201
Moderate
Lennox · HVAC Systems (AC, Furnaces & Heat Pumps)
Pressure Switch Stuck Open
Quick Answer
Error code 201 on your Lennox HVAC Systems (AC, Furnaces & Heat Pumps) means: Pressure Switch Stuck Open. This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Inspect the flue pipe and combustion air intake for blockages such as ice, debris, or animal nests
2
Check pressure switch hose connections and inspect for cracks or water accumulation
3
Verify the inducer motor is running by listening for operation at the start of a heating cycle
4
Clear the condensate drain line using compressed air or a wet-dry vacuum
5
Measure draft pressure at the pressure switch port with a digital manometer and compare to the switch rating
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Pressure switch
Pressure switch tubing
Inducer motor assembly
Related Error Codes