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Furnace Not Working? - What to Check First

Tuesday, May 30 2017 1:02 PM
By 360 Administrator

When your furnace isn't blowing warm air like it should, you may want to check your furnace first before you call a repair technician. Sometimes there is a simple fix that you may be able to do yourself immediately.

If you do need furnace repair in Aurora, Naperville, Downers Grove and the western suburbs, call AccuMax at (630) 800-1598.

Here is a list of what you should check first on your furnace before you call a repair service.

Make sure there is power to your furnace

The first thing to do is check your fuse box for any tripped circuit breakers. Not only could this be why there is no heat, this could indicate a bigger problem with your electrical system.

Check your thermostat settings

Make certain your thermostat has been set to "heat" and that it is set to a temperature high enough for the furnace to come on. While that sounds obvious, it's a small detail that is easily forgotten by a worried homeowner. It's a good idea to keep your thermostat's user guide stored near the thermostat. That way, you can consult its troubleshooting section in the event of a start-up problem.

Check that the furnace power switch has been switched "On"

We often see furnaces squeezed into tight spaces, sometimes in hall closets. Because of this, it's possible someone could accidentally switch the furnace to off by something as simple as putting a broom in the closet. Check the power switch mounted on the side of the furnace. It may also include a liftable metal housing containing a fuse. If the fuse is blackened and burnt, then it will need to be replaced. Remember that a blown fuse may also indicate a bigger system problem, so the system should be inspected by a licensed technician.

Check the pilot light

You may have an older furnace with a pilot light, it's possible the pilot may have gone out for some reason. The thermocouple may be loose or faulty, the pilot orifice may be clogged, or the pilot’s flame may be set too low. Be sure to check your owner's manual instructions before attempting to relight it.

Look outside to make sure that nothing is blocking the fresh air intake and the exhaust

Not all furnaces vent through chimneys. Many newer furnaces have their fresh air intakes and exhausts run through the side of the home and sometimes windblown leaves, insects, and moisture affects the heating system. If this is the case, you might want to consult a licensed technician about possible venting solutions.

Check thermostat batteries

Many programmable thermostats feature a flashing "low battery" icon on their control screen. If you see a low battery warning, promptly replace the batteries with new ones.

Check your furnace filter

If your furnace is firing up but it's not blowing as hard as it normally does, then it might mean that the air filter needs to be changed. Air filters trap dust, hair, and other particles in the air and, over time, the filter gets so full of debris that it can restrict air flowing through your furnace system. On most residential heating systems, air filters should be changed every 3 months.

Next Steps

If you have checked everything on this list but it is still not working, this is the time to call a professional repair technician. 

You can call AccuMax at (630) 800-1598 during normal business hours or 630-774-4937 for emergency after hours service.

We also offer you HVAC maintenance plans so that your system is checked twice a year with regularly schedule maintenance to keep your furnace or air conditioning running at its best. This gives you more security and better HVAC performance.

This informational post to help our customers is based on an article which originally appeared on

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