Gas Furnace

Re: Making Loud Noise While Heating

• Noises from equipment can be very difficult to identify unless something is obviously broken.
• Be sure to work with the customer to identify the noise they are hearing.

CHECKOUT:

1. Interview Customer

• Ask the customer where, and during what conditions they hear the noise.
  • You may save yourself a lot of time.

2. Check Inducer

• Initiate a call for heat from the thermostat and monitor the ignition sequence.
  • The inducer motor should start with no difficulty.
    • Inducer Motor Hums bur Doesn't Start = Bad Inducer Motor / Capacitor
    • Inducer Motor Starts and is Very Noisy = Bad Inducer or Items in Inducer

3. Check Ignition / Burners

• The pressure switch should close within a couple seconds of the inducer starting.
• The glow plug should energize within 30 seconds of the pressure switch closing.
• The gas valve should open within 20 seconds of the glow plug energizing.
• Monitor the burners for delayed ignition or unusual burner noise.
  • Ignition is delayed and makes a "Boom" = Clogged Burners or Mis-Aligned Glow Plug

4. Check Blower

• Within 60 seconds of the burners igniting, the blower motor should start.
• Monitor blower operation.
  • Blower Motor Hums bur Doesn't Start = Bad Motor / Capacitor
  • Blower Motor Starts and "Clangs" = Broken Blower Wheel or Broken Motor Bracket
    • Shut-Down Furnace Immediately!

5. Check For Air Noise

• After the blower motor starts, listen for any unusual air noises.
  • Loud, vibrating, "V-V-V-V" noise = Bad Blower Wheel or Air Sucking Around Tape
  • Whistling Noise = Restricted Airflow

6. Re-Check With The Customer

• Confirm with the customer that the noise is gone or if they still hear the noise.