nced service personnel familiar with the
proper use of electrical diagnostic instruments and all personal safety
procedures when working on live electrical circuits.
This Manual is not intended for individuals who have not been properly trained
in handling live electrical circuits.
Environmental Concerns!
Scientific research has shown that certain man-made chemicals can affect the
earths naturally occurring stratospheric ozone layer when released to the
atmosphere. In particular, several of the identified chemicals that may affect the
ozone layer are refrigerants that contain Chlorine, Fluorine and Carbon (CFCs)
and those containing Hydrogen, Chlorine, Fluorine and Carbon (HCFCs). Not all
refrigerants containing these compounds have the same potential impact to the
environment. Trane advocates the responsible handling of all refrigerants
including industry replacements for CFCs such as and HCFCs and HFCs.
Responsible Refrigerant Practices!
Trane believes that responsible refrigerant practices are important to the
environment, our customers, and the air conditioning industry. All technicians
who handle refrigerants must be certified. The Federal Clean Air Act (Section
608) sets forth the requirements for handling, reclaiming, recovering and
recycling of certain refrigerants and the equipment that is used in these service
procedures. In addition, some states or municipalities may have additional
requirements that must also be adhered to for responsible management of
refrigerants. Know the applicable laws and follow them.
WARNING
Contains Refrigerant!
System contains oil and refrigerant under high pressure. Recover refrigerant to
relieve pressure before opening the system. See unit nameplate for refrigerant
type. Do not use non-approved refrigerants, refrigerant substitutes, or refrigerant
additives.
Failure to follow proper procedures or the use of non-approved refrigerants,
refrigerant substitutes, or refrigerant additives could result in death or serious
injury or equipment damage.
NOTICE: Warnings and Cautions appear at appropriate sections through-
out this literature. Read these carefully.
WARNING: Indicates a potentially hazardous situation which, if not
avoided, could result in death or serious injury.

CAUTION: Indicates a potentially hazardous situation which, if not
avoided, may result in minor or moderate injury. It may also be used to
alert against unsafe practices.
CAUTION: Indicates a situation that may result in equipment or property-
damage only accidents. RLC-SVD03A-EN
3
Contents
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Service Philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
System Level Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Interprocessor Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
IPC Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Troubleshooting Modules Using IPC Diagnostics . . . . . . . . . . . . . . . . . . . . . . . 9
Troubleshooting Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Temperature Sensor Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Temperature Sensor Checkout Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Compressor Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Restart Inhibit Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Compressor Start/Stop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Variable Speed Inverter/Condenser Fan Control . . . . . . . . . . . . . . . . . . 21
Outdoor Air Temperature and Fan Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
VSF Inverter Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Current Transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
CT and MCSP Compressor Current Input Checkout Procedure . . . . . . . . . . . 24
Under-Over Voltage Transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Under-Over Voltage Transformer Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Compressor Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Checkout Procedure for MCSP Load/Unload Outputs . . . . . . . . . . . . . . . . . . 35
Checkout Procedure for the Slide Valve and Load/
Unload Solenoids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Checkout Procedure for MCSP Step Load Output . . . . . . . . . . . . . . . . . . . . . 39
Checkout Procedure for Step Load Solenoid Valve
and Piston . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Module Power and Miscellaneous I/O . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Clear Language Display (CLD) 1U6 Keypad Overview . . . . . . . . . . . . . . . . . . 42
Chiller Module (CPM) (1U1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Options Module (CSR) (1U2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Electronic Expansion Valve Module (EXV) (1U3) . . . . . . . . . . . . . . . . . . . . . . . 58
Compressor Module (MCSP) (1U4 AND 1U5) . . . . . . . . . . . . . . . . . . . . . . . . . 72
Interprocessor Communication Bridge Module (IPCB) (1U7) . . . . . . . . . . . . . 78
LonTalk® Communications Interface - Chillers Module
(LCI-C) (1U8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Variable Speed Fan System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Inverter Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Troubleshooting Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Other Service Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Service Pumpdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Circuit Lockout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Circuit Diagnostic Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 4
RLC-SVD03A-EN
General Information
The Unit Control Modules (UCMs) described in this troubleshooting guide
provide a microprocessor based refrigeration control system, intended for
use with Trane 70-125 ton helical rotor chillers. Six types of modules are
used, and throughout this publication will be referred to by their abbreviations
or their Line Wiring Drawing Designations, see
Table 1
.
Service Philosophy
With the exception of the fuses, no other parts on or within the modules are
serviceable. The intent of the troubleshooting is to determine which module
is potentially at fault and then to confirm a module problem. This is done
either through voltage or resistance measurements at the suspected input or
output terminals or by checking related wiring and external control devices
(connectors, sensors, transformers, contactors etc.) in a process of elimi-
nation. Once a problem has been traced to a module, the module can be
easily replaced using only basic tools. In general, all dip switch settings of the
replaced modules should be copied onto the replacement module's dip
switches before applying control power. CPM replacement is more involved
as there are numerous configuration and set-up items that must be
programmed at the Clear Language Display in order to insure proper unit
operation.
It is helpful to include with the return of a module, a brief explanation of the
problem, sales office, job name, and a contact person for possible follow-up.
The note can be slipped into the module enclosure. Early and timely
processing of Field Returns allows for real measurements of our product
quality and reliability, providing valuable information for product improvement
and possible design changes.
Table 1
Unit Control Module Designations
Line Drawing
Designation
Controller Name
Chiller Module
Abbrev.
CPM
1U2
Options Module
CSR
1U3
Expansion Valve Module
EXV
1U4 & 1U5
Compressor Module
MCSP A & B
1U6
Clear Language Display
CLD
1U7
Interprocessor
Communications Bridge
(Remote Display Buffer)
IPCB RLC-SVD03A-EN
5
General Information
System Description
The CPM is the master module and coordinates operation of the entire
system. One is used per chiller. The MCSP is a compressor protection
module with one being used for each of the compressors in the chiller. The
EXV is the expansion valve controller module which controls two Electronic
Expansion Valves. There is one valve on each of the two refrigeration circuits.
The CLD is a two line, 40 character alphanumeric interface to the system. It
allows the operator to read operating and diagnostic information, as well as
chang