Philco Open 24V Control Circuit

Thermostat shows heat call but furnace does nothing; no sounds from furnace.

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 low-voltage fuse, Broken thermostat wire, Failed 24V transformer, Faulty door switch

Safety first: Turn off power before checking internal components.

Step-by-step checks:

1. Verify blower door: Ensure the blower door is fully closed and engaging the door switch.
2. Check low-voltage fuse: Replace if blown with the same rating.
3. Inspect thermostat cable: Look for breaks or damage along the cable path.

When to call a professional: A technician should test the 24V transformer and control board on your Philco furnace and replace failed components.

Medium 3/5

24V Transformer

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