Heil
No Heat Call Reaching Furnace
Thermostat calls for heat but furnace does not respond; LED shows normal idle or no fault.
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Possible Causes
Broken W (heat) thermostat wire, Faulty thermostat, Loose low-voltage connection at furnace, Blown low-voltage fuse
How to Fix / Troubleshooting
Safety: Turn off power before moving thermostat wires.
Steps to check:
- Thermostat mode: Ensure thermostat is set to HEAT and setpoint is above room temperature.
- Check furnace R-W jumper test: At the Heil control board, temporarily jumper R to W with a short piece of wire. If the furnace starts, the problem is in the thermostat or wiring.
- Inspect thermostat cable: Look for damage where the cable enters the wall or furnace cabinet.
- Check low-voltage fuse: Verify the 3A/5A fuse on the board is intact.
When to call a pro: If the furnace does not respond even when R and W are jumpered, a technician should test the control board and transformer.
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Repair Difficulty
Easy
2/5
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