Payne Low-Voltage Power Interruption / Transformer Overload

Furnace starts and stops repeatedly within a minute or two; thermostat display may flicker or reset.

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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.

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Possible Causes

Shorted thermostat wiring, overloaded 24V circuit (humidifier, zone valves), failing transformer, loose low-voltage connections

How to Fix / Troubleshooting

Safety first: Turn off power before working on low-voltage circuits to avoid shorting the transformer.

  • Inspect thermostat cable: Look for staples driven too tightly, pinched wires, or bare copper touching metal.
  • Disconnect accessories: Temporarily disconnect humidifier, zone controls, or other 24V accessories from the R and C circuit to see if the problem resolves.
  • Check transformer temperature: If the transformer is very hot to the touch, it may be overloaded or failing. Replace with the correct VA rating.
  • Tighten low-voltage terminals: Ensure all R, C, W, Y, G connections are snug at the control board and thermostat.
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Repair Difficulty

Medium 3/5

Required Part

24V Control Transformer
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