Goodman Furnace Code f02 [Cause and Fix]

The f02 error code on a Goodman furnace usually indicates that there is not enough vacuum on the pressure switch for it to close and so the furnace wont run. Insufficient vacuum  on the pressure switch can be caused by blocked flue or weak induced draft motor or malfunctioning switch contacts.

The above mentioned factors are just a few of the many possible causes for low vacuum on the pressure switch.

This problem can be caused by a few issues that we are going to discuss shortly.

Possible Causes For Goodman Furnace Code f02 

Blocked flue and/or inlet air pipe, blocked drain system, or weak induced draft blower.Inspect flue and/or inlet air piping for blockage, proper length, elbows, and termination. Check the drain system. 
Pressure switch hose blocked, pinched orconnected improperly.In spect pressure switch hose. Repair, ifnecessary,
Incorrect pressure switch setpoint or malfunctioning switch contacts.Correct pressure switch setpoint orcontact motion.
Loose or improperlyconnected wiring.Tighten or correct wiring connection.

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Troubleshooting Steps For Goodman Furnace Code f02 

Verify Inducer Motor Operation   

Check if the inducer motor is running; it should create a vacuum to engage the pressure switch.

If the motor is not operational, the pressure switch may not close due to lack of vacuum.

Inspect Pressure Switch Hose

Check  the hose connected to the pressure switch for blockages, pinches, cracks, or improper connections. Any obstruction in the hose can prevent the pressure switch from closing.

Check the  Flue and Induced Draft Blower

Ensure the flue is clear and unblocked. Confirm the induced draft blower is functioning correctly; a weak blower might not create enough vacuum.

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Check Pressure Switch Settings

Confirm the pressure switch’s setpoint is correct. Malfunctioning switch contacts can also prevent proper closure.

Verify Wiring Connections

Ensure all wiring connections are secure and properly attached. Loose or incorrectly connected wires can disrupt the pressure switch’s operation.

Confirm Vent Motor Operation:

Ensure the small vent motor is operational; it contributes to the vacuum generation.

Inspect Vent and Intake:

Check for any obstructions in the vent or intake.

If the furnace has a drain connected, ensure no water is backed up in hoses.

Pressure Switch Test:

Disconnect the rubber hose from the inducer but leave it attached to the switch.

Call for heat using the thermostat, then suck on the hose to check for a clicking sound from the switch and ignition of burners.

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Pressure Switch Bypass Test

Allow the inducer to start and bypass the pressure switch using a jumper wire. This mimics the switch being closed and determines if the furnace ignites.

By using advanced troubleshooting techniques

  • Advanced troubleshooting requires specialized tools like a vacuum manometer or magnehelic gauge.
  • Connect the gauge between the inducer and the pressure switch to measure the vacuum.
  • Verify if the vacuum meets the required amount to “close” the switch or exceeds the vacuum needed for it to “open” (as marked on the switch label).

Replacing the Pressure Switch

If the issue persists, consider replacing the pressure switch as it is relatively inexpensive. If changing the pressure switch doesn’t resolve the problem, the inducer assembly could be the next component to consider replacing.

Final Thoughts

In conclusion, I hope you have managed to find a solution to a Goodman Furnace Code f02 after going through our guide.  

As a courtesy, remember to service your furnace at least twice a year to prevent unforeseen breakdowns.

 It is also worth noting that while  the average furnace will last about 15 to 20 years,  the maximum lifespan of a furnace pressure switch is about 10 years.

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