Furnace attempts to start but shuts down quickly; status LED shows 2 flashes repeating; inducer may start then stop.

Safety: Turn off power before opening the blower or burner compartment. Do not bypass the pressure switch for operation; this is unsafe.

Steps to check:

• Inspect pressure switch tubing: Locate the rubber or silicone tube between the inducer housing and the pressure switch on the Luxaire furnace. Remove it and blow through it to ensure it is clear. Check for water, cracks, or kinks. Reinstall firmly on both barbs.
• Check condensate drain (if high-efficiency model): Ensure the condensate trap and hoses are not clogged. Clean the trap and flush with warm water. A blocked drain can cause water to back up into the pressure tubing.
• Tap the pressure switch: With power off, gently tap the pressure switch housing with a screwdriver handle to free a stuck diaphragm. Do not hit hard enough to crack the housing.
• Verify inducer operation: Restore power and call for heat. Confirm the inducer motor starts and runs smoothly. If the inducer is noisy or fails to start, it may be drawing incorrect pressure on the switch.

When to call a pro: If the pressure switch remains stuck closed or the furnace continues to show 2 flashes after tubing and drains are cleared, a technician should test the switch with a manometer and replace it with the correct Luxaire-rated pressure switch if needed.