, check blower belts and replace if necessary.

10. If the furnace turns on and off repeatedly, make sure the air filter and oil filters are clean. The motor or blower may need lubrication, or the blower may require cleaning.
If the blower won't stop running, try resetting the thermostat from ON to AUTO. You may also try resetting the limit switch.

11. If the furnace is noisy, the access panels may be loose. The blower belts may be worn or loose. Tighten, replace or treat with belt dressing. The motor or blower may need lubrication.

If you are concerned you may do more damage, or you are nervous about working around a furnace, call a professional.