Fault Code Lookup

HVAC Sales Master
8 red flashes
Flame lost five times / too many recycles during heating cycle
This code typically points to
  • Low gas pressure
  • Dirty or faulty flame sensor
  • Faulty gas valve

Next checks to confirm
  1. Measure flame current (normal ~3.7 µA)
  2. Verify gas pressure under load
  3. Inspect burner stability and sensor

Escalation
Repeated flame loss indicates combustion instability.
Reset behavior
1-hour lockout then retry.
Urgent
Fix now
Source
TG9S/TM8Y install manuals