Trane Modu Heating System User Manual


 
SCXG-SVX01B-EN 119
Diagnostic
Troubleshooting Diagnostics
W
WSM Communications Fail
Problem: The RTM has lost
communication with the WSM.
Check: Field/unit wiring between RTM
and WSM.
Reason for Diagnostic: The RTM has lost
communication with the WSM.
UCMs Reaction: The UCM will react as if
a freezestat has occurred by issuing:
An All Heat On or Mod Output Full
Open request to Heat Control
A Fan off request to Supply Fan
Control
A Close Damper request to
Economizer Actuator Control
The water pump to turn on and position
all water valves to provide maximum
flow through all water source heat
exchangers
Disables preheat function if WSM Mixed
Air Temp Sensor is selected as Preheat
Sensor
Reset Required: An automatic reset
occurs after one complete set of IPC
packets is received.
WSM Mixed Air Temp Sensor Fail
b. Activation Conditions: temperature < -
50 F or temperature > 209 F, and sensor
is selected for use by Water Side
Economizer Temperature Enable
Function or Preheat Function
c. Time to React: 10 sec < T < 20 sec
e. Actions to be Initiated: Water Side
Economizer Temperature Enable
Function uses Supply Air Cooling
Setpoint instead of Mixed Air
Temperature. If Mixed Air Temperature is
being used for Preheat Function, issue
a Disable request to Preheat
Function.
f. Reset: An automatic reset occurs after
the Mixed Air Temp. input returns to
within range continuously for 10 seconds.
Water Flow Fail
a. Data used (module,packet,byte,bit):
WSM, 01,19,05
b. Activation Conditions: The water flow
input is detected open ;
1. at the end of precool water flow
initiation state, or
2. continuously for five minutes while:
·water side economizer is open 100%,
· presetting of a Head Pressure Valve, or
· demand for mechanical cooling.
Unit must be: a. configured with water
cooled condenser and/or water
economizer and b. have water flow
switch installed.
c. Time to React: immediate
e. Actions to be Initiated: A Lockout All
Ckts request is issued to the
Compressor Staging Function
f. Reset: An automatic reset occurs after
the Water Flow input returns to within
range continuously for 3 seconds, the
water pump is requested OFF, or the
water flow switch becomes not installed.
Z
Zone Cool Setpoint Failure
Problem: The occupied zone cooling
setpoint is out of range.
Reason for Diagnostic: The input
designated as occupied zone cooling
setpoint source is out of range (temp. <
45 F or temp > 94 F).
UCMs Reaction: The active occupied
zone cooling setpoint reverts to the
default occupied zone cooling setpoint.
Reset Required: (PAR) an automatic reset
occurs after the designated occupied
zone CSP input returns to its allowable
range for 10 continuous seconds, or after
a different valid occupied zone CSP
selection source is user-defined.