Trane S*HF*20-75 Troubleshooting Manual page 140

DIAGNOSTICS Menu
Table 11: Diagnostics Troubleshooting Chart (continued)
Supply Fan Failure
Module: RTM
Supply Fan Proving
Failure
Used With: Required w/
units with isolation
dampers (fire dampers)
installed to insure proper
airflows and proving switch
operation.
Module: RTM
140
Problem: There is no
supply irflow indication
after the supply fan has
been requested on. The
supply airflow proving
input is detected OPEN for
40 continuous seconds
during any period of time in
which the supply fan relay
is ON. This input is ignored
for up to 5 minutes after the
supply fan is first started,
until airflow is first
detected.
Check: Check belts,
linkages, etc. on the Supply
Fan assembly. If these are
ok, check field/unit wiring
between RTM and Supply
Fan.
If Supply Fan will run in
service mode, then verify
airflow proving switch and
wiring.
Problem: The unit has
isolation dampers and the
Isolation Damper Interlock
function is set to ENABLED.
When the supply fan is
requested OFF the unit
expects the proving input
to OPEN and will prevent
the supply fan relay on the
RTM from turning on again
if being requested to do so.
If the switch does not open
within 5 minutes this
diagnostic will occur.
Check: Check the supply
fan airflow proving switch
and wiring.
"OFF or "Close" requests
are issued as appropriate to
the following functions:
a. Compressor staging/
Chilled Water control
b. Heat operation
c. Supply fan control and
proof of operation.
d. Return fan control and
proof of operation.
e. Exhaust fan control and
proof of operation
f. Exhaust actuator control
g. Economizer actuator
control
h. IGV / VFD control
The unit will trip all outputs,
de-energize dx cooling,
staged heating, fans, etc.,
and will drive all analog
ouputs closed/stop, fan
speed, dampers,
modulating heat, etc.
(PMR) A manual reset is
required anytime after the
Diagnostic is set. The
Diagnostic can be reset by
the Human Interface or
Tracer, or by cycling power
to the RTM.
(PMR) A manual reset is
required anytime after the
Diagnostic is set. The
Diagnostic can be reset by
the Human Interface or
Tracer, or by cycling power
to the RTM.
RT-SVP07B-EN