Status LED on Lennox furnace control board flashes 2 times repeatedly; inducer may run but burners do not light.

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.

Possible Causes

Blocked flue or intake vent, Clogged condensate trap or drain, Loose or cracked pressure switch tubing, Faulty pressure switch on Lennox furnace

Safety: Turn off power and gas before working on venting or internal parts.

1. Inspect vent terminations: Check outside intake and exhaust for obstructions and clear them.
2. Check condensate system: For high-efficiency Lennox furnaces, clean the condensate trap and ensure hoses are not kinked.
3. Inspect tubing: Remove and blow through the pressure switch tubing to clear moisture or debris. Replace if brittle or cracked.
4. Reset and test: Restore power and call for heat. If the code persists, the pressure switch may need replacement.

Medium 3/5

Pressure Switch

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