Furnace not working

Furnace Flames

Furnace Not Working? 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 HVAC Professional.

 

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 Draft (Inducer) 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. High Limit Fault. (One of the most common and could be frustrating for the new trainee.) The most often missed diagnosed fault.
    1. Check for Air Flow Restriction such as Dirty Air Filter, Restriction in your Duct work and/ or block evaporator coil.
    2. Faulty Limit Switch staying open.
    3. Faulty Fan Limit Combination Switch (Controls the timing on the fan and safety switch.) Found on older Furnaces.
  2. You have a blockage of your flue(exhaust) pipe on your furnace. Causing a Open Pressure Switch Fault Code.
  3. Other Pressure Switch Common Problems:
    1. If you have a high efficiency furnace make sure the condensate drain/pump is clogged/ kinked and draining correctly.
    2. Cracked or broken pressure switch tubing.
    3. Inducer Draft Motor not working.
  4. Flame Not Proven Fault.
    1. Flame Sensor is dirty.
    2. Flame Sensor is defective.
    3. Bad thermocouple.
  5. Control Fault. (Usually indicates their is a problem with the control board.) Sometimes it is a voltage issue such as a bad ground connection. Visually inspect control board thoroughly. Check Voltage.
  6. Flame Rollout Fault.(The Safety Switches are usually manually reset, there is a reason the manufactures require a manual reset of this fault code. It is the most dangerous.). Sometimes things such as too much wind etc. can trip these, but they usually indicate your gas pressure is incorrect or you have a cracked/ damaged heat exchanger. Contact a HVAC Professional to Diagnose and Fix.
  7. 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.
  8. 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.

If still your furnace is not working, feel free to contact us at (931) 239-2611.