Alpha Low Voltage Short / Transformer Overload

Furnace starts then shuts off after a few seconds; thermostat display goes blank or resets.

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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 cable, Miswired accessory (humidifier, UV light) on 24V circuit, Failing 24V transformer, Shorted coil on Alpha gas valve or contactor

How to Fix / Troubleshooting

Safety: Turn off power before working on low-voltage wiring.

  • Inspect thermostat cable: Look for pinched or damaged thermostat wires along their path, especially where they pass through metal.
  • Disconnect accessories: Temporarily disconnect non-essential 24V accessories from the Alpha control board (HUM, EAC, etc.) and test operation.
  • Replace fuse: If the low-voltage fuse is blown, replace it once after correcting any obvious shorts.

If the transformer overheats or the fuse blows repeatedly, a technician should test the 24V circuits and components.

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Repair Difficulty

Medium 3/5

Required Part

Alpha 24V Control Transformer
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