E1
Low-stage pressure switch circuit is closed at start of heating cycle
This code typically points to
- Low-stage pressure-switch contacts sticking
- Short in pressure-switch circuit wiring
Next checks to confirm
- Replace low-stage pressure switch if contacts are sticking
- Repair short in wiring
Escalation
Furnace fails to operate until startup condition is corrected
Reset behavior
Clears after switch/wiring fault is corrected and startup proves normal.
Urgent
Fix now