Trane TUHMB060ACV3VA - Page 52

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