Ducane Low-Voltage Control Circuit Failure

Thermostat clicks, but the furnace does not respond; no inducer or blower.

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.

Possible Causes

Blown 24V transformer on Ducane furnace, open low-voltage fuse, broken R wire between transformer and thermostat, shorted thermostat cable.

Safety first: Turn off power before testing low-voltage circuits.

Step 1 – Check board LED: If no LED or display is lit, the 24V control power may be lost.
Step 2 – Inspect fuse: Replace a blown low-voltage fuse on the board after checking for shorts in the thermostat wiring.
Step 3 – Test transformer (pro recommended): A technician should measure primary and secondary voltages on the transformer and replace it if it has failed.

Hard 4/5

24V Control Transformer

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