Fault Code Lookup

HVAC Sales Master
E203
Appliance capacity/size not programmed
This code typically points to
  • Missing or invalid unit code

Next checks to confirm
  1. Program valid unit size code per configuration guide

Escalation
Critical alert
Reset behavior
Clears after valid code is read following reset.
Urgent
Fix now
Source
Lennox unit information doc 100027, p.12