Trane UHMB060ACV3VA Series Service Facts page 52

Service Facts
Replace IFC
NO
Check operation
52
10 Flash Fault LED
User Interface
shows NO SYS
CLK?
After ~10
seconds; Is Bit
Master (BM)
LED on solid?
YES
Is COMM LED
rapidly
flashing?
YES
Is ~12VDC measured
NO
from terminals D-B at
the IFC?
YES
Internal control
failure. Replace
IFC. Check
operation
Scroll through
User Interface to
View number 1 of
Last 4 Faults
User Interface
ERR 139 appears on
the Comfort Control
The mode of
operation has
been changed to
Change mode of
"COMM" Check
Good communications are verified
with ~12VDC. Correct field wiring.
Check operation
shows 24V
COMM
MSMTCH?
24VAC.
See user interface
operation to
menu in Service
Facts or Installer's
operation.
Guide to change
mode of operation.
UHM-DHM-SF-1H