3 GREEN FLASHES
Coleman Limit or Rollout Switch Open (Soft Lockout)

Status LED flashes green three times repeatedly; furnace may start but shut down unexpectedly.

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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

High limit switch opening intermittently, Manual reset rollout switch open, Loose wiring to safety switches, Overheating due to restricted airflow

How to Fix / Troubleshooting

Safety first: Turn off power and gas before inspecting safety switches. Flame rollout conditions are hazardous.

Steps to check:

  • Check air filter and airflow: Replace dirty filters and ensure all registers are open. Verify blower wheel is clean and spinning freely.
  • Inspect wiring to limits: Locate the high limit and rollout switches in the burner compartment. Check for loose spade connectors or burned wires. Tighten or replace as needed.
  • Reset rollout switches cautiously: If a rollout switch has a manual reset button, press it once. If it trips again, do not continue resetting; call a technician to inspect burners and heat exchanger.

Persistent limit or rollout openings require professional diagnosis to rule out heat exchanger damage or venting problems.

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Repair Difficulty

Hard 4/5

Required Part

High Limit Switch
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