Furnace shuts down on high temperature; status LED shows 6 flashes repeating; blower may run continuously to cool the unit.

Safety: Turn off power before removing panels. Components may be hot; allow time to cool.

Steps to check:

• Replace or clean air filter: Locate the filter rack on the return side of the Luxaire furnace. Remove the filter and inspect. Replace with the correct size and airflow rating if dirty.
• Check registers and grilles: Ensure all supply registers and return grilles are open and not blocked by furniture, rugs, or drapes.
• Verify blower operation: With panels in place and power restored, set the thermostat fan to ON. Confirm the indoor blower starts promptly and delivers strong airflow. Listen for unusual noises or slow start.
• Inspect ductwork: Look for crushed or disconnected ducts, especially on flexible duct runs.

When to call a pro: If airflow is good and the furnace still trips the limit (6 flashes), a technician should test the high limit switch, check temperature rise across the heat exchanger, and adjust blower speed or replace the limit switch as needed.