Gas Furnace

Gas Furnace Fan Not Coming On: Troubleshooting and Fixing the Issue

Gas Furnace Fan Not Coming On

Why Won’t My Gas Furnace Fan Turn On?

The gas furnace fan may not activate due to several key reasons, including thermostat settings, fan limit switch malfunctions, and electrical problems. Identifying the root cause is crucial to resolving the issue.

What Causes a Gas Furnace Fan to Not Come On?

Gas Furnace Fan Not Coming On

  1. Thermostat Settings: The thermostat might not be set to ‘heat’ or the fan setting might be incorrect.
  2. Fan Limit Switch Malfunctions: The fan limit switch could be faulty, preventing the fan from turning on.
  3. Electrical Problems: Issues such as blown fuses, tripped circuit breakers, or faulty wiring can prevent the fan from receiving power.

How to Troubleshoot a Gas Furnace Fan That Won’t Start?

  1. Check Power Supply:
  2. Ensure the power switch to the furnace is on.
  3. Verify that the circuit breaker hasn’t tripped or a fuse hasn’t blown.
  4. Thermostat Settings:
  5. Make sure the thermostat is set to ‘heat’ and the fan setting is correct.
  6. Try setting the thermostat to ‘on’ to see if the fan turns on.
  7. Inspect Fan Limit Switch:
  8. Check if the fan limit switch is functioning correctly. This switch controls when the fan turns on and off based on the furnace’s temperature.
  9. Inspect for Blockages:
  10. Ensure that the air filters are clean and not clogged, and that the vents are clear of blockages.

What are the Common Reasons for a Gas Furnace Fan Not Working?

  • Blown Fuses or Tripped Circuit Breakers: These can cut off power to the fan.
  • Faulty Wiring: Loose or damaged wiring can prevent the fan from receiving power.
  • Malfunctioning Fan Motor: The fan motor itself could be faulty or burnt out.
  • Capacitor Issues: A weak or dead capacitor can prevent the fan motor from starting.

Why Does My Gas Furnace Fan Continue to Run Even After the Thermostat is Turned Off?

Possible reasons include:
– Stuck Fan Relay: The relay that controls the fan might be stuck in the ‘on’ position.
– Malfunctioning Limit Switch: The fan limit switch could be faulty, causing the fan to run continuously.
– Incorrect Thermostat Settings: The thermostat might be set incorrectly, causing the fan to run even when it shouldn’t.

How to Troubleshoot and Fix a Gas Furnace Fan That Won’t Turn Off?

  1. Check Thermostat Settings:
  2. Ensure the thermostat is set correctly and that it is sending the correct signal to turn off the fan.
  3. Inspect Fan Limit Switch:
  4. Check the fan limit switch for any signs of malfunction. If faulty, replace it.
  5. Test the Relay:
  6. Check the fan relay for proper operation. If it’s stuck, replace it.

Reference:

  1. Furnace Blower Not Working? Common Causes & Fixes – ALP Heating
  2. Furnace Blower Not Working – How to Check It – YouTube
  3. 10 Reasons a Blower Fan Won’t Start in a Furnace, AC or Heat Pump – AC Service Tech.

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