Fault Code Lookup

HVAC Sales Master
Amber flame LED SLOW BLINK
Marginal flame sense
This code typically points to
  • Dirty flame sensor
  • Improper polarity/phasing
  • Poor equipment grounding
  • Weak flame carryover
  • Incorrect manifold pressure

Next checks to confirm
  1. Check polarity/phasing and equipment grounding
  2. Inspect and clean flame rod
  3. Verify manifold pressure and flame carryover
  4. Verify wiring continuity between flame rod and IFC

Escalation
Advisory/status until flame signal falls below minimum threshold or contributes to flame-loss/ignition-failure lockout
Reset behavior
Clears automatically when flame signal rises above threshold; lockout reset only if a lockout condition also occurred.
Service Soon
Schedule repair
Source
Rheem 90RS/90RT/90TS Installation Instructions 92-24161-66 Rev. 3, flame LED legend and flame-sense troubleshooting notes; Rheem Gas Furnace FAQ flame-sense causes