Lennox Equipment not specified Error Code 223

Priority condition: Service Soon The furnace low pressure switch is open. • Check pressure (inches w.c.) of the low pressure switch closing during a heat call. • Measure operating pressure (inches w.c.). • Inspect vent for blockages and combustion air inducer for correct operation and restriction. • Check for blocked cold end heater box or condensate drain or drain strainers at outlet of cold end heater box. • Check for cracked hoses. • Check levelness of unit. NOTE: Check Service Manual and Service and Application Note H-13-07 “Condensing Furnace Pressure Switch Troubleshooting” for additional information.