Hansberger Refrigeration Blog: Your AC Repair Resource

Troubleshooting Furnace Ignition Problems

Here in Yuma, we’ve had below-freezing record lows in all five months between November and March. When even a well-maintained furnace fails to ignite, it may seem a call to the professionals is your only resort. However, failure to ignite is typically a symptom of issues other than at the burner itself. This simple troubleshooting guide to furnace ignition problems may help the competent do-it-yourselfer discover the problem, then fix it.

Start With the SuppliesTroubleshooting Furnace Ignition Problems

Your thermostat instructs the furnace to fire up. If the thermostat isn’t switched to “heat,” or if the control has been mistakenly moved to a setting that’s colder than room temperature, it won’t instruct the furnace to ignite.

Ensure that the fuse or circuit breaker that protects the equipment isn’t blown or tripped. If it’s properly set, this can indicate an electrical problem “downstream.” You can check to ensure no wires are loose around the furnace, and that no burn scars on the control panel indicate a failure there.

If the electricity is live to the equipment, check the furnace’s gas valve, ensuring that it hasn’t been accidentally moved to the closed, perpendicular position. Also make sure the supply pressure is good to the house; depending on whether you use natural gas or LPG, it could be that your local utility is working on their infrastructure, or your propane supply is exhausted.

Ignition Source

Older furnaces need a standing pilot light to function. The flame should be burning a clear, sharp blue, and its tip must envelope the thermocouple. If these check out, the thermocouple itself may have failed.

More modern furnaces don’t have a pilot but, rather, use electronic ignition. Can you hear a rapid, ongoing clicking sound from inside the heat exchanger when the furnace is try to start up? If not, your ignition module may well have failed.

Remote Components

A large number of failsafes are built into the system to prevent furnace ignition if all is not well. Resolving those problems is a job for the professionals. Across the greater Yuma area, please contact Hansberger Refrigeration and Electrical to arrange for a technician to call.

Our goal is to help educate our customers in Yuma, Arizona about energy and home comfort issues (specific to HVAC systems).  For more information about furnaces and other HVAC topics, download our free Home Comfort Resource guide.

Image courtesy of Shutterstock