Oil Furnace Repair: Furnace Blower Troubleshooting

Even beginners can practice a little bit of oil furnace repair by troubleshooting problems with the furnace blower. Most problems with furnaces tend to require the assistance of a professional, as the risk to the amateur and the possibility of damaging the furnace is usually too high. However, you can sometimes assess or even repair the furnace blower without as much effort or risk. If you want to try troubleshooting, consider these ideas.

Understanding the Furnace Blower

Before you begin any kind of oil furnace repair, you should understand the purpose of your blower. This device is controlled by the thermostat linked to the furnace. It turns on when the air in the heater reaches a certain temperature. Blowers keep the temperature within the furnace constant once the desired heat has been reached. The basic circuitry is the same whatever kind of furnace you operate, whether it is gas- or oil-fired, or fully controlled by electricity.

Oil Furnace Repair and Your Fuse

Before you begin troubleshooting, get a schematic of the electrical wiring within the furnace. Turn all your furnace power to the "Off" position with the disconnect switch. Take out the fuse and check it by running it through a digital multimeter or by putting it into a working system and testing. If your fuse seems to have failed, replace it with another and check the furnace blower again.

Wiring and Oil Furnace Repair

If this does not work, take a wire from the circuit breaker in your blower and check it for damage. If the circuit breaker is reading as "Open," push and hold the "Reset" button and then recheck. If your breaker returns immediately to "Open," you should either replace the breaker and try again or call out an engineer to check the wiring.

While you are checking the wiring, examine the thermostat which dictates whether the blower operates or not. A broken heating monitor could be the cause of your machine's failure, so put a jumper across it with alligator clip leads. Turn the furnace back on while the jumper is across the thermostat. Your blower will start immediately if there is any problem with the heat control. If it does come back online, shut the furnace off at the disconnect switch and either replace the thermostat yourself or have someone else come in and do it.

More Troubleshooting for Your Oil Furnace Repair

If the blower does not start up immediately, take out a multimeter, and check the line voltage of the motor. If the motor does not have voltage between its terminals, you should check for a reading by placing the multimeter between the hot side of the motor and the ground. A reading in that space will suggest that you have a neutral that is open somewhere on the motor, and you will need to examine the blower motor carefully. If you get a reading between the motor's terminals, the motor itself is the problem.

At this point, turn the furnace back on and check to see if the blower will work. If it still fails, disconnect the furnace again and call out a professional.