Low Pressure Switch Failed Open Lennox. Lennox Furnace Reset Button Checked both high and low vacuum switch pairs for voltage across (good 27v) and continuity before and during induction fan running I think because the faults are so different, it's something else.
Furnace Pressure Switch Repair and Replace YouTube from www.youtube.com
This could be caused by a plugged intake or exhaust pipe, bad inducer motor, or bad pressure switch. I have reset the indoor (using switch on unit) and outdoor (using breaker panel) units
Furnace Pressure Switch Repair and Replace YouTube
When trying to turn on heat on my Lennox SL280UH070V36A-03, I get a fault called GF primary limit switch open Checked both high and low vacuum switch pairs for voltage across (good 27v) and continuity before and during induction fan running This video will go over how we resolved the low pressure switch stuck open error message we received on our furnace
Carrier HK02ZB063 Low Pressure Switch 22 PSI with 7 PSI Differential. Checked both high and low vacuum switch pairs for voltage across (good 27v) and continuity before and during induction fan running Decided to order a replacement for the now failing high fire pressure switch
Lennox 23W26 Low Pressure 40psi Switch NEW Other HVAC & Refrigeration. Inspect vent and combustion air in- ducer for correct operation and restriction Re- sumes normal operation after fault is cleared