HVAC Sales Master

Fault Code Lookup

HVAC Sales Master
4
Open Limit or Rollout Switch
This code typically points to
  • Open limit
  • Rollout switch open
Next checks to confirm
  1. Check limit and rollout continuity
  2. Inspect burner-box manual-reset limit
  3. Check vent/combustion-air blockage
Escalation
Heating interrupted / gas off
Reset behavior
Manual-reset burner-box limit after blockage correction, or qualified-servicer reset.
Safety Critical
Immediate concern
⚠ Cross-generation conflict
Legacy Code 4 was 'open limit'. The newer S-series e04 includes rollout and reverse-airflow switches in the same code — diagnostic path must branch on which device opened.
Source
Trane 18-CD26D1-13 Installer's Guide, p.42-43
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