Fault Code Lookup

HVAC Sales Master
20
Twinning problem / twinning fault
This code typically points to
  • Twinning detected then lost in same power cycle
  • Bad twin wiring
  • Mismatched boards
  • Phasing issue

Next checks to confirm
  1. Confirm identical boards
  2. Verify twin wiring between boards
  3. Confirm phasing and twinning configuration

Escalation
Fault display until twinning issue is corrected
Reset behavior
Clears when twin configuration is corrected; may require power cycle.
Urgent
Fix now
Source
Rheem Select / W801T Installation Instructions, twinning section and figure notes