McQuay WSC, WDC, TSC, WCC, HSC Operating Manual
Operating Manual
OM CentrifMicro II-5
MicroTech ΙΙΙΙΙΙΙΙ Controller
With Starter Information
For Centrifugal Chillers and Templifiers
Models WSC, WDC, WCC, HSC, TSC
Software Version: WCFU3UU04C/D/E
OITS Version: 2.05.03
Group: Chiller
Part Number: 331374901
Effective: March 2011
Supersedes: November 2010
WSC, WDC
Table of Contents
Introduction ............................................... 3
Features of the Control Panel................... 4
General Description................................... 5
Component Description ............................6
Operator Interface Touch Screen ........................... 6
Unit/Compressor Controller Description ............... 6
Software................................................................. 7
Unit Controller....................................................... 7
Compressor Controller .......................................... 8
Guardister Board ................................................ 9
Signal Converter Board ......................................... 9
Transducer Converter Board.................................. 9
PLAN Isolator ....................................................... 9
Field Wiring Diagram..........................................10
Dual/Multi-Chiller Operation ................12
Multiple Chiller Setup ......................................... 12
WCC Settings ......................................................15
Ice Mode Operation................................. 16
Operator Interface Touch Screen........... 16
Navigation ........................................................... 16
Screen Descriptions ............................................. 18
VIEW Screens ..................................................... 18
SET Screens.........................................................23
SERVICE Screen ................................................. 37
HISTORY Screens ...............................................38
Download from the USB .....................................39
ACTIVE ALARM Screen.................................... 40
Unit Controller......................................... 43
Navigating ........................................................... 43
Screen Descriptions ............................................. 46
SET Screens.........................................................49
Unit Controller Setpoints..................................... 51
Compressor Controller ........................... 61
Navigating ........................................................... 61
Compressor Controller Setpoints......................... 62
Optional Starter Screens......................... 67
Low Voltage Starters, 200 – 600 Volts.... 68
General ................................................................ 68
LED Display........................................................ 69
Faults and Alarms ................................................ 74
Troubleshooting................................................... 77
Preventive Maintenance ...................................... 82
Medium/High Voltage Starters, 2300V
– 7.2KV..................................................... 83
View Parameters .................................................. 84
Set Parameters ..................................................... 84
Quick Start........................................................... 86
Troubleshooting................................................... 88
Fault/Log Codes .................................................. 90
LED Diagnostics ................................................. 93
Preventive Maintenance ...................................... 93
Sequence of Operation ............................ 94
Unit Operation..................................................... 94
Operating the Chiller Control System... 96
Interface Panel On/Off ........................................ 96
Start/Stop Unit..................................................... 96
Change Setpoints................................................. 97
Alarms ................................................................. 97
Component Failure .............................................. 97
Standby Power..................................................... 97
Maintenance Schedule ............................ 98
McQuay" and MicroTech II are registered trademarks of McQuay International
"Illustrations and information cover McQuay International products at the time of publication and we reserve the right to make changes in design and
2 OM CentrifMicro II-5
ETL applies only to models
Manufactured in an ISO certified facility.
2005 McQuay International
construction at anytime without notice."
Introduction
This manual provides operating, maintenance and troubleshooting information for McQuay
centrifugal chillers with MicroTech ΙΙ control and for the majority of starters used on McQuay
centrifugal chillers.
Software Version
Software Code: WCFU3UU04C/D/E
Notations stating previous content are made when a new version changes a previous value or
statement.
Electric shock hazard. Can cause personal injury or equipment damage. This
equipment must be properly grounded. Connections to and service of the
WARNING
MicroTech control panel must be performed only by personnel that are
knowledgeable
in the operation of the equipment being controlled.
CAUTION
Static sensitive components. A static discharge while handling electronic circuit
boards can damage components. Discharge any static electrical charge
by touching the bare metal inside the control panel before performing
any service work. Never unplug any cables, circuit board terminal blocks,
or power plugs while power is applied to the panel.
NOTICE
This equipment generates, uses and can radiate radio frequency energy and,
if not installed and used in accordance with this instruction manual,
may cause interference to radio communications. Operation of this equipment in a
residential area is likely to cause harmful interference in which case the user
will be required to correct the interference at his own expense.
McQuay International Corporation disclaims any liability resulting
from any interference or for the correction thereof.
CAUTION
Do not install any non-McQuay authorized software or alter operating systems in
any unit microprocessor, including the interface panel. Failure to do so can cause
malfunction of the control system and possible equipment damage.
Temperature and Humidity Limits
The MicroTech ΙΙ controller is designed to operate within an ambient temperature range of 20°F to
130°F (-7°C to 54°C) with a maximum relative humidity of 95% (non-condensing).
OM Centrif Micro ΙΙ-5 3
Features of the Control Panel
• Control of leaving chilled water within a ±0.5°F (±0.3°C) tolerance. Systems with a large water
volume and relatively slow load changes can do better.
• Readout of the following temperature and pressure readings:
• Entering and leaving chilled water temperature
• Entering and leaving condenser water temperature
• Saturated evaporator refrigerant temperature and pressure
• Saturated condenser temperature and pressure
• Suction line, liquid line and discharge line temperatures - calculated superheat for discharge
and suction lines – calculated subcooling for liquid line
• Oil sump temperature - oil feed temperature and pressure
• Optional condenser heat recovery temperature
• Automatic control of primary and standby evaporator and condenser pumps.
• Control of up to 4 stages of cooling tower fans plus modulating bypass valve and/or tower fan
VFD.
• The controller will store and display key historic operating data for recall in a graphic format on
the screen. Data can also be exported for archival purposes via a USB port.
• Three levels of security protection against unauthorized changing of setpoints and other control
parameters.
• Warning and fault diagnostics to inform operators of warning and fault conditions in plain
language. Al1 warnings, problems and faults are time and date stamped so there is no guessing
of when the fault condition occurred. In addition, the operating conditions that existed just prior
to shutdown can be recalled to aid in isolating the cause of the problem.
• Twenty-five latest faults are displayed on the unit controller, eight can be displayed on the touch
screen. Data can be exported for archival purposes via a 3.5-inch floppy drive.
• Soft loading feature reduces electrical consumption and peak demand charges during loop
pulldown.
• Adjustable load pull-down rate reduces under-shoot during loop pulldown.
• Remote input signals for chilled water reset, demand limiting, unit enable.
• Manual control mode allows the service technician to command the unit to different operating
states. Useful for system checkout.
• BAS communication capability via LONM
BAS manufacturers.
• Service Test mode for troubleshooting controller hardware.
• Pressure transducers for direct reading of system pressures. Preemptive control of high motor
amps, low evaporator pressure conditions and high discharge temperature takes corrective action
prior to a fault trip.
ARK
, Modbus or BACnet standard protocols for
4 OM Centrif Micro ΙΙ-5
Digital
Outputs
General Description
General Description
The centrifugal MicroTech ΙΙ control system consists of microprocessor-based controllers that
provide all monitoring and control functions required for the controlled, efficient operation of the
chiller. The system consists of the following components:
• Operator Interface Touch Screen (OITS), one per unit-provides unit information and is the
primary setpoint input instrument. It has no control function.
• Unit Controller, one per chiller-controls unit functions and communicates with all other
controllers. It is the secondary location for setpoint input if the Interface Screen is inoperative.
It is located in a panel adjacent to the OITS.
• Compressor Controller for each compressor on a chiller-controls compressor functions and can
operate a compressor without the unit controller or Operator Interface Panel. The controller is
located in a panel adjacent to the compressor.
The operator can monitor all operating conditions by using the unit-mounted OITS. In addition to
providing all normal operating controls, the MicroTech II control system monitors equipment
protection devices on the unit and will take corrective action if the chiller is operating outside of
it’s normal design conditions. If a fault condition develops, the controller will shut the compressor
or entire unit down and activate an alarm output. Important operating conditions at the time an
alarm condition occurs are retained in the controller’s history log to aid in troubleshooting and
fault analysis.
The system is protected by a password scheme that only allows access by authorized personnel.
The operator must enter the password into the touch screen (or one of the controller's keypad)
before any setpoints can be altered.
NOTE: It is important to understand that the OITS is the operator interface device under normal
conditions. If, and only if, it is unavailable, the unit controller can be used to operate the chiller.
Furthermore, if the unit controller is unavailable, the compressor controller(s) will still operate the
compressors and try to maintain chilled water temperature. Certain data and operability will not
be available under either of these operating modes. If the MicroTech II controller controls the
tower and system pumps, they will have to run manually during this emergency situation.
Control Architecture
Figure 1, Major Control Components
OPERATOR
INTERFACE
TOUCH-SCREEN
Universal
Comm. Module
UNIT
BAS
CONTROLLER
OM Centrif Micro ΙΙ-5 5
pLAN
COMPRESSOR
CONTROLLER
SECOND
COMPRESSOR
CONTROLLER
D3 Starter
D3 Starter
Color Graphics
Touch-Screen Interface
View Data, Input Setpoints
Stores History
UNIT
Analog Inputs
Analog Outputs
Digital Inputs
COMPRESSOR
Analog Inputs
Analog Outputs
Digital Inputs
Digital Outputs
ALARM
Component Description
Operator Interface Touch Screen
The operator interface touch screen (OITS) is the primary
device by which commands and entries into the control system
are made. It also displays all controller data and information
on a series of graphic screens. A single OITS is used on both
single and dual compressor units.
The control panel contains a USB port that can be used for
loading information to and from the controll system.
The OITS panel is mounted on a moveable arm to allow
placement in a convenient position for the operator.
There is a screen-saver programed into the system. The screen is reactivated by touching it
anywhere.
Unit/Compressor Controller Description
Hardware Structure
The controller is fitted with a 16-bit microprocessor for running the control program. There are
terminals for connection to the controlled devices (for example: solenoid valves, tower fans,
pumps). The program and settings are saved permanently in FLASH memory, preventing data loss
in the event of power failure without requiring a back-up battery.
The controller connects to other controllers and the OITS via a local communications network (pLAN). It also has remote communication access capability for BAS interface.
Keypad
A 4 line by 20 character/line liquid crystal display and 6-button keypad is mounted on the unit and
compressor controllers. Its layout is shown below.
Key-to-Screen Pathway
Air Condit ioning
Red Fault
Light
MENU Key
<
VIEW
<
<
ARROW Keys
SET
ENTER Key
The four arrow keys (UP, DOWN, LEFT, RIGHT) have three modes of use.
• Scroll between data screens in the direction indicated by the arrows (default mode).
• Select a specific data screen in the menu matrix using dynamic labels on the right side of the
display such as ALARM, VIEW, etc (this mode is entered by pressing the MENU key). For
ease of use, a pathway connects the appropriate button to its respective label on the screen.
• Change field values in setpoint programming mode according to the following table:
LEFT key = Default RIGHT key = Cancel
UP key = Increase (+) DOWN key = Decrease (-)
These four programming functions are indicated by one-character abbreviation on the right
side of the display. This programming mode is entered by pressing the ENTER key.
6 OM Centrif Micro ΙΙ-5
Software
The same model controller is used as either a unit controller or a compressor controller. The
controller operation is determined by the setting of the controller pLAN address. These settings
are all made in the factory during unit testing. Settings are different with multiple chillers and will
be set by the startup technician.
The operating software is revised occasionally. The version residing in a given control is
identified on the screen at boot-up or can be viewed at any time by pressing the Right and Up
Arrows simultaneously. It is also displayed on the OITS SERVICE screen.
Unit Controller
There is one unit controller mounted on the chiller that serves both compressor units.
Unit and compressor on/off switches are mounted in the unit controller panel located adjacent to
the OITS panel. They are designated 1 for on and O for off. The compressor on/off switch should
only be used when an immediate stop is required since the normal shut down sequence is
bypassed.
The switch panel also has a circuit breaker that interrupts power to the cooling tower fans, valves
and evaporator and condenser pumps, if any of these are tied into the MicroTech II for control of
their operation. If these components operate independently from the chiller control, the breaker
has no effect.
There is an emergency shutdown switch located on the left outside of the panel that causes an
immediate shutdown of both compressors.
The unit controller's primary function is processing data relating to the entire chiller unit
operation, as compared to data relating to the compressor operation. The unit controller processes
information and sends data to other controllers and devices and relays information to the OITS for
graphic display. It has a 4x20 LCD display and keys for accessing data and changing setpoints.
The LCD can display most of the same information as the OITS and can operate the chiller
independently if the OITS is not available. Inputs and outputs are shown in the following tables.
Table 1, Unit Controller, Analog Inputs
# Des cription Signal Source Ran ge
Res et of Leaving Water T emperature 4-20 mA Current 0-(10 to 80°F)
B1
Entering E va po ra tor W ater Temperature NTC Thermi ster (10k @25°C) -58 to 212°F
B2
Entering Condens er Water T em perature NTC Thermi ster (10k @25°C) -58 to 212°F
B3
Leavi ng Condenser W at er Temp erat ure NTC Thermister (10k@2 5°C) -58 to 2 12 °F
B4
Liquid Line Refrigerant Tem perature NTC Thermi ster (10k @25°C) -58 to 212°F
B5
Dem and Lim it 4-20 mA Current 0-100 %RLA
B6
Evaporator W ate r Flow 4 to 20 mA Current 0 to 10, 00 0 gpm
B7
Con denser Water Flow 4 to 20 mA Current 0 to 10, 00 0 gpm
B8
Entering Heat Recovery Temp. NTC Therm ist er (10k@25°C) -58 to 212°F
B9
Leavi ng Heat Rec ov er y Temperatu re NTC Thermi ster (10k @25°C) -58 to 212°F
B10
Table 2, Unit Controller, Digital Inputs
# Description Signal Signal
Unit OFF Switch 0 VAC (Stop) 24 VAC (Auto)
ID1
Remote Start/Stop 0 VAC (Stop) 24 VAC (Start)
ID2
Mode Switch 0 VAC (Cool) 24 VAC (Ice or Heat)
ID3
OM Centrif Micro ΙΙ-5 7
Table 3, Unit Controller, Digital Outputs
# Description Load Output OFF Output ON
NO1
NO2
NO3
NO4
NO5
NO6
NO7
NO8
NO9
NO10
Primary Evaporator Water Pump Pump Contactor Pump OFF Pump ON
Standby Evaporator Water Pump Pump Contactor Pump OFF Pump ON
Primary Condenser Water Pump Pump Contactor Pump OFF Pump ON
Standby Condenser Water Pump Pump Contactor Pump OFF Pump ON
Tower Fan #1 Fan Contactor Fan OFF Fan ON
Tower Fan #2 Fan Contactor Fan OFF Fan ON
(unused)
Alarm Alarm Indicator Alarm OFF Alarm ON
Tower Fan #3 Fan Contactor Fan OFF Fan ON
Tower Fan #4 Fan Contactor Fan OFF Fan ON
Table 4, Unit Controller, Analog Outputs
# Description Output Signal Range
Cooling Tower Bypass Valve Position 0 to 10 VDC 0 to 100% Open
Y1
Cooling Tower VFD Speed 0 to 10 VDC 0 to 100%
Y2
Electronic Expansion Valve (EEV) 0 to 10 VDC 0 to 100% Open
Y3
Compressor Controller
The compressor controller's primary function is controlling and protecting the compressor. No
setpoint inputs are made with it. There is one compressor controller for each compressor on a dual
chiller unit. The compressor controller receives, processes, and sends data to other controllers and
devices and to the compressor starter or variable frequency drive (VFD). With some operator
intervention the compressor controller can operate the compressor(s) if the unit controller and/or
the operator interface touch screen are unavailable. Inputs and outputs are as follows:
Table 5, Compressor Controller, Analog Inputs
# Description Signal Source Range
Oil Sump Pressure 0.5 to 4.5 VDC 0 to 150 psi
B1
Oil Supply Pressure to Compressor 0.5 to 4.5 VDC 0 to 450 psi
B2
Evaporator Refrigerant Pressure 0.1 to 0.9 VDC 0 to 150 psi
B3
Oil Sump Temperature NTC Thermister (10k@25°C) -58 to 212°F
B4
Compressor Suction Temperature NTC Thermister (10k@25°C) -58 to 212°F
B5
Condenser Refrigerant Pressure 0.5 to 4.5 VDC 0 to 450 psi
B6
Compressor Discharge Temperature NTC Thermister (10k@25°C) -58 to 212°F
B7
Motor Current 0.5 to 4.5 VDC 0 to 125% RLA
B8
Oil Feed Temperature NTC Thermister (10k@25°C) -58 to 212°F
B9
Leaving Evaporator Water Temperature NTC Thermister (10k@25°C) -58 to 212°F
B10
Table 6, Compressor Controller, Digital Inputs
# Description Signal Signal
Manual Off 0 VAC (Off) 24 VAC (Auto)
ID1
Mech High Pressure 0 VAC (High Pressure ) 24 VAC (OK)
ID2
Motor High Temperature 0 VAC (High Temp) 24 VAC (OK)
ID3
Vanes Closed Switch 0 VAC (Not Closed) 24 VAC (Closed)
ID4
Starter Transition 0 VAC (No Transition) 24 VAC (Transition)
ID5
Starter Fault 0 VAC (Fault) 24 VAC (No Fault)
ID6
Evap Flow 0 VAC (N0 Flow) 24 VAC (Flow)
ID7
Cond Flow 0 VAC (N0 Flow) 24 VAC (Flow)
ID8
Vanes Open Switch 0 VAC (Not Open) 24 VAC (Open)
ID9
8 OM Centrif Micro ΙΙ-5
Table 7, Compressor Controller, Analog Outputs
# Description Output Signal Range
Compressor VFD Speed 0 to 10 VDC 0 to 100%
Y1
Open
Y2
Oil Cooler 0 to 10 VDC 0 to 100%
Y3
Hot Gas Bypass 0 to 10 VDC 0 to 100%
Y4
Table 8, Compressor Controller, Digital Outputs
# Description Load Output OFF Output ON
NO1
NO2
NO3
NO4
NO5
NO6
NO7
NO/C8
Motor Control Relay Starter Compressor OFF Compressor ON
Hot Gas Bypass Solenoid No Bypass Bypass
Liquid Injection Solenoid No Injection Injection
Oil Pump Pump Contactor Pump OFF Pump ON
Oil Sump Heater Heater Heater OFF Heater ON
Oil Cooler Solenoid Cooling OFF Cooling ON
Vane Pulse Solenoid Hold Move Vanes
Load/Unload Solenoid Unload Load
Guardister Board
The Guardister board monitors the motor winding temperature through embedded Guardistor
temperature sensors in the motor. If the motor temperature rises to an unsafe level, the board will
signal the compressor controller and the compressor will shut down.
Signal Converter Board
On medium voltage starters, the AC current signal generated by the starter is converted by the
separate signal board into a 0-5 VDC signal that is directly proportional to the compressor motor
amp draw. The amp draw signal is sent to the compressor controller.
On low voltage starters, the D3 starter feature eliminates the need for this board.
Transducer Converter Board
The transducer converter board converts the pressure transducer signal to the correct voltage signal
and relates it to the compressor controller.
PLAN Isolator
Provides voltage isolation on the pLAN (RS485) when interconnecting chillers on the pLAN.
OM Centrif Micro ΙΙ-5 9
Field Wiring Diagram
NOTES for Following Wiring Diagram
1. Compressor motor starters are either factory mounted and wired, or shipped separate for
field mounting and wiring. If provided by others, starters must comply with McQuay
specification 7359999 Rev 29 available on mcquay.com. All line and load side power
conductors must be copper.
2. If starters are freestanding, then field wiring between the starter and the control panel is
required. Minimum wire size for 115 Vac is 12 GA for a maximum length of 50 feet. If
greater than 50 feet, refer to McQuay for recommended wire size minimum. Wire size for 24
Vac is 18 GA. All wiring to be installed as NEC Class 1 wiring system. All 24 Vac wiring must
be run in separate conduit from 115 Vac wiring. Main power wiring between starter and
motor terminal is factory-installed when units are supplied with unit-mounted starters. Wiring
of free-standing starter must be wired in accordance with NEC and connection to compressor
motor terminals must be made with copper wire and copper lugs only.
3. For optional sensor wiring, see unit control diagram. It is recommended that dc wires be run
separately from 115 Vac wiring.
4. Customer furnished 24 or 120 Vac power for alarm relay coil can be connected between
UTB1 terminals 84 power and 51 neutral of the control panel. For normally open contacts,
wire between 82 & 81. For normally closed contacts, wire between 83 & 81. The alarm is
operator programmable. The maximum rating of the alarm relay coil is 25 VA.
5. Remote on/off control of unit can be accomplished by installing a set of dry contacts between
terminals 70 and 54.
6. Evaporator and condenser paddle type flow switches or water pressure differential switches
are required and must be wired as shown. WDC dual compressor units require DPDT
switches. If field supplied pressure differential switches are used then these must be
installed across the vessel and not the pump.
7. Customer supplied 115 Vac, 20 amp power for optional evaporator and condenser water
pump control power and tower fans is supplied to unit control terminals (UTBI) 85 power / 86
neutral, PE equipment ground.
8. Optional customer supplied 115 Vac, 25 VA maximum coil rated chilled water pump relay (EP
1 & 2) can be wired as shown. This option will cycle the chilled water pump in response to
building load.
9. The condenser water pump must cycle with the unit. A customer supplied 115 Vac 25 VA
maximum coil rated condenser water pump relay (CP1 & 2) is to be wired as shown.
10. Optional customer supplied 115 Vac, 25 VA maximum coil rated cooling tower fan relays (CL C4) can be wired as shown. This option will cycle the cooling tower fans in order to maintain
unit head pressure.
11. Auxiliary 24 Vac rated contacts in both the chilled water and condenser water pump starters
must be wired as shown.
12. For VFD, Wye-Delta, and solid state starters connected to six (6) terminal motors. The
conductors between the starter and motor carry phase current and selection shall be based
on 58 percent of the motor rated load amperes (RLA). Wiring of free-standing starter must be
in accordance with the NEC and connection to the compressor motor terminals shall be
made with copper wire and copper lugs only. Main power wiring between the starter and
motor terminals is factory-installed when chillers are supplied with unit-mounted starters.
13. Optional Protocol Selectability BAS interfaces. The locations and interconnection
requirements for the various standard protocols are found in their respective installation
manuals, obtainable from the local McQuay sales office and also shipped with each unit:
Modbus IM 743 LONW
14. The “Full Metering” or “Amps Only Metering” option will require some field wiring when freestanding starters are used. Wiring will depend on chiller and starter type. Consult the local
McQuay sales office for information on specific selections.
ORKS
IM 735 BACnet IM 906
10 OM Centrif Micro ΙΙ-5
CP2
CP1
H
O
A
C
25
11
11
12
22
11
12
22
NOTE 2
NOTE 2
H
O
A
C
H
O
A
C
H
O
A
C
T3-S
PE
L1
L2
24
23(5A)
84
EP2
EP1
L1L2L3
T4T5T6
T1T2T3
T4T5T6T1T2
T3
T1T2T3
T3T1T2
V
W
T4T3T5T1T6
T2
T1T2T3
T4T3T5T1T6
T2
53
71
71
52
1-10 VDC
1-10 VDC
MICROTECH CONTROL
MICROTECH
- FOR DC VOLTAGE AND 4-20 MA
- FOR DETAILS OF CONTROL REFER
Figure 2, Field Wiring Diagram
BOX TERMINALS
(115V) (24V)
PE
85
86
80
74
86
86
* COOLING
TOWER
FOURTH
STAGE
STARTER
* NOTE 10
H
O
A
GND
POWER
* NOTE 7
NEUTRAL
C4
54
70
55
* COOLING
TOWER
THIRD
STAGE
STARTER
* COOLING
TOWER
SECONDH
STAGE
STARTER
* COOLING
TOWER
FIRST
STAGE
STARTER
* NOTE 10
H
O
A
* NOTE 10
H
O
A
* NOTE 10
H
O
A
COOLING TOWER
BYPASS VALVE
COOLING TOWER VFD
C3
C2
C1
COMMON
POWER
79
73
78
77
76
75
EF
CF
81
82(NO)
83(NC)
A
ALARM RELAY
(NOTE 4)
COMPRESSOR
MOTOR
STARTER
(NOTE 1)
-LOAD-
NOTE: See notes on previous page.
OM Centrif Micro ΙΙ-5 11
COMPRESSOR CONT ROL
GND
CP1
CP2
24(5)
25
1
2
3
4
6
BOX TERMINALS
CTB1
115 VAC
23
1
2
3
4
LESS
THAN
30V
OR
24VAC
STARTER LOAD SIDE TERMINBALS
STARTER LOAD SIDE TERMINBALS
STARTER LOAD SIDE TERMINBALS
STARTER LOAD SIDE TERMINBALS
VFD
U
COMPRESSOR TERMINALS
WYE-DELTA
COMPRESSOR TERMINALS
SOLID STATE
COMPRESSOR TERMINALS
MEDIUM AND HIGH VOLTAGE
COMPRESSOR TERMINALS
CONNECTIONS (SEE NOTE 3)
TO UNIT CONTROL SCHEMATIC
330342101
- COMPRESSOR CONTROL
SCHEMATIC 330342201
- LEGEND: 330343001
* FIELD SUPPLIED ITEM
NOTE 12
330387901-0A
Dual/Multi-Chiller Operation
Multiple Chiller Setup
Single compressor chillers WSC and dual compressor chillers WDC and WCC have their main
control components factory wired to an internal pLAN network so that they can communicate
with each other, within the chiller itself.
On multi-chiller applications, up to four chillers, either single, or dual compressor, can be
interconnected by this internal pLAN. All that is required is simple field RS485 interconnecting
wiring, the addition of accessory communication isolation board(s) 485OPDR (McQuay P/N
330276202), and some MicroTech II control settings (see special WCC instructions at the end of
this section). The 485OPDR isolation board can be purchased with the unit or separately, during
or after chiller installation. The number of chillers minus one boards are required.
pLAN Setup
Interconnecting MicroTech II pLAN RS485 wiring should be installed by the installing contractor
prior to start-up. The McQuay start-up technician will check the connections and make the
necessary set point settings.
1. With no pLAN connections between chillers, disconnect chiller control power and set the
pLAN address as shown in Table 9.
2. With all manual switches off, turn on control power to each chiller and set each OITS
address (see Note 2 on page 14).
3. Verify correct nodes on each OITS Service Screen.
4. Connect chillers together (pLAN, RS485 wiring) as shown in Figure 3. The first chiller in
the connection can be designated as Chiller A. The isolation board is attached to the DIN
rail adjacent to the Chiller A unit controller. The isolation board has a pigtail that is
plugged into J10 on the controller. Most chillers will already have a universal
communication module (UCM) that connects the controller to the touchscreen already
plugged onto J10. If this is the case, plug the isolation module pigtail into the empty RJ11
pLAN port on the UCM. This is equivalent to plugging into the unit controller directly.
Next, interconnecting wiring is needed between Chiller A and Chiller B.
Two Chillers: If only two chillers are to be connected, Belden M9841 (RS 485 Spec Cable) is
wired from the 485OPDR isolation board (terminals A, B, and C) on Chiller A to the J11 port
on the unit controller of Chiller B. At J11, the shield connects to GND, the blue/white wire to
the (+) connection, and the white/blue to the (-) connection.
Note that Chiller B does not have an isolation board. The last chiller (B in this case) to be
connected does not need an isolation board.
Three or Four Chillers: If three or more chillers are to be connected, the interconnecting
wiring is still made to Chiller B’s J11 port. The second chiller (Chiller B) must have a
485OPDR isolator board that will be plugged into Chiller B’s UCM pLAN port. Chiller B will
look like Chiller A.
The wiring from Chiller B to Chiller C will be the same as A to B. That is, Belden cable
connects from A, B, and C on B’s 485OPDR board to chiller C’s L11 port. Chiller C has no
485OPDR isolation board.
The procedure is repeated to the fourth chiller if four chillers are interconnected.
5. Verify correct nodes on each OITS Service Screen.
12 OM Centrif Micro ΙΙ-5
Chiller A
UCM
J10
J11
BLU/WHT
WHT/BLU
(+)
(-)
UNIT CONTROL
UNIT CONTROL
P
Figure 3, Communication Wiring
485
OPDR
C
P
UCM
A
B
BLU/WHT
WHT/BLU
SHIELD
PIGTAIL
P
485
OPDR
AB
C
SHIELD
Chiller B
P
J10
PORT
UNIT CONTROL
J11 PORT
(+) (-)
J11 Port
Chiller C
NOTE: A fourth chiller, Chiller D would be connected to chiller C same as chiller C to chiller B.
OM Centrif Micro ΙΙ-5 13
Table 9, pLAN address and DIP Switch Settings for Controllers Using pLAN.
Chiller
(1)
A
B
C
D
Comp 1
Controller
Dec. 1 2 5 6 7 8
Bin. 100000 010000 101000 011000 N/A 000100
Dec. 9 10 13 14 15 16
Bin. 100100 010100 101100 011100 N/A 000010
Dec. 17 18 21 22 23 24
Bin. 100010 010010 101010 011010 N/A 000110
Dec. 25 26 29 30 31 32
Bin. 100110 010110 101110 011110 N/A 000001
Comp 2
Controller
Unit
Controller
Reserved Operator
Interface (2)
Reserved
NOTES for pLAN multi-chiller communication setup:
1. Up to four single or dual compressors can be interconnected.
2. Operator Interface Touch Screen (OITS) setting is not a DIP switch setting. The OITS address is selected
by selecting the ‘service’ set screen. Then, with the Technician level password active, select the ‘pLAN
Comm’ button. Buttons A(7), B(15), C(23), D(31) will appear in the middle of the screen, then select the
letters for the OITS address for the chiller that it is on. Then close the screen. Note that A is the default
setting from the factory.
3. For the pCo2 controller, the pLAN address can be confirmed by viewing the DIP switch positions and
comparing to
(see picture below)
Table 9
(Bin. rows). Up is ‘On’, indicated by ‘1’. Down is ‘Off’, indicated by ‘0’.Operation.
4. For the pCo3 controller, there are no DIP switches as shown below.
14 OM Centrif Micro ΙΙ-5
The pLAN address can only be confirmed as follows:
A) Disconnect pLAN (connectors J10 and J11) from all pCo2 and pCo3 controller(s).
B) Cycle power to the controller and then hold down both the Left Arrow (alarm) and the Up Arrow keys
simultaneously as the controller completes its Self-Test routine. The controller will then show you the
present pLAN address of the controller. Verify that the pLAN address matches the desired address from the
above table (Dec. rows). If the address needs to be changed, follow the instructions displayed on the pCo3
controller’s LCD display. Press enter when done.
C) Only after all controllers pLAN addresses have been set/confirmed can the pLAN network connectors be
re-connected.
MicroTech II Operator Interface Touch Screen (OITS) Settings
Settings for any type of linked multiple compressor operation must be made to the MicroTech II controller.
Settings on a dual compressor unit are made in the factory prior to shipment, but must be verified in the field
before startup. Settings for multiple chiller installations are set in the field on the Operator Interface Touch
Screen as follows:
Maximum Compressors ON – SETPOINTS - MODES screen, Selection #10 ‘= 2 for a dual, 4 for 2 duals, 3 for
three separate, single compressor chillers, etc. If all compressors in the system are to be available as normal
running compressors, then the value entered in #10 should equal the total number of compressors. If any
compressors are for standby and not operated in normal rotation, they should not be included in the compressor
count in Selection #10. The Max Comp ON setting can be made in only one touchscreen, the system will observe
the highest number set on all chillers-it is a global setting.
Sequence and Staging – SETPOINTS - MODES screen, Selection #12 & #14; #11 & #13. Sequence sets the
sequence in which compressors will start. Setting one or more compressors to “1” evokes the automatic lead/lag
feature and is the normal setting. The compressor with least starts will start first and the compressor with
maximum hours will stop first, and so on. Units with higher numbers will stage on in sequence.
The Modes setpoints will do several different types of operation (Normal, Efficiency, Standby, etc.) as described
in the operating manual.
The same Modes setting must be replicated on each chiller in the system.
Nominal Capacity – SETPOINTS - MOTOR screen, Selection #14. The setting is the compressor design tons.
Compressors on dual units are always of equal capacity.
Operating Sequence
For multiple-chiller, parallel operation, the MicroTech II controllers are tied together by a pLAN network and
stage and control compressor loading among the chillers. Each compressor, single or dual compressor chiller, will
stage on or off depending on the sequence number programmed into it. For example, if all are set to “1”, the
automatic lead/lag will be in effect.
When chiller #1 is fully loaded, the leaving chilled water temperature will rise slightly. When the Delta-T above
setpoint reaches the Staging Delta-T, the next chiller scheduled to start will receive a start signal and start its
pumps if they are set up to be controlled by the MicroTech controller. This procedure is repeated until all chillers
are running. The compressors will load-balance themselves.
If any of the chillers in the group are dual compressor, they will stage and load according to the staging
instructions.
WCC Settings
Since the WCC is essentially two chillers combined into one counterflow, single pass, dual-circuit chiller, the
compressor on the downstream circuit (leaving chilled water) must always be designated as the Stage 1
compressor-first on, last off.
OM Centrif Micro ΙΙ-5 15
Ice Mode Operation
If available modes is set to ICE only the chiller will start (at start delta t) and run the Ice cycle described as
follows: The chiller will ignore softload and all Demand limits and rapidly load up to Maximum Amps setpoint.
The compressor(s) do not unload. If the chiller has dual compressors (WDC), the lead compressor will unload
approx. one minute after starting to allow the second compressor to start (at reduced lift pressure), then both
compressors will load to Max Amps. When both compressors have achieved the Ice LWT setpoint both
compressors will shutdown. The Evap pump will continue to run and if the Evap LWT climbs to the Start Delta
T the chiller will restart this process.
The following failsafe feature has been incorporated into the code. If one compressor reaches the Stop Delta
Temp (below the setpoint) before the other compressor has achieved the setpoint, both compressors will
shutdown.
If available modes is set to Cool/Ice with Ice mode operation selected, the chiller will run one ICE cycle and
shutdown (compressors and pumps) no automatic restart allowed. When the operator switches the chiller from
Ice to Cool mode the chiller will reset for operation. Changing modes can be done through the OITS, switches
or BAS interface, which ever is selected.
Some sort of migration freeze protection needs to be in place when the chiller terminates ice mode. This is
usually sensed by the liquid line sensor and forces a condenser pump to circulate to prevent freeze up of the
condenser.
Operator Interface Touch Screen
Navigation
The home screen shown in VIEW screen on page 18 is usually left on (there is a screen-saver built in that is
reactivated by touching the screen anywhere). This VIEW screen contains the STOP and AUTO buttons used to
start and stop the unit when in Local control. Other groups of screens can be accessed from the Home screen by
pressing one of three buttons on the bottom of the screen; HISTORY, VIEW, SET.
• HISTORY will go to the last history screens viewed and can toggle between the two history screens.
• Trend History
• Alarm History
• VIEW will go to the next View screen and other sub-View screens used to look in detail at settings and the
operation of the chiller. Pressing View from any other screen will return to the Home View screen.
• SET will go to a series of screens used to set setpoints.
The figure on the following page illustrates the arrangement of the various screens available on the OITS. A few
minutes practice on an actual OITS should provide a comfortable level of confidence in navigating through the
screens.
16 OM Centrif Micro ΙΙ-5
ALARM
ALARMS
VALVE (TOWER)
HISTORY
CHILLER
POWER
Figure 4, OTIS Screen Layout
SET SCREENS
HOME
SCREEN
SET
PRESS VIEW
SETPOINTS
EACH GROUP OF
SETPOINTS HAVE
SETTING AND RANGE
EXPLAINED ON SCREEN
PRESS SET
SEE FIGURE 12
TOWER (FANS)
TIMERS
MOTOR
MODES
HOME
SCREEN
HISTORY
TREND
OR
HISTORY
PRESS HISTORYPRESS VIEW
LABELED BAR GRAPHS
BAR GRAPHS
VIEW SCREENS
PRESS VIEW
PRESS MENU
WATER
HOME
SCREEN
VIEW
DETAIL
VIEW
SCREEN
MENU
SEE FIGURE 4
PRESS VIEW
SEE FIGURE 5
PRESS VIEW
SEE FIGURE 7
COMPRESSOR STATE
COMPRESSOR I/O
UNIT I/O
SEE FIGURE 10
SEE FIGURE 8
SEE FIGURE 9
Pressing VIEW from any sub-menu will toggle back to the home screen.
Pressing MENU when in any sub-menu will return to the view screen.
Pressing SET or HISTORY will go to these groups of menus.
OM Centrif Micro ΙΙ-5 17
EVAPORATOR
CONDENSER
Screen Descriptions
VIEW Screens
View screens are used for looking at unit status and conditions.
Figure 5, Home View Screen, Dual Compressor Unit
Home View Screen
The Home View Screen shows the basic condition of the chiller and is the screen that is normally
left on. Dual compressor (WDC, WCC) units, as shown, will show two compressors and the status
of both. Single Compressor units (WSC, TSC) will show only the one compressor. The pressures
and temperatures shown are common to the unit and correct for both single and dual compressor
chillers. Superimposed on a chiller schematic is:
Information
• Active chilled water setpoint
• Entering and leaving chilled water temperatures
• Entering and leaving condenser water temperatures
• Percent motor amps
• UNIT STATUS is MODE followed by STATE followed by the SOURCE that is the device or
signal that created the STATE. The possible combinations are in the following table:
18 OM Centrif Micro ΙΙ-5
Table 10, UNIT STATUS Combinations
MODE STATE SOURCE
COOL OFF Manual Switch
ICE SHUTDOW N (Note 1) Remote Switch
HEAT AUTO Local
BAS Network
TEST
Note: Shutdown is the state of shutting down; vane close, postlube, etc.
• COMPRESSOR STATUS is MODE followed by STATE followed by the SOURCE that is the
device or signal that created the STATE. The possible combinations are in the following table
Table 11, COMPRESSOR STATUS Possibilities
Complete STATUS Text
(in priority sequence)
OFF Manual Switch
OFF Compressor Alarm
OFF Unit State
OFF Evap Flow/Re-circulate
OFF Low Oil Sump Temp
OFF Start to Start Timer=xxx
OFF Stop to Start Timer=xxx
OFF Staging (Next ON)
OFF Awaiting Load
PRELUBE Vanes Open
PRELUBE Timer=xxx
PRELUBE Condenser Flow
RUN Unload Vanes-Max Amps
RUN Hold Vanes-Max Amps
RUN Manual Vanes & Speed
RUN Load Vanes-Manual Speed
RUN Hold Vanes-Manual Speed
RUN Unload Vanes-Manual Speed
RUN Load Speed-Manual Vanes
RUN Hold Speed-Manual Vanes
RUN Unload Speed-Manual Vanes
RUN Unload Vanes-Lag Start
RUN Hold Vanes-Evap Press
RUN Unload Vanes-Evap Press
RUN Unload Vanes-Soft Load
RUN Hold Vanes-Soft Load
RUN Load Vanes-Disch Temp
RUN Hold Vanes-Pull-down Rate
RUN Unload Vanes-Demand Limit
RUN Hold Vanes-Min Amps
RUN Load Vanes
RUN Hold Vanes
RUN Unload Vanes
SHUTDOWN Unload Unloading during the shutdown sequence
POSTLUBE Timer=xxx Postlube timer on
POSTLUBE Motor Current High Compressor motor running during the shutdown mode. It should be off.
Used for service purposes. "T" password required. Operated from
Reason for the compressor being off.
Current state of the Prelube sequence
Overrides water temperature command
Overrides water temperature command
Notes
compressor controller
Normal operation
NOTES:
1. Timer countdown values will be shown where “(xxx)” is shown below.
2. For a VFD equipped compressor, “Vanes” or “Speed” is shown in the RUN state to indicate if the capacity is
controlled by speed from the VFD or by vane control.
3. When the compressor is in the START state (oil pump started but still waiting for oil pressure), “PRELUBE –
Vanes Open” or “PRELUBE – Timer=(xxx)” is shown as appropriate.
OM Centrif Micro ΙΙ-5 19
Action Buttons for:
• AUTO and STOP buttons, normal start (AUTO) and STOP button activates the normal start
and shutdown sequence. These buttons are only active when the control is in the "Local
Control" mode. This eliminates the possibility of inadvertently shutting off the unit locally
when it is under control of a remote signal such as a BAS.
• HISTORY, toggles between the Trend History screen and the Alarm History screen.
• SET, toggles between the Set Points screen that are used for changing setpoints and the
Service screen.
Returning
Pressing the VIEW button from any screen will return to the HOME VIEW screen.
Figure 6, Detail View Screen
Pressing the VIEW button on the bottom of the Home View screen (Figure 5) accesses the Detail View
Screen shown above. This screen gives additional information on the refrigerant pressures and
temperatures and lubricant data.
Pressing the STATE button will bring up a display of the compressor state as described in Figure 9 on
page 22.
Pressing the I/O button displays the status of the compressor inputs and outputs as described on page 22.
Dual compressor units will have a COMP button that will toggle between the two compressors' data,
allowing the STATE and I/O detail screens to be viewed for either compressor.
Pressing the UNIT I/O button displays the unit inputs and outputs as described in Figure 11 on page 1.
20 OM Centrif Micro ΙΙ-5
Figure 7, Expanded Power View Screen
Pressing the EVAP or COND button will give detailed information on the
evaporator or condenser pressures and temperatures.
Pressing the MENU button on the bottom of the screen will go to a menu
(see Figure 8) from which the above listed screens can also be accessed.
Pressing the POWER button will access a screen showing power data for
the unit. The ability to view the unit’s electrical performance and to set
starter setpoints on the interface screen is an optional extra available at
the time of purchase. If the option is supplied on the unit, a “POWER”
button will be visible on the upper left side of the VIEW screen. Pressing
the button will open the screen shown in Figure 7.
The screen shown to the right will be superimposed on the right
side of the VIEW screen shown in Figure 6 when the optional
“Full Meter Display” is included with the unit. This screen will
remain visible until another display button; such as STATE, I/O,
etc is pressed.
If this option is not included, Percent Unit RLA on the HOME
VIEW screen displays the current percent of the unit rated loads
amps.
Figure 8, View Menu
This View Menu is accessed by
pressing the MENU button from
the Detail View Screen. The
menu screen is used to access
other screens containing various
data. A screen with unit
temperatures and pressures is
shown on a BAR CHART
SCREEN (see Figure 12 on page
23). This screen is accessed by
pressing LABELED BAR
GRAPHS. Pressing BAR
GRAPHS will access the same
screen, but without the labels
There is more data available to
view and it is accessed through
the buttons on the right of the
screen. It is segregated by
general topics that are selfexplanatory. These buttons are also repeated on the Detail View Screen as previously noted. If the starter
display option has been included, a POWER button will be located above the STATE button.
OM Centrif Micro ΙΙ-5 21
Figure 9, View Compressor State Screen
For example, pressing the Compressor-State button will yield the
following screen superimposed on the right side of the Detail
View Screen. The Compressor State screen is basically a
compilation of the events that the chiller sequences through at
startup. A green light (light gray in the figure) indicates that a
particular sequence requirement has been satisfied. It is
recommended that this screen be viewed during the start up
sequence. One can see the requirements light up as they are met
and quickly see why a non-start may have occurred. For example,
The Evap Flow OK will light when the evaporator flow switch is
closed by flow, Oil Sump Temp OK will light if (or when) the oil
temperature is above the Startup Temperature Setpoint, both
timers must be timed out, Oil Pressure OK will light when
sufficient oil pressure is achieved, etc.
The bottom three sections (from "RUN" down) are in effect
during the shut down process. The compressor is officially off
when the Postlube Timer is Done. The sequence transitions back
to OFF at this point and the OFF light will be illuminated.
Figure 10, View Compressor Input/Output Status
Pressing the Compressor I/O button on the
VIEW MENU screen will access the screen
shown to the right. It is superimposed on the
right side of the Detail View Screen. It gives
the status of the compressor digital inputs and
analog and digital outputs. Many of these I/Os
also appear in the Compressor State screen
since they are part of the start up sequence and
define the compressor state at any given time.
Dual compressor units will have two of any
compressor screen.
A COMP button will appear in the lower lefthand corner of the Detail View Screen (Figure
6 on page 20) on dual compressor WDC units.
This button will toggle compressor data from
#1 compressor to #2 compressor.
22 OM Centrif Micro ΙΙ-5
Figure 12, Bar Chart with Labels
The bar chart screen is accessed from the MENU screen (Figure 8) by selecting LABELED BAR
GRAPHS. Selecting BAR CHARTS will access the same graph, but without the labels.
SET Screens
The set screens on the Interface Panel are used to input the many setpoints associated with equipment
of this type. MicroTech II provides an extremely simple method for accomplishing this. (NOTE: If
the Interface Panel is unavailable, the unit controller can be used to change setpoints.) Appropriate
setpoints are factory set and checked by McQuayService or Factory Authorized Service Company
during commissioning. However, adjustments and changes are often required to meet job conditions.
Certain settings involving pumps and tower operation are field set.
Pressing the SET button found on almost every screen accesses the last SET screen used or the
SERVICE screen, whichever of the two was used last.
When in any SET screen, pressing the SET button again will toggle to the SERVICE screen shown on
page 37.
OM Centrif Micro ΙΙ-5 23
Groups
Buttons
Buttons
Figure 13, A Typical SETPOINT Screen
Setpoint
Description
Numeric
Keypad
Action
Setpoints
Setpoint
Selection
Setpoint
Initiate
Change
Button
The above figure shows the SETPOINT screen with WATER setpoints selected. The various setpoint
groups are in a column on the right side of the screen. Each button contains a number of setpoints
grouped together by similar content. The WATER button (as shown) contains various setpoints
relating to water temperatures. If either starter display option has been included, an additional button,
STARTER, will be located above the TIMERS button.
NOTE: Some setpoints that do not apply to a particular application may still be listed on the screen.
They will be inactive and can be ignored. For example, of setpoints 1, 2, and 3 above, only one will
be active depending on the unit mode selected in the MODE setpoints, 10 and 11 only for Templifiers.
The numbered buttons in the second from right column are pressed to select a particular setpoint. The
selected setpoint will appear in blue on the screen and a description of it (with the range of available
settings) will appear in the upper left-hand box.
Procedure for Changing a Setpoint
A list of setpoints, their default value, their available setting range, and password authority are in
Table 23 on page 51 for the unit and Table 24 on page 63 for the compressor.
1. Press the applicable Setpoint Group Button. A complete explanation of setpoint content of
each group follows this section.
2. Select the desired setpoint by pressing the numbered button.
3. Press the CHANGE button indicating that you wish to change a setpoint value. The
KEYBOARD screen will be turned on automatically for entering the password.
• O = Operator level password is 100
• M = Manager level password is 2001
• T = Technician level password is reserved for authorized technicians
24 OM Centrif Micro ΙΙ-5
4. Press the appropriate numbers in the numeric keyboard to enter the password. There is a small
delay between pressing the keypad and recording the entry. Be sure that an asterisk appears in
the window before pressing the next number. Press ENTER to return to the SETPOINT
screen. The password will remain open for 15 minute after initiation and does not need to be
re-entered during this period.
5. Press CHANGE again. The right side of the screen will turn blue (inactive).
6. The numeric keypad and action buttons in the lower left-hand corner of the screen will be
activated (the background will turn green). Setpoints with numeric values can be changed in
two ways:
• Select the desired value by pressing the numbered buttons. Press ENTER to enter the
value or CANCEL to cancel the transaction.
• Press the UP or DOWN button to increase or decrease the value displayed. Press ENTER
to enter the value or CANCEL to cancel the transaction.
Some setpoints are text rather than numeric values. For example, LWT Reset Type can be
"None" or "4-20 ma". The selection can be made by toggling between choices using the
UP or Down button. If dashed lines appear in the setpoint window, it indicates that you
have toggled too far and need to reverse direction. Press ENTER to enter the choice or
CANCEL to cancel the transaction.
Once CHANGE is selected, the CANCEL or ENTER buttons must be pressed before
another setpoint can be selected.
7. Additional setpoints can be changed by selecting another setpoint on the screen or by selecting
an entirely new group of setpoints.
Explanation of Setpoints
Each of the seven setpoint group of screens are detailed in the following section. In many cases
the setpoint content is obvious and no explanation is included.
1. TIMERS, for setting timers such as start-to-start, prelube, postlube, etc.
2. ALARMS, for setting the limit and shutdown alarms.
3. VALVE, sets the parameters for operation of an optional field installed tower bypass valve.
4. TOWER, selects the method of controlling the cooling tower and sets the parameters for fan
staging/VFD.
5. MOTOR, selects motor related setpoints such as amp limits, VFD settings, etc. Also has
maximum and minimum rate of change of chilled water temperature.
6. MODES, selects various modes of operation such as control source, multiple compressor
staging, pump staging, BAS protocol, etc.
7. WATER, leaving water temperature setpoint, start and stop delta-T, resets, etc.
OM Centrif Micro ΙΙ-5 25
STARTER SETPOINTS
Figure 14, Optional Starter Setpoint Screen
Table 12, Starter Setpoints
Description No. Default Range
Ground Fault Current Trip 8 1 % 1 to 100% RLA M
Ground Fault Enable 7 OFF On or OFF M Turns the ground fault option on or off
Maximum Current Unbalance 6 10% 5% to 40% T
Starter Ramp Time 5 15 sec. 0 to 30 seconds T
Maximum Starter Current 4 600%
Initial Starter Current 3 100%
Rated load Amps 2 1 A
Full Load Amps 1 1 A
100% to 800%
of FLA (SP1)
50% to 400% of
FLA (SP1)
Factory set at
design conditions
Factory set to
motor max current
rating
Password
Sets the value for ground current above
which the compressor will be shut down
Sets the value for current unbalance above
which the compressor will be shut down
Sets the time the starter ramps up the
motor current
Sets the maximum current when the
T
compressor starts
Sets the initial current when the
T
compressor starts
Value that gives the 100% RLA value and
T
used for motor protection
T Value used to compute SP3 and SP4
Comments
The setpoints shown above are for solid state starters. Other types of starters will have slightly different
setpoints. Units without the starter display option will have their setpoints set in the starter itself.
26 OM Centrif Micro ΙΙ-5
TIMERS Setpoint
Figure 15, TIMERS Setpoint Screen
Table 13, TIMER Setpoints
Description No. Default Range
Postlube Timer 8 30 sec 10 to 240 sec T Time for postlube before compressor can stop
Unload Timer 7 30 sec 10 to 240 sec T Time compressor will unload before going to postlube
Full Load Timer 6 300 sec 0 to 999 sec T Time compressor must load for full open vanes
Interlock 5 WMC only
Prelube Timer 4 30 sec 10 to 240 sec T Time compressor must prelube before starting
Stop-Start 3 3 min 3 to 20 min M
Start-Start 2 40 min 15 to 60 min M
Evap
Recirculate
1 30 sec
15 sec to 5
min
Pass-
word
M
Comments
Time from when compressor stops to when it can
restart
Time from when compressor starts to when it can start
again
Time that evaporator pump must run before
compressor start
OM Centrif Micro ΙΙ-5 27
ALARMS Setpoint
Figure 16, ALARMS Setpoint Screen
Table 14, ALARM Setpoints
Description No. Default Range
Low Net Oil Pressure 14 50 psi 50 to 90 psi T Min net pressure (feed minus sump)
Low Oil Delta Temperature 13
High Oil Feed Temperature 12
Condenser Freeze 11
Evaporator Freeze 10
Motor Current Threshold 9 10% 3% to 99% T Min %RLA to consider motor off
Surge Slope Limit 8 20 1 – 99 deg F/min. T Surge slope temp that triggers alarm
Surge Temperature Limit 7 6 2 – 25 deg F T See screen above
High Discharge Temp-
Shutdown
High Discharge Temp-Load 5
High Condenser Pressure 4 140 psi 120 to 290 psi T
Low Evap Pressure, Stop 3 29 psi 10 to 45 psi T Min evap pressure – stop compressor
Low Evap Pressure-Unload 2 31 psi 20 to 45 psi T Min evap pressure – unload compressor
Low Evap Pressure-Inhibit 1 33 psi 20 to 45 psi T Min evap pressure – inhibit loading
40 °F 20 to 80 °F
140 °F 120 to 240 °F
34.0 °F -9.0 to 45.0 °F
34.0 °F -9.0 to 45.0 °F
6
190 °F 120 to 240 °F
170 °F 120 to 240 °F
Pass-
word
T Min Delta-T (sat evap minus oil temp)
T Max oil temperature
T Minimum cond. sat. temp. to start pump
T Minimum evap. sat. temp. to start pump
Max discharge gas temp, stop
T
compressor
T Max discharge gas temp – load comp
Max discharge pressure, stop
compressor
Comments
28 OM Centrif Micro ΙΙ-5
Cooling Tower Bypass VALVE Settings
Figure 17, Tower Bypass VALVE Setpoint Screen
Table 15, Tower Bypass VALVE Setpoints (See page 31 for complete explanation.)
Description No. Default Range
Slope Gain 15 25 10 to 99 M Control gain for temperature (or lift) slope
Error Gain 14 25 10 to 99 M Control gain for temperature (or lift) error
Valve Control Range(Max) 13 100% 0 to 100% M
Valve Control Range (Min) 12 10% 0 to 100% M Minimum valve position, overrides all other settings
Temp - Maximum Position 11
Maximum Start Position 10 100% 0 to 100% M
Temp - Minimum Position 9
Minimum Start Position 8 10% 0 to 100% M
Stage Down @ 7 20% 0 to 100% M
Stage Up @ 6 80% 0 to 100% M
Valve Deadband (Lift) 5 4.0 psi
Valve Deadband (Temp) 4
Valve Target (Lift) 3 30 psi
Valve Setpoint (Temp) 2
Valve Type 1
90 °F 0 to 100 °F
60 °F 0 to 100 °F
1.0 to 20.0
psi
2.0 °F
65 °F
NC (To
Tower)
1.0 to 10.0
°F
10 to 130
psi
40 to 120
°F
NC, NO M Normally closed or normal open to tower
Pass-
word
Maximum valve position, overrides all other
settings
Condenser EWT at which valve should be open to
M
tower
Initial valve position when condenser EWT is at or
above Setpoint # 9
Condenser EWT at which initial valve position is
M
set to Setpoint # 6
Initial position of valve when condenser EWT is at
or below Setpoint # 7
Valve position below which the fans can stage
down (Tower Setpoint #2 = Valve Stage Down
VFD speed below which the next fan speed can
turn off (Tower Setpoint # 2 = valve/VFD ????
Valve position above which the fans can stage up
(Tower Setpoint #2 = Valve Stage Down
VFD speed above which the next fan speed can
turn on (Tower Setpoint # 2 = valve/VFD ????
M Control deadband, Tower Setpoint #1=Lift
M Control deadband, Tower Setpoint #1=Temp
Target for lift pressure (Tower Setpoint #1= Lift),
M
Works with Setpoint # 5
Target for condenser EWT (Tower Setpoint #1=
M
Temp), Works with Setpoint # 4
Comments
OM Centrif Micro ΙΙ-5 29
Cooling TOWER Fan Settings
Figure 18, Cooling TOWER Fan Setpoint Screen (See page 31 for complete explanation.)
Table 16, Tower Fan Settings
Description No. Default Range
Stage #4 On (Lift) 15 65 psi 10 to 130 psi M Lift pressure for fan stage #4 on
Stage #3 On (Lift) 14 55 psi 10 to 130 psi M Lift pressure for fan stage #3 on
Stage #2 On (Lift) 13 45 psi 10 to 130 psi M Lift pressure for fan stage #2 on
Stage #1 On (Lift) 12 35 psi 10 to 130 psi M Lift pressure for fan stage #1 on
Stage #4 On (Temp) 11
Stage #3 On (Temp) 10
Stage #2 On (Temp) 9
Stage #1 On (Temp) 8
Stage Differential (Lift) 7 6.0 psi 1.0 to 20.0 psi M Fan staging deadband with Setpoint # 1=Lift
Stage Differential
(Temp)
Stage Down Time 5 5 min 1 to 60 min M
Stage Up Time 4 2 min 1 to 60 min M
Tower Stages 3 2 1 to 4 M Number of fan stages used
Valve/VFD Control 2 None
Tower Control 1 None
85 °F 40 to 120 °F
80 °F 40 to 120 °F
75 °F 40 to 120 °F
70 °F 40 to 120 °F
6
3.0 °F 1.0 to 10.0 °F
None, Valve
Setpoint, Valve
Stage, VFD
Stage, Valve
SP/VFD Stage
None,
Temperature,
Lift
Pass-
word
M Temperature for fan stage #4 on
M Temperature for fan stage #3 on
M Temperature for fan stage #2 on
M Temperature for fan stage #1 on
M Fan staging deadband with Setpoint #1=Temp
Time delay between stage up/down event and
next stage down
Time delay between stage up/down event and
next stage up
None: No tower valve or VFD
Valve Setpoint: Valve controls to VALVE SP3(4)
& 5(6)
M
Valve Stage: Valve control setpoint changes to
fan stage setpoint
VFD Stage: 1st fan is VFD controlled, no valve
Valve Setpoint/VFD Stage: Both valve and VFD
None: No tower fan control
M
Temperature: Fan and valve controlled by EWT
Lift: Fan and valve controlled by lift pressure
Comments
30 OM Centrif Micro ΙΙ-5
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