Fault Code Lookup

HVAC Sales Master
E276
Watchguard calibration failure
This code typically points to
  • Pressure-switch calibration failure
  • Vent problem
  • Wiring issue

Next checks to confirm
  1. Check vent system
  2. Check pressure-switch wiring

Escalation
1-hour soft lockout
Reset behavior
Clears when calibration finishes successfully.
Urgent
Fix now
Source
Lennox unit information doc 100027, p.14