Furnace Troubleshooting Tips

February 21, 2012

Despite the unusually warm days we’ve had this warmer, furnaces around the area have been running hard for months, and about this time every year, our customers start calling with furnace issues. One of the most common questions people have is whether a particular furnace problem is easy to fix or they need to schedule an appointment for furnace repair. At Rick’s Heating & Air Conditioning, we want to make it easy for you to decide when you need furnace repair!

What furnace problems can you fix?

The following is a quick and dirty furnace troubleshooting guide you can follow to try and diagnose any problems you’re having with your furnace:


Start at the thermostat – this may seem obvious, but the first thing you should do is make sure your thermostat is switched to HEAT mode and is set to the right temperature. Believe it or not, this is a surprisingly common furnace problem – sometimes the switch accidentally gets moved and the furnace appears to stop working. If it’s set to HEAT mode, check the fan setting. Most of the time, fans are set to AUTO which allows them to run most efficiently. If your fan is not blowing enough air, you can switch it to ON temporarily which will cause it to run constantly.

Can you fix the thermostat? YES.


Check the connections – next, check the actual furnace. If the fan isn’t running, check the breaker, fuse and switch for the furnace. If you find the breaker tripped, first look at the furnace wiring for loose connections before you try to reset it. Check for burned spots on the control board while you’re doing this – these will indicate that the board needs to be replaced. If the breaker wasn’t tripped, you probably have a problem with a different furnace component, such as the:

  • Transformer
  • Thermostat
  • Furnace control board
  • Blower motor
  • Run capacitor

Can you fix the connections? SOMETIMES.


Check your pilot – most gas furnaces use a small flame called a pilot light that runs at all times and allows them to create heat. Every now and then, this flame goes out and has to be relit. If this is the case, simply relight it. If the pilot is on but the main burners aren’t coming on, carefully feel the side of the furnace. If it feels cool, the problem could be with the:

  • Thermostat
  • Furnace control board
  • Limit control
  • Gas valve

Can you fix the pilot? SOMETIMES.


Check the rest of the pilot light assembly – if your furnace has an inducer motor, check to see if it is running. If not, there could be a problem with the inducer motor or the furnace control board.

If the inducer motor is running, but the pilot light doesn’t ignite, the flue could be blocked, the furnace control board should be shot or the limit control could be bad.

If the pilot tries to light but goes out, the pilot assembly or flame sensor could be dirty.

Can you fix the pilot light assembly? NO.


Check the main burners – if the pilot light is on, check out the main burners. Do they light? If not, make sure you have gas supplied to the furnace. If you do, you could have a problem with the gas valve or furnace control board. If the burners come on but don’t stay on for more than 3 seconds, the flame sensor could be dirty or the furnace control board could be bad.

Can you fix the main burners? NO.


Hopefully following these steps helped you take care of your furnace problems. If you not, call Rick’s Heating & Cooling for furnace repair in Cincinnati today!