Low pressure switch failed open.
Lennox E223 on the SL280DFNV means the low pressure switch failed open. The row says to measure the switch in inches of water column on a heat call and to inspect the vent and the combustion air inducer. The outdoor termination is the homeowner look. It is not the ML180 red-off / green-slow prove-switch pattern.
Likely causes
- Low pressure switch did not close on a heat call
- Vent or combustion-air inducer restricted or not operating
Safe checks for E223
- With the furnace off, look at the outdoor intake and exhaust terminations for snow, ice, leaves or a nest. Do not take the vent apart
- Technicianmeasure the pressure switch in inches of water column on a heat call, and inspect the vent and the combustion-air inducer
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
If the terminations are clear and E223 returns, the switch, the inducer and the vent are technician work. The code resumes normal operation only after the fault is cleared. Do not jumper the switch.
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Furnace pressure switch: guide
In this code: Low pressure switch did not close on a heat call
This one is for a technician to test or replace, so we only explain it and do not link to buy it.
Furnace inducer (draft) motor: guide
In this code: Vent or combustion-air inducer restricted or not operating
This one is for a technician to test or replace, so we only explain it and do not link to buy it.