Fault Code Lookup

HVAC Sales Master
8
Low flame sense signal
This code typically points to
  • Weak flame-sense current

Next checks to confirm
  1. Clean flame sensor
  2. Measure flame current
  3. Verify ground path

Escalation
Can lead to recycle/lockout
Reset behavior
Clears when flame signal strengthens.
Urgent
Fix now
Source
Trane 18-CD19D5-21 Installer's Guide, p.37