Keeprite
No Response to Heat Call
The thermostat is calling for heat, but the furnace does not respond; the LED on the furnace is on and shows no fault code.
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Possible Causes
Broken W thermostat wire, faulty thermostat relay, loose connection at the control board W terminal, control board input failure.
How to Fix / Troubleshooting
Safety: Turn off power before moving thermostat wires.
Steps:
- Verify 24V: Confirm approximately 24VAC between R and C at the control board.
- Test W input: With the thermostat calling for heat, measure between W and C; you should see approximately 24VAC. If not, the thermostat or wiring is faulty.
- Jumper test: Temporarily jumper R to W at the control board. If the furnace starts, the thermostat or its wiring is the issue.
If the furnace does not start even with R and W jumpered, the control board is likely defective and should be replaced by a technician.
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Repair Difficulty
Easy
2/5
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