Fraser-Johnston
No Call Reaching Control Board
Furnace will not start at all; thermostat shows a call for heat but nothing happens.
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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
Broken thermostat wire between R and W, Faulty thermostat, Blown low‑voltage fuse on IFC board, Open 24 VAC transformer
How to Fix / Troubleshooting
Safety first: Turn off power before handling wiring.
- Check low‑voltage fuse: Inspect the 3–5 amp fuse on the IFC board and replace if blown. If it blows again, there is a short in the thermostat or accessory wiring.
- Test thermostat bypass (advanced): With power off, remove the thermostat wires at the furnace R and W terminals. Restore power and temporarily jumper R to W. If the furnace starts, the thermostat or its wiring is faulty.
- Inspect thermostat cable: Look for damage where the cable enters the furnace cabinet and at the thermostat location.
- Replace thermostat if needed: Install a compatible heating thermostat following the wiring diagram.
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Repair Difficulty
Medium
3/5
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