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Why Won’t My Furnace Turn On?


During the winter, there are few frustrations more annoying and uncomfortable than a furnace that won’t turn on. If you’ve had your furnace maintained annually during the fall, you likely won’t run into a problem like this—but there’s never any guarantee of a perfect furnace performance. 

If you’re currently facing a furnace not heating in Clovis, CA, you can call our team to see what repairs it may need. In some cases, you may only need to do a bit of troubleshooting to correct the problem. Below, we’ll look at reasons for an obstinate furnace, what you can do about it, and when you need to contact us. 

Troubleshooting Solutions for Common Issues

Check the Thermostat

Do a quick check-in with the thermostat to ensure you have it set correctly and that someone else in your house hasn’t made adjustments that might cause the furnace to fail to turn on when necessary. Maybe an older program got activated by mistake. 

Inspect the Power Source

Is the furnace actually on? There’s a switch near the furnace used as a breaker that might be shut off and cutting off its power supply. Also check the electrical panel for your home to see if any breaker has tripped. Yes, this applies to gas furnaces as well. 

Examine the Air Filter

A clogged air filter in a furnace can cause it to come to a halt, overloading the blower and tripping a circuit breaker or overheating and making the limit switch shut the furnace off. This filter will clog up after one to three months and needs to be replaced. Put in a new filter if your furnace won’t turn on and see if this solves the problem.

Check for Blocked Vents and Ducts

Tour the rooms to see if there are any room vents that have become blocked with furniture, rugs, or anything else that might have been moved. Blocked ducts can cause the furnace to shut down.

Problems That Need the Pros

Malfunctioning Ignition System

An electronic ignition failure will prevent the furnace from sending gas to the burners as a safety precaution. You’ll need professionals to replace the igniter.

Faulty Thermostat or Wiring

Incorrect settings on the thermostat are one thing. It’s quite another when the thermostat is reading incorrect temperatures or has bad wiring that isn’t connecting to the furnace.

Issues with the Blower Motor

A faulty blower motor can lead to the furnace overheating, which will trigger the limit switch that shuts the whole unit off. The blower assembly is a powerful part of the HVAC system and only pros can repair it.

Gas Flow Problems

There may be blockage in the gas line, dirt on the burners, or even a gas leak. You must not attempt to do any work on a gas line yourself because of possible safety issues. 

Failing Furnace

Finally, you may be facing an aging furnace that can no longer do its job effectively. In this case, the only repair is to have professionals replace the furnace.

Look to Purl’s Sheet Metal & Air Conditioning for all your heating needs! Uncompromised Quality & Customer Service Since 1952. 

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