Fault Code Lookup

HVAC Sales Master
8
Gas heating lockout
This code typically points to
  • Stuck-closed gas valve relay on control
  • Miswire/short to gas valve wire

Next checks to confirm
  1. Verify valve not being backfed or miswired
  2. Verify control relay state

Escalation
Hard safety/electrical isolation issue.
Reset behavior
Does not auto-reset; power off and wait 5 minutes to retry.
Safety Critical
Immediate concern
Cross-generation conflict
Source
OEM flow chart/service label