RRU-SVX02F-EN 45
Alarms and Troubleshooting
Standard Unit Controller RRUCM
Model UC600
Microprocessor Control
The Main Unit Display and RTRM have the ability to
provide the service personnel with some unit diagnostics
and system status information.
1. Verify that the Liteport LED on the RTRM is burning
continuously. If the LED is lit, go to Step 3.
2. If the LED is not lit, verify that 24 Vac is presence
between J1-1 and J1-2. If 24 Vac is present, proceed to
Step 3. If 24 Vac is not present, check the unit main
power supply, check transformer (TNS1). Proceed to
Step 3 if necessary.
3. Utilizing “Method 1” in the RTRM “System Status
Checkout Procedure”, check the following:
• System status
• Cooling status
If a System failure is indicated, proceed to Step 4. If no
failures are indicated, proceed to Step 5.
4. If a System failure is indicated, recheck Step 1 and Step
2. If the LED is not lit in Step 1, and 24 Vac is present in
Step 2, the RTRM has failed. Replace the RTRM.
5. If no failures are indicated, use one of the override
options to start the unit. Following the Override
procedure will allow you to check all of the operating
modes, and all of the external controls (relays,
contactors, etc.) for each respective mode.
6. Refer to the sequence of operations for each mode, to
assist in verifying proper operation. Make the
necessary repairs and proceed to Step 7.
7. If no abnormal operating conditions appear in the
Override mode, release the override and turn the
power “Off” at the main power disconnect switch.
System Alarms
The Main Unit Display has built in alarms to help the
operator troubleshoot system failures. This section will
describe these alarms and provide a guide to
troubleshooting the all unit operating modes.
Comprehensive system alarms and diagnostics are
accessed through the Alarms icon at the unit display
discussed later in the section, or through Tracer TU
programming on connected computer. Sensor failures
may be viewed through the Alarms icon.
If an alarm is present, the main indicator light on the
UC600 will blink red. If the optional unit display is installed,
the Alarm icon on the display will register ALARM,
illuminate red and flash.
Important: The space temperature sensor (SPTC) and
space relative humidity sensor (SPHC) will
read failed if they are not connected; they
will Alarm as “In Fault.”
Sensor Failure Alarm Display
Press the Alarm button on the Home display of the Unit
Display to display system sensor status as described in
Table 8 and Table 9, p. 46.
WARNING
Live Electrical Components!
Failure to follow all electrical safety precautions when
exposed to live electrical components could result in
death or serious injury.
When it is necessary to work with live electrical
components, have a qualified licensed electrician or
other individual who has been properly trained in
handling live electrical components perform these
tasks.
Table 8. TOAU UC600 alarms
Point Diagnostic Possible Cause
1
Indoor Fan
Failure
VFD not operating
Outdoor and/or Return Air Dampers not
Operating Properly
Indoor Fan Motor Failure
Indoor Fan Failure Switch IFFS (pressure)
Failure
IFFS Tubing damaged or not properly
connected
Refer to startup procedure
3
OAD Proving
Switch
No voltage at actuator
Failed OAD power transformer
No continuity thru end switch (check at UC)
Note: If unit optional RA damper is
installed, send switch on OAD is always
proven
6
Discharge Air
Temp Source
Failure
BAS communication down
Failed sensor or improper sensor
installation
8 Fire Shutdown BAS ONLY
10
Low Temp
Lockout
Heat Overridden OFF
Compressor(s) Overridden ON
Setpoint Failures Incorrect
DAT sensor malfunction
Reference Table 9, p. 46 for heat failure
issues
11
Space Temp
Source Failure
BAS communication down
Failed sensor or improper sensor
installation
13
OA Temp Source
Failure
BAS communication down
Failed sensor or improper sensor
installation
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