STEADY GREEN ON
Coleman No Call for Heat or Thermostat Circuit Open

Status LED is solid green; furnace appears to have power but does not respond to thermostat; no inducer or blower operation.

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Possible Causes

Open thermostat wiring between R and W, Thermostat set to OFF or wrong mode, Blown low-voltage fuse on control board, Broken R wire or loose connection at control board

How to Fix / Troubleshooting

Safety first: Turn off power before handling low-voltage wiring to avoid shorting the control board.

Steps to check:

  • Check thermostat settings: Ensure the thermostat is set to HEAT and the setpoint is above room temperature. Replace thermostat batteries if applicable.
  • Inspect low-voltage fuse: Locate the 3–5 amp automotive-style fuse on the Coleman control board. If blown, replace with the same rating. If it blows again immediately, there is a short in the low-voltage circuit that must be found.
  • Test R to W call: With power off, remove the thermostat wires from R and W at the furnace. Restore power and temporarily jumper R to W at the control board. If the furnace starts, the issue is in the thermostat or thermostat wiring.
  • Inspect thermostat cable: Look for staples driven too tightly, damaged insulation, or splices that may have come loose. Repair or replace damaged cable.

If the furnace does not respond even when R and W are jumpered, the control board may be faulty and should be tested by a technician.

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Repair Difficulty

Easy 2/5
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