Fault Code Lookup

HVAC Sales Master
E312
Restricted airflow in cooling or continuous fan mode is lower than CFM setting
This code typically points to
  • Dirty filter
  • Duct restriction
  • Indoor blower in cutback mode
  • Total external static outside design range

Next checks to confirm
  1. Check filter and duct system
  2. Correct restriction or add/repair duct
  3. Verify blower is not operating outside design parameters

Escalation
Warning only; indoor blower running at reduced CFM in cutback mode
Reset behavior
Cleared after current service demand is satisfied.
Service Soon
Schedule repair
Source
Lennox unit information doc 100027, p.15