Lennox Furnace Code E226
Warning
The high pressure switch failed closed. It reads closed when the control expects it to be open.
Manual wording: “High pressure switch failed closed. Check operation of high pressure switch closing on heat call. Measure operating pressure (inches w.c.). Inspect vent and combustion air inducer for correct operation and restriction.”
Documented for: EL296UHE and SLP98UHV series
Likely causes, most common first
- High pressure switch stuck closed
- Pressure switch tubing misrouted or blocked
- Shorted pressure switch wiring
What you can safely check yourself
- Turn the furnace power switch off for 30 seconds and back on once
When to call a technician
A pressure switch stuck closed is a failed safety device and must be replaced by a technician, never bypassed.
A Lennox furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- EL296UHE Service Literature (Corp. 1246-L10), Table 4 - Integrated Control Diagnostic Codes (Lennox Industries Inc., EL296UHE series 96% AFUE two-stage upflow/horizontal gas furnace (EL296UH045XE36B, EL296UH070XE36B, EL296UH090XE48C)) · checked 2026-08-25
- SLP98UHV Service Literature (Corp. 1029-L7), Table 14 - LED 7 Segment Status / Error Code and Integrated Control Diagnostic Codes (Lennox Industries Inc., SLP98UHV series variable-capacity communicating gas furnace (66,000-132,000 Btuh)) · checked 2026-08-25