HVAC Sales Master

Fault Code Lookup

HVAC Sales Master
16 (fan coil)
System Communication Fault on communicating fan coil (FE4A/FE5A/FV4C). If system communications unsuccessful for >2 minutes, fan coil displays Status Code 16 and drops into emergency-operable state that can only run with common thermostat wiring and non-communicating outdoor unit.
This code typically points to
  • ABCD bus miswire
  • Open/shorted ABCD conductors
  • Loss of UI power
  • Failed device loading communication bus
  • Loss of communication long enough to force emergency operation
Next checks to confirm
  1. Check fan coil COMM LED — should light during startup
  2. Verify UI is powered
  3. Inspect ABCD wiring end-to-end
  4. Confirm conductor-to-conductor continuity and no shorts
  5. Verify correct polarity/landing
Escalation
Public docs allow temporary emergency heating/cooling fallback using common heat/cool thermostat wired to R, Y, W, C and non-communicating outdoor unit — temporary measure only.
Reset behavior
Not a manual-reset lockout. Local board indication clears when communications are restored. Emergency-mode operation remains available while board is powered and displaying 16.
Urgent
Fix now
Need deeper detail?
Retrieve the subcode for this platform:
  1. From the main screen, touch Menu
  2. Touch and hold the Service icon for at least 10 seconds until it turns green
  3. Open Service Information
  4. Use View Diagnostics for the most recent fault's top three likely root causes
  5. Use Last 10 System Events for timestamped recent events
  6. Use Run/Fault History for resettable fault counters, cycle counters, and run times
Source
Carrier FV4C Service Manual, FE4A/FE5A installation instructions, Carrier fan-coil wiring diagram/troubleshooting legend, Sigler NorCal public master fault code list.
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