Furnace not working/ how to troubleshoot your Furnace

Furnace Flames

What to do when your furnace is not working. Here are the most common problems and fixes to furnace problems. We highly recommend if you are not properly trained and qualified to contact a professional. A mixture of high electrical current and natural or propane gas is a dangerous combination.


Furnace Will Not Start

There are many things that can contribute to your furnace not working when your thermostat is set to heat. Here are the most common fixes. Make sure when your furnace door is open that if you have a door switch it is engaged.

  1. Turn Power off at Breaker or Furnace Switch and then back on. This will reset your furnace control board.
  2. Check Gas Supply. Make Sure your gas cocks(valves) are not closed and that you have paid your gas bill.
  3. Check your Air Filter. A dirty or blocked air filter can cause your furnace to shut down on high limit situations.
  4. Your are having a problem with your Motor not starting.
  5. Blown Fuse on Furnace Board. A blown fuse might seem like an easy fix, but usually is not the case. A blown fuse is a sign there is too much current running through the circuit. Check for broken, burnt, loose or grounded(Wires touching bare metal) wires.

Fixing a Furnace

Gas Furnace Will Not Stay Running

Does your Furnace Run but occasionally shut down? There are many possible problems causing your furnace to stop running. Here are the most common remedies.

  1. Restriction in your Duct work/ Dirty Air Filter. (Possible collapsed Return Duct, Blocked Air Filter).
  2. You have a blockage of your flue(exhaust) pipe on your furnace.
  3. You are having a Problem with your Pressure Switch, if you have a high efficiency furnace make sure the condensate drain/pump is not clogged and draining correctly.
  4. Your are reaching a high limit scenario. High limit for Heat or Roll out of Flame(These are safety switches which should NOT be bypassed, doing so could cause serious damage to you and your home). Sometimes things such as too much wind etc. can trip these, but they could also indicate you have a potential serious problem with your furnace and you need a HVAC Professional to Diagnose.
  5. Blower Motor not working properly. A failing blowing motor or relay can cause your furnace to quit running.
  6. Cracked Heat Exchanger. This usually causes a roll out condition where the flames are “Rolling Out” of there normal place. Furnaces older than 7 years need a visual check or combustion analysis of the heat exchanger for cracks or holes, as this could pose a serious carbon monoxide risk to the conditioned space.
  7. Call a HVAC Professional. We recommend doing a NATE Contractor Search to help find a NATE Professionally Certified Technician. NATE Certified Technicians can help avoid unnecessarily high energy bills ensuring your furnace is firing at its optimal condition. NATE Certified Technicians have to pass rigorous testing base on knowledge of field experience to earn certification. They know how to make the most of your furnace.



How to Fix Your Own Furnace
Article Name
How to Fix Your Own Furnace
How to Troubleshoot and Fix your own Furnace. DIY Furnace Repair tips for homeowners. Common Repair Problems and Solutions.
Publisher Name
ACE Heating & Cooling in Crossville, TN
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