Goodman Intermittent Power or Internal Fault

Thermostat frequently reboots or restarts on its own

Advertisements

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Advertisements

Possible Causes

Loose R or C connection at thermostat, Undersized or failing 24VAC transformer, Shorted thermostat cable intermittently grounding, Internal thermostat power regulator failure

How to Fix / Troubleshooting

Safety first: Turn off power to the furnace/air handler at the breaker before tightening or changing wiring.

Steps to stop frequent thermostat reboots:

  • 1. Tighten connections: Remove the thermostat and tighten all low-voltage terminal screws, especially R and C, at both the thermostat and Goodman control board.
  • 2. Inspect cable: Look for staples driven too tightly, pinched sections behind the thermostat, or rodent damage. Replace damaged cable runs.
  • 3. Measure voltage under load: With the system running, measure 24VAC between R and C at the thermostat. If voltage drops significantly when equipment starts, the transformer may be undersized or failing.
  • 4. Reduce load on transformer: Disconnect non-essential accessories (humidifier, UV lights, etc.) from the 24VAC circuit and see if the issue improves.
  • 5. Replace thermostat: If power is stable but reboots continue, the thermostat's internal power supply may be defective and the thermostat should be replaced.
Advertisements

Repair Difficulty

Medium 3/5

Required Part

Goodman furnace/air handler 24VAC transformer
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements