Fault Code Lookup

HVAC Sales Master
A111_F
One-hour lockout: main limit switch
This code typically points to
  • Corresponding underlying active fault family: main limit open

Next checks to confirm
  1. Find and correct underlying active fault before resetting
  2. Red LED only blinks latest fault in buffer

Escalation
One-hour soft lockout
Reset behavior
Auto-clear after one hour OR interrupt electrical power for at least 5 seconds OR remove heat call.
Urgent
Fix now
Deeper detail available
The manufacturer has pushed full per-code troubleshooting trees into the Rheem Contractor App (QR code on equipment). Use the app for subcode detail beyond what's shown here.
Source
Rheem RDFXYC Installation Instructions one-hour soft-lockout section and fault table