My Furnace Won’t Start – 5 Things You Can Check Yourself

The cold weather has arrived for the Central Valley homeowners.  

When the furnace won’t come on, it can be very frustrating and a cause for concern. It’s even more frustrating when you can hear the furnace clicking on and getting ready to blow the toasty warm air…but then the thing just shuts down.

Furnaces are designed for reliability (assuming they’ve been maintained) over a long period and are one of the most expensive and most needed appliances in almost every home.

Reasons for the furnace not working can be complex or very simple. While you are probably better off leaving the difficult problems of thermocouples, wiring and motors to a qualified professional, there are a good number of things you can check before you phone a qualified HVAC contractor for service.

Before you attempt to fix a furnace that won’t start, make sure you know what kind of furnace you have. The most common in this area is a forced air, gas furnace.

Here are 5 things you can do on your own to troubleshoot the problem:

  1. Check to make sure the furnace filter is clean. If the air flow out of your registers seems low, check the air filter. An extremely dirty air filter can block air flow. Make sure all registers are open and not obstructed.
  1. Check the pilot light. (Electronic ignitions will not have a pilot light). If your furnace clicks on or initiates the start cycle, but does not fire up, you likely have a faulty or dirty ignitor/sensor. This is one of the most common furnace problems. Under normal conditions, the furnace is notified by the thermostat to click on, the ignitor gets red hot and then initiates the entire process of igniting the gas and blowing the hot air.
  1. Check the settings on your thermostat. Make sure the temperature control selector is set above the current room temperature, and the system switch is on the HEAT or AUTO position. The fan switch should be set to ON for continuous airflow or AUTO if you want the blower to operate only while the furnace is operating. Try to get the furnace to turn on by raising the thermostat to its highest temperature setting.
  1. Check to make sure power to the furnace is on. There’s a power disconnect switch by the furnace, even gas systems use electricity. Check the fuse/breaker at the electrical panel for the furnace to make sure the breaker has not tripped. Make sure the power switch next to the furnace is in the “On” position.
  1. Finally, make sure the gas supply to the furnace is open. Check to make sure the gas control valve to the furnace is open. A disruption of the gas supply to your heating system could leave your heating system without fuel. If you smell gas, leave your home immediately and then call us for emergency repair.

If the problem persists, please feel free to call us anytime, we’re happy to help!

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