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TRAM R Series General Service Bulletin

Air-cooled chiller control panel
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Literature Change History
RTAA-SB-5 - Original Service Bulletin
Control Operation, Setup and Troubleshooting for RTAA
Subject:
(Series R) Air-Cooled Chiller Control Panel.
Introduction:
The purpose of this Service Bulletin is to provide control operation and general troubleshooting information for Trane Model RTAA
microprocessor control panels. It is recommended that the service technician be familiar with the UCM operation before servicing
the microprocessor.
Discusion:
This bull tin is intended to serve as a supplement to the RTAA-IOM manual, the operation and maintenance for the RTAA units.
Subjects covered in this bulletin are intended to provide more comprehensive information for RTAA units.
Caution: Be sure to refer to wiring diagrams that apply specifically to the design sequence of the unit being serviced
when reading this manual.
TRAM'
General
Service
Bulletin
Library
Product Section
Product
Model
Literature Type
Sequence
Date
File No.
Supersedes
Since The Trane Company has a policy of continuous product improvement, it reserves the right to change specifications and
designs without notice. The installation and servicing of the equipment referred to in this booklet should be done by qualified,
experienced technicians.
RTAA-SB-5
Service Literature
Refrigeration
Rotary Liquid Chiller
RTAA
General Service Bulletin
5
June 1992
SV-RF-RLC-RTAA-SB-5-692
Original

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Summary of Contents for TRAM R Series

  • Page 1 • TRAM' General RTAA-SB-5 Service Bulletin Library Service Literature Product Section Refrigeration Product Rotary Liquid Chiller Model RTAA Literature Type General Service Bulletin Sequence Date June 1992 File No. SV-RF-RLC-RTAA-SB-5-692 Original Supersedes Literature Change History RTAA-SB-5 - Original Service Bulletin...
  • Page 2 • IMPORTANT NOTICE World environmental scientists have concluded, based on the best currently available evidence, that ozone in our upper atmosphere is being reduced, due to the release of CFC fully-halogenated compounds. The Trane Company urges all HVAC servicers, working on Trane equipment and other manufacturer's products, to make every effort to eliminate, if possible, or vigorously reduce emissions of CFC HCFC and HFC refrigerants to the atmosphere resulting from installation, operation, routine maintenance, or major service on this equipment.
  • Page 3 IMPORTANT NOTICES TO BE READ BEFORE SERVICING THE RTAA Warnings and Cautions Warnings are provided to alert personnel to potential hazards that can result in personal injury or death; they do not replace the manufacturer's recommendations. Cautions alert personnel to conditions that could result in equipment damage. Your personal safety and reliable operation of this machine depend upon strict observance of these precautions.

  • Page 4: Table Of Contents

    Table of Contents 7 Overview 47 Module Power and Miscellaneous I/O 7 General 47 General Service Philosophy 47 Power Supply 7 System Description Module Interchanging 48 Chiller Module (CPM) (1U1) --Phase 1 Units 48 --Vaccum Flourescent Display 48 --Display Up-Down. Keys --Phase 2 Units 9 System Level Components 48 --Set Point Up-Down Keys...
  • Page 5 • List of Illustrations Figure 1 Full System UCM for a 400 Ton Chiller 16 Figure 2 IPC Link Order for 400 Ton RTAA 17 Figure 3 Module Fuse and Power Connection 17 Figure 4 IPC Jumper for Bypassing Modules 30 Figure 5 Fan Staging, 130-200 Ton 44 Figure 6...
  • Page 6 List of Tables 7 Table 1 Unit Control Module Designations 14 Table 2 IPC Diagnostic Codes 15 Table 3 IPC Address DIP Switch (SW1) Settings for MCSP and EXV Modules 21 Table 4 Sensor Conversion Data 22 Table 5 Sensor Conversion Data 23 Table 6 Sensor Conversion Data 34 Table 7...

  • Page 7: Overview

    • Overview General The Unit Control Modules (UCMs) described in this troubleshooting guide comprise of a microprocessor based refrigeration control system intended for use with Trane 130-400 ton helical rotor chillers. Four types of modules are used, and throughout this publication will be referred to by their abbreviations or their Line Wiring Drawing Designations.

  • Page 8: Figure 1

    • As some larger tonnage refrigeration circuits employ two Expansion valves piped in parallel, a second "Slaved" EXV module will then be required to control the second valve on that circuit. The CSR is an optional communications module which allows for serial communications between the chiller and a remote building automation system.

  • Page 9: Module Interchanging

    • In addition to the modules, there are a number of "system level" components that are closely associated with the modules. These components were specifically designed and/or characterized for operation with the modules. For this reason, the exact Trane part must be used in replacement.
  • Page 10 • Chiller Module (CPM) 1U1 The CPM module performs machine (chiller) level control and protection functions. It also provides for the display of operating states, parameters and diagnostics, the adjustment of setpoints, and the selection of operating states through the front panel user interface (Vacuum Fluorescent Display and pushbutton/rocker switches).
  • Page 11 Operating Codes and Diagnostics Normal Operation and Operation Codes When power is first applied to the module, the CPM display (1U1) will briefly turn all of its segments on, to provide a visual test of their operation. Following this, the display will show an "A 88"...
  • Page 12 • • RTAA-SB-5...

  • Page 13: Description

    • Interprocessor Communication (IPC) Description The respective modules communicate with each other via an InterProcessor Communication link (IPC). The IPC allows the modules to work in a coordinated manner with the CPM directing overall chiller operation while each module handles specific sub-functions. This IPC link is integral and necessary to the operation of the Unit Controls and should not be confused with the Optional ICS (Integrated Comfort System) communication.
  • Page 14 Table 2. IPC Diagnostic Codes IFW, Use default/local setpoints. CPM (1U1) CSR (1U2) Same EXV MASTER(1U3) CPM (1U1) CMR, Cktl Same MCSP A (1U4) CPM (1U1) Same CMR, Affected Ckt CPM (1U1) MCSP B (1U5) Same CMR, Ckt2 CPM (1U1) MCSP C (1U6) Same MCSP D (1U7)

  • Page 15: Troubleshooting Modules Using Ipc Diagnostics

    • It is often the case that when some problem exists with the IPC link or a module fails, there will be more than one of these IPC diagnostics. These diagnostics could all be read in the "C" register of the display. (Remember that only those diagnostics that are flashing are currently active, others not flashing are historic only and should be disregarded for purposes of this troubleshooting.

  • Page 16: Figure 2

    • 2. Opens or shorts in the twisted pair IPC wiring or connectors: One or more modules may be affected by an open or a short in the IPC wiring, depending on the location of the fault in the daisy chain. The diagram below shows the daisy chain order and is helpful in diagnosis of an open link.

  • Page 17: Figure 3

    3. Loss of power to a module: Generally a power loss to a particular module will only affect communications with that module. The module can usually be identified by analysis of the IPC diagnostics. (When the display is blank, check power at the CPM). Loss of power can most directly be diagnosed then by measuring the AC voltage at the top of the fuse, with respect to the neutral of the power connection (pins 4 or 5) on the terminal just below the fuse: Figure 3.

  • Page 18: Troubleshooting Procedure

    • 5. Improper connections to terminal J2: Jack J2, present on all modules, should have no connections. This input is for manufacturing test purposes only and any connections, shorts, etc. will potentially cause the module to not respond, respond to the wrong address, or (in the case of the CPM) fail to initiate any communications and thus fail the entire IPC.

  • Page 19: Temperature Sensor Checkout

    Temperature Sensor Checkout • General With the exception of the thermostats located in the motor windings of the screw compressors, all the temperature sensors used on the UCMs are negative temperature coefficient (NTC) thermistors. The thermistors employed all have a base resistance of 10 Kohms at 77F (25C) and display a decreasing resistance with an increasing temperature.
  • Page 20 • 9. A decade box can be substituted for the sensor and any sensor table value used to relate resistance to temperature. By removing the MTA plug and applying the resistance to the proper pin terminals, the temperature as sensed by the UCM can be confirmed. Using the service menu display mode, scroll to the display of the temperature of interest.
  • Page 21 • Table 4. Sensor Conversion Data: Outdoor Air (5RT3), Entering and Leaving Evaporator Water Temp Matched Pairs (6RT7,6RT8), and Saturated Evaporator and Compressor Suction Refrigeration Temp Matched Pairs (6RT9,6RT5;6RT10,6RT6) -20.0 4.448 170040.3 30.0 34838.9 3.120 80.0 9297.5 1.533 -19.0 164313.4 4.434 31.0 33833.3...
  • Page 22 Table 5. Sensor Conversion Data: Saturated Condenser Refrigeration Temperature (6RT12,6RT13,6RT20) 50.0 19826 3.765 100.0 5782 2.356 87274 4.651 2.327 4.641 51.0 19301 3.740 101.0 5653 84511 18791 3.715 102.0 5527 2.300 81844 4.630 52.0 18297 3.689 103.0 5404 2.272 79270 4.619 53.0 54.0...
  • Page 23 • Table 6. Sensor Conversion Data: Optional Zone Temperature (6RT4) 10.0 63768.7 4.063 55.0 17471.6 2.910 100.0 5824.3 1.621 11.0 4.043 61815.3 56.0 17018.0 2.871 101.0 5694,2 1.602 12.0 59927.8 4.023 57.0 16577.8 2.832 102.0 5567.4 1.582 13.0 58103.1 4.004 58.0 16150.5 2.813...
  • Page 24 RTAA-SB-5...

  • Page 25: Operation Of Compressor Starting/Stopping, Anti-Cycle Timing And Restart Inhibit Timer

    Operation of Compressor Starting/Stopping, Anti-cycle Timing and Restart Inhibit Timer This feature is called the Auto Lead/Lag and can be found in Menu 4, Item 43. When this function is disabled in the UCM, the UCM always starts compressor "A" first. When this function is enabled, the following occurs: The UCM equalizes operating hours on the starting of a compressor.
  • Page 26 • RTAA-SB-5...

  • Page 27: Compressor Start/Stop Strategy For Normal Start And Shutdown

    • Compressor Start/Stop Strategy for Normal Start and Shutdown (includes action the UCM takes for abnormal shutdowns and a procedure for checking the differential oil pressure switch) To start a compressor after either a "normal' shutdown, a Unit Switch reset, or power-on-reset, the following sequence will occur: 1.
  • Page 28 • RTAA-SB-5...

  • Page 29: Condenser Fan Control Operation Via Microprocessor

    Condenser Fan Control Operation • via Microprocessor Fan Staging Each compressor has its own fans and independent staging control. Fans are controlled based on the high to low side pressure differential and/or saturated condensing temperature rate change. Evaporator and condenser temperatures will be sensed and used as inputs to the UCM for this function.
  • Page 30 • Figure 5. Fan Staging „, ,4AUST TRIP 10 SEC ,2)4r 4044;!rfV, ;> OtiASSIel%A;')_*, Z742?4A a0i•1 41.1 f1 INTEGRATE W--; ., : f1),41 4.e4 24,,:;1 1"..MNtip.U5144 g.:11/4.1.;:„%k 4).14 — : MUST HOLD 1 HO 300 = 151 F 148 F "PANIC"...

  • Page 31: Current Transformer And Current Input Checkout

    • Current Transformer And Current Input Checkout General Each compressor motor has all three of its line currents monitored by torroid (doughnut) current transformers. While the MCSP utilizes at three of the signals, it only displays the maximum phase at any given time. These currents are normalized with respect to the Rated Load Amps of the respective compressor and thus are expressed in terms of % (percent) RLA.

  • Page 32: Ct And Mcsp Compressor Current Input Checkout Procedure

    • CT and MCSP Compressor Current Input Checkout Procedure 1. Check incoming 3-phase power for voltage within ± 10% of nominal per Chiller nameplate. 2. Interrogate the CPM for all of the presently active (flashing) diagnostic codes or the historic (not flashing) diagnostic codes in the C register of Menu P0.
  • Page 33 • More than one current transformer is terminated to a single MTA. When replacing, take care to note the proper positions of the respective transformer wire terminations on the MTA for the re- termination. (The current transformers are NOT polarity or directionally sensitive however). The transformer lead wiring is #22 AWG, UL 1015 600V and the proper MTA connector (red color code) must be used to ensure a reliable connection.
  • Page 34 Table 7. Compressor Overload Dip Switch Settings And Current Transformer Selection 200/230,60 563 1689 00100/04 11110/30 380,60 10000/16 460,60 11110/30 575,60 11011/27 346,50 380/415,50 200 10000/16 200/230,60 681 2044 01011/11 10001/17 380,60 460,60 10110/22 00110/06 575,60 01100/12 346,50 10110/22 380/415,50 242 200/230,60 797 2391 11010/26...
  • Page 35 • Table 8. Trip Times Vs. % Current No Trip No trip No Trip 127.7 or below 27.2 No Trip No Trip 132.0 No Trip 30.08 132.1 27.2 25.28 28.09 140.0 (must trip pt.) 22.8 20.48 22.89 150.0 18.8 17.28 19.29 160.0 16.0...
  • Page 36 • Table 10. Compressor Phase Current Vs. AC Input Voltage at MCSP 0.00 1.19 1.37 1.53 1.67 1.81 1.95 2.09 2.23 2.36 2.50 2.63 2.77 2.90 3.03 3.17 3.30 3.43 3.57 3.70 3.83 3.96 4.10 4.23 4.36 4.49 4.62 4.75 4.88 5.02 5.15...
  • Page 37 • Table 11. Overload Dip Switch Setting Vs. Internal Sortware Gain 00000 1.500000 00001 1.483870 00010 1.467743 00011 1.451613 00100 1.435483 00110 1.403226 00111 1.387097 01000 1.370969 01001 1.354839 01010 1.338709 01011 1.322580 01100 1.306452 01101 1.290323 01111 1.258065 01111 1.258065 10000 1.241936...
  • Page 38 RTAA-SB-5...

  • Page 39: Under-Over Voltage Transformer

    Under-over Voltage Transformer General The Under-Over voltage function of the CPM module is optional. A custom designed transformer whose primary is connected across the Line Voltage phases B To C, provides a stepped down and isolated AC voltage to the CPM at input J4. This secondary voltage is directly proportional to the line voltage applied to the primary.
  • Page 40 • • RTAA-SB-5...

  • Page 41: Compressor Slide Valve

    Compressor Slide Valve (Load/Unload) Checkout Procedure General The helical rotory screw compressors are loaded and unloaded by means of an internal slide valve. In simple terms, the slide valve can regulate the amount of "bite" of the compressor rotors as they turn at relatively constant speeds. This slide valve is moved by a hydraulic cylinder and piston internal to the compressor (the hydraulic fluid is oil from the refrigerant system).

  • Page 42: Checkout Procedure For Slide Valve And Load/Unload Solenoids

    • The best time to check the unload solenoid is immediately after a power-up reset of the MCSP. For the first 30 seconds after applying power the unload solenoid should be on continuously. The next best time to check it is after the compressor starts. For the first 30 seconds after a start the unload solenoid should be on continuously.

  • Page 43: Load

    • Load. 6. Once the compressor has started, allow the Unload Solenoid Valve to remain energized for approximately 30 seconds, then open the Unload toggle switch to de-energize the valve. Verity that at least one condenser fan is on before continuing with the checkout, as low differential refrigerant pressures will preclude proper Slide Valve operation.
  • Page 44 • Figure 6. Manual Slide Valve Diagnostic Flow Chart - Load 1. Install toggle switches across load and unload solenoid valves. 2. Install Pressure Gage on compressor Cavity Pressure Port. 3. Start Unit. Load: 4. Manually load compressor in short increments. Good 5.

  • Page 45: Unload

    • Unload Note: the following assumes that the compressor's slide valve is already at some loaded position and %RLA is higher than the minimum noted in step 7. 8. Manually close the Unload toggle switch to continuously energize the Unload Solenoid Valve. A.
  • Page 46 Figure 7. Manual Slide Valve Diagnostic Flow Chart Unload: 10. Manually unload compressor. Good 11. Does RLA Decrease? Check UCM Stop Replace UCM 12. Does Cavity Press decrease Slide valve mechanism bound to a level close to suet slide valve seal is leaking pressure? 13.

  • Page 47: Module Power And Miscellaneous I/O

    • Module Power And Miscellaneous I/O General This section will detail the normal voltage levels present on each of the modules inputs and outputs under various conditions or states. Typical operation of the I/O will be discussed in terms of chiller operation. This should help the serviceman determine when and how they should function.

  • Page 48: Chiller Module (Cpm) (1U1)

    • Chiller Module (CPM) (1U1) Vacuum Fluorescent Display The seven segment, seven digit vacuum fluorescent display should be lit, displaying alphanumeric operating codes, diagnostics, setpoints or temperatures at all times when power is applied to the CPM. A flashing display is indicative of a diagnostic, or an attempt to violate margins for cutout setpoints.

  • Page 49: Test Points

    • If the Chiller rocker switch does not function as described above, replace the CPM. Keep in mind, however, that certain external faults can cause diagnostics to recur immediately after a reset. It may appear as though the diagnostic couldn't be cleared, when in fact the original fault is causing an immediate recurrence of the diagnostic.
  • Page 50 Figure 9. CPM Module (1U1) 05-1 115V H O TP1 +5V J5-2 115V H O TP2 +12V J5-3 O TP3 -30V - KEY (N/C) J5-4 115V ( +) J5-5 115V N J1-3 JI-2 J1-1 TB3-1 CHILLED WATER FLOW — J2-2 MANUF.

  • Page 51: I/O Terminals

    • I/O terminals For the checkout of the I/O, refer to the block diagram of the module in Figure 6 and the Chiller Wiring Diagrams for both high and low voltage circuits. All voltages are measured differentially between terminal pairs specified unless otherwise indicated. The first terminal in the pair is the positive (or hot) terminal.
  • Page 52 Table 12. CPM Nominal Terminal Voltages (1U1)(cont.) TB4-1,2 Dry SPDT Contact *Chiller Alarm closes on Alarm, intended for or Alarm Ckt 1 115 VAC customer control circuit (N.O. Contact) TB4-1,3 *Chiller Alarm Dry SPDT Contact opens on Alarm, intended for or Alarm Ckt 1 (N.C.

  • Page 53: Options Module (Csr) (1U2)

    Options Module (CSR) (1U2) Test Points There are three test points associated with the CSR module. They are easily read with a DC voltmeter by probing the PC board solder pads found in the upper left hand corner of the module.
  • Page 54 • The 4-20mA/2-10V inputs may be tested in the following ways: 1. Enable External Chilled Water Setpoint and/or External Current Limit Setpoint in Menu 3 on the front panel of the CPM. Advance display to Active Chilled Water Setpoint or Active Current Limit Setpoint to observe the respective setpoint.

  • Page 55: Setpoint Priority

    • Table 14. Input Values Vs. External Current Limit Setpoint 49000 29000 19000 13000 10.0 9000 12.0 6143 14.0 4010 16.0 2333 18.0 1000 20.0 10.0 Note: This table will only apply to Options and Chiller Modules manufactured after May of '91, Options Module software part number starting with 6200-0023-03 and higher, and Chiller Module software part number 6200-0010-03 and higher.
  • Page 56 • Figure 10. START Chilled Water Setpoint Arbitration Remote Local LOCAL OR REMOTE? EXCEPT FOR CHILLED WATER EXCEPT FOR CHILLED WATER USE ALL OTHER REMOTE USE ALL OTHER FRONT PANEL SETPOINTS SETPOINTS EXTERNAL EXTERNAL SETPOINT INPUT SETPOINT INPUT ENABLED? ENABLED? REMOTE ICE MODE CMND?
  • Page 57 • Figure 11. Current Limit Setpoint Arbitration START EXTERNAL CURRENT LIMIT INPUT ENABLED? • LOCAL OR REMOTE? Local TIMED EXTERNAL USE FRONT PANEL USE REMOTE USE FRONT PANEL CURRENT LIMIT CURRENT LIMIT CURRENT LIMIT CURRENT LIMIT SETPOINT SETPOINT SETPOINT SETPOINT "REMOTE"...

  • Page 58: Ics Communications

    • ICS Communications ICS Tracer communication is handled the same as on previous products using the Trane proprietary Comm3 standard 1200 baud isolated serial communication link. The following are some things to check when experiencing loss of ICS communications: 1. If ICS control is desired, check that the Chiller Switch of the Chiller Module (CPM) is set in the "Auto Remote"...
  • Page 59 • Table 15. CSR Normal Terminal Voltages For Options Module 1U2 J1-4 to 3 IPC Communications 19.2 kbaud serial data, or J1-2 to 1 5 volt signal level. J2-2,1 Manufacturing +5 VDC No connection intended. Address Use Only TB1-1,2 Zone Refer to Interprocessor Temperature Communication (IPC)
  • Page 60 Figure 12. CSR Module (1U2) FJ4-1 115VAC HOT O TP1 +5V J4-2 115VAC HOT o TP2 +6V J4-3 KEY (N/C) O TP3 +12V NEUTRAL IPC (+)-- J1-4 J4-5 NEUTRAL IPC (-) J1-3 IPC (+)-- JI-2 IPC (-) J1-1 MANUF. NO CONN. — J2-2 USE ONLY NO CONN.

  • Page 61: Electronic Expansion Valve Module (Exv) (1U3 And 1U8)

    Electronic Expansion Valve Module (EXV) (1U3 and 1U8) • Valve Operation The electronic expansion valve is an electronic flow device that replaces the thermostatically controlled expansion valve and liquid line solenoid. A sectional view of the valve is shown in Figure 13.

  • Page 62: Electronic Expansion Valve Location

    • The valve is a stepper-motor type, direct acting valve. It uses a three-phase motor (not to be confused with 3-phase AC), with each phase having 40 ohms of resistance. The supply voltage (24 VDC) is switched on and off to each phase, to step the valve open or closed. Each step is 0.0003' of stroke, with a full stroke of 757 steps.

  • Page 63: Test Points

    • Test Points There is only one test point associated with the EXV module. It is easily read with a DC voltmeter by probing the PC board solder pad found in the upper left hand corner of the module. The positive meter lead should be connected to the pad while referencing the negative meter lead to the board edge ground plane.

  • Page 64: Stroke Timing Test

    • Stroke Timing Test 5. At this time the UCM will drive the valve closed by executing a total of 1250 steps at a rate of 50 steps/sec. Thus the total closing time, including clicking time, will be 25 seconds. Due to mechanical characteristics of the valve, it will make a clicking sound when it reaches its end stops (either full open or full closed).
  • Page 65 • Table 16. Test Results Logic Table PASS PASS NOT.REQ. VALVE/BOARD ARE WORKING PROPERLY - NO ACTION REO. PASS FAIL PASS VALVE IS MECHANICALLY STUCK - REPLACE / REPAIR VALVE PASS FAIL FAIL HIGHLY UNLIKELY CONDITION- RETEST-REPLACE MODULE FAIL PASS PASS HIGHLY UNLIKELY CONDITION- RETEST-NO ACTION REQ.

  • Page 66: Solder Techniques For Installation

    • Solder Techniques for Installation It is not necessary to disassemble the valve when soldering to the connecting lines. Most commonly used types of solder (eg. Sil-Fos, Easy-Flow, Phos-Copper or equivalent) are satisfactory. Regardless of the solder used, it is important to direct the flame away from the valve body.
  • Page 67 • 5. Remove pushrod and check for excessive wear or scratches. The pushrod must move freely in the valve body. 6. Remove the bottom cap, spring and piston. Inspect these parts for foreign matter and physical damage. 7. Clean all parts with a suitable solvent and blow dry with clean compressed air. 8.
  • Page 68 Figure 16. Electronic Expansion Valve Exploded View DO NOT SEPARATE ACTIVATOR ASSEMBLY MOTOR ADAPTOR ASSEMBLY W/PUSHROD BONNET 0 PUSHROD 0 VALVE BODY ASSEMBLY 0 PISTON ASSEMBLY 0 SPRING 0 BOTTOM CAP R :37 k MOTOR/ADAPTOR ASSEMBLY PUSHROD VALVE ASSEMBLY BODY PISTON ASSEMBLY SPRING BOTTOM CAP...
  • Page 69 Figure 17. Electronic Expansion valve (1U3) Master J6-1 115VAC HOT TP1 +5V J6-2 115VAC HOT J6-3 - KEY (N/C) J6-4 NEUTRAL IPC (+)-- J1-4 J6-5 NEUTRAL IPC (-)-- J1-3 IPC (+)-- JI-2 IPC (-) J1-1 MANUF. NO CONN. -- USE ONLY NO CONN.
  • Page 70 Figure 18. Electronic Expansion valve (1U8) Slave 115VAC HOT TP1 +5V J6-2 115VAC HOT J6-3 - KEY (N/C) J6-4 NEUTRAL J1-4 IPC (+)-- J6-5 NEUTRAL J1-3 IPC (-)-- JI-2 (+)-- J1-1 IPC (-) J2-2 1--11of f MANUF. NO CONN. — J2-1 SW-1 USE ONLY...
  • Page 71 terminals For the checkout of the I/O, refer to the block diagram of the EXV module i n Figure 17 and the Chiller Wiring Diagrams for both high and low voltage circuits. All voltages are measured differentially between terminal pairs specified, unless otherwise indicated. The first terminal in the pair is the positive (or hot) terminal.
  • Page 72 Table 17. EXV Module Normal Terminal Voltages (cont.) J4-3 EXV CKT1 Phase 1 0 VDC open circuit (with valves unconnected) with respect to chassis. With valves connected and running*, voltage will vary between the above 24.2 ±17% VDC to .5 volts or less as the phase is "stepped"...

  • Page 73: Compressor Module (Mcsp) (1U4, 1U5, 1U6, And 1U7)

    • Compressor Module (MCSP) (1U4, 1U5, 1U6, and 1U7) Test Points There are two test points associated with the MCSP module. They are easily read with a DC voltmeter by probing the PC board solder pads found in the upper left hand corner of the module.

  • Page 74: Binary Inputs

    • Binary Inputs Table 18. Binary Inputs Circuit Inhibit* No diagnostic but Circuit Lockout caret will be lit in Menu 0 and Compressor Mode Menu item 20 will indicate lockout whenever this input is open with the feature enabled (Menu item 3b).

  • Page 75: Temperature Inputs

    • Temperature Inputs Table 19. Temperature Inputs Sat. Cond. Rfgt. Temp. 8F Cond. Rfgt. Temp. Sensor - Ckt 1 90 Cond. Rfgt. Temp. Sensor - Ckt 2 Sat. Evap. Rfgt. Temp. None These inputs use Trane's standard thermistor, an NTC device giving 10,000 ohms at 25 C. Refer to Temperature Sensor Checkout for a table of temperature vs.

  • Page 76: Current Inputs

    • Current Inputs Table 20. Current Inputs Phase A, B, C Current Xfmr Overload Trip - Cprsr A Overload Trip - Cprsr B Overload Trip - Cprsr C Overload Trip - Cprsr D CA Contactor - Cprsr A Cb Contactor - Cprsr B Contactor - Cprsr C Cd Contactor - Cprsr D 184 Phase Rotation - Cprsr A...

  • Page 77: Isolated Binary Input: Winding Temperature

    • Isolated Binary Input: Winding Temperature This input may be checked by disconnecting all wiring from the terminals and measuring the open circuit voltage. It should read between 10 and 15 Vac. A 1 bE, 1bF, 1C0 or 1C1 diagnostic should appear on the CPM's display depending on which compressor module it is.
  • Page 78 • Table 21. Compressor Module Normal Terminal Voltages (IU4, 1U5, 1U6 and 1U7) J1-4 to 3 IPC Communications 19.2 kbaud serial data, 5 volt signal level. or J172 to 1 Manufacturing +5 VDC No connection intended. J2-2,1 Address Use Only Open= 12 VDC: ckt lockout J3-7,6 External Circuit...
  • Page 79 • Table 21. Compressor Module Normal Terminal Voltages (IU4, 1 U5, 1U6 and 1U7) (cont.) J6-1 or 2 Input Power 115 VAC, Refer to Power Supply in Module to J6-4 or 5 Power and Miscellaneous I/O E3, E4 Compressor Motor Internally powered Isolated input Winding Temp.
  • Page 80 • Figure Compressor Module (1U4, IU5, 1U6 and 1U7) J6-1 115VAC HOT 0 TP1 +5V J6-2 115VAC HOT TP2 +12V 3 - KEY (N/C) J6-4 NEUTRAL IPC (+)-- J1-4 J6-5 NEUTRAL IPC (-)-- J1-3 IPC (+)-- JI -2 COMPRESSOR MOTOR IPC (-) J1-1 WINDING THERMOST.

  • Page 81: Other Service Features

    Other Service Features Phase I Pueblo Pilot Production UCM's (Aug. 1990) and First Production UCM's (Jan. 1991), designed for 130-200T chillers, do not have the features presented in this section. Only UCM's with date codes 91Hxxx or later will have the Phase II software, as first released in July 1991 with the following features.

  • Page 82: Compressor Test

    Compressor Test The UCM provides for a Compressor Test feature which is designed to allow a service- technician to direct a particular compressor to be the next compressor to stage on, run and modulate. This allows the temporary override of the lead/lag sequencing currently in effect and relieves the technician from forcing staging of compressors thru load or setpoint changes.
  • Page 83 RTAA-SB-5...
  • Page 84 For further information on this product or other Trane products, refer to the "Trane Service Literature Catalog", ordering number IDX-10M-1. This catalog contains listings and prices for all service literature sold by Trane. The catalog may be ordered by sending a $15.00 check to: The Trane Company, Service Literature Sales, #600 Pammel Creek, La Crosse, WI 54601.

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