McQuay WGS 130AA Installation Manual

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Operating Manual

Group: Chiller Part Number: 330599503 Effective: October 2004 Supersedes: OM WGS

Water-Cooled Screw Compressor Chillers

WGS 130AW To WGS 190AW, Packaged Water-Cooled Chiller WGS 130AA To WGS 190AA, Chiller with Remote Condenser

120 to 200 Tons, 420 to 700 kW

R-134a, 60 Hz Software Version WGSD30101C

OM WGS-1

Table of Contents

Introduction........................................3

General Description .....................................3

Nomenclature...............................................3

Definitions...........................................4

Wiring Diagrams................................8

Control Panel Layout......................10

MicroTech II Controller..............13

System Arch itecture ...................................13

General Description ...................................14

Sequence of Operation ....................16

Start-Up and Shutdown...................22

Pre Start-up ................................................22

Start-up.......................................................22

Weekend or Temporary Shutdown.............23

Start-up after Temporary Shutdown...........23

Extended Shutdown....................................23

Start-up after Extended Shutdown..............23

Unit Controller.................................27

Unit Inputs/Outputs....................................27

Unit Setpoints.............................................27

Circuit Controller............................30

Circuit Inputs and Outputs .........................30

Circuit Setpoint Table ................................31

Alarms, W arnings, Events...............32

Stop Alarms (Shutdown)............................32

Events (Limit)............................................34

Unit Controller Functions...............35

Unit Enable ................................................36

Unit Mode Selection ..................................37

Unit States..................................................38

Evaporator Pump Control...........................39

Leaving Water Temperature (LWT) Reset..40

Planned Unit Capacity Overrides...............42

Condenser Pump and Tower Control..........43

Cooling Tower Control...............................44

Evaporative Condenser Control.................46

Circuit Controller Functions.......... 48

Refrigerant Calculations.............................48

Compressor Control...................................49

Internal Capacity Overrides........................52

Slide Positioning ........................................53

Expansion Valve Control............................55

Oil Heater Control......................................59

Starter Communications.............................59

Condenser Fan Control...............................61

Digital Output Control................................62

Using the Controller...................................63

Security ......................................................65

Entering Passwords....................................65

Editing Setpoints........................................65

Clearing Alarm s..........................................65

Menu Descriptions...........................66

Unit Controller...........................................66

Circuit Controller.......................................80

Editing Review...........................................86

BAS Interface...................................87

Troubleshooting Chart....................88

Troubleshooting Chart................................88

Unit controllers are LONMARK

certified with an optional L

communications module.

Illustrations and data cover McQuay International products at the time of publication and we reserve the right to

make changes in design and construction at anytime without notice.

 The following are trademarks or registered trademarks of their respective companies:

BACnet from ASHRAE; L

GeneSys, McQuay and MicroTech II from McQuay International.

2 WGS 130A to WGS 190A OM WGS-1

2004 McQuay International

ONMARK and LONWORKS from Echelon Corporation;

ONWORKS

Introduction

General Description

McQuay Model WGS water chillers are designed for indoor installations and are available with factory-mounted water-cooled condensers (Model WGS AW), or arranged for use with remote air-cooled or evaporative condensers (Model WGS AA). Each water-cooled unit (WGS-AW) is completely assembled and factory wired before factory evacuation, charging and testing. The units consist of two semi-hermetic rotary screw compressors, a two-circuit shell-and-tube evaporator, two shell-and-tube water-cooled condensers, and complete refrigerant piping.

Units manufactured for use with remote condensers (Models WGS-AA) have all refrigerant specialties factory-mounted and have two sets of connection points for refrigerant discharge and liquid lines to and from the remote condenser. Discharge valves are included

Each circuit’s liquid line components are manual liquid line shutoff valve, charging valve, filter-drier, liquid line solenoid valve, sight glass/moisture indicator, and electronic expansion valve.

The electrical control center includes a MicroTech II microprocessor control system and equipment protection and operating controls necessary for dependable, automatic operation.

The compressor circuits are equipped with individual circuit breakers and a unit disconnect switch is available as an option over the standard power block.

Water-Cooled Condensing

Rotary Screw Compressor

Nominal Capacity (Tons)

Global

Nomenclature

W G S 130 - A W

W = Water-Cooled Condenser A = Unit Less Condenser

Design Vintage

OM WGS-1 WGS 130A to 190A 3

Definitions

Active Setpoint

The active setpoint is the setting in effect at any given moment. This variation occurs on setpoints that can be altered during normal operation. Resetting the chilled water leaving temperature setpoint by one of several methods, such as return water temperature, is an example.

Active Capacity Limit

The active setpoint is the setting in effect at any given moment. Any one of several external inputs can limit a compressor’s capacity below its maximum value.

Condenser Recirc Timer

A timing function, with a 30-second default, that holds off any reading of condenser water for the duration of the timing setting. This delay allows the water sensors (especially water temperatures) to take a more accurate reading of the condenser water system conditions.

Condenser Saturated Temperature Target

The saturated condenser temperature target is calculated by first using the following equation:

Sat condenser temp target raw = 0.833(evaporator sat temp) + 68.34 The “raw” value is the initial calculated value. This value is then limited to a range defined

by the Condenser Saturated Temperature Target minimum and maximum setpoints. These setpoints simply cut off the value to a working range, and this range can be limited to a single value if the two setpoints are set to the same value.

CPU Error

These are problems caused by a malfunction of the central processing unit.

Dead Band

The dead band is a set of values associated with a setpoint such that a change in the variable occurring within the dead band causes no action from the controller. For example, if a temperature setpoint is 44°F and it has a dead band of ± 2 degrees, nothing will happen until the measured temperature is less than 42°F or more than 46°F.

DIN

Digital input, usually followed by a number designating the number of the input.

Discharge Superheat

Discharge superheat shall be calculated for each circuit using the following equation: Discharge Superheat = Discharge Temperature – Condenser Saturated Temperature

Error

In the context of this manual, “Error” is the difference between the actual value of a variable and the target setting or setpoint.

Evaporator Approach

The evaporator approach is calculated for each circuit. The equation is as follows: Evaporator Approach = LWT – Evaporator Saturated Temperature

4 WGS 130A to 190A OM WGS

Evap Recirc Timer

A timing function, with a 30-second default, that holds off any reading of chilled water for the duration of the timing setting. This delay allows the chilled water sensors (especially water temperatures) to take a more accurate reading of the chilled water system conditions.

EXV

Electronic expansion valve, used to control the flow of refrigerant to the evaporator, controlled by the circuit microprocessor.

High Saturated Condenser – Hold Value

High Cond Hold Value = Max Saturated Condenser Value – 5°F This function prevents the compressor from loading whenever the pressures approach

within 5 degrees of the maximum discharge pressure. The purpose is to keep the compressor online during periods of possibly temporary elevated pressures.

High Saturated Condenser – Unload Value

High Cond Unload Value = Max Saturated Condenser Value – 3°F This function unloads the compressor whenever the pressures approach within 3 degrees of

the maximum discharge pressure. The purpose is to keep the compressor online during periods of possibly temporary elevated pressures.

High Superheat Error

The degrees of temperature difference between 40°F and the actual discharge temperature.

Light load Stg Dn Point

The percent load point at which one of two operating compressors will shut off, transferring the unit load to the remaining compressor.

Load Limit

An external signal from the keypad, the BAS or a 4-20 ma signal that limits the compressor loading to a designated percent of full load. Frequently used to limit unit power input.

Load Balance

Load balance is a technique that equally distributes the total unit load among the running compressors.

Low Ambient Lockout

Prevents the unit from operating (or starting) at ambient temperatures below the setpoint.

Low Pressure Hold Setpoint

The psi evaporator pressure setting at which the controller will not allow further compressor loading.

Low/High Superheat Error

The difference between actual evaporator superheat and the superheat target.

LWT

Leaving water temperature. The “water” is any fluid used in the chiller circuit.

OM WGS-1 WGS 130A to 190A 5

LWT Error

Error in the controller context is the difference between the value of a variable and the setpoint. For example, if the LWT setpoint is 44°F and the actual temperature of the water at a given moment is 46°F, the LWT error is +2 degrees.

LWT Slope

The LWT slope is an indication of the trend of the water temperature. It is calculated by taking readings of the temperature every few seconds and subtracting them from the previous value, over a rolling one-minute interval.

Milli-second

Maximum Saturated Condenser Temperature

The maximum saturated condenser temperature allowed is calculated based on the compressor operational envelope.

Normally closed - usually refers to a contactor or valve.

Normally open - usually refers to a contactor. or valve.

OAT

Outside ambient air temperature.

Offset

Offset is the difference between the actual value of a variable (such as temperature or pressure) and the reading shown on the microprocessor as a result of the sensor signal. See notes on page 32 for explanation of sensor off set.

pLAN

Peco Local Area Network is the proprietary name of the network connecting the control elements.

Rapid Stop

A compressor stop process that circumvents the normal pumpdown cycle.

Refrigerant Saturated Te mperature

Refrigerant saturated temperature is calculated from the pressure sensor readings for each circuit. The pressure is fitted to an R-134a temperature/pressure curve to determine the saturated temperature.

Soft Load

Soft Load is a control sub-routine that allows the chiller to load up gradually. It requires setpoint inputs of selecting it by Yes or No inputs, by selecting the percent load to start ramping up, and by selecting the time to ramp up to full load (up to 60 minutes).

Setpoint

SSS

Solid state starter as used on McQuay screw compressors.

Suction Superheat

Suction superheat is calculated for each circuit using the following equation: Suction Superheat = Suction Temperature – Evaporator Saturated Temperature

6 WGS 130A to 190A OM WGS

Stage Up/Down Accumulator

The accumulator can be thought of as a bank storing occurrences that indicate the need for an additional fan.

Stageup/Stagedown Delta-T

Staging is the act of starting or stopping a compressor or fan when another is still operating. Startup and Stop is the act of starting the first compressor or fan and stopping the last compressor or fan. The Delta-T is the “dead band” on either side the setpoint in which no action is taken.

Stage Up Delay

The time delay from the start of the first compressor to the start of the second.

Startup Delta-T

Number of degrees above the LWT setpoint required to start the first compressor.

Stop Delta-T

Number of degrees below the LWT setpoint required for the last compressor to stop.

VAC

Volts, Alternating current, sometimes noted as vac.

VDC

Volts, Direct current, sometimes noted as vdc.

VFD

Variable Frequency Drive, a device used to vary an electric motor’s speed.

OM WGS-1 WGS 130A to 190A 7

Wiring Diagrams

Figure 1, WGS 130AW – 190AW Field Wiring Diagram (Optional Single Point Connection)

3 PHASE

POWER SUPPLY

DISCONNECT (BY OTHERS)

UNIT MAIN

TERMINAL BLOCK

GND LUG

TO COMPRESSOR(S)

NOTE: ALL FIELD WIRING TO BE INSTALLED AS NEC CLASS 1 WIRING SYSTEM WITH CONDUCTOR RATED 600 VOLTS

FACTORY SUPPLIED ALARM

FIELD WIRED

ALARM BELL OPTION

ABR

LARM BELL RELAY

FUSED CO N T RO L

CIRCUIT TRANSFORMER

CHWR

EVAP. PUMP RELAY #1

(BY OTHERS)

120 VAC 1.0 AMP MAX

CHWR

EVAP. PUMP RELAY #2

(BY OTHERS)

120 VAC 1.0 AMP MAX

CWR

COND. PUMP RELAY #1

(BY OTHERS)

120 VAC 1.0 AMP MAX

CWR

COND. PUMP RELAY #2

(BY OTHERS)

120 VAC 1.0 AMP MAX

M11

TOWER FAN #1

(BY OTHERS)

120 VAC 1.0 AMP MAX

M12

TOWER FAN #2

(BY OTHERS)

120 VAC 1.0 AMP MAX

COOLING TOWER BYPASS

(BY OTHERS)

FU4 FU5

120 VAC

FU7

TB1

(115 VAC)

2 82

85 2

86 2

87 2

88 2

89 2

78 77

80 79

81 75

TB1-2

24 VAC

120 VAC

0-10VDC N

0-10VDC

BELL

LARM BELL

RELAY

COM NO

LARM BELL OPTION

TIME

REMOTE STOP

SWITCH

(BY OTHERS)

ICE MODE

SWITCH

(BY OTHERS)

EVAP. FLOW

SWITCH

(BY OTHERS)

*MANDATORY IF FACTORY FLOW SWITCH OPTION IS NOT SELECTED

COND. FLOW

SWITCH

(BY OTHERS)

*MANDATORY IF FACTORY FLOW SWITCH OPTION IS NOT SELECTED

CLOCK

NOR. OPEN PUMP AUX. CONTACTS (OPTIONAL)

4-20MA FOR

EVAP. WATER RESET

(BY OTHERS)

4-20MA FOR

DEMAND LIMIT

(BY OTHERS)

UTO

MANUAL UTO

MANUAL

OFF

TB1

(24 VAC OR 30 VDC)

60 66

IF REMOTE STOP CONTROL

897

IS USED, REMOVE LEAD 897 FROM TERM. 40 TO 53.

60 68

60 67

72 70

71 70

DWG. 330588201 REV . 0B

GND

8 WGS 130A to 190A OM WGS

Figure 2, WGS 130AA – 190AA Field Wiring Diagram (Remote Air-cooled Condenser)

UNIT MAIN

3 PHASE

POWER

SUPPLY

DISCONNECT

(BY OTHERS)

TERMINAL BLOCK

GND LUG

TO COMPRESSOR(S)

NOTE: ALL FIELD WIRING TO BE INSTALLED AS NEC CLASS 1 WIRING SYSTEM WITH CONDUCTOR RAT E D 60 0 V OLTS

FACTORY SUPPLIED ALARM

ALARM BELL OPTION

CIRCUIT #1

M11

CONDENSER FAN

CONTACTOR COIL #1

M12

CONDENSER FAN

CONTACTOR COIL #2

M13

CONDENSER FAN

CONTACTOR COIL #3

M14

CONDENSER FAN

CONTACTOR COIL #4

M15

CONDENSER FAN

CONTACTOR COIL #5

M16

CONDENSER FAN

CONTACTOR COIL #6

FIELD WIRED

TB6

144

145

146

145

148

145

150

145

152

145

154

145

REMOTE STOP

SWITCH

(BY OTHERS)

ICE MODE

SWITCH

(BY OTHERS)

ABR

ALARM BELL RELAY

NO1

NO2

NO3

NO4

NO5

NO6

FUSED CONTROL

CIRCUIT T RANSFORMER

EVAP. PUMP RELAY #1

120 VAC 1.0 AMP MAX

EVAP. PUMP RELAY #2

120 VAC 1.0 AMP MAX

120 VAC

(LOCATED ON

CONTROLLER)

120 VAC

(LOCATED ON

CONTROLLER)

120 VAC

TIME

CLOCK

UTO

MANUAL

UTO

MANUAL

OFF

CHWR

(BY OTHERS)

CHWR

(BY OTHERS)

J12

CIRCUIT

J13

CIRCUIT

FU4

120 VAC

FU7

TB1

(115 VAC)

CIRCUIT #2

CONDENSER FAN

CONT A CTOR COIL #1

CONDENSER FAN

CONTA CTOR COIL #2

CONDENSER FAN

CONTA CTOR COIL #3

CONDENSER FAN

CONT A CTOR COIL #4

CONDENSER FAN

CONTA CTOR COIL #5

CONDENSER FAN

CONTA CTOR COIL #6

TB1

(24 VAC)

FU5

TB1-2

120 VAC

24 VAC

BELL

LARM BELL OPTION

LARM BELL

RELAY

COM

TB7

244

245

246 245

248

245

250 245

252 245

254

245

NO1

NO2

NO3

NO4

NO5

NO6

M21

M22

M23

M24

M25

M26

IF REMOTE STOP CONTROL

897

IS USED, REMOVE LEAD 897 FROM TERM. 40 TO 53.

120 VAC

J12

(LOCATED ON

CIRCUIT

CONTROLLER)

J13

(LOCATED ON

CIRCUIT

CONTROLLER)

EVAP. FLOW

SWITCH

(BY OTHERS)

*MANDATORY IF FACTORY FLOW SWITCH OPTION IS NOT SELECTED.

NOR. OPEN PUMP AUX. CONTACTS (OPTIONAL)

4-20MA FOR

EVAP. WATER RESET

(BY OTHERS)

4-20MA FOR

DEMAND LIMIT

(BY OTHERS)

GND

DWG. 330588101 REV. 0C

OM WGS-1 WGS 130A to 190A 9

Control Panel Layout

Figure 3, Outer (Microprocessor) Panel

T2, Unit Controlle

T13, Circ#1 Controller

T14, Circ#1 Load Solenoid

T15, Circ#1 EXV Power

T23, Circ#2 Controlle

T24, Circ#2 Load Solenoid

T25, Circ#2 EXV Power

Unit Controller

MHPR11 &12, Mechanical High Pressure Rel ay

Circ#1 Controller

Circuit Breaker & Switch Panel

External Disconnect Handle

Circ#1 & 2 EXV Drivers

Circ#2 Controller

TB3, Circ#2 Controller Terminal Board

TB2, Circ#1 Controller Terminal Board

TB1 Unit Controller Terminal Board

NOTES:

1. Transformers T2 through T25 are class 100, 120V to 12V.

2. Switches for MHPR 11 and 12 (Mechanical High Pressure Switches) are located on the compressors.

3. Mechanical High Pressure Switches Open at 310 psi, Close at 250 psi.

10 WGS 130A to 190A OM WGS

Figure 4, Inner (Power) Panel (Opti onal Single-Point Power wi th Disconnect Switches

Shown)

Circ#1 Solid State Starter

Circ#2 Solid State Starter

SSS1 Bypass Contactor

SSS2 Bypass Contactor

Secondary Fuses

External Disconnect Handle

Circ#1 Circuit Breaker

Circ#2 Circuit Breaker

Unit Disconnect Switch W/ External Handle

T1, Supply Voltage to 120V Transf ormer

Primary Fuses

Outside (Microprocessor) Panel

OM WGS-1 WGS 130A to 190A 11

Figure 5, Circuit Breaker/Fuse Panel

Open Location

S1 Main Unit On-Off Switch

CS2, Circuit#2 On-Off Switch

CS1, Circuit#1 On-Off Switch

CB11 Circ#1 Circuit Breaker

CB12, Circ#1 Sump Heater

Open Locatio

CB21, Circ#2 Circui

CB22, Circ#2 Sump Heate

Open Locations

Location for Optional

115V Receptacle

OUTER PANEL INNER PANEL

T13T2 T14 T15 T23 T24 T25

UNIT

CONTROLLER

EXV.

DRIVER

CIRCUIT CONTROLLER

MODBUS CARD

CONVERTER BOARD

EXV.

DRIVER

CIRCUIT CONTROLLER

TB1

TB11 TB21

MHPR1MHPR

CS1

S1S

REC

OPTION

CS2

CB11 CB12 SP CB21 CB22

SP FU7

SINGLE

POINT

CIR. #1

DS HANDLE (MULTI-

POINT)

CIR. #2

DS HANDLE (MULTI-

POINT)

SSS #1 SSS #2

CT2

F U 5

CONTACTOR

CT1

THERM-

ISTOR CARD

BYPASS

C B 1

(DS1 DS2

MULTIPOINT

POWER)

CT3

C B 2

CONTR.

BRD.

CT3

F U 6

F U 4

CONTR.

BRD.

CT2

DS1

CONTACTOR

CT1

THERM-

ISTOR CARD

BYPASS

G N D

330589001 REV. 00 - Legen

12 WGS 130A to 190A OM WGS

MicroTech II Controller

System A rchitecture

The WGS MicroTech ΙΙ distributed control system consists of multiple microprocessorbased controllers that provide monitoring and control functions required for the controlled, efficient operation of the chiller. The system consists of the following components:

• Unit Controller

and communicates with the other controllers. It is located in the control panel and is labeled “UNIT CONTROL”.

• Circuit Controllers

settings specific to the circuit. The controllers are located in the control panel and are labeled “CIRCUIT CONROL”.

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 its normal design envelope. If an alarm condition develops, the controller will shut down the compressor, or entire unit, and activate an alarm output. Important operating conditions at the time an alarm condition occurs are retained in the controller’s memory to aid in troubleshooting and fault analysis.

The system is protected by a password scheme that allows access only by authorized personnel. The operator must enter the operator password into the controller’s keypad before any setpoints can be altered.

, one per chiller − controls functions and settings that apply to the unit

for each compressor/circuit that control compressor functions and

BAS Interface-

Modbus, BACnet,

Lonworks

Chiller

RS485/

LON

Unit Controller

4x20 LCD

Carel pLAN

Circuit Controller

Solid

State

Starter

RS485 RS485

Circuit Control l e r

4x20 LCD

Solid

State

Starter

PLAN A ddressing

The pLAN (proprietary local area network) addressing is based on a commonly used scheme among all applications using pLAN networked MicroTech II controllers. Only three addresses are needed, and are designated as shown in the following table.

Controller Address Dip Sw 1 Position Dip Sw 2 Position Dip Sw 3 Position

Unit 5 Up Down Up Circuit 1 1 Up Down Down Circuit 2 2 Down Up Down

The Dip switches are located on the upper front of the controller above the screen.

OM WGS-1 WGS 130A to 190A 13

General Description

The MicroTech II controller’s design permits the chiller to run more efficiently, and it simplifies troubleshooting if a system failure occurs. Every MicroTech II controller is programmed and tested prior to shipment to assist in a trouble-free start-up. The MicroTech II controller can be used to cycle fans on remote air-cooled condensers for head pressure control when the setpoint Water Cooled=N is selected in one of the setpoint menu screens. Water Cooled=Y sets the chiller for operation with the water-cooled condenser and activates settings for cooling tower control. Remote evaporative condensers will have to have self-contained, on-board, head pressure control systems.

Units of measure

Version “C”, as described in this manual, supports metric (SI) units of measure.

Inch-Pound SI

°F to 0.1°F °C to 0.1°C

psi to 0.1 psi KPa to 1.0 kPa

Distributed Control

The WGS units have three MicroTech II microprocessors, a Unit Controller plus a Circuit Controller for each of the two circuits. The Circuit Controllers are independent such that either one will operate its circuit if the other Circuit Controller is out of service.

Operator-friendly

The MicroTech II controller menu structure is separated into three distinct categories, which provide the operator or service technician with a full description of the following:

1. Current unit status

2. Control parameters (setpoint settings and adjustment). Security protection prevents unauthorized changing of the setpoints and control parameters.

3. Alarm notification and clearing

The MicroTech II controller continuously performs self-diagnostic checks, monitoring system temperatures, pressures and protection devices, and will automatically shut down a refrigerant circuit or the entire unit if a fault occurs. The cause of the shutdown and date stamp are retained in memory and can be easily displayed in plain English for operator review, which is an extremely useful feature for troubleshooting. In addition to displaying alarm diagnostics, the MicroTech II controller also provides the operator with a warning of pre-alarm limit conditions.

Staging

The two screw compressors are loaded and staged on and off as a function of leaving chilled water temperature, number of starts and run-hours. See Sequence of Operation beginning on page 13.

Equipment Protection

The unit is protected by alarms that shut it down and require manual reset, and also by limit alarms that limit unit operation in response to some out-of-ordinary condition. Shutdown alarms activate an alarm signal that can be wired to a remote device.

14 WGS 130A to 190A OM WGS

Unit Enable Selection

(4)

Enables unit operation from local keypad or digital input.

Unit Mode Selection

Selects standard cooling, ice, glycol, or test operation mode.

Keypad/Display

A 4-line by 20-character/line liquid crystal display and 6-key keypad is mounted on each controller. Its layout is shown below.

Figure 6, Keypad and Display in MENU Mode

Air Condi ti oni ng

Key to Screen Pathway

ALARM

VIEW

Arrow Keys

SET

"Enter" Key and Green Comp. Run Light

Red Alarm Light

Menu Key

The four arrow keys (UP, DOWN, LEFT, RIGHT) have three modes of use.

1. Scroll between data screens as indicated by the arrows (default mode).

2. Select a specific data screen in a hierarchical fashion using dynamic labels on the right side of the display (this mode is entered by pressing the MENU key).

3. Change field values in edit mode according to the following table:

LEFT Default RIGHT Cancel UP Increment DOWN Decrement These four edit functions are indicated by one-character abbreviations on the right side of the display (this mode is entered by pressing the ENTER key).

OM WGS-1 WGS 130A to 190A 15

Sequence of Operation

Compressor Heaters

With the control power on, 120V power is applied through the control circuit Fuse FU7 to the compressor oil separator heater (HTR-OIL SEP).

Startup/Compressor Staging

During Cool Mode the following must be true to start a circuit operating. The evaporator and condenser pump (WGS-AW only) outputs must be energized and flow must be established for a period of time defined by the evaporator recirculate setpoint. Established flow will be detected by evaporator and condenser water flow switches. The water temperature leaving the evaporator must be greater than the Active Leaving Water Temperature setpoint, plus the Startup Delta-T, before a circuit will start. The first circuit to start is determined by sequence number. The lowest sequence numbered circuit will start first. If all sequence numbers are the same (default), then the circuit with the fewest number of starts will start first. During operation, the slide valves for loading and unloading will be pulsed until the active leaving water temperature setpoint is maintained. The second circuit start will occur once the first circuit has loaded to 75% slide capacity or is in Capacity Limit and the water temperature leaving the evaporator is greater than the active leaving water temperature Setpoint plus Stage Delta-T. The circuits will load or unload simultaneously through a continuous capacity control to maintain the evaporator leaving water temperature. If all sequence numbers are the same, the circuit with the most run hours will be shut down first. The circuit with the most run hours will stop when the water temperature leaving the evaporator is less than the Active Leaving Water Temperature Setpoint minus Stage Delta-T. The last remaining circuit will shut down when the water temperature leaving the evaporator is lower than the Active Leaving Water Temperature Setpoint minus the Stop Delta-T.

Automatic Pumpdown

The Model WGS chiller has two separate refrigerant circuits so the refrigerant charge is stored in the condenser when the circuit is off. Pumpdown to the condenser helps keep refrigerant from migrating to the compressor. It also helps establish a pressure differential on start for oil flow. In a normal shutdown, each circuit will close its expansion valve, causing the evaporator pressure to reach a low-pressure setpoint. Once this setpoint is reached, or a specified amount of time has elapsed, the running circuit will be shut down.

Chilled Water and Condenser Water Pumps

The chiller’s MicroTech II controller has a total of four pump outputs, two for the evaporator and two for the condenser (WGS-AW only). There is a manual setting in the software for the user to select either pump output 1 or 2. It is recommended that the chiller’s outputs control the water pumps, as this will offer the most protection for the unit.

Cooling Tower Control

The MicroTech II controller can control the cooling tower fans and/or a tower bypass valve. This provides a simple and direct method to control the unit’s discharge pressure. Programming directions and the sequence of operation can be found on page 44. Some means of discharge pressure control is recommended and must be installed if the entering condenser water temperature to the condenser can fall below 60°F.

Condenser Fan Control

The MicroTech II controller can be programmed to cycle air-cooled condenser fans on and off based on the discharge pressure. Details are on page 61.

16 WGS 130A to 190A OM WGS

Unit Controller Sequence of Operation

Unit power up

Unit in Off state

The chiller may be disabled via the unit switch, the remote switch, the keypad enable setting, or the BAS network. In addition, the chiller will be disabled if both circuits are disabled, either because of an alarm or the circuit pumpdown switch on

each circuit, or if there is a unit alarm. If the chiller is disabled, the unit status display will reflect this and also show why it is disabled.

Is unit enabled?

Yes

Evaporator pump output on

Is flow present?

Yes

Wait for chilled water loop to

recirculate.

If the unit switch is off, the unit status will be disabled due to network command, the unit status will be the remote switch is open, the unit status will be alarm is active, the unit status will be are enabled, the unit status will be

Off:All Cir Dis abl e d

Off:Unit Switch

Off:Remote Switch

Off:Unit Alarm

. If the chiller is

Off:BAS Disa bl e

. When a unit

. In cases where no circuits

If the chiller is enabled, then the unit will be in the Auto state and the evaporator water pump output will be activated.

The chiller will then wait for the flow switch to close, during which time the unit status will be

Auto:Wait for flow

After establishing flow, the chiller will wait some time to allow the chilled water loop to recirculate for an accurate reading of the leaving water temperature. The unit status during this time is

Auto:Evap Recirc

. When

Keep evaporator pump

output on while unit is

enabled.

The chiller is now ready to start if enough load is present. If the LWT is not high

Is there enough load to

start chiller?

Yes

enough to start, the unit status will be If the LWT is high enough to start, the unit status will be

Auto:Wait Evap Flow

Auto

OM WGS-1 WGS 130A to 190A 17

Is unit watercooled?

Yes

If the unit is configured as watercooled, the condenser pump will need to be started. Otherwise, the unit can start the first circuit at this point.

Condenser pump output on

Is flow present?

Yes

Wait for condenser water

loop to recirculate.

Keep condenser pump

output on while u n it is

enabled and load is present.

Start first circuit.

Load/unload as needed to

satisfy load.

Is more capacity

needed to satisfy load?

If load is present, the condenser water pump output will be activated.

The chiller will then wait for the condenser flow switch to close, during which time the unit status will be

Auto:Wait Cond Flow

After establishing condenser flow, the chiller will wait some time to allow the condenser water loop to recirculate and guarantee consistent flow. The unit status during this time is

Auto:Cond Recirc

Once the condenser flow has been present for enough time, the unit status will become

Auto

. The tower control logic will start working to control the condenser water temperature, using outputs from the unit controller to control tower fans, bypass valves, and vfd's as determined by the tower set points.

The first circuit to start is generally the one with the least number of starts, or circuit one if there is a tie. This circuit will go through its start sequence at this point.

A number of fans may be started with the compressor based on the OAT. Fan stages will be added/removed as needed to control condenser pressure. The EXV will begin controlling at this point as well. The compressor cannot start loading until it has at least 22

discharge superheat for more than 30 seconds.

The first circuit will load and unload as needed in an attempt to satisfy the load. It will eventually get to a point where it is considered to be at full load. A circuit is at

full load when it reaches 75% slide target, it reaches the max slide target setting, or it encounters a problem and is running in an inhibited state.

If a single circuit is not enough to satisfy the load, the second circuit will need to be started.

Yes

Has the stage up time

delay expired?

Yes

A minimum time must pass between the start of the first circuit and the second circuit.

18 WGS 130A to 190A OM WGS

The second circuit will go through its start sequence at this point.

Start second circuit.

Load/unload as needed to

satisfy load.

Can one circuit handle

the load?

Yes

Shut down one circuit.

Load/unload as needed to

satisfy load.

discharge superheat for more than 30 seconds.

Both circuits will now load/unload as needed to satisfy the load. In addition, they will load balance so that both circuits are providing nearly equal capacity.

As the load drops off, the circuits will unload accordingly. If the LWT gets low enough, or both circuits unload enough, one circuit can shut off.

The first circuit to shut off is generally the one with the most run hours. The circuit will do a pumpdown by closing the EXV and continuing to run the compressor until it reaches the pumpdown pressure or exceeds the pumpdown time limit. Then, the compressor and all fans will be turned off.

The single running circuit will load/unload as needed to satisfy the load.

With one circuit running, the load may drop off to the point where even minimum

Is load satisfied?

Yes

unit capacity is too much. The load has been satisfied when the LWT drops below the shutdown point. At this time the only running circuit can shut down.

The last circuit running now shuts down. The circuit will do a pumpdown by closing the EXV and continuing to run the compressor until it reaches the pumpdown

Shut down last circuit.

pressure or exceeds the pumpdown time limit. Then, the compressor and all fans will be turned off.

The unit should be ready to start again when the LWT gets high enough. The unit

Turn off condenser pump

and tower control.

status at this time will be

Auto:Wait for load

The condenser pump and tower control outputs are turned off until the LWT is high enough to start again.

OM WGS-1 WGS 130A to 190A 19

Circuit Controller Sequence of Operation

Unit power up

Circuit is in Off state

Next on?

Yes

Stage up now?

Yes

When the circuit is in the Off state the EXV is closed, compressor is off, and all fans are off. The oil heater will be on at this time as long as oil is detected in the separator.

If the compressor is ready to start when needed, the circuit status will be

Off:Ready

. When the circuit switch is off, the circuit cannot start and the status will

Off:Pumpdown Switch

If this compressor has the least starts, the other compressor is disabled for some reason, or the other compressor is already running, then this compressor will be designated as the next one on.

If there is a need for more cooling capacity , the compressor designated as next on can start.

Is unit watercooled?

Yes

Preopen EXV

Start Compressor

If the unit is configured as watercooled, then the EXV preopen process must be performed. Otherwise, this is skipped and the compressor can be sta rted.

At this point, the EXV will perform a preopen. While the compressor is off, the EXV is opened for a period of time to prime the evapora tor an d avoid low pressure at startup. The circuit status will display

EXV Preopen

When the compressor starts, the EXV will open (if not already open) and hold at 3000 steps for 15 seconds.

If the unit is aircooled, depending on the OAT, a number of fans may be started with the compressor to keep condenser pressure from climbing too fast.

The circuit status will normally be

Run: Disc SH Low

after the compressor starts.

20 WGS 130A to 190A OM WGS

Run Compressor

Next off?

Yes

Stage down now?

Yes

When in the Run state, the compressor will load/unload as needed to satisfy the load. The compressor will also load/unload to load balance with the other compressor if it is running and not in a limited condition. However, it cannot load up until the discharge superheat has been over 22 F for at least 30 seconds. After this, the circuit status will be

Run:Normal

The EXV will operate in either Pressure Control or Superheat Control. In Pressure Control, the evaporator pressure is controlled to a target pressure, which is adjusted based on LWT and discharge superheat. In Superheat Control, the suction

superheat is controlled to a target that varies with discharge superheat. If unit is aircooled, fans will be staged on and off to control the condenser pressure.

The condenser pressure is controlled to a target that is based on evaporator pressure, with the target getting higher as the evaporator pressure gets higher.

If this compressor has the most run hours or the other compressor is already off, then this compressor will be designated as the next one off.

If less cooling capacity is needed, the compressor designated as next off can shut down. This condition may arise when either the LWT has dropped far enough below the active set point or both circuits are running at a low capacity.

When the circuit does a normal shutdown, a pumpdown is performed. The EXV is closed while the compressor continues to run. As soon as the pumpdown is initiated, the compressor is unloaded to the minimum. The condenser fans continue to control normally during this process. The circuit status during this time

Run:Pumpdown

Pumpdown circuit

After the evaporator pressure drops below the pumpdown pressure or enough time has passed, the compressor and fans are shut off to end the pumpdown process. The circuit status will normally be

Off:Cycle Timers

at this time.

OM WGS-1 WGS 130A to 190A 21

Start-Up and Shutdown

Pre Start-up

1. Flush and clean the chilled-water system. Proper water treatment is required to prevent corrosion and organic growth.

Failure to flush and clean system and provide water treatment can damage the unit.

2. With the main disconnect open, check all electrical connections in control panel and starter to be sure they are tight and provide good electrical contact. Connections are tightened at the factory, but can loosen enough in shipment to cause a malfunction.

Lock and tag out all power sources when checking connections. Electrical shock can

3. Check and inspect all water piping. Make sure flow direction is correct and that piping is made to the correct connection on evaporator and condenser.

4. Check that refrigerant piping on remote condensers is connected to the correct circuits and not crossed and has been properly leak tested and evacuated.

5. Open all water flow valves to the condenser and evaporator.

6. Flush the cooling tower and system piping to be sure the system is clean. Start evaporator pump and manually start condenser pump and cooling tower. Check all piping for leaks. Vent the air from the evaporator and condenser water circuit, as well as from the entire water system. The cooler circuit should contain clean, treated, noncorrosive water.

7. Check to see that the evaporator water temperature sensor is securely installed.

8. Make sure the unit control switch S1 is open OFF and the circuit switches CS1 and CS2 are open. Place the main power disconnect switch to ON. This will energize the compressor sump heaters. Wait a minimum of 12 hours before starting the unit.

9. Measure the water pressure drop across the evaporator and condenser, and check that water flow is correct (on pages 25 and 26) per the design flow rates.

10. Check the actual line voltage to the unit to make sure it is the same as called for on the compressor nameplate, within + 10%, and that phase voltage unbalance does not exceed 2%. Verify that adequate power supply and capacity is available to handle load.

11. Make sure all wiring and fuses are of the proper size. Also make sure that all interlock wiring is completed per McQuay diagrams.

12. Verify that all mechanical and electrical inspections by code authorities have been completed.

13. Make sure all auxiliary load and control equipment is operative and that an adequate cooling load is available for initial start-up.

CAUTION

cause severe personal injury or death.

Start-up

1. Open the compressor discharge shutoff valves until backseated. Replace valve seal caps.

2. Open the two manual liquid line shutoff valves (king valves).

22 WGS 130A to 190A OM WGS

3. Verify that the compressor sump heaters have operated for at least 12 hours prior to start-up. Crankcase should be warm to the touch.

4. Check that the MicroTech II controller is set to the desired chilled water temperature.

5. Start the system auxiliary equipment for the installation by turning on the time clock, ambient thermostat and/or remote on/off switch and water pumps.

6. Switch on the unit circuit breakers.

7. Set circuit switches CS1 and CS2 to ON for normal operation.

8. Start the system by setting the unit system switch S1 to ON.

9. After running the unit for a short time, check the oil level in each compressor, rotation of condenser fans (if any), and check for flashing in the refrigerant sight glass.

Weekend or Temporary Shutdown

Move circuit switches CS1 and CS2 to the OFF pumpdown position. After the compressors have shut off, turn off the chilled water pump if not on automatic control from the chiller controller or building automation system (BAS). With the unit in this condition, it will not restart until these switches are turned back on.

Leave on the power to the unit (disconnect closed) so that the sump heaters will remain energized.

Start-up after Temporary Shutdown

1. Start the water pumps.

2. Check compressor sump heaters. Compressors should be warm to the touch.

3. With the unit switch S1 in the ON position, move the circuit switches CS1 and CS2 to the ON position.

4. Observe the unit operation for a short time, noting unusual sounds or possible cycling of compressors.

Extended Shutdown

1. Close the manual liquid line shutoff valves.

2. After the compressors have shut down, turn off the water pumps.

3. Turn off all power to the unit.

4. Move the unit control switch S1 to the OFF position.

5. Close the discharge shutoff valves.

6. Tag all opened disconnect switches to warn against start-up before opening the compressor suction and discharge valves.

7. Drain all water from the unit evaporator, condenser and chilled water piping if the unit is to be shut down during the winter and exposed to below-freezing temperatures. To help prevent excessive corrosion, do not leave the vessels or piping open to the atmosphere over the shutdown period.

Start-up after Extended Shutdown

1. Inspect all equipment to see that it is in satisfactory operating condition.

2. Remove all debris that has collected on the surface of the condenser coils (remote condenser models) or check the cooling tower, if present.

OM WGS-1 WGS 130A to 190A 23

3. Open the compressor discharge valves until backseated. Always replace valve seal caps.

4. Open the manual liquid line shutoff valves.

5. Check circuit breakers. They must be in the OFF position.

6. Check to see that the circuit switches CS1 and CS2 and the unit control switch S1 are in the OFF position.

7. Close the main power disconnect switch. The circuit disconnects switches should be off.

8. Allow the sump heaters to operate for at least 12 hours prior to start-up.

9. Start the chilled water pump and purge the water piping as well as the evaporator in the unit.

10. Start the system auxiliary equipment for the installation by turning on the time clock, ambient thermostat and/or remote on/off switch.

11. Check that the MicroTech II controller is set to the desired chilled water temperature.

12. Switch the unit circuit breakers to ON.

13. Start the system by setting the system switch S1 and the circuit switches to ON.

CAUTION

Most relays and terminals in the control center are powered when S1 is

closed and the control circuit disconnect i s on. Therefore, do not close S1

until ready for start-up or serious equipment damage can occur.

14. After running the unit for a short time, check the oil level in the compressor oil sight glass and check the liquid line sight glass for bubbles.

24 WGS 130A to 190A OM WGS

Figure 7, Evaporator Pressure Drop WGS 130 – WGS 190

(

)

Flow Rate (L/s)

6131925323844505763

126

180

9 8

Pressure Drop (ft of water)

6 5

WGS 130, 140

WGS 160, 170, 190

150

120

30 27

24 21

Pressure Drop

kPa

100 200 300 400 500 600 700

800

900

1000

2000

Flow Rate (GPM)

Minimum Flow Nominal Flow Maximum Flow

WGS Model

130AW/AA 140AW/AA 160AW/AA 170AW/AA 190AW/AA

Note: Minimum, nominal, an d maximum flows are at a 16°F, 10°F, and 6°F chilled water temperature range respectively and at ARI tons.

Flow Rate Pressure Drop Flow Rate Pressure Drop Flow Rate Pressure Drop

gpm L/s Ft. kPa gpm L/s Ft. kPa gpm L/s Ft. kPa

195 12.3 5.8 17.4 312 19.7 13.5 40.4 520 32.9 33.9 101.1 211 13.4 6.7 20.0 338 21.4 15.6 46.6 563 35.6 39.0 116.5 235 14.9 4.6 13.8 376 23.8 10.8 32.3 627 39.7 27.3 81.6 254 16.1 5.3 15.9 407 25.8 12.5 37.3 678 42.9 31.6 94.2 273 17.3 6.1 18.1 437 27.7 14.2 42.5 728 46.1 35.9 107.2

OM WGS-1 WGS 130A to 190A 25

Figure 8, Condenser Pressure Drop WGS 130 – WGS 190

Flow Rate (L/s)

6131925323844505763

126

180

rop (ft of water)

ressure

WGS

Model

130AW 140AW 160AW 170AW 190AW

WGS

Model

130AW 140AW 160AW 170AW 190AW

WGS 170, 190

150

120

with Manifold

WGS 130, 140, 160

with Manifold

9 8

7 6

WGS 170, 190

30 27

24 21

without Manifold

WGS 130, 140, 160

100 200 300 400 500 600 700

without Manifold

800

900

1000

2000

Flow Rate (GPM)

Pressure Drop Without Optional Condenser Manifold

Minimum Flow Nominal Flow Maximum Flow

Flow Rate Pressure Drop Flow Rate Pressure Drop Flow Rate Pressure Drop

gpm L/s Ft. kPa gpm L/s Ft. kPa gpm L/s Ft. kPa

304 19.2 4.1 12.2 390 24.7 6.5 19.3 650 41.1 16.0 47.9 304 19.2 4.1 12.2 422 26.7 7.4 22.2 704 44.5 18.5 55.1 304 19.2 4.1 12.2 470 29.8 9.0 26.9 784 49.6 22.4 66.8 372 23.5 4.3 12.8 509 32.2 7.9 23.7 848 53.7 19.8 59.1 372 23.5 4.3 12.8 546 34.6 9.0 26.9 911 57.6 22.5 67.1

Pressure Drop With Optional Condenser Manifold

Minimum Flow Nominal Flow Maximum Flow

Flow Rate Pressure Drop Flow Rate Pressure Drop Flow Rate Pressure Drop

gpm L/s Ft. kPa gpm L/s Ft. kPa gpm L/s Ft. kPa

304 19.2 4.7 14.0 390 24.7 7.4 22.0 650 41.1 18.5 55.1 304 19.2 4.7 14.0 422 26.7 8.5 25.3 704 44.5 21.3 63.5 304 19.2 4.7 14.0 470 29.8 10.3 30.7 784 49.6 25.8 77.1 372 23.5 5.3 15.8 509 32.2 9.4 28.1 848 53.7 23.8 71.1 372 23.5 5.3 15.8 546 34.6 10.7 32.0 911 57.6 27.1 80.9

Pressure Drop (kPa)

26 WGS 130A to 190A OM WGS

Unit Controller

Unit Inputs/Outputs

Table 1, Analog Inputs

# Description Signal Source Range 1

2 3 4

C1 = Refrigerant Circuit #1, C2 = Refrigerant Circuit #2, UT = Unit

Table 2, Analog Outputs

# Description Output Signal Range 1

2 3 4

Table 3, Digital Inputs

# Description Signal Signal 1

2 3 4 5 6 7 8

Condenser EWT or Outdoor Ambient Temp. Demand Limit 4-20 mA Current 0 to 100% limit

Chilled Water Reset 4-20 mA Current Leaving Evaporator Water Temp. Thermister (10k@25°C) -58 to 212°F

Entering Evaporator Water Temp. Thermister (10k@25°C) -58 to 212°F

Cooling Tower Bypass Valve Position 0 to 10 VDC 0 to 100% Cooling Tower VFD Speed 0 to 10 VDC 0 to 100% Open Open

Unit Switch 0 VAC (Stop) 24 VAC (On) Remote Switch 0 VAC (Stop) 24 VAC (Start) Evaporator Water Flow Switch 0 VAC (No Flow) 24 VAC (Flow) Mode Switch 0 VAC (Cool) 24 VAC (Ice) Condenser Water Flow Switch 0 VAC (No Flow) 24 VAC (Flow) Open Open Open

Thermister (10k@25°C) -58 to 212°F

0 to 10 degrees

60°F max.

Table 4, Digital Outputs

# Description Load Output OFF Output ON

Evaporator Water Pump 1 Pump Contactor Pump OFF Pump ON

Evaporator Water Pump 2 Pump Contactor Pump OFF Pump ON

Condenser Water Pump 1 Pump Contactor Pump OFF Pump ON

Condenser Water Pump 2 Pump Contactor Pump OFF Pump ON

Tower Fan 1 Fan Contactor Fan OFF Fan ON

Tower Fan 2 Fan Contactor Fan OFF Fan ON

Remote Run Status All Circuits Off Any Circuit On

Alarm Remote Alarm No alarm Stop alarm

Unit Setpoints

The following parameters are retained during power off, are factory set to the Default value, and can be adjusted to any value in the Range column.

The Type defines whether the setpoint is part of a coordinated set of duplicate setpoints in different controllers. Types are as follows:

N = Normal setpoint – Not copied from, or copied to, any other controller M = Master setpoint – Setpoint is copied to all controllers in the “Sent To” column

The PW (password) column indicates the password level that must be active in order to change the setpoint. Passwords are as follows:

O = Operator [0100] M = Manager (8745)

OM WGS-1 WGS 130A to 190A 27

Toggle: Setpoints that have two choices, such as ON and OFF are toggled between the two settings using the Up or Down keys on the controller. NOTE: in some software versions the terms “inhibit” and “hold” are used interchangeably.

Table 5, Unit Controller Setpoints

Description Default Range Type PW Unit

Unit Enable OFF OFF, ON N O Unit Mode Cool Cool, Ice, Test M O Control source Switches Switches, Keypad, Network N O

Available Modes Cool Cool LWT

Ice LWT Start Delta T Stop Delta T Stage Up Delta T Stage Down Delta T Max Pulldown Evap Recirc Timer 30 0 to 300 seconds N M Evap Pump Select #1 Only #1 Only, #2 Only, Auto N M Water-cooled Yes No, Yes N M

Cond Recirc Timer (watercooled only) Cond Pump Select (watercooled only)

LWT Reset Type NONE NONE, RETURN, 4-20mA, OAT N M Max Reset Start Reset Delta T Soft Load Off Off, On N M Begin Capacity Limit 40% 20-100% N M Soft Load Ramp 20 min 1-60 minutes N M Demand Limit Off Off, On N M

Low OAT Operation (air-cooled only) Low Ambient Lockout (air cooled only)

Ice Time Delay 12 1-23 hours N M Clear Ice Timer No No,Yes N M Evap LWT sensor off set 0 -5.0 to 5.0 deg N T Evap EWT sensor of fset 0 -5.0 to 5.0 deg N T Cond EWT/OAT sensor offset 0 -5.0 to 5.0 deg N T Cond LWT sensor off set 0 -5.0 to 5.0 deg N T Units BAS Protocol Modbus BACnet, LonWorks, Modbus N M Ident number 1 0-200 N M Baud Rate 19200 1200,2400,4800,9600,19200 N M

Compressors

Sequence # Cir 1 1 1-2 M M Sequence # Cir 2 1 1-2 M M Start-start timer 20 min 15-60 minutes M M Stop-start tim er 5 min 3-20 minutes M M Pumpdown Pressure 25 psi 10 to 40 psi M T Pumpdown Time Limit 120 sec 0 to 180 s ec M T Light Load Stg Dn Point 25% 20 to 50% M T Stage Up Delay 5 min 0 to 60 min M T

44 °F 30(40) to 60 °F 25 °F 20 to 38°F 10 °F 0 to 10 °F

1.5 °F 0 to 3 °F 2 °F 0 to 3 °F 1 °F 0 to 3 °F

5 °F/min 0.5-5.0 °F /min

30 0 to 300 seconds N M

#1 Only #1 Only, #2 Only, A uto N M

0 °F 0 to 20 °F

10 °F 0 to 20 °F

No No, Yes N M

55 °F 0(35) to 70 °F

°F/psi °F/psi, °C/kPa

Continued next page

Cool, Cool w/Glycol, Cool/Ice

w/Glycol, ICE w/Glycol, TEST

N T N O

N O M O M O M O M O M M

N M N M

N M

28 WGS 130A to 190A OM WGS

Description Default Range Type PW Alarms

Low Evap Pressure-Unload 28 psi [0,26] to 45 psi M T Low Evap Pressure-Hold 30 psi [ 0,28] to 45 psi M T Low Oil Level Delay 120 s ec 10-180 sec M T High Oil Press Diff Delay 15 sec 0-60 sec M T High Discharge Temperature High Lift Pressure Delay 5 sec 0 to 30 sec M T Evaporator Water Freeze Evaporator Flow Proof 3 sec 3 to 10 sec N T

Low OAT Start Timer (air cooled only) Condenser Water Freeze (water cooled only) Condenser Flow Proof (water cooled only)

Cooling Tower(available for Water cooled only)

Tower Control None None, Temperature N M Tower Stages 2 0 to 2 N M Stage #1 On Stage #2 On Stage Differential Stage Up Time 2 min 1 to 60 min N M Stage Down Time 5 min 1 to 60 min N M Stage Fan Down @ 20% 0 to 100% N M Stage Fan Up @ 80% 0 to 100% N M

Valve/VFD Control None Valve Type NC to tower NC, NO N M

Valve Setpoint Valve Deadband Minimum Start P osition 0% 0 to 100% N M Minimum Position @ Maximum Start Position 100% 0 to 100% N M Maximum Position @ Valve Control Range (Min) 10% 0 to 100% N M Valve Control Range(Max) 90% 0 to 100% N M Error Gain 25 10 to 99 N M Slope Gain 25 10 to 99 N M

200 °F

36 °F 15(36) to 42 °F

60 sec 20 to 90 sec M T

38 °F 34 to 42 °F 3 sec 3 to 10 sec N T

70 °F 40 to 120 °F 75 °F 40 to 120 °F

3.0 °F 1.0 to 10.0 °F

None, Valve Setpoint, Valve S t age,

VFD Stage, Valve SP/V FD Stage

65 °F 60 to 120 °F

2.0 °F 1.0 to 10.0 °F

60 °F 0 to 100 °F

90 °F 0 to 100 °F

150 to 200 F M T

N T

N M N M N M

N M

N M N M

N M

Auto A dj usted Ranges

The following settings have different ranges of adjustment based on other settings.

Table 6, Cool LWT

Mode Range

Unit Mode = Cool 40 to 60oF Unit Mode = Cool w/Glycol, Ice w/ Glycol 20 to 60oF

Table 7, Evaporator Water Freeze

Mode Range

Unit Mode = Cool 34 to 42oF Unit Mode = Cool w/Glycol, Ice w/ Glycol 15 to 42oF

OM WGS-1 WGS 130A to 190A 29

Table 8, Low Evaporator Pressure Inhibit

Unit Mode = Cool 30 to 45 Psig Unit Mode = Cool w/Glycol, Ice w/ Glycol 15 to 45 Psig

Table 9, Low Evaporator Pressure Unload

Unit Mode = Cool 28 to 45 Psig Unit Mode = Cool w/Glycol, Ice w/ Glycol 15 to 45 Psig

Circuit Controller

Circuit Inputs and Outputs

Table 10, Analog Inputs

# Description Signal Source Range

1 Evaporat or Pressure 0.1 to 0.9 VDC 2 Condens er P ressure 0.1 to 0.9 VDC 3 Open 4 Suction Temperature NTC Thermister (10k@25°C) -58 to 212°F 5 Dis charge Temperature NTC Thermister (10k @25° C) -58 to 212°F 6 Open 7 Sl i de Load Indicator 4 to 20 mA 8 Condenser LWT (circuit 1, water c ool ed onl y) NTC Thermister (10k@25°C) -58 to 212°F

Mode Range

0 to 132 psi

3.6to 410 psi

0 to 100%

Table 11, Analog Outputs

# Description Output Signal Range

1 Fan VF D (ai r cooled only) 0 to 10 VDC 0 to 100% (1000 steps resol ution) 2 Open 3 EXV Driver 0 to 10 VDC 0 to 6386 steps (1000 steps res ol ution) 4 Open

Table 12, Digital Inputs

# Description Signal Signal

1 Circuit Switch 0 VAC (Off) 24 VAC (Auto) 2 Open 3 Open 4 VFD Fault 0 VAC (Fault) 24 VAC (No Fault) 5 Oil Differential Pressure Switch 0 VAC (Fault) 24 VAC (No Fault) 6 Mechanical High Pressure Switc h 0 VAC (Fault) 24 VAC (No Faul t ) 7 Open 8 Open 9 Oil Level Sensor 0 VAC (Fault) 24 VAC (No Fault)

10-14 Open

The status of digital inputs may be viewed on Circuit Status screen 5, on the circuit controllers only.

30 WGS 130A to 190A OM WGS

Table 13, Digital Outputs

# Description Output OFF Output ON

1 Fan 1 Contactor (air cooled only) Fan off Fan on 2 Fan 2 Contactor (air cooled only) Fan off Fan on 3 Fan 3 Contactor (air cooled only) Fan off Fan on 4 Fan 4 Contactor (air cooled only) Fan off Fan on 5 Fan 5 Contactor (air cooled only) Fan off Fan on 6 Fan 6 Contactor (air cooled only) Fan off Fan on 7 Load/Unl oad Pulse Hold load slide Move load slide 8 Load/Unload Select Unload Load

9 Compressor SSS Contact Compressor off Compressor on 10 Open 11 Oil Heater Heater off Heater on 12 Interstage Injection (future us e) Injection off Injection on

13 EXV Close Signal

EXV follows

0 –10 VDC

EXV closed, ignores 0 –

10 VDC

Circuit Setpoint Table

The following parameters must be remembered during power off, are factory set to the Default value, and can be adjusted to any value in the Range column.

The PW (password) column indicates the password that must be active in order to change the setpoint. Codes are as follows:

O = Operator (100) M = Manager T = Technician

Table 14, Circuit Setpoints

Description Default Range PW

Compressor

Circuit mode enable Disable, enable, test T Slide control auto Auto, manual T Slide target 0 0-100 T Compressor Size 167 167, 179, 197 T Clear Cycle Timers No No, Yes T Maximum Slide Target 100.0 0-100.0% T Motor FLA See Table 15 1 to 321 amps T Motor RLA See Table 15 1 to 321 amps T Ground Fault Enable Disable Disable, Enable T Ground Fault Trip Level 1 0 to 100% T

EXV

EXV control Auto Auto, manual T Manual EXV position 0 0-6386 T Service Pumpdown No No,Yes T Preopen Timer (water cooled only) 20 20 to 120 seconds T

Sensors (NOTE 1)

Evap pressure offset 0 -10.0 to 10.0 psi T Cond pressure offset 0 -10.0 to 10.0 psi T Suction temp offset 0 -5.0 to 5.0 deg T Discharge temp offs et 0 -5.0 to 5.0 deg T Slide Minimum Posi t i on Offset 0 -15 to 15% T Slide Maximum Position Offset 0 -15 to 15% T

Continued next page

OM WGS-1 WGS 130A to 190A 31

Description Default Range PW

Fans (available for air-cooled only)

Fan VFD enable On Off, On T Number of fans 4 4 to 6 T Saturated Condenser Temp Target Min 90.0 80. 0-110.0 Saturated Condenser Temp Target Max 110.0 90.0-120.0 oF T Stage 1 On Deadband 8.0 1.0-20.0 oF T Stage 2 On Deadband 10.0 1.0-20.0 oF T Stage 3 On Deadband 11.0 1.0-20.0 oF T Stage 4 On Deadband 12.0 1.0-20.0 oF T Stage 2 Off Deadband 20.0 1.0-25.0 oF T Stage 3 Off Deadband 16.0 1.0-25.0 oF T Stage 4 Off Deadband 11.0 1.0-25.0 oF T Stage 5 Off Deadband 8.0 1.0-25.0 oF T VFD Max Speed 100% 90 to 110% T VFD Min Speed 25% 20 to 60% T Forced Fantrol 1 2 1 to 4 T Forced Fantrol 2 3 1 to 4 T Forced Fantrol 3 4 1 to 4 T

Notes:

1. Offsets are used to fine-tune certain readings generated by sensors. For example, if the controller was showing a 125 psi value and a calibrated pressure gauge at the same location showed 127 psi, an offset of +2 psi would be entered and the controller would then read the corrected value of 127 psi.

F T

Table 15, RLA/FLA Values

Compressor 575V 460V 380V 230V 208V 400V (50Hz)

197 113 141 178 282 312 141 179 94 122 145 240 267 122 167 85 112 128 210 232 112

All 113 141 178 282 312 141

NOTE: Table values used for circuit controller input.

Alarms, Warnings, Events

Stop Alarms (Shutdown)

Equipment protection alarms trigger a rapid unit or compressor shutdown. The following tables identify each equipment protection alarm, give the condition that causes the alarm to occur, and states the action taken because of the alarm. All stop alarms require a manual reset. These alarms will energize a remote alarm (if the unit is so wired in the field), will energize a red light behind the left arrow button on the display and will be logged in the Alarm Log.

Table 16, Unit

Alarm Description Occurs When: Action Taken Reset

No Evaporator Water Flow

Continued next page

Stop Alarms, Shutdown

Evap Pump State = RUN AND Evap Flow

Digital Input = No Flow for time > Flow Proof

SP, OR Evap Pump State = START AND

Evap Flow Digital Input = No Flow for time >

RLA

FLA

Rapid Stop See Note

Evap Recirc Time SP

32 WGS 130A to 190A OM WGS

Alarm Description Occurs When: Action Taken Reset

Cond Pump State = RUN AND Cond Flow

No Condenser Water Flow

Evaporator Water Freeze Protect Leaving Evaporator Water Temperature Sensor Fault Cond EWT/Outside Air Temperature Sensor Fault

pLAN Failure

Digital Input = No Flow for time > Flow Proof

SP, OR Cond Pump State = START AND

Cond Flow Digital Input = No Flow for time >

Cond Recirc Time SP

Evap LWT goes below evap freeze protect

setpoint

Sensor shorted or open Rapid Stop Manual

No other controllers found on pLAN for 60

seconds

Rapid Stop See Note

Rapid Stop Manual

NOTE: Each day (beginning at 12:00 am), two automatic resets (based on the flow switch closing) are allowed before a manual reset requirement occurs. When an auto-clear occurs, the unit will go to the Start state and be waiting for flow. When flow is detected, the unit goes through the normal starting sequence and the flow loss alarm will clear. Flow loss is only triggered when a compressor is running.

Condenser flow loss is auto-reset, regardless of the number of occurrences. When a flow loss is detected, the unit goes back to the “Start” state, waiting for flow

Table 17, Circuit Stop Alarms, Shutdown

Alarm Description Occurs When: Action Taken Reset

Low Evaporator

Pressure

High Lift Pressure Cond Sat Temp > Max Sat Cond Value Rapid Stop Manual

Mechanical High

Pressure

Below Minimum Lift

Pressure

High Discharge

Temperature

Low Oil Level

High Oil Pressure

Difference

Starter Fault

Current Overload

Trip

Current Imbalance Low Motor Current

High Motor

Temperature

Phase Loss

Phase Reversal

Overvoltage

Undervoltage

Continued next page.

Evaporator Press < 5 psi OR [Freezestat

trip AND Compressor State = Run]

Digital Input 6 = Open Rapid Stop Manual

Cond Press < Min Sat Cond Value for time

> Min Lift Delay SP Temp > High Discharge Temperature SP Rapid Stop Manual DI9 = Open for Time greater than Low Oil

Level Delay AND the Low Oil Level Event

has occurred in the past hour

Digital Input 5 = Open for time greater than

High Press Diff Delay SP

Starter Status bit 4 set (fault) and Starter

Fault Code =

12,13,40,47,50,51,52,61,71,94,95,96,97,9

8,99

Starter Status bit 4 set (fault) and Starter

Fault Code = 2, 30, or 31

Starter Status bit 4 set (fault) and Starter

Fault Code = 37

Starter Status bit 4 set (fault) and Starter

Fault Code = 39

Starter Status bit 4 set (fault) and Starter

Fault Code = 60

Starter Status bit 4 set (fault) and Starter

Fault Code = 15 or 27

Starter Status bit 4 set (fault) and Starter

Fault Code = 10

Starter Status bit 4 set (fault) and Starter

Fault Code = 24, 25, or 26

Starter Status bit 4 set (fault) and Starter

Fault Code = 21, 22, 23, or 28

Rapid Stop Manual

Pumpdown Manual

Rapid Stop Manual

Rapid Stop Manual Rapid Stop Manual Rapid Stop Manual Rapid Stop Manual Rapid Stop Manual Rapid Stop Manual Rapid Stop Manual Rapid Stop Manual

OM WGS-1 WGS 130A to 190A 33

Alarm Description Occurs When: Action Taken Reset

Ground Fault

Protection

No Starter Transition

Evaporator Pressure

Sensor Fault

Condenser Pressure

Sensor Fault

Liquid Line Pressure

Sensor Fault

Suction Temperature

Sensor Fault

Discharge

Temperature Sensor

Fault

Liquid Line

Temperature Sensor

Fault

Slide Position

Sensor Fault

Starter Status bit 4 set (fault) and Starter

Fault Code = 38

Starter Status bit 4 set (fault) and Starter

Fault Code = 1 or 48

Sensor shorted or open Rapid Stop Manual Sensor shorted or open Rapid Stop Manual Sensor shorted or open Pumpdown Manual Sensor shorted or open Pumpdown Manual

Sensor shorted or open Pumpdown Manual

Rapid Stop Manual Rapid Stop Manual

Events (Limit)

The following events do not cause a rapid shutdown, but limit chiller operation in some way as described in the Action Taken column. These events do not trigger a remote alarm signal or the red Alarm LED on the controller. They appear only in the Event Log menu. They reset automatically when conditions return to a normal range.

If the chiller fails to make the chilled water setpoint, the Event Log should be checked as a forced limit on loading, or actual compressor unloading may be occurring.

NOTE: In some software versions the terms “inhibit” and “hold” are used interchangeably. The following unit events are logged in the event log with a time stamp

Table 18, Unit Events (Limits)

Description Occurs When: Action Taken Reset

Entering Evaporator Temperature Sensor Fault Condenser LWT Sensor Fault

Sensor is open or shorted

Sensor is open or shorted None Automatic

Cannot use

return water

reset

Automatic

Table 19, Circuit Events (Limits)

Event Description Occurs When: Action Taken Reset

Low Evaporator Pressure – Hold Low Evaporator Pressure – Unload

High Lift Pressure Hold

High Lift Pressure Unload

Subcooling Low

Continued on next page.

Pressure < Low Evap Pressure –

Hold SP

Pressure < Low Evap Pressure –

Unload SP

Pressure > High Sat Cond -

Hold Value

Pressure > High Sat Cond -

Unload Value

Subcool < Low Subcool SP for

longer than 5 minutes

Inhibit loading

Unload

Inhibit loading

Unload

None

Evap Press rises

above (SP + 3psi)

Evap Press rises

above (SP + 5psi) Cond Press drops

below (Hold Value –

Cond Press drops

below (Unload Value

Subcool > setpoint

or Comp state = off

– 10

34 WGS 130A to 190A OM WGS

Event Description Occurs When: Action Taken Reset

Input Open for Time greater than

Oil Level Low

Failed Prepurge

Failed Pumpdown

Condenser Freeze Protect

Power Loss While Running

Low Oil Level Delay AND more

than one hour since last

occurrence

Circuit state = prepurge for more

than the Prepurge Time SP

Circuit state = pumpdown for

more than the Pumpdown Time

Cond Sat Refr Temp <

Condenser Freeze SP AND

Cond Pump State = OFF

Note: Water Cooled = Y Only

Circuit controller is powered up

after losing power while

compressor was running

Rapid stop Comp state = off

Open EXV N/A

Stop N/A

Start

condenser

pump

Delay start of

compressor

Cond Sat Refr Temp

> (Condenser

Freeze SP + 2°F)

N/A

Clearing Alarms

Alarms may be cleared at the unit controller if any password level is active. If the user attempts to clear an alarm while no password is active, then the controller will automatically go to the ENTER PASSWORD screen. The user can then enter a password normally, and scroll back to the active alarm column to clear the active alarm(s). The BAS can clear evaporator flow loss, evaporator water freeze and pLAN failure regardless of what other alarms are active.

Unit Controller Functions

Calculations

LWT Slope

LWT slope is calculated such that the slope represents the change in LWT over a time frame of one minute.

Every 12 seconds, the current LWT is subtracted from the value 12 seconds back. This value is added to a buffer containing values calculated at the last five intervals. The final result is a slope value that is an average over the past 60 seconds.

Pulldown Rate

The slope value calculated above will be a negative value as the water temperature is dropping. For use in some control functions, the negative slope is converted to a positive value by multiplying by –1.

Unit Capacity

Unit capacity is estimated based on the slide target of each running circuit. The capacity of a running circuit is estimated with this equation:

Circuit capacity = 0.8(slide target) + 20 A circuit that is off is assumed to be at 0% capacity. The unit capacity is then calculated by

this equation: Unit capacity = (Circuit 1 capacity + Circuit 2 capacity)/2

OM WGS-1 WGS 130A to 190A 35

Unit Enable

Enabling and disabling the chiller is controlled by the Unit Enable Setpoint with options of OFF and ON. Enabling allows the unit to start if there is a call for cooling and also starts the evaporator pump.

This setpoint (in other words, enabling the unit to run) can be altered by the:

− Unit OFF input (unit On/Off switch)

− a field installed remote stop switch

− a keypad entry

− a BAS request

The Control Source Setpoint determines which sources can change the Unit Enable Setpoint with options of SWITCHES, KEYPAD or NETWORK.

Changing the Unit Enable Setpoint can be accomplished according to the following table. NOTE: An “x” indicates that the entry is ignored.

Table 20, Unit Enable Combinations

Unit On/Off

Switch

OFF x x x x OFF

ON/OFF SWITCHES OFF x x OFF

ON SWITCHES ON x x ON ON KEYPAD x OFF x OFF ON KEYPAD x ON x ON ON NETWORK x x OFF OFF ON NETWORK OFF x x OFF ON NETWORK ON x ON ON

Control Source

Setpoint

Remote

Stop Switch

Key-pad

Entry

BAS

Request

Resultant

Unit Enable

Status

Example:

1. If the Control Source is set to “Switches”, enabling is controlled by the field-installed remote stop switch. If the unit-mounted On/Off switch is either On or Off, the unit will be disabled if the remote switch is Off. If the unit-mounted On/Off switch is On, the unit will be enabled if the remote switch is On.

Chiller Control Source Options:

Set Unit Setpoints Screen #1 (shown below) has three fields: “Enable”, “Mode” and “Source.”

Unit Setpoints

SET UNIT SPs (1) Enable=On Mode= COOL Source = KEYPAD

The Enable field can only be used with Source = Keypad, to enable and disable the chiller through the key pad, any other control inputs including unit and pumpdown switches and BAS controls are ignored. The Enable field toggles between On and Off using the Up or Down key on the controller.

1. The Mode field is an informational display, showing the active control mode of the chiller. It is used as an input only when the source is set to keypad, only then can this field be changed manually.

2. The Source field has three options, “SWITCHES”(default), “KEYPAD”, and “BAS NETWORK”.

36 WGS 130A to 190A OM WGS

a. Switches source is used when there is no BAS interface used. This allows the unit

switches to function as pumpdown and shut down switches for the circuit. This option is also used with applications using the remote start/stop input and not using a BAS interface.

b. Keypad source is used to override BAS or remote start/stop commands. This

would be used for servicing only.

c. BAS Network source would be used for those applications using “MODBUS”,

“BACnet”, or “LON” communications through a building automation system. BAS

Protocol is set at Set Unit Setpoints item #14. All methods of disabling the chiller, except for the unit switch, will cause a normal pumpdown shutoff of any running circuits. Any time the unit switch is used to disable the chiller, all running circuits will shut down immediately, without pumping down.

Shutdown by the unit switch without going through the pumpdown cycle is undesirable and should only be used for an emergency shutdown or for manually and locally disabling the unit after both circuits have gone through a normal shutdown.

Unit Mode Selection

The overall operating mode of the chiller is set by the Unit Mode setpoint with options of COOL, ICE and TEST. This setpoint can be altered by the keypad, BAS, and Mode input. Changes to the Unit Mode Setpoint are controlled by two additional setpoints.

• Available Modes setpoint: usually set during initial setup and determines the

operational modes available at any time with options of:

− COOL, cooling only operation, with setpoints available for normal chilled water

temperatures

− COOL w/Glycol, cooling only operation, allows lower setpoints than COOL

− COOL/ICE w/Glycol, allows both cooling and ice mode operation, switchable by a

field-installed remote ICE mode switch, by the BAS or through the keypad.

− ICE w/Glycol, ice mode only, i.e., full load operation until LWT setpoint is reached

− TEST

• Control Source Setpoint: The setting determines the source that can change the Unit

Mode Setpoint with options of KEYPAD, NETWORK, or SWITCHES. When the Control source is set to KEYPAD, the Unit Mode stays at its previous setting until changed by the operator. When the Control source is set to BAS, the most recent BAS mode request goes into effect, even if it changed while the Control source was set to KEYPAD or DIGITAL INPUTS.

Changing the Unit Mode Setpoint can be accomplished according to the following table. NOTE: An “x” indicates that the value is ignored.

Table 21, Unit Mode Setpoint Sources

Control Source

Setpoint

x x x x COOL COOL

x x x x COOL w/Glycol COOL w/Glycol SWITCHES OFF x x COOL/ICE w/Glycol COOL w/Glycol SWITCHES ON x x COOL/ICE w/Glycol ICE w/Glycol

KEYPAD x COOL w/Glycol x COOL/ICE w/Glycol COOL w/Glycol

KEYPAD x ICE w/Glycol x COOL/ICE w/Glycol ICE w/Glycol NETWORK x x COOL COOL/ICE w/Glycol COOL w/Glycol NETWORK x x ICE COOL/ICE w/Glycol ICE w/Glycol

x x x x ICE w/Glycol ICE w/ Glycol x x x x TEST TEST

OM WGS-1 WGS 130A to 190A 37

Remote

ICE Mode

Switch

Ke ypad Entr y

BAS

Request

Available Modes

Setpoint

Resultant Unit

Mode

The Remote ICE Mode Switch (usually a time clock) is a field installed option and is used to switch from ice mode operation at night to cooling mode operation during the day. This requires that the Control Source be set to SWITCHES, which in this case refers to the Remote ICE Mode Switch.

There are really only three operational modes for the unit, although they can be used in combination:

1. COOL, the unit unloading and compressor staging is controlled by the Active LWT Setpoint. COOL w/ Glycol is a special case, providing for lower setpoint ranges.

2. ICE, the unit runs with all compressors fully loaded until the LWT (set for making ice) is reached, and the unit shuts off. The Ice Delay Timer can be set to prevent restarting until the next ice making cycle.

3. TEST, manually energize controller outputs to test functionality.

Unit Test Mode

The unit test mode allows manual testing of controller outputs. Entering this mode shall require the following conditions.

− Unit OFF input = OFF (i.e. entire chiller is shut down).

− Technician password active.

− Available Circuit Mode setpoint = TEST

A test menu can then be selected to allow activation of the outputs. It shall be possible to switch each digital output ON or OFF and set the analog outputs to any value.

Unit States

The unit will always be in one of three states.

Unit States

Power ON

PUMPDOWN

Transitions:

T1 – Transition from Off to Auto Requires all of the following

• Unit enabled based on settings and switches

• If unit mode is ice, the ice timer has expired

• No unit alarms exist

• At least one circuit is enabled and available to start

T2 – Transition from Auto to Pumpdown Requires any of the following

• Control source is keypad and the unit enable keypad setting is “off”

• Control source is BAS and either the remote switch is “off” or the BAS command is

“off”

• Control source is switches and the remote switch is “off”

OFF

AUTO

38 WGS 130A to 190A OM WGS

T3 – Transition from Pumpdown to Off Requires any of the following

• All circuits have finished pumpdown and are off

• A unit alarm is active

• Unit switch is “off”

T4 – Transition from Auto to Off Requires any of the following

• Unit switch is “off”

• A unit alarm is active

• All circuits are unavailable to start (cannot start even after any cycle timers have

expired)

• The unit mode is ice, all circuits are off, and the ice mode delay is active

Ice Mode Start Delay

An adjustable start to start ice delay timer will limit the frequency with which the chiller may start in Ice mode. The timer starts when the first compressor starts while the unit is in ice mode. While this timer is active, the chiller cannot restart in Ice mode. The time delay is user adjustable.

The ice delay timer may be manually cleared to force a restart in ice mode. A setpoint specifically for clearing the ice mode delay is available. In addition, cycling the power to the controller will clear the ice delay timer.

Evaporator Pump Control

The state-transition diagram shown below controls operation of the evaporator pump.

Evaporator Pump

States

OFF

START

Power ON

RUN

Transitions:

T1 – Transition from Off to Start Requires any of the following

• Unit state = Auto AND [If Low OAT Lockout active then LWT <=40]

• LWT < Freeze setpoint - 1

T2 – Transition from Start to Run

• Flow ok for time > evaporator recirculate time

OM WGS-1 WGS 130A to 190A 39

T3 – Transition from Run to Off Requires any of the following

• Unit state = Off AND LWT > Freeze setpoint

• Low OAT Lockout is active AND No compressors running AND LWT > 70°F

T4 – Transition from Start to Off Requires any of the following

• Unit state = Off AND LWT > Freeze setpoint

• Low OAT Lockout is active AND No compressors running AND LWT > 70°F

T5 – Transition from Run to Start Requires all of the following

• Evaporator water flow loss for time > flow proof

• All circuits in Off state

Pump Selection

The controller’s pump output used will be determined by the Evap Pump Control setpoint. This setting allows the operator to select pump #1, pump #2, or auto. The first two selections will use a single pump output all the time. The auto selection will start the pump with the least run hours.

The selected output will be ON if the Evap State is set to START or RUN. Both outputs will be OFF if the Evap State is set to OFF.

Leaving Water Temperature (LWT) Reset

The Active Leaving Water variable shall be set to the current Leaving Water Temperature (LWT) setpoint unless the unit is in COOL mode and any of the reset methods below are selected. The type of reset in effect is determined by the LWT Reset Type setpoint. The Active Leaving Water variable is sent from the unit controller to all circuits for capacity control after the applicable reset is applied.

Reset Type – NONE

The Active Leaving Water variable is set equal to the current LWT setpoint.

Reset Type – RETURN

The Active Leaving Water variable is adjusted by the return water temperature.

Return Reset

LWT set Point+Max Reset

(54)

Active

LWT

(

Max Reset

(10)

LWT Set Point

(44)

Start Reset Delta T

Evap Delta T (oF)

40 WGS 130A to 190A OM WGS

The active setpoint is reset using the following parameters:

1. Cool LWT setpoint

2. Max Reset setpoint

3. Start Reset Delta T setpoint

4. Evap Delta T Reset is accomplished by changing the Active Leaving Water variable from the Cool LWT

setpoint to the Cool LWT set-point + Max Reset setpoint as the Evaporator EWT – LWT (Evap Delta T) varies from the Start Reset Delta T setpoint to 0.

Referring to the above figure as an example, the LWT is 44°F and a 10-degree maximum reset value was selected. The Active LWT setpoint would range from the normal 44°F setting up to 54°F depending on the Evap Delta-T. The amount of reset would be at the maximum value (10 degrees) when the Evap Delta-T is zero and at the minimum value when the Evap Delta-T is at the Start Reset Delta T value and is proportional in between. The Start Reset Delta T function is available so that the start of reset can be adjusted. For example, on a system with a 10-degree Delta-T, it may be desirable to not start the resetting until the evaporator Delta-T goes down to eight degrees (80% load), or some other value.

Reset Type – 4-20 mA

The Active Leaving Water setpoint is adjusted by the 4 to 20 mA reset analog input, using:

1. Cool LWT setpoint

2. Max Reset setpoint

3. LWT Reset signal Reset is 0 if the reset signal is less than or equal to 4 mA. Reset is equal to the Max Reset

Delta T setpoint if the reset signal equals or exceeds 20 mA. The amount of reset will vary linearly between these extremes if the reset signal is between 4 mA and 20 mA. An example of the operation of 4-20 reset in Cool mode is shown below.

4-20 mA Reset - Cool Mode

(54)

Active

LWT

(

Max Reset

(10)

Cool LWT Set

Point (44)

Reset Signal (mA)

Reset Type – OAT

This reset can only be used if the unit is configured as air-cooled. The Active Leaving Water variable is reset based on the outdoor ambient temperature.

Parameters used:

1. Cool LWT setpoint

2. Max Reset setpoint

3. OAT

OM WGS-1 WGS 130A to 190A 41

Reset is 0 if the outdoor ambient temperature is greater than 75 F. From 75 down to 60 F the reset varies linearly from no reset to the max reset at 60 F. At ambient temperatures less than 60 F, reset is equal to the Max Reset setpoint.

OAT Reset

Cool LWT+Max Reset

(54)

Active

LWT

(

Max Reset

(10)

Cool LWT Set-Point

(44)

OAT (oF)

Planned Unit Capacity Overrides

Unit capacity limits can be used to limit total unit capacity in COOL mode only. Multiple limits may be active at any time, and the lowest limit is always used in the compressor capacity control.

The estimated unit capacity and the active capacity limit are sent to all circuits for use in compressor capacity control.

Soft Load

Soft Loading is a configurable function used to slowly ramp up the unit capacity over a given time. The setpoints that control this function are:

• Soft Load – (ON/OFF)

• Begin Capacity Limit – (Unit %)

• Soft Load Ramp – (seconds)

The Soft Load Unit Limit increases linearly from the Begin Capacity Limit setpoint to 100% over the amount of time specified by the Soft Load Ramp setpoint. If the option is turned off, the soft load limit is set to 100%.

Demand Limit

The maximum unit capacity can be limited by a 4 to 20 mA signal on the Demand Limit analog input at the unit controller. This function is only enabled if the Demand Limit setpoint is set to ON.

As the signal varies from 4 mA up to 20 mA, the maximum unit capacity changes linearly from 100% to 0%. Although the demand limit can call for 0% capacity, this signal will never cause a running compressor to shut down. Rather, all running compressors will be held at minimum load, and this may occur at a demand limit value that is actually less than 20mA.

Network Limit

The maximum unit capacity can be limited by a network signal. This function is only enabled if the unit control source is set to network. The signal will be received through the BAS interface on the unit controller.

42 WGS 130A to 190A OM WGS

As the signal varies from 0% up to 100%, the maximum unit capacity changes linearly from 0% to 100%. Although the network limit can call for 0% capacity, this signal will never cause a running compressor to shut down. Rather, all running compressors will be held at minimum load, and this may occur at a network limit value that is actually less than more than 0%.

Condenser Pump and Tower Control

Condenser pump and cooling tower control logic requires that the unit be configured as water-cooled in order to be active. The unit controller controls water-cooled components such as condenser pumps and tower controls, since there is usually one tower per unit. Aircooled equipment, associated with the remote condenser option, is controlled by the circuit controllers. Remote evaporative condensers require a self-contained, on-board, discharge pressure control system.

Condenser Water Pump State Control

If the unit is configured as water-cooled, then the condenser pump is controlled by the statetransition diagram shown below.

Condenser Pump

States

OFF

START

Power ON

RUN

Transitions:

T1 – Transition from Off to Start Requires any of the following

• Unit state = Auto AND any circuit available AND LWT error > Startup Delta

• Cond W ater Freeze Alarm

T2 – Transition from Start to Run

• Flow ok for time > cond recirculation timer setpoint

T3 – Transition from Run to Off Requires all of the following

• Unit state = Off OR No circuit available OR LWT error < Start Delta

• Cond Water Freeze Alarm not active

• No compressors running

T4 – Transition from Start to Off Requires all of the following

• Unit state = Off OR No circuit available OR LWT error < Start Delta

• Cond Water Freeze Alarm not active

• No compressors running

T5 – Transition from Run to Start Requires all of the following

• Condenser water flow loss for time > flow proof

• All circuits in Off state

OM WGS-1 WGS 130A to 190A 43

Pump Selection

The pump output used will be determined by the Condenser Pump Control setpoint. This setting allows the operator to select pump #1, pump #2, or auto. The first two selections will use a single pump output all the time. The auto selection will start the pump with the least run hours.

The selected output will be ON if the Evap State is set to START or RUN. Both outputs will be OFF if the Evap State is set to OFF.

Cooling Tower Control

Tower Fans

Tower fan control is active when the unit is set up as water-cooled, Tower Control is set to Temperature, and the condenser pump is in the RUN state. Staging is based on Condenser Entering Water Temperature. Operation depends on the following parameters.

• Condenser pump state

• Condenser EWT

• Stage up and stage down timer values

• Tower setpoints (Tower Control, Tower Stages, Stage Up Time, Stage Down Time,

Stage Differential, Stage #1 ON, Stage #2 ON, Stage Down @, Stage Up @)

When the condenser pump starts, the stage up timer shall start. The first stage shall turn ON when the following conditions are met:

• The stage up timer completes

• The Condenser EWT is > Stage #1 ON setpoint

• Bypass valve position is > the Stage Up @ setpoint (only if Valve/VFD Control setpoint

= Valve Stage)

• VFD Speed is > the Stage Up @ setpoint (only if Valve/VFD Control setpoint = VFD Stage OR Valve SP/VFD Stage)

Additional stages can turn on (up to the number specified by the Tower Stages setpoint) when above conditions are met for the next stage.

Down staging shall occur when the following conditions are met:

• The stage down timer completes

• The Condenser EWT is < Stage #X ON (Temp) setpoint – Stage Differential (Temp)

setpoint

• Bypass valve position is < the Stage Down @ setpoint (only if Valve/VFD Control setpoint = Valve Stage)

• VFD Speed is < the Stage Down @ setpoint (only if Valve/VFD Control setpoint = VFD Stage OR Valve SP/VFD Stage)

Each stage up or stage down event shall restart both the stage up and stage down timers. Only one fan output shall be switched at a time (except that all outputs switch OFF when the condenser pump state equals OFF).

Cooling Tower Bypass Valve

When the Valve/VFD Control setpoint is set to None OR VFD Stage, this output shall be set to 0. Otherwise, it shall be controlled as described below.

44 WGS 130A to 190A OM WGS

Initial Va lve Position

When the condenser pump is not in the RUN state, the valve output shall be set as a function of entering condenser water temperature (ECWT)) per the following graph.

Initial Valve Position

Max Position @

(values are examples only)

Set Point

(90°F)

Min Position @

Set Point

(60°F)

Min Start Position

Set Point (10%)

Operation After Start

Max Start Position

Set Point (90%)

When the condenser pump is in the RUN state, the valve output shall be controlled in one of two modes as specified by the Valve/VFD Control setpoint. The controlled parameter shall be the condenser entering water temperature. When the desired output signal varies from 0 to 100%, the output voltage shall vary as shown below.

− 0 to 10 VDC (Valve Type = NC to tower)

− 10 to 0 VDC (Valve Type = NO to tower)

Valve Setpoint Mode

This mode is operational when the Valve/VFD Control setpoint is set to Valve setpoint OR Valve SP/VFD Stage. In this mode the valve output is varied with a proportional-derivative (PD) algorithm (with deadband) in order to maintain the controlled parameter (CP) at the desired value. The output is always limited between the Valve Control Range (Min) setpoint and the Valve Control Range (Max) setpoint. A valve increment shall be computed once every 5 seconds according to the following equation.

• Increment = [(Error) * (Error Gain setpoint)] + [(Slope) * (Slope Gain setpoint)]

Where: Error = ECWT – Valve Setpoint Slope = (Present CP) – (Previous CP)

When the Error is > the Valve Deadband setpoint, the valve position analog output (% of full scale) is updated according to the following equation.

• New %Position = Old %Position + Increment/10.

Valve Stage Mode

This mode is only operational when the Valve/VFD Control setpoint is set to Valve Stage. In this mode the valve output is controlled as for Valve setpoint mode (above) except that the active setpoint for the controlled parameter is selected according to the following table.

# of Fans ON Active Setpoint

0 Valve Setpoint 1 Stage #1 ON 2 Stage #2 ON

OM WGS-1 WGS 130A to 190A 45

Cooling Tower Fan VFD

When the Valve/VFD Control setpoint is set to None, Valve Setpoint, OR Valve Stage, this output shall be set to 0. Otherwise, it shall be controlled in a manner identical to Valve Stage Mode (above) except that (1) it shall be kept at zero until the first fan stage is ON and (2) the following setpoints do not apply.

− Valve Control Range (Min)

− Valve Control Range (Max)

− Valv e Type

Evaporative Condenser Control

It is acceptable to use WGS-A chillers (less condenser) with evaporative condensers. It is the installer's responsibility to provide the evaporative condenser control because this condenser type is not available from McQuay. The WGS-A software does not directly support evaporative-cooled applications since there is a variety of fan configurations and pumps available from the manufacturers of evaporative condensers. In addition, the WGS software does not support the auxiliary functions of the evaporative condenser such as make up water valves, sump drain valves, electronic make up water valves, water freeze protection, variable frequency drives, damper controls or water treatment options. The WGS software will provide equipment protection and operational limits as if it were a remote air-cooled condenser application. See other sections of this manual for complete descriptions.

The system must be comprised of two controls systems that operate together to make a complete system. First, the WGS-A software provided with the unit will control the indoor chiller section of the unit including compressor loading/unloading, equipment protection, BAS interface (when applicable), and other functions as described in this manual without the condenser control. The WGS software setup shall be treated as a remote air-cooled application. The second control system is required to control the condenser and auxiliary functions. The best method for interfacing the two systems is through the "first on, last off" fan contacts as if the application was a remote air-cooled condenser. At start up of the compressors, the Fan 1 Contactor fan contacts will close and activate the condenser control system provided by others. At shut down, the reverse occurs where the condenser control will be deactivated when the compressor stops as the Fan 1 fan contacts open.

Special considerations must be given to the condenser control including (but not limited to) the following items.

1. All WGS-A chillers have two refrigerant circuits and an evaporative condenser with two refrigerant circuits is also required.

2. A control system for each refrigerant circuit is required. It is best to have separate fans and pumps for each refrigerant circuit to prevent "fighting" of control signals between the two refrigerant circuits.

3. The control system shall maintain a minimum condenser pressure at all times.

4. The normal control philosophy is to maintain the lowest possible condensing pressure above the minimum allowable to provide the best operating efficiency throughout the chiller's entire operating range.

46 WGS 130A to 190A OM WGS

5. For a normal starting sequence, it is best to start the fans first with minimum airflow. As the condenser pressure rises, increase the airflow by increasing the fan RPM, opening inlet vanes, opening outlet dampers, or other meaning of increasing airflow. If condensing pressure continues to rise after maximum airflow is reached, start the circulating pump (s). Reverse the sequence for the shut down procedure.

6. Provide the maximum number of condenser staging steps as possible to provide as stable operation as possible.

7. Recognize that condenser pressure will change drastically and rapidly, when the water pump starts and stops. This is the reason for starting the fan first in an increasing capacity situation and stopping the fan operation last with a shutdown procedure.

8. It is important for the control pressure settings for the fans and pumps to have a large control band so that condenser component cycling does not occur. It is also good practice for the fan and pump control to "overlap". Overlap means that the control bands must be determined so that there is a pressure range between when a pump starts/ stops with fan operation. Use caution to be certain that fan & pump cycling does not occur which causes rapid changes in condensing pressure which causes instability in the refrigeration system.

9. Refer to the installation, operation and maintenance manuals of the manufacturer of the evaporative condenser for their guidelines and recommendations. Give special consideration to preventing freezing conditions, make up water, and other functions common to evaporative condensers that should be described in those brochures.

CAUTION

Use water treatment with evaporative condensers. Failure to prevent

microbiology growth, scaling and corrosion can damage the uni t .

10. Damage caused or contributed by improper water treatment may not be covered by McQuay’s warranty.

11. For recommendations and answers to system questions, contact the McQuay Applications Group in Staunton, Virginia.

Building Automation System (BAS) interface and monitoring is an optional accessory required for many systems. The WGS-A interface options are communication cards supporting L

ONWORKS, BACnet or Modbus. Refer to the other McQuay brochures listed

in this manual for a complete description of capabilities. As a general statement, the McQuay communication cards do NOT support the evaporative condenser. The desired interface points for the condenser must be provided by others and through the control system provided with the evaporative condenser. Use caution in the ability to change condenser setpoints through the BAS system as such changes can impact chiller operation.

OM WGS-1 WGS 130A to 190A 47

Circuit Controller Functions

Refrigerant Calculations

Refrigerant Saturated Te mperature

Refrigerant saturated temperature is calculated from the pressure sensor readings for each circuit. The pressure will be fitted to a curve made up of 12 straight line segments. The points used to define these segments are shown in the following tables.

Table 22, Evaporator Pressure Conversion:

Pressure (PSI) Temperature (oF)

0 -15.0

7.1 0

19.0 20.0

34.7 39.0

50.7 54.0

70.4 69.0

99.6 87.0

129.2 102.0

166.8 118.0

205.4 132.0

246.5 145.0

320.0 165.0

428.5 188.1

Table 23, Condenser Pressure Conversion:

Pressure (PSI) Temperature (oF)

0 0.6

17.5 18.5

31.5 35.9

50.0 53.7

76.0 73.4

115.0 95.6

161.5 116.2

185.0 125.2

260.0 149.2

284.5 155.9

349.5 172.0

365.5 175.5

428.5 188.1

Circuit Operating Mode

The circuits on the chiller can each be individually enabled or disabled. Test mode on each circuit can also be entered independent of all other circuits. With the circuit switch on, the circuit mode setpoint offers settings of either enable or disable. This simply allows the circuit to be disabled through a keypad setting.

48 WGS 130A to 190A OM WGS

Circuit Test Mode

The circuit test mode allows manual testing of all controller outputs. Entering this mode requires the following conditions.

− Circuit Switch = OFF

− Technician password active

− Circuit Mode setpoint = TEST

A test menu can then be selected to allow activation of the outputs. It is possible to switch each digital output ON or OFF and set the analog outputs to any value. Upon entering test mode, all outputs will always default to the off state. Upon leaving test mode, all outputs will automatically reset to the off state.

Compressors cannot be started in TEST mode.

Compressor Control

Multiple Compressor Staging

This section defines which compressor is the next one to start or stop. Compressors with fewer starts will normally start first, and compressors with more run hours will normally stop first.

Functions

− Can start/stop compressors according to an operator defined sequence.

− Can start compressors based on number of starts (run hours if starts are equal) and stop

on run hours

− The above two modes can be combined, so that there are two or more groups, where all compressors in the first group are started (based on number of starts/hours) before any in the second group, etc. Conversely, all compressors in a group are stopped (based on run hours) before any in the preceding group, etc.

Multiple Compressor Start/Stop Timing – Cool Mode

This section defines when a compressor is to start or stop when the chiller is operating in cool mode.

− Required Parameters

− Startup Delta T setpoint.

− Stage Up Delta T setpoint

− Stage Down Delta T setpoint

− Stop Delta T setpoint

− LWT error (See definition under Compressor Capacity Control section.)

− Full load indicator for each compressor

Full Load Indicator

A circuit is considered to be at full load in the compressor staging logic when any of the following occur:

− Slide control = manual

− A low or high pressure limit event has been active for 10 seconds

− Slide target >= 75% AND max slide target > 75%

Slide target >= max slide target AND max slide target <= 75%

OM WGS-1 WGS 130A to 190A 49

Starting

A compressor will start (stage up): IF LWT is above the Active LWT Setpoint plus the Startup Delta-T SP AND no

compressors are running OR all running compressors are at full load

Stopping

A compressor will stop (stage down); IF LWT is below the Active LWT Setpoint minus the Stop Delta-T SP AND other

compressors are running or not;

OR IF LWT is below the Active LWT Setpoint minus the Stop Delta-T SP AND all other running compressor’s slide position is less than the light load stagedown setpoint.

Multiple Compressor Start/Stop Timing – Ice Mode

This section defines when a compressor is to start or stop when the chiller is operating in ice mode.

Required Parameters

− Startup Delta T setpoint.

− Stage Up Delta T setpoint

− LWT error (See definition under Compressor Capacity Control section.)

Starting

A compressor will start (stage up): IF LWT is above the Active LWT Setpoint plus the Startup Delta-T SP AND no

compressors are running OR all running compressors are at full load.

Stopping

The compressor will stop. IF LWT reaches the ICE LWT Setpoint

Compressor Capacity Control

Compressor capacity is determined by calculating a slide position target. Adjustment to the slide target for normal running conditions occurs every 5 seconds. For loading a maximum change of 1% is allowed, and for unloading a maximum change of 2% is allowed.

Required parameters

− Count In Load Balance status for each compressor

− Slide targets of all compressors

− LWT error

− LWT slope

LWT Error

LWT error compares the actual LWT to the active LWT setpoint. The equation is: LWT error = LWT – active LWT setpoint

LWT Slope

LWT slope is calculated in the unit controller and sent to circuits via pLAN. In the unit controller, this value is calculated such that the slope represents a time frame of

one minute.

50 WGS 130A to 190A OM WGS

Count In Load Balance Flag

A circuit will be counted for load balancing only if all of the following are true:

• Compressor state is run

• Compressor is able to load up (no limits in effect due to pressure or superheat)

• Slide control is auto

• Slide position target is less than the max slide target setpoint

Cool Mode

When the chiller is in COOL mode, capacity of the compressor is adjusted to maintain leaving water temperature at the Active LWT setpoint while balancing the load between running circuits. Load balance offset, LWT error, and LWT slope are used to calculate a change in slide position as described below.

Load balance offset:

IF other compressor is flagged to be counted in load balance

THEN Load Balance Offset = slide target - (cir 1 target + cir 2 target)/2

ELSE Load Balance Offset = 0

LWT Error:

LWT Error = (Leaving Evaporator Water Temp) – (Active LWT setpoint).

LWT slope:

Slope (deg/minute) = sum of last five LWT changes as calculated every 12 seconds Slide target adjustment = [LWT Error + (LWT Slope x 4) – Load Balance Offset] / #

Compressors Running

Ice Mode

In ICE mode, the compressor capacity is increased at the maximum rate continuously until reaching the maximum slide position. Load balancing, LWT error, and LWT slope are ignored.

Low OAT Start Logic

In order to avoid low pressure alarms at the start of a circuit, low OAT start logic allows for running at low pressures for a longer time than normal, as well as multiple start attempts. This logic is only used for air-cooled operation.

A low OAT start is initiated if the condenser saturated temperature is less than 60°F when the compressor starts. Once this happens, the circuit is in the low OAT start state for a time equal to the low OAT start timer setpoint. During this time, the freezestat logic and the low pressure events are disabled. The absolute limit of –10 psi is still enforced.

At the end of the low OAT start, the evaporator pressure is checked. If the pressure is greater than, or equal to, the low evaporator pressure unload setpoint, the start is considered successful. If the pressure is less than the unload setpoint, the start is not successful and the compressor will stop. Three start attempts are allowed before tripping on the restart alarm; so if on the third attempt the start is not successful, the restart alarm is triggered.

The restart counter will be reset when either a start is successful or the circuit is off on an alarm.

OM WGS-1 WGS 130A to 190A 51

Internal Capacity Overrides

The following conditions override the automatic slide control when the chiller is in COOL mode or ICE mode. These overrides keep the circuit from entering a condition in which it is not designed to run. Any compressor running with capacity limits because of these conditions is considered to be at full load in the compressor staging logic.

Low Evaporator Pressure

If the evaporator pressure drops below the Low Evaporator Pressure Hold setpoint while the compressor is running, the Low Evaporator Pressure Inhibit (Hold) event is triggered. When triggered, the compressor will not be allowed to increase in capacity.

If the evaporator pressure drops below the Low Evaporator Pressure Unload setpoint while the compressor is running, the Low Evaporator Pressure Unload event is triggered. When triggered, the compressor will begin reducing capacity. The maximum allowed slide target will be adjusted down 5% every 5 seconds until the evaporator pressure rises above the Low Evaporator Pressure-Unload setpoint.

These events are logged to an event log when they occur. Both remain active until the evaporator pressure rises above the hold setpoint plus 2 psi, or the circuit goes to a state other than Run.

High Lift Pressure

If the compressor is running and the condenser pressure rises above the High Lift Pressure Hold setpoint, the High Lift Pressure Inhibit event is triggered. When this happens, the compressor will not be allowed to increase capacity. This event is active until the condenser pressure drops 10 psi below the hold setpoint.

If the compressor is running above minimum load capacity and the condenser pressure rises above the High Lift Pressure Unload setpoint, the High Lift Pressure Unload event is triggered. When this happens, the compressor will begin reducing capacity. The maximum allowed slide target will be adjusted down 5% every 5 seconds until the condenser pressure drops below the High Condenser Pressure Unload setpoint. The compressor will not be allowed to increase in capacity until the condenser pressure drops to 10 psi below the unload setpoint.

Maximum LWT Pulldown Rate

The maximum rate at which the leaving water temperature can drop is limited by the Maximum Rate setpoint, only when the LWT is less than 60 slope unload factor is used to reduce the slide target if the pulldown rate exceeds the Maximum Rate setpoint.

Slope Unload Factor: Maximum Rate + LWT slope If the pulldown rate is too fast, then the slide adjustment made will be equal to the slope

unload factor.

F and the unit mode is Cool. A

High Water Temperature Capacity Limit

If the evaporator LWT exceeds 55°F, compressor slide position will be limited to a maximum of 75%. Compressors shall unload to 75% or less if running at greater than 75% slide position when the LWT exceeds the limit. This feature is to keep the circuit running within the capacity of the condenser coil.

52 WGS 130A to 190A OM WGS

Unit Capacity Overrides

Unit capacity limits override the automatic slide control when the chiller is in COOL mode only. The active capacity limit as well as the estimated unit capacity will be calculated in the unit controller and sent to all circuits.

If the unit capacity is greater than the active capacity limit, then no circuit will increase slide position. If the unit capacity is greater than the active limit plus 1%, the circuits will unload until the unit capacity is less than 1% greater than the active limit.

Pumpdown

When a circuit reaches a condition where the compressor needs to shut down normally, a pumpdown will be performed. The slide target will automatically go to 0 while pumping down, and the compressor will run until the pumpdown pressure has been reached, or the pumpdown time has been exceeded.

Service Pumpdown

If the option for a service pumpdown is enabled, then on the next pumpdown the pressure setpoint will be 5 psi. The circuit will pumpdown to this pressure and shut off. When the compressor has completed the service pumpdown, the setpoint is reset to No.

Slide Positioning

Slide Position Indicator

Each compressor estimates its slide load percentage from the present value of the slide position indicator. The percentage is based on the 4-20mA signal from the slide load indicator. A percentage value of 0 corresponds to approximately a 4mA signal, a percentage value of 100 corresponds to approximately a 20mA signal.

AGS-C Slide Calibration Procedure

Slide Position is a relative capacity adjustment from 0.0%(Min load) to 100.0%(Max Load). There are two MicroTech readings that apply to the indicator, Slide Target and Slide Position. It is important to understand the difference between these. The Slide Target is the value in which the controller uses to display the calculated prediction of slide position, this value represents the destination or goal of pulsing the load and unload solenoid coils. The slide target is used for direction of control for all load and unload operations, including alarm limit events. When putting a circuit in Manual mode, the slide target is the value that you will be adjusting. The controller will load or unload the chiller to match, with in about 3%, the target entered with the current slide position value. The second value is the Slide Position (Pos) this is the slide position value which is the 4-20mA reading received from the position indicator. These values can be viewed at the circuit controller on screen “VIEW CIR STATUS (1)”.

A slide target of 0.0% is fully unloaded and the unload solenoid will be constantly energized. A slide target of 100.0% means that the chiller is at full load and the load solenoid is continually energized. The chiller will regulate the slide position to infinite steps between 0% and 100% by pulsing the appropriate solenoid. Facing the discharge end of the compressor, looking along the left side, the solenoid coil on the top is for load (oil vent) and the solenoid coil on the side is for unload (oil feed). During normal operation, the controller makes decisions to move the Slide target, the calculated value, and pulses the proper solenoid in order to keep the actual and the target position with in a few percent.

OM WGS-1 WGS 130A to 190A 53

Figure 9, Slide Indicator and Coils

Load Coil

Unload Coil

Slide Indicator

Calibration Procedure:

1. The circuit to be calibrated should be near normal operating temperatures. Note that the compressor requires sufficient oil pressure to unload the compressor while it is running, and may load up due to lack of oil feed pressure.

2. On the Circuit controller, first verify what your current slide target is at screen “View Circ Status (1)” and then go to screen “SET COMP SPs (2)” to switch circuit into manual slide control. Note: Some hold limits will be ignored but all alarm limits are still active while in manual slide control.

3. Slowly take the circuit to 0% slide position. When the slide target is at 0%, verify that the unload coil is energized.

4. Find the slide indicator device located on the left side of the compressor facing the discharge end. Unscrew the metal cap and press the calibrate button beside the LED. The red LED will come on for about 30 seconds and then start to blink. The indicator is now calibrated at 0%.

5. Now, slowly take the circuit to 100% slide position, watching that the suction pressure and other unit readings are OK. Always keep discharge superheat above 22°F. When the slide target is at 100%, verify that the load coil is energized. Press the calibrate button. The red LED will come on for about 30 seconds and then the green LED will come on. The indicator is now calibrated at 100%.

6. The mechanical calibration is now complete for the compressor you are working with. Replace the calibration cap.

7. Once you have the mechanical slide calibration complete you may fine tune the calibration from the circuit controller, if necessary. On the circuit controller scroll all the way to the right, this is the calibration and offsets menu. Scroll down until you see “SET SENSOR OFFSET(3)”. You will see an adjustment for Min Load and Max Load and on the bottom line you will see the value of actual slide position indicator. Add offset until value is within +/-.5% of the corresponding full load or minimum load position.

8. Repeat calibration procedure until all circuits have min and max positions calibrated.

54 WGS 130A to 190A OM WGS

Note: The Slide Indicator Transducers may vary a considerable amount with

temperature change, and therefore they need to be calibrated at typical running temperatures.

Manual Slide Control Mode

The slide position on each circuit can be controlled manually. A setting on the compressor setpoints screen in each circuit controller allows the operator to select manual slide control. On the same screen, a slide target can be selected, from 0% to 100%.

Anytime a circuit is in manual slide control, it is considered to be at full load in the staging logic. It also will not be considered in load balancing calculations. None of the capacity limits outlined above will apply in manual slide control, but all stop alarms are still applicable.

Slide control will revert back to automatic control if a stop alarm occurs on the circuit or unit, or the slide control has been manual for four hours.

Slide Pulse

The slide pulse output moves the compressor slide in order to reach the capacity requested by the slide position target. The output will pulse for 200 ms every 6 seconds while the Slide Pulse flag is true, that is, whenever there is a difference between the actual slide position and the requested position.

Expansion Valve Control

The electronic expansion valve (EXV) can be in one of four control states. Each state is described below.

Preopen

The preopen state occurs before the compressor starts. This mode is used only in watercooled operation, and helps prime the evaporator prior to starting as well as getting the EXV in a better starting position. During preopen, the EXV signal is held at 3000 steps.

Pressure Control

In pressure control, the evaporator pressure is controlled by the EXV position. The pressure target varies based on evaporator LWT and discharge superheat values. A PID logic will be used to control the pressure to the target value.

The base pressure target is calculated using the following formula: Base target = 0.6(LWT) – 2 The base target is limited to a range from the low pressure inhibit setpoint plus 2 psi, up to

52 psi. The pressure control target may be adjusted if the discharge superheat is not within an

acceptable range. If the superheat is less than 22 degrees F, the base pressure target will be reduced by a value equal to the low superheat error. If the superheat is more than 40 degrees F, the base pressure target will be increased by a value equal to the high superheat error. At any time, the adjusted target pressure cannot go below the low pressure inhibit setpoint or above 52 psi.

When the EXV transitions to the pressure control state, the target will start at the current evaporator pressure value. The pressure target will then decrement 0.2 psi every second

OM WGS-1 WGS 130A to 190A 55

until reaching the normal calculated target. If the pressure at transition is less than the calculated target, then pressure control will start immediately with the calculated target.

Superheat Control

In superheat control, suction superheat is controlled directly by the EXV. The superheat target varies linearly from 6 to 10 degrees F as discharge superheat changes from 30 degrees F to 22 degrees F. A PID logic will be used to control the superheat to the target value.

When the EXV transitions to the superheat control state, the target will start at the current suction superheat value. This target will then decrement 0.1F every second until reaching the normal target.

Closed

Any time the EXV is not in pressure control or superheat control, it will be in a closed state. At this time, the EXV position is 0 steps and the EXV close signal (digital output) is active.

EXV State Transitions – Water-cooled

Any time the EXV is not in pressure control or superheat control, it will be in a closed state. At this time, the EXV position is 0 steps and the EXV close signal (digital output) is active.

Power ON

Closed

EXV States

Preopen

T6T7

Superheat

Pressure

Transitions:

T1 – Transition from Closed to Preopen, Requires all of the following:

• Unit State = Auto

• Evap State = Run

• Compressor is available

• Compressor is next on

• Stage up now flag is set

• Compressor State = Off

T2 – Transition from Preopen to Pressure Control, Requires the following:

• EXV State has been Preopen for a time greater than the preopen timer setpoint

56 WGS 130A to 190A OM WGS

T3 – Transition from Pressure Control to Superheat Control, Requires all of the following:

• Suction Superheat > Superheat target

• Evap LWT <= 60 F

• EXV State = Pressure AND Discharge Superheat >= 22 F for at least 3 minutes

T4 – Transition from Superheat Control to Pressure Control, Requires any of the following

• Evap LWT > 63 F

• Low Evap Pressure Unload event active

• Discharge Superheat < 22 F or > 40 F

T5, T6, T7 – Transition from any state to Closed state, Requires the following Compressor State not Run

EXV State Transitions – Air-cooled

The following state diagram shows the transitions between EXV control states for aircooled operation only.

EXV States

Closed

Power ON

T1T4T5

Superheat

Pressure

Transitions:

T1 – Transition from Closed to Pressure Control, Requires all of the following:

• Unit State = Auto

• Evap State = Run

• Compressor is available

• Compressor is next on

• Stage up now flag is set

• Compressor State = Off

T2 – Transition from Pressure Control to Superheat Control, Requires all of the following:

• Suction Superheat >= Superheat target

• Evap LWT <= 60 F

• EXV State = Pressure AND Discharge Superheat >= 22 F for at least 3 minutes

• Discharge Temperature <= 180 F

OM WGS-1 WGS 130A to 190A 57

T3 – Transition from Superheat Control to Pressure Control, Requires any of the following:

• Evap LWT > 63 F

• Low Evap Pressure Unload event active

• Discharge Superheat < 22 F

• Discharge Temperature > 185 F

T4, T5 – Transition from any state to Closed state, Requires the following:

• Compressor State not Run

EXV Control Range

The table below shows the EXV range of steps (positions) for each size compressor, at minimum and maximum capacity, as determined by the slide position. The minimum and maximum values vary linearly with slide position, defining a new EXV control range for every change in slide position. Thus, the range of EXV steps allowed (minimum and maximum step) increases as the load increases and more refrigerant flow is required. The minimum and maximum opening also increases as the compressor size, and its capacity and motor cooling requirement, increases.

EXV

Min 0 250 250 250

Unloader

Slide %

167

Compressor S ize

179 197

Max 0 3000 3000 3000 Min 100 870 1080 1300

Max 100 3400 4200 5000

Based on the values in the above table, the EXV control range varies as shown in the table below. The shaded area the control range. The control range considers factors such as providing sufficient refrigerant flow for motor cooling and preventing liquid flood-back.

EXV Control Range

Max EXV

@ 100%

EXV

Steps

Max EXV

@ 0%

Min EXV @ 100%

Min EXV

@ 0%

Slide Position (%)

100

Manual EXV Control

The EXV position can be set manually. Manual control can only be selected when the compressor is in the run state. At any other time, the EXV control setpoint is forced to auto.

58 WGS 130A to 190A OM WGS

When EXV control is set to manual, the EXV position is equal to the manual EXV position setting. If set to manual when the compressor state transitions from run to another state, the control setting is automatically set back to auto.

Oil Heater Control

The oil heater shall be on when the compressor is not running AND the oil level input is closed for 15 seconds. This output will turn off immediately when either the oil level switch opens or the compressor state is no longer off.

Starter Communications

The Modbus protocol is used to establish communications between the compressor starter and the circuit controller on the supervisor port, with the circuit controller acting as the master and the starter as the slave.

Table 24, Parameters to be Read/Written:

Bit Mask

1020 Starter Control R/W

1021 Starter Status R

1026 Avg Current R Amps

0: Run/Stop 1: Fault Reset Bit Mask 0: Ready 1: Running 2: UTS 3: Alarm 4: Fault 5: Lockout

1027 L1 Current R Amps 1028 L2 Current R Amps

1029 L3 Current R Amps 1032 Avg Voltage R Volts 1033 L1-L2 Voltage R Volts 1034 L2-L3 Voltage R Volts 1035 L3-L1 Voltage R Volts

1037 PF R 1038 KW R KW

1039 KVA R KVA 1045 Motor FLA R/W 1-9999 Amps 1046 Motor RLA R/W 1-9999 Amps

1057 1058 Ground Fault Trip Level R/W 1-100 % RLA 1078

Ground Fault Trip Enable

Fault Code – Most Recent Fault Log Entry

R/W

R -

-99 to 100 (in 16 bit two’s compliment signed format)

0: Disabled 1: Enabled

0.01

OM WGS-1 WGS 130A to 190A 59

Read-only parameters are displayed at the circuit controller, and sent over pLAN to the unit controller where they will also be displayed. Read/write parameters are accessible at the circuit controller only. These read/write parameters are changeable when the starter communication is working and the proper password is active.

Starter Faults

Starter faults can be viewed from the unit controller. Some starter faults will be implemented as unique alarms, and others are grouped into a generic starter fault alarm. The most recent fault code shall be stored in the alarm log parameter list. The fault reset signal is sent to the starter when the operator clears the active alarm on the unit controller.

The starter fault codes and their corresponding alarms are shown in the table below:

Table 25, Starter Fault Codes

Fault Code Starter Fault Description Alarm Trig gered

00 No Fault N/a 01 UTS Time Limit Expired No Starter Transition 02 Motor Thermal Overload Trip Compressor Current Overload Trip 10 Phase Rotation Error, not ABC Phase Reversal 12 Low Line Frequency Starter Fault 13 High Line Frequency Starter Fault 15 Input power not three phase Phase Loss 21 Low Line L1-L2 Voltage Undervoltage 22 Low Line L2-L3 Voltage Undervoltage 23 Low Line L3-L1 Voltage Undervoltage 24 High Line L1-L2 Voltage Overvoltage 25 High Line L2-L3 Voltage Overvoltage 26 High Line L3-L1 Voltage Overvoltage 27 Phase Loss Phase Loss 28 No Line Voltage Undervoltage 30 Instantaneous Overcurrent Compressor Current Overload Trip 31 Overcurrent Compressor Current Overload Trip 37 Current Imbalance Motor Current Imbalance 38 Ground Fault Ground Fault Protection 39 No Current at Run Low Motor Current 40 Shorted/Open SCR Starter Fault 47 Stack Protection Fault Starter Fault 48 Bypass Contactor Fault (on Stop Input) No Starter Transition 50 Control Power Low Starter Fault 51 Current Sensor Offset Error Starter Fault 52 Burden Switch Error Starter Fault 60 Thermistor Trip (on DIN#1) High Motor Temperature 61 Stack OT Switch Trip (on DIN#2) Starter Fault 71 Analog Input Trip Starter Fault 82 Modbus Timeout Starter Fault (detected by circuit controller) 94 CPU Error – Software Fault Starter Fault 95 CPU Error – Parameter Storage Fault Starter Fault 96 CPU Error – Illegal Instruction Trap Starter Fault 97 CPU Error – Software Watchdog Fault Starter Fault 98 CPU Error – Spurious Attempt Starter Fault 99 CPU Error – Program Storage Fault Starter Fault

If a starter fault is active and the active alarms are cleared at the unit controller, the clear alarm signal will also be sent to the starter to clear the alarm status in the starter.

60 WGS 130A to 190A OM WGS

Loss of Starter Comm

If starter communication is lost for 10 seconds while the circuit is in a state other than Off or there is a start request, then the Starter Fault alarm will be triggered. Without communication, the fault code cannot be read from the starter so the code 82 will be automatically logged with the alarm.

Condenser Fan Control

Condenser fan control from the MicroTech II controller is used only for air-cooled condenser operation. Head pressure control, as part of the condenser, can be used instead.

Remote evaporative condensers require their own self-contained, on-board, head pressure controls. See page 46.

Fan Stages

There are up to 6 stages of Fantrol available. See the table below:

Table 26, Fantrol Staging

Fantrol Stage Fans On

1 1 2 1,2 3 1,2,3 4 1,2,3,4 5 1,2,4,5,6 6 1,2,3,4,5,6

Staging Up

The controller looks at high the discharge pressure is and how quickly it is rising by accumulating “points” in a collection bin called the “Stage Up Accumulator”.

There are four Stage Up deadbands that apply to the Fantrol stages. Stages one through three use their respective deadbands. Stage four to six share the fourth Stage Up dead band.

When the saturated condenser temperature is above the Target + the active deadband, a Stage Up Error is accumulated.

Stage Up Error Step = Saturated Condenser Refrigerant temperature – (Target + Stage Up dead band). If the condensing temperature is high (rising quickly) relative to the Target plus the dead band, multiple Stage Up Error Steps will be accumulated. This will start a fan sooner than if the temperature is rising slowly.

The Stage Up Error Step is added to Stage Up Accumulator once every Stage Up Error Delay seconds. When the Stage Up Error Accumulator is greater than the Stage Up Error Setpoint, another stage is added.

When a stage up occurs or the saturated condenser temperature falls back within the Stage Up deadband, the Stage Up Accumulator is reset to zero.

Forced Fan Stage At Start

Fans may be started simultaneously with the compressor based on outdoor ambient temperature. When the compressor starts, a Fantrol stage is forced based on the following table. Since this logic applies only to Fantrol fans, the VFD fan is not affected.

OM WGS-1 WGS 130A to 190A 61

Table 27, Forced Fan Staging

OAT Fantrol Stage At Start

> 75 oF Forced Fantrol 1 SP > 90 oF Forced Fantrol 2 SP > 105 oF Forced Fantrol 3 SP

Staging Down

There are four Stage Down dead bands. Stages one through three use their respective deadbands. Stages four to eight share the fourth Stage Down deadband.

The Stage Down process is similar to the Stage Up except in reverse. When the saturated condenser refrigerant temperature is below the Target – the active

deadband, a Stage Down error is accumulated. Stage Down Error Step = (Target - Stage Down dead band) - Saturated Condenser

Refrigerant temperature. The Stage Down Error Step is added to Stage Down Accumulator once every Stage Down

Error Delay seconds. When the Stage Down Error Accumulator is greater than the Stage Down Error Setpoint, another stage of condenser fans turned off.

When a stage down occurs or the saturated temperature rises back within the Stage Down deadband, the Stage Down Error Accumulator is reset to zero. The accumulator is also held at zero after startup until either the outside ambient temperature is less than or equal to 75°F, or the saturated condenser temperature is greater than the condenser target less the active stage down deadband.

Digital Output Control

Each digital output is controlled according to the following rules. All outputs are initialized to OFF at power on.

Alarm – (Terminals J12 – NO1)

This output is turned ON when any Equipment Protection ALARM occurs. It is turned OFF when all alarms have been cleared.

Evaporator Pump – (Terminals J12 – NO2)

An Evaporator Water Pump output is ON if the Evap State is set to START or RUN.

Fan #1 to #8 (Air-Cooled Condensers)

[Water Cooled = N] - Condenser Fans Staging is based on condenser pressure as selected by Fan Stage On & Off setpoints. Fans 1, 3, 5 and 7 are for circuit 1, and fans 2, 4, 6, and 8 are for circuit 2. Fans 1 and 2 start with the first compressor on the respective circuit when the ambient temperature is greater than 75°F. Below 75°F, these fans start when the condenser pressure gets up to the stage on setpoint.

62 WGS 130A to 190A OM WGS

Using the Controller

4x20 Display & Keypad

Layout

The 4-line by 20-character/line, liquid crystal display and 6-key keypad for both of the circuit controller and the unit controller is shown below.

Figure 10, Display (in MENU mode) and Keypad Layout

Air Conditioni ng

Left Arrow Key and

Red Alarm Light

ALARM

VIEW

< <

SET

MENU Key

Key-to-Screen Pathwa

ARROW Keys (4)

ENTER Key and Green

Compressor Run Light

Note that each ARROW key has a pathway to a line in the display. Pressing an ARROW key will activate the associated line when in the MENU mode

. There is no display line

associated with the Down Arrow.

Arrow Keys

The four arrow keys (UP, DOWN, LEFT, RIGHT) have three modes of use.

1. Scroll between data screens as indicated by the arrows (default mode).

2. Select a specific data screen in a hierarchical fashion using dynamic labels on the right side of the display (this mode is entered by pressing the MENU key).

3. Change field values in edit mode according to the following table:

LEFT Default (D) RIGHT Cancel (C) UP Increment (+) DOWN Decrement (-) These four edit functions are indicated by one-character abbreviations on the right side of the display (this mode is entered by pressing the ENTER key).

Getting Started, Navigating - Press the MENU key t o get star ted. The navigatin g

procedures are the same for both the unit controller and the circuit controller

MENU Key

The MENU key is used to switch between the MENU mode as shown in Figure 10 and the SCROLL mode as shown in Figure 11. The MENU mode is basically a shortcut to specific groups of menus used for checking ALARMS, for VIEWING information, or to SET

OM WGS-1 WGS 130A to 190A 63

setpoint values. The SCROLL mode allows the user to move about the matrix (from one menu to another, one at a time) by using the four ARROW keys.

When in the MENU mode (as shown in Figure 10), pressing the LEFT ARROW key will select the ALARM menus, the RIGHT ARROW key will select the VIEW menus and the UP key the SET menus. The controller will go the next lower menu in the hierarchy, and then other menus can be accessed by using the ARROW keys. Pressing the MENU key from any menu screen will automatically return to the MENU mode as shown in Figure 10.

Another way to navigate through the menus is to press the MENU key when in the MENU mode (as above). This will switch the controller to the SCROLL mode. The controller will automatically go to the first screen as shown below (the upper-left menu on the menu matrix shown on pages 66 and 81. From there, the four ARROW keys can be used to scroll up, down, or across to any other menu.

Figure 11, Display in the Shortcut (SCROLL) M ode and Keypad Layout

Red light for fault indication

Air Conditioni ng

MENU Key

VIEW UNIT ST ATUS Unit = COOL Compr. #1/#2=OFF/OFF Evap Pump = RUN

ARROW Keys (4)

ENTER Key

ENTER Key + Green light for comp. On

Pressing the ENTER key changes the function of the ARROW keys to the editing function as shown below:

LEFT key Default RIGHT key Cancel

, changes a value to the factory-set default value.

, cancels any change made to a value and returns to the original

setting. UP key Increment DOWN key Decrement

, increases the value of the setting

decreases the value of a setting.

These four edit functions are indicated by one-character abbreviation on the right side of the display (this mode is entered by pressing the ENTER key).

Changing Setpoints

Most menus containing setpoint values have several different setpoints shown on one menu. When in a setpoint menu, the ENTER key is used to proceed from the top line to the second line and on downward. The cursor will blink at the entry point for making a change. The ARROW keys (now in the edit mode) are used to change the setpoint as described above. When the change has been made, press the ENTER key to enter it. Nothing is changed until the ENTER key is pressed.

For example, to change the chilled water setpoint:

1. Press MENU key to go to the MENU mode.

2. Press SET (the UP Key) to go to the setpoint menus.

3. Press UNIT SPs (the Right key) to go to setpoints associated with unit operation.

64 WGS 130A to 190A OM WGS

4. Press the DOWN key to scroll down through the setpoint menus to the third menu

which contains Evap LWT=XX.X°F.

5. Press the ENTER key to move the cursor down from the top line to the second line in order to make the change.

6. Use the ARROW keys (now in the edit mode as shown above) to change the setting.

7. When the desired value is achieved, press ENTER to enter it and also move the cursor down.

At this point, the following actions can be taken:

1. Change another setpoint in this menu by scrolling to it with the ENTER key.

2. Using the ENTER key, scroll to the first line in the menu. From there, the ARROW keys can be used to scroll to different menus.

Security

All setpoints on the unit controller, as well as the circuit controllers, are protected using passwords. Two four-digit passwords provide OPERATOR and MANAGER levels of access to changeable parameters.

Entering Passwords

Passwords can be entered using the ENTER PASSWORD screen on the unit controller, which is the last screen in the Unit SPs column. The password is entered by pressing the ENTER key, scrolling to the correct value with the UP and DOWN arrow keys, and pressing ENTER again. The longer a key is held down, the faster it will increment. The entered password is not shown after the enter key is pressed. The operator password is 100.

Once the correct password has been entered, the ENTER PASSWORD screen indicates which password is active (none, operator, technician, or manager). If the wrong password is entered, a temporary message will appear so stating. If no valid password is active, the active password level displays “none”.

Entering an incorrect password while a password is active will render that password inactive. Entering a valid password that is not the same as the active password will result in the active password level being changed to reflect the new password level.

Editing Setpoints

After a valid password has been entered at the unit controller, setpoints on the circuit controllers and the unit controller can be changed. If the operator attempts to edit a setpoint for which the necessary password level is not active, no action will be taken.

Once a password has been entered, it remains valid for 60 minutes after the last key-press on the unit controller.

Clearing Alarms

Alarms are only shown on the unit controller and are cleared at the unit controller No password is required.

To clear an alarm, go to the unit controller Alarm Log. Scroll down to the last alarm listed. The screen will note “No More Alarms”. Press and hold ENTER for several seconds until the circuit controllers get a clear signal. If there are no active alarms, the red Alarm light will be off and alarms status will clear from the unit and circuit controllers.

OM WGS-1 WGS 130A to 190A 65

Menu Descriptions

Unit Controller

Various menus are shown in the controller display. Each menu screen shows specific information. In some cases menus are used only to view the status of the unit, in some cases they are used for checking and clearing alarms, and in some case they are used to set the setpoint values that can be changed.

The menus are arranged in a matrix of screens across a top horizontal row. Some of these top-level screens have sub-screens located under them. The content of each screen and its location in the matrix are shown in Menu Matrix. Each menu screen’s detailed description begins on page 67.

The ARROW keys on the controller are used to navigate through the menus. The keys are also used to change numerical setpoint values contained in certain menus.

As an alternate to selecting screens with the menu function, it is possible to scroll through all of them with the 4 arrow keys. For this use, the screens are arranged logically in a matrix as shown below.

Shortcut Menus

These menus are accessed by pressing the Menu button at any time. The hierarchical structure of the shortcut menus is shown below.

Table 28, Unit Controller Shortcut Menus

LEVEL 1 LEVEL 2 LEVEL 3

STATUS VIEW UNIT STATUS (1-4)

TEMP VIEW UNIT TEMP (1-3) CIR 1 VIEW CIR 1 STAT US (1-5) CIR 2 VIEW CIR 2 STAT US (1-5) CIR 1 VIEW REFR CIR 1 (1-5) CIR 2 VIEW REFR CIR 2 (1-5)

VIEW

ALARM

SET

UNIT

CIR STATUS

REFRIGERANT

FANS VIEW FANS

TOWER VIEW TOWER (1-2)/

LOG EVENT/ALARM LOG

ACTIVE ALARM ACTIVE

UNIT SPs SET UNIT SPs (1-15)

COMPRESSOR SPs SET COMP SPs (1-4)

ALARM LIMITS SET ALARM LI MITS (1-4)

TOWER SPs SET TOWER SPs (1-8)

66 WGS 130A to 190A OM WGS

Menu Matrix

When scrolling through the screens, the following matrix is used:

“VIEW” SCREENS

VIEW

UNIT

STATUS

(1)

VIEW

UNIT

STATUS

(2)

VIEW

UNIT

STATUS

(3)

VIEW

UNIT

STATUS

(4)

CONTINUATION

FROM ABOVE

VIEW

UNIT

TEMP

(1)

VIEW

UNIT

TEMP

(2)

VIEW

UNIT

TEMP

(3)

VIEW

CIR 1

VIEW

CIR 1

VIEW

CIR 1

VIEW

CIR 1

VIEW

CIR 1

(1)

(2)

(3)

(4)

(5)

“ALARM”

SCREENS

ALARM

LOG

(1)

. . . .

ALARM

LOG

(25)

VIEW CIR 2

(1)

VIEW CIR 2

(2)

VIEW CIR 2

(3)

VIEW CIR 2

(4)

VIEW CIR 2

(5)

ALARM

ACTIVE

(1)

. . . .

ALARM

ACTIVE

(n)

VIEW

REFRG

CIR 1

(1)

VIEW

REFRG

CIR 1

(2)

VIEW

REFRG

CIR 1

(3)

VIEW

REFRG

CIR 1

(4)

VIEW

REFRG

CIR 1

(5)

VIEW

REFRG

CIR 2

(1)

VIEW

REFRG

CIR 2

(2)

VIEW

REFRG

CIR 2

(3)

VIEW

REFRG

CIR 2

(4)

VIEW

REFRG

CIR 2

(5)

SET UNIT

SPs

(1)

. . . .

SET UNIT

SPs

(15)

VIEW

FANS

VIEW

TOWER

(1)

VIEW

TOWER

(2)

“SET SCREENS” TEST

SET COMP

SPs

(1)

SET COMP

SPs

(2)

SET COMP

SPs

(3)

SET COMP

SPs

(4)

SET ALARM

LMTS

(1)

LMTS

(2)

LMTS

(3)

LMTS

(4)

EVENT

LOG

(1)

. . . .

EVENT

LOG

(25)

CONTINUED

SET

TOWER

SPs (1)

. . . .

SET

TOWER

SPs (8)

BELOW

TEST

UNIT

Selection can be made within the matrix by using the LEFT/RIGHT keys to move between columns and the UP/DOWN keys to move between rows.

Unit Controller Menu Descriptions

This section contains information on each screen of the unit controller. The menu screens are in order of the matrix above, going from left to right and also down when there are submenus. Many menus are self-explanatory. A Setpoint menu allows selection of whether the unit has a water-cooled condenser, Water-Cooled = Y (Yes) or a remote condenser, Water-Cooled = N (No). This selection will alter some menus as appropriate to the type of condenser.

Screen Definitions – ME NU

Top level menu:

< ALARM < VIEW < SET <

OM WGS-1 WGS 130A to 190A 67

ALARM menu:

ALARM < ACTIVE

< LOG < <

VIEW menu: Water-cooled Air-cooled

VIEW < UNIT VIEW < UNIT

< CIR STATUS < CIR STATUS <REFRIGERANT <REFRIGERANT < TOWER < FANS

VIEW UNIT menu:

VIEW < STATUS UNIT < TEMP

< <

VIEW CIRCUIT STATUS menu:

VIEW CIR < CIR 1 STATUS < CIR 2

< <

VIEW REFRIGERANT menu:

VIEW REFR < CIR 1

< CIR 2 < <

SET menu: Water-cooled Air-cooled

SET < ALARM LIMITS SET < ALARM LIMITS

< UNIT SPs < UNIT SPs < COMPRESSOR SPs < COMPRESSOR SPs < TOWER SPs

Screen Definitions – VIEW

View Unit Status

Water-cooled: Air-cooled:

VIEW UNIT STATUS (1) VIEW UNIT STATUS (1) {Unit Status} {Unit Status} Evap Pump= {state} Evap Pump= {state} Cond Pump= {state}

68 WGS 130A to 190A OM WGS

Unit Status will display one of the following: Auto Off:Ice Mode Timer Off:All Cir Disabled Off:Unit Alarm Off:Keypad Disable Off:Remote Switch Off:BAS Disable Off:Unit Switch Off:Test Mode Auto:Wait for load Auto:Cond Recirc Auto:Evap Recirc Auto:Wait Cond Flow Auto:Wait Evap Flow Auto:Pumpdown

Pump states include Off, Start, and Run. The condenser pump state is visible only for water-cooled operation.

VIEW UNIT STATUS (2) Softload Limit=XXX.X Demand Limit= XXX.X Network Limit= XXX.X

VIEW UNIT STATUS (3) Unit Capacity=XXX.X% Ice Delay= XXh XXm

Ice Delay will be visible only when unit mode is ice. It prevents the unit from undesirable starts before the next day’s ice-making cycle.

VIEW UNIT STATUS (4)

1234568 D.O. XXXXXXX D.I. XXXXX

The digital input and output status will show either a “0” or a “1” designating Off and On states respectively.

View Unit Temperature

VIEW UNIT TEMP (1) Evap LWT= XXX.XoF Evap EWT= XXX.XoF Active SP= XXX.XoF

VIEW UNIT TEMP (2) LWT Pulldn= 0.0oF/m Evap Delta T= XX.X

Water-cooled: Air-cooled:

VIEW UNIT TEMP (3) VIEW UNIT TEMP (3) Cond EWT= XXX.XoF OAT= XXX.XoF Cond LWT= XXX.XoF

OM WGS-1 WGS 130A to 190A 69

View Circuit Status

In the following VIEW CIR screens, the N field indicates which circuit (#1, #2) is being viewed. Certain screens located in the circuit controller are also displayed here on the unit controller for convenience.

VIEW CIR N STATUS(1) {Circuit Status} Slide Pos= 000.0% Slide Target=000.0%

Circuit Status will display one of the following: Off:Ready Off:Cycle Timer Off:Low OAT Lock Off:Keypad Disable Off:Pumpdown Switch Off:Alarm Off:Test Mode EXV Preopen Run:Pumpdown Run:Normal Run:LWT PullDn Limit Run:Unit Cap Limit Run:High LWT Limit Run:Evap Press Low Run:Lift Press High Off:pLAN failure

VIEW CIR N STATUS(2) Hours = XXXXX Starts = XXXXX

VIEW CIR STATUS (3) Current (amps)

L1 L2 L3 Avg XXX XXX XXX XXX

VIEW CIR STATUS (4) Voltage L1-2 L2-3 L3-1 Avg XXX XXX XXX XXX

VIEW CIR STATUS (5) PF= 0.XX %RLA=XXX.X KW= XXX KVA= XXX

View Refrigerant

In the following VIEW REFR screens, the N field indicates which circuit (#1, #2) is being viewed.

VIEW REFR CIR N (1) Evap Press=XXX.X psi Cond Press=XXX.X psi

70 WGS 130A to 190A OM WGS

VIEW REFRG CIR N (2) Sat Evap= XXX.X°°°°F Sat Cond= XXX.X°°°°F

VIEW REFRG CIR N (3) Suct Temp = XXX.X °°°°F Disc Temp = XXX.X °°°°F

VIEW REFRG CIR N (4) Suct SH= XXX.X °°°°F Disc SH= XXX.X °°°°F

VIEW REFRG CIR N (5) Evap Approach=XX.X°°°°F Cond Approach=XX.X°°°°F

EXV position = XXXX

View Fans

This screen is only viewable when unit is configured for air-cooled

VIEW FANS Fans On, Cir 1= X Fans On, Cir 2= X

View Tower

These screens is only viewable when unit is configured for water-cooled

VIEW TOWER (1) Fans On= X of X

Cond EWT= XXX.X °°°°F Set Point=XXX °°°°F

VIEW TOWER (2) Bypass Valve=XXX.X% VFD Speed= XXX.X%

OM WGS-1 WGS 130A to 190A 71

Screen Definitions – ALARM

ALARM LOG: XX {Alarm Description} hh:mm mm/dd/yy {Parameters}

The most recent 25 alarms, either shutdown or limit, are shown in this menu and subsequent menus located under it. The last alarm is shown first. ARROW DOWN from this menu will go to the next-to-last alarm, ARROW DOWN again will go to the second from last, and so on through the last 25 occurrences. The screens are numbered (1), (2), (3), etc.

Alarm Description will indicate which alarm occurred. If the alarm is a circuit alarm, then the circuit for which the alarm occurred will also be indicated.

Parameters at the time of the alarm are shown on the bottom line of the screen one at a time. These are scrolled through by pressing the edit key and using the up and down arrows to scroll through the list. Parameters include:

Unit State Evap LWT Evap EWT Cond EWT/OAT Circuit State Evaporator Pressure Condenser Pressure Suction Temperature Discharge Temperature Discharge Superheat EXV Position EXV State Slide Position Fans On

Starter Fault Code (will show “00” when the alarm logged is not a starter fault)

EVENT LOG: XX {Event Description} hh:mm mm/dd/yy

*** ALARM ***

hh:mm mm/dd

{Alarm Description}

NO MORE ALARMS

Press ENTER to clear

If the unit is off on a shutdown alarm or running, but in a limit alarm condition, the cause and date will appear in the above screen. If there is a simultaneous occurrence of more than one alarm, the others will appear in additional screens below the first one, accessed by the DOWN ARROW. Either type alarm will light a red light in back of the LEFT-ARROW KEY. The light will go out when the fault is cleared. To clear the fault, scroll down to the last screen and press ENTER. If other faults have appeared, they will all be cleared at the same time.

72 WGS 130A to 190A OM WGS

Screen Definitions – SET

Unit Set Points

SET UNIT SPs (1) Enable=On Mode= COOL Source = KEYPAD

Unit Enable settings can be OFF and ON as determined from the Unit Enable setpoint. Unit Enable is an external signal or a keypad setting that keeps the unit off when the setting

is OFF and allows it to run if there is a call for cooling when the setting is ON. The source for the signal is selected in the 4

1. KEYPAD, in which case the selection is made in line 2 and would be normally selected

as ON. This is the normal setting when no external signals are controlling the unit.

2. SWITCHES, in which an external switch is wired across terminals #25 and #35. (See

wiring diagram page 8 or 9.)

3. NETWORK, used with BAS signal, which is wired to the three communication ports. Unit Mode settings can be

1. COOL, normal setting used with chilled water air-condition applications.

2. COOL w/GLYCOL, used with low temperature, glycol applications. It allows a lower

LWT setpoint to be used.

line and can be:

3. ICE w/GLYCOL, used with ice storage systems, allows changing from chilled glycol

operation to lower temperature ICE operation. In ICE, the unit runs at full load until the ICE setpoint is reached, at which time the unit shuts off. A three-position switch wired to terminals #28 and #38 initiates the change from glycol cooling to making ice. (See wiring diagrams on page 8 or 9.)

Unit Mode settings can be COOL COOLw/Glycol, or ICEw/Glycol, as determined from the Unit Mode setpoint.

Source settings can be KEYPAD, SWITCHES, or NETWORK as determined from the Mode Source setpoint.

SET UNIT SPs (2) Available Modes

= COOL

Select w/Unit Off

SET UNIT SPs (3) Cool LWT = XX.X°°°°F Ice LWT = XX.X°°°°F StartDelta=XX.X°°°°F

SET UNIT SPs (4) StopDelta= X.X°°°°F Stg Up Delta= X.X°°°°F Stg Down Delta=X.X°°°°F

OM WGS-1 WGS 130A to 190A 73

SET UNIT SPs (5) Max Pulldn=X.X°°°°F/min

EvapRecTimer=XXX sec Evap Pump= #1 Only

Water-cooled: Air-cooled:

SET UNIT SPs (6) SET UNIT SPs (6) Watercooled= Yes Watercooled= No CondRecTimer=XXX sec Cond Pump= #1 Only

SET UNIT SPs (7) Reset Type= none

Max Reset = XX.X°°°°F StrtResetDT= XX.X°°°°F

SET UNIT SPs (8) Soft Load= Off Begin Capacity= XXX% SoftLoadRamp= XXmin

Water-cooled: Air-cooled:

SET UNIT SPs (9) SET UNIT SPs (9) Demand limit= Off Demand limit= Off

LowOAT Operation=No Low Amb Lock= XX.X°°°°F

SET UNIT SPs (10) Ice Time Delay=XXhrs Clear Ice Timer=No

SET UNIT SPs (11) Sensor Offset

Evap LWT= XX.X°°°°F Evap EWT= XX.X°°°°F

Water-cooled: Air-cooled:

SET UNIT SPs (12) SET UNIT SPs (12) Sensor Offset Sensor Offset

Cond EWT= XX.X°°°°F OAT= XX.X°°°°F Cond LWT= XX.X°°°°F

SET UNIT SPs (13)

CLOCK mm/dd/yyyy hh:mm day

74 WGS 130A to 190A OM WGS

SET UNIT SPs (14) Units = °°°°F/psi

Lang = ENGLISH

After entering a valid manager password, selecting °F/psi will provide IP units; selecting °C/kPa will provide SI units.

SET UNIT SPs (15) Protocol= Ident Number= Baud Rate=

SET UNIT SPs (16) Enter Password:0000

Active Password Level:none

Compressor Set Points

SET COMP SPs (1) Seq # Comp 1= X Seq # Comp 2= X

SET COMP SPs (2) Start-Start =XX min Stop-Start =XX min

This menu sets the anti-recycle timers. Stop-Start is the time required before starting a compressor after it has stopped. Start-Start is the time required before starting a compressor after the last time it has started. It is recommended that the default values of 5 minutes and 15 minutes not be changed.

SET COMP SPs (3) Pumpdown Pressure= XX.X psi Time Limit= XXX sec

SET COMP SPs (4) Light Load Stage Down Point=XX% slide Stg Up Delay= XX min

Alarm Set Points

SET ALARM LIMITS (1) Low Evap Pressure Hold=XX.Xpsi Unload=XX.Xpsi

OM WGS-1 WGS 130A to 190A 75

The LowEvPrHold (Low Evaporator Pressure Hold) and LowEvPrUnld (Low Evaporator Pressure Unload) have the same default value of 59 psi. If two compressors are running, the LowEvPrUnld is in effect and the lag compressor will be shut off to unload the unit. If one compressor is running, the LowEvPrHold is in effect and the lag compressor is prevented from starting, thereby holding the unit capacity.

The last action to take place is the shutoff of all compressors running when the LowEvPrStop setting is reached (default is 58 psi). Reducing these time intervals will increase detrimental compressor cycling. It is recommended that these settings not be changed.

SET ALARM LIMITS (2) LowOilDelay= XXX sec HighOilDpDel=XXX sec

SET ALARM LIMITS (3) High Disc Temp=XXX°°°°F

HighLift Delay=XXsec

Water-cooled: Air-cooled:

SET ALARM LIMITS (4) SET ALARM LIMITS (4) Evap Freeze= XX.X°°°°F Evap Freeze= XX.X°°°°F

Evap Flow Proof=XXXs Evap Flow Proof=XXXs

LowOATStartTmr=XXsec

Evap Freeze (the unit freeze protection shutdown) is actually a stop alarm and shuts off the unit when the LWT reaches 36°F. It is cleared by going to the CLEAR ALARM menu in the ACTIVE ALARM hierarchy.

Evap/Cond FlowProof is the flow switch interlock. Closing the flow switch, and therefore proving the existence of chilled water flow, resets this trip. It is recommended that these settings not be changed.

SET ALARM LIMITS (5) Cond Freeze= XX.X°°°°F

Cond Flow Proof=XXXs

Set Alarm Limits (5) is accessible only if unit is configured as water-cooled

Tower Setpoints

Tower set points are only available when the unit is configured as water-cooled. The MicroTech II controller is capable of controlling cooling tower water temperature on

chillers using water-cooled condensers. Output wiring connection points are shown on the field wiring diagrams beginning on page 8.

[Water Cooled = Y] - Condenser Pump on with first Compressor on. Tower fan control is active when the Tower Control setpoint is set to Temperature and the condenser pump is in the RUN state. Staging is based on Entering Condenser Water Temperature (ECWT). Operation depends on the following parameters.

• Condenser pump state

• ECWT OR Lift pressure

• Stage up and stage down timer values

76 WGS 130A to 190A OM WGS

• Tower setpoints (Tower Control, Tower Stages, Stage Up Time, Stage Down Time,

Stage Differential, Stage #1 ON, Stage #2 ON, Stage Down @, Stage Up @) When the condenser pump starts, the stage up timer shall start. The first stage shall turn ON when the following conditions are met:

• The stage up timer completes

• The ECWT is > Stage #1 ON setpoint

• Bypass valve position is > the Stage Up @ setpoint (only if Valve/VFD Control setpoint

= Valve Stage) Additional stages can turn on (up to the number specified by the Tower Stages setpoint) when above conditions are met for the next stage plus the following condition:

• VFD Speed is > the Stage Up @ setpoint (only if Valve/VFD Control setpoint = VFD

Stage OR Valve SP/VFD Stage) Down staging shall occur when the following conditions are met:

• The stage down timer completes

• The ECWT is < Stage #X ON (Temp) setpoint – Stage Differential (Temp) setpoint

point

• Bypass valve position is < the Stage Down @ setpoint (only if Valve/VFD Control

setpoint = Valve Stage)

• VFD Speed is < the Stage Down @ setpoint (only if Valve/VFD Control setpoint =

VFD Stage OR Valve SP/VFD Stage)

Each stage-up or stage-down event shall restart both the stage-up and stage-down timers. Only one fan output shall be switched at a time (except that all outputs switch OFF when the condenser pump state equals OFF).

SET TOWER SPs (1) Tower Control=None Tower Stages= 2

When Tower Control is None, the control of condenser water temperature is not by the MicroTech II controller and assumed to be furnished elsewhere.

Tower Stages is the number of tower fans to be staged by the controller, choices are 0, 1, or

2. "0" indicates control will be by a bypass valve or variable speed pump controlled by the MicroTech II controller.

StageUP/DN imposes a time delay between fan stages when turning on or turning off.

SET TOWER SPs (2) Stage 1 On =XXX Stage 2 On =XXX StageDiff = XX.X

SET TOWER SPs (3) Stage Up Tmr= XX min Stage Dn Tmr= XX min Stage Up/Dn=XXX/XXX%

StageDiff is the number of degrees below the Stage ON that will turn off the tower fans. For example, if Stage ON #1 is 70°F and StageDiff is 5°F, tower fan #1 will stage off when

OM WGS-1 WGS 130A to 190A 77

the ECWT drops to 65°F and stage the fan on when the ECWT rises to 70°F. T he same is true for fan #2.

Stage Up timer is the number of minutes that must elapse between the condenser pump starting (it starts with the unit) and fan #1 starting or the time between fan #1 starting and fan #2 starting.

StageDown is the elapsed time between staging down the fan motors.

SET TOWER SPs (4) Valve/VFD Control=

None

Valve Type=NC to twr

Valve/VFD Control settings are None, Valve Setpoint, Valve Stage, VFD Stage, or ValveSP/VFDStage. Default is None which results in no control of the tower from the MicroTech II controller.

• Valve Setpoint

, the valve will control (bypass tower) to hold the minimum temperature

as established by the Set Tower SPs in screen number 5 shown on the following page. This mode is operational when the Valve/VFD Control setpoint is set to Valve Setpoint

OR Valve SP/VFD Stage. In this mode the valve output is varied with a proportionalderivative (PD) algorithm (with deadband) in order to maintain the controlled parameter (CP) at the desired value. The output is always limited between the Valve Control Range (Min) setpoint and the Valve Control Range (Max) setpoint. A valve increment shall be computed once every 5 seconds according to the following equation. (Error Gain and Slope Gain are set in menu screen #8.)

Increment = [(Error) * (Error Gain setpoint)] + [(Slope) * (Slope Gain setpoint)] Where: Error = ECWT – Valve Setpoint Slope = (Present CP) – (Previous CP)

When the Error is > the Valve Deadband setpoint, the valve position analog output (% of full scale) is updated according to the following equation.

New %Position = Old %Position + Increment/10

• Valve Stage

, controls from the fan stage setpoint in use. It is recommended that the

Valve Setpoint method explained above be used rather than this mode. This mode is only operational when the Valve/VFD Control setpoint is set to Valve

Stage. In this mode the valve output is controlled as for Valve Setpoint mode (above), except that the active setpoint for the controlled parameter is selected according to the following table.

# Of Fans ON Active Setpoint

0 Valve Setpoint 1 Stage #1 ON 2 Stage #2 ON 3 Stage #3 ON 4 Stage #4 ON

• VFD Stage, ValveSP/VFDStage, When the Valve/VFD Control setpoint is set to None,

Valve Setpoint, OR Valve Stage, this output is set to 0. Otherwise, it will be controlled in a manner identical to Valve Stage Mode (above) except that (1) it shall be kept at zero until the first fan stage is ON, and (2) the following setpoints do not apply.

78 WGS 130A to 190A OM WGS

Valve Control Range (Min)

Valve Control Range (Max)

Valve Type

Valve Type settings are NC (normally closed to tower) or NO (normally open). These settings establish the operation of a tower bypass valve (must be a 3-way valve).

Initial Va lve Position

When the condenser pump is not in the RUN state, the valve output shall be set as a function of entering condenser water temperature (ECWT) per the following graph.

Figure 12, Initial Valve Position

Initial Valve Position

Max Position @

(values are examples only)

Setpoint

(90°F)

Min Position @

Setpoint

(60°F)

Min Start Position

Setpoint

Operation After Start

0 to 10 VDC (Valve Type = NC) 10 to 0 VDC (Valve Type = NO)

(10%)

Max Start Position

Setpoint

(90%)

SET TOWER SPs (5) Valve SP=XXX Valve DB=XX.X

Valve SP is the minimum tower water temperature acceptable, default is 65°F. Valve DB is the dead-band in degrees, default is 2.0°F.

SET TOWER SPs (6) Valve Start Position

Min= XXX% @XXX Max= XXX% @XXX

The ValveStart position is the position of the valve when the unit starts. Default for minimum start position is 0%, and 100% for maximum position.

OM WGS-1 WGS 130A to 190A 79

SET TOWER SPs (7) Valve Control Range

Min= XXX% Max= XXX%

Defaults are 10% minimum and 90% maximum.

SET TOWER SPs (8) PD Control Loop

Error Gain=XX Slope Gain=XX

Defaults are 25 for both error and slope.

Screen Definitions – TEST

TEST UNIT (1) Alarm Out=Off Evap Pump 1= Off Evap Pump 2= Off

TEST UNIT (2) Cond Pump 1= Off Cond Pump 1= Off

TEST UNIT (3) Tower Fan 1= Off Tower Fan 2= Off

TEST UNIT (4) Tower Bypass= XXX.X Tower VFD Spd= XXX.X

Circuit Controller

The display on the circuit controller displays information about the circuit that it is controlling. Setpoint availability will be limited to setpoints that are unique to that circuit. Other set points are changed at the Unit Controller.

Shortcut Menus

Pressing the Menu button at any time accesses these menus. The hierarchical structure of the shortcut menus is shown below.

80 WGS 130A to 190A OM WGS

LEVEL 1 LEVEL 2 LEVEL 3 (No. of Screens)

UNIT VIEW UNIT (1-2)

VIEW

CIR STATUS VIEW CIR STATUS (1-9)

REFRIGERANT VIEW REFRIGERANT (1-7)

FANS VIEW FANS (1-2)

COMPRESSOR SPs SET COMP SPs (1-4)

SET

EXV SPs SET EXV SPs (1-2) FAN SPs SET FANS (1-6)

SENSOR OFFSETS SET SENSOR OFFSET (1-3)

Menu Matrix

When scrolling through the screens, the following matrix is used:

VIEW

UNIT (1)

VIEW

UNIT (2)

VIEW CIR

STATUS

(1)

VIEW CIR

STATUS

(2)

VIEW CIR

STATUS

(3)

VIEW CIR

STATUS

(9)

VIEW

REFRG

(1)

VIEW

REFRG

(2)

VIEW

REFRG

(3)

VIEW

REFRG

(7)

VIEW FANS

(1)

VIEW FANS

(2)

SET COMP SPs (1)

SET COMP SPs (2)

SET COMP SPs (3)

SET COMP SPs (4)

SET EXV

SPs (1)

SET EXV

SPs (2)

FANS (1)

FANS (2)

FANS (3)

FANS (5)

SET

SENSOR

OFFSETS

SENSOR

OFFSETS

SENSOR

OFFSETS

SET

(1)

SET

(2)

SET

(3)

TEST

CIRCUIT

(1)

TEST

CIRCUIT

(2)

TEST

CIRCUIT

(3)

TEST

CIRCUIT

(4)

Screen Definitions – ME NU

Top level menu:

< VIEW < SET < <

View menu:

VIEW < UNIT

< CIR STATUS <REFRIGERANT < FANS

Fan data is available only when unit is configured as air-cooled.

Set menu:

SET <COMPRESSOR SPs

< EXV SPs < FAN SPs <SENSOR OFFSETS

Fan setpoints are available only when unit is configured as air-cooled.

OM WGS-1 WGS 130A to 190A 81

Screen Definitions – VIEW

View Unit Status

Water cooled: Air cooled:

VIEW UNIT (1) VIEW UNIT (1) {Unit status} {Unit status} Evap pump = {State} Evap pump = {State} Cond pump = {State}

Pump states include Off, Start, and Run. The condenser pump state is visible only for water-cooled operation.

VIEW UNIT (2) Evap LWT= XXX.X°°°°F Active SP= XX.X°°°°F LWT pulldn= XX.X°°°°F/m

View Circuit Status

VIEW CIR STATUS (1) {Circuit Status} Slide Pos= XXX.X% Slide Target= XXX.X%

VIEW CIR STATUS (2) Hours = XXXXX Starts = XXXXX

VIEW CIR STATUS (3) Current (amps)

L1 L2 L3 Avg

XXX XXX XXX XXX

82 WGS 130A to 190A OM WGS

VIEW CIR STATUS (4) Voltage L1-2 L2-3 L3-1 Avg XXX XXX XXX XXX

VIEW CIR STATUS (5) PF= 0.XX %RLA=XXX.X KW= XXX KVA= XXX

VIEW CIR STATUS (6)

Digital Outputs 12345678910 XXXXXXXXXX

Status will be “0” for OFF and “!” for ON.

VIEW CIR STATUS (7) Digital Outputs 11 12 13

XXX

VIEW CIR STATUS (8)

Analog Outputs

(volts X 100)

1=XXXX 3=XXXX

VIEW CIR STATUS (9)

Digital Inputs

1345679

XXXXXXX

View Refrigerant

VIEW REFRIGERANT (1) Evap Press=XXX.X psi Cond Press=XXX.X psi

VIEW REFRIGERANT (2) Sat Evap = XXX.X °°°°F Sat Cond = XXX.X °°°°F

VIEW REFRIGERANT (3) Suct Temp = XXX.X °°°°F Disc Temp = XXX.X °°°°F

OM WGS-1 WGS 130A to 190A 83

VIEW REFRIGERANT (4) Suct SH= XXX.X °°°°F Disc SH= XXX.X °°°°F

VIEW REFRIGERANT (5) Evap Approach=XX.X°°°°F Cond Approach=XX.X°°°°F

VIEW REFRIGERANT (6) MaxCondSatT= XXX.X°°°°F

EXV Ctrl=Superheat SH target= XX.X°°°°F

VIEW REFRIGERANT (7) EXV Steps= XXXX EXV ctrl range:

XXXX – XXXX steps

View Fans

View Fans screens are only available when the unit is configured as air-cooled.

VIEW FANS (1) Fans Running= X Stage Up Err= XXX Stage Dn Err= XXX

VIEW FANS (2) Target Sat T=XXX.X°°°°F

Screen Definitions – SET

Compressor Set Points

SET COMP SPs (1) Clear Cycle Tmr= no Comp Size= XXX Max Slide= XXX.X %

SET COMP SPs (2) Circuit Mode=Enable Slide Target= XXX.X% Slide Control=auto

84 WGS 130A to 190A OM WGS

SET COMP SPs (3) Motor FLA= XXX amps Motor RLA= XXX amps

SET COMP SPs (4) Ground Fault=No GF Trip Level= XXX%

EXV Set Points

SET EXV SPs (1) Manual EXV Pos= XXXX EXV Control=auto Service Pumpdown=No

SET EXV SPs (2) Preopen Timer=XXXsec

Sensor Offsets

SET SENSOR OFFSET(1) Evap Press= XX.X psi Cond Press= XX.X psi

SET SENSOR OFFSET(2) Suct Temp= X.X °°°°F Disch Temp= X.X °°°°F

SET SENSOR OFFSET(3) Slide min pos= XX% Slide max pos= XX%

Slide Pos= XXX.X%

Fan Set Points

SET FAN SPs (1) Number of fans = X

SET FAN SPs (2) Stg On Deadband(°°°°F)

Stg1=XX.X Stg2=XX.X Stg3=XX.X Stg4=XX.X

OM WGS-1 WGS 130A to 190A 85

SET FAN SPs (3) Stg Off Deadband(°°°°F)

Stg2=XX.X Stg3=XX.X Stg4=XX.X Stg5=XX.X

SET FAN SPs (4) Cond Sat Temp Target

Max= XXX.X °°°°F Min= XXX.X °°°°F

SET FAN SPs (5) # Fans On At Startup

>75°°°°F >90°°°°F >105°°°°F

XXX

Screen Definitions – TEST

TEST CIRCUIT (1) Slide Direction = Unload Pulse = Off

TEST CIRCUIT (2) Oil Heater= Off EXV Closed= Off

TEST CIRCUIT (3) EXV Position=XXXX

TEST CIRCUIT (4) Condenser Fans: 1=Off 2=Off 3=Off 4=Off 5=Off 6=Off

Editing Review

Editing is be accomplished by pressing the ENTER key until the desired field is selected. This field shall be indicated by a blinking cursor under it. The arrow keys shall then operate as defined below.

CANCEL (Right).............. Reset the current field to the value it had when editing began.

DEFAULT (Left) .............. Set value to original factory setting.

INCREMENT (Up)..........Increase the value or select the next item in a list.

DECREMENT (Down)....Decrease the value or select the previous item in a list.

86 WGS 130A to 190A OM WGS

During edit mode, the display shows a two-character wide menu pane on the right as shown below.

SET UNIT SPs (X) <D

(data) <C (data) <+ (data) <-

Additional fields can be edited by pressing the ENTER key until the desired field is selected. When the last field is selected, pressing the ENTER key switches the display out of “edit” mode and returns the arrow keys to “scroll” mode.

Alarms

When an alarm occurs, the alarm type, limit value (if any), date, and time are stored in the active alarm buffer corresponding to that alarm (viewed on the Alarm Active screens) and also in the alarm history buffer (viewed on the Alarm Log screens). The active alarm buffers hold a record of the last occurrence of each alarm and whether or not it has been cleared. The alarm can be cleared by pressing the Edit key. A separate buffer is available for each alarm (High Cond Pressure, Evaporator Freeze Protect, etc.). The alarm history buffer holds a chronological account of the last 25 alarms of any type.

Security

Two four-digit passwords provide OPERATOR and MANAGER levels of access to changeable parameters. Either password can be entered using the ENTER PASSWORD screen which can be accessed either through the SET OTHER menu or by simply pressing the ENTER key while on one of the SET screens. The password can then be entered by pressing the ENTER key, scrolling to the correct value with the UP and DOWN arrow keys, and pressing ENTER again. Once the correct password has been entered, the previously selected screen will reappear. Once a password has been entered, it will remain valid for 15 minutes after the last key-press.

BAS Interface

The MicroTech II controller is equipped with the Protocol Selectability feature, an exclusive McQuay feature that provides easy unit interface with a building automation system (BAS). If the unit will be tied into a BAS, the controller should have been purchased with the correct factory-installed interface module. The modules can also be added in the field during or after installation.

If an interface module was ordered, one of the following BAS interface installation manuals was shipped with the unit. Contact your local McQuay sales office for a replacement, if necessary or obtain from www.mcquay.com.

• IM 735, LONWORKS Communication Module Installation

• IM 736, BACnet Communication Module Installation

• IM 743, Modbus Communication Module Installation

• ED 15062-0, MicroTech II Chiller Protocol Information – BACnet and L

• ED 15063-0, MicroTech II Chiller Unit Controller Protocol Information – Modbus

Connection to Chiller

Connection to the chiller for all BAS protocols will be at the unit controller. An interface card will have to be installed in the unit controller depending on the protocol being used.

ONWORKS

OM WGS-1 WGS 130A to 190A 87

Troubleshooting Chart

Troubleshooting can cause severe personal injury or death. Troubleshooting

must be performed by trained, experienced technicians only

Troubleshooting Chart

PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS

1. Main switch, circuit break ers open.

2. Fuse blown.

3. Thermal overloads tripped or fuses

Compressor Will Not Run

Compressor Noisy or Vibrating

High Discharge Pressure

Low Discharge Pressure

High Suction Pressure

Continued on next page.

blown.

4. Defective contactor or c oi l .

5. System shut down by equipment protection devices.

6. No cooling required.

7. Liquid line solenoid will not open.

8. Motor electrical trouble.

9. Loose wiring.

1. Fl oodi ng of refrigerant into compres sor.

2. Improper piping support on suc t i on or

liquid line.

3. Worn compressor.

1. Condenser water insufficient or

temperature too high.

2. Foul ed condenser tubes (water-cooled

condenser). Clogged spray nozzles (evaporative condenser). Dirty tube and fin surface (air cooled c ondenser).

3. Noncondensables in system.

4. System overcharge with refrigerant.

5. Di scharge shutoff valve partial l y closed.

6. Condenser undersized (air-cooled).

7. Hi gh ambient conditions.

1. Faul ty condenser temp. regulati on.

2. Insufficient refri gerant in system.

3. Low suction pressure.

4. Condenser too large.

5. Low am bi ent conditions.

1. Excessive load.

2. Expansion valve overfeeding.

WARNING

1. Close switch

2. Check el ectrical circuits and motor winding for shorts or grounds. Investigate for possi ble overloading. Replace fuse or reset breakers after fault is corrected.

3. Overloads are auto reset. Check unit closely when unit comes back on line.

4. Repair or replace.

5. Determ i ne type and cause of shutdown and correct it before resetting protection switch.

6. None. Wait until unit calls for cooling.

7. Repair or replace coil.

8. Check motor for opens, short circuit, or burnout.

9. Check all wire junc tions. Tighten all terminal screws.

1. Check superheat setting of expansion

valve.

2. Rel ocate, add or remove hangers.

3. Replace.

1. Readj ust temperature control or water

regulating valve. Investigat e ways t o increase water supply.

2. Clean.

3. EPA purge t he noncondensables.

4. Remove excess refrigerant.

5. Open valve.

6. Check condenser rating tables agai nst

the operation.

7. Check condenser rating tables agai nst

the operation.

1. Check condenser control operati on.

2. Check for leaks. Repair and add c harge.

3. See corrective steps for low suction

pressure below.

4. Check condenser rating table against the

operation.

5. Check condenser rating tables agai nst

the operation.

1. Reduce load or add additional

equipment.

2. Check remote bulb. Regulat e superheat.

88 WGS 130A to 190A OM WGS

PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS

Low Suction Pressure

Little or No Oil Pressure

Compressor Loses Oil

Motor Overload Relays or Circuit Breakers Open

Compressor Thermal Switch Open

Freeze Protection Opens

1. Lack of refrigerant.

2. Evaporator dirty.

3. Cl ogged l i qui d l i ne filter-drier.

4. Expansion valve malfunctioning.

5. Condensing temperature too low.

6. Compressor will not unload.

7. Insufficient water flow.

1. Cl ogged suction oil strainer.

2. Excessive liquid in crankcase.

3. Low oil level.

4. Fl oodi ng of refrigerant into crankcase.

1. Lack of refrigerant.

2. Velocity in risers t oo l ow (A-C only).

3. Oi l trapped in line.

1. Low voltage duri ng hi gh l oad conditions.

2. Defective or grounded wiring in motor or power circuits.

3. Loose power wiring.

4. Hi gh condensing temperature.

5. Power line fault causing unbalanced voltage.

6. Hi gh ambient temperature around t he overload relay

1. Operating beyond design conditions.

2. Di scharge valve partially shut.

1. Thermostat set too low.

2. Low water flow.

3. Low suction pressure.

1. Check for leaks. Repair and add c harge.

2. Clean chemically.

3. Replace cartridge(s).

4. Check and reset for proper superheat. Replace if necessary.

5. Check means for regulati ng condensing temperature.

6. See corrective steps f or f ai l ure of compressor to unload.

7. Adjust flow.

1. Clean.

2. Check sump heater. Res et expansion valve for higher superheat. Check li qui d line solenoid valve operation.

3. Add oil.

4. Adjust expansion valve.

1. Check for leaks and repair. A dd refrigerant.

2. Check riser sizes.

3. Check pitch of lines and refrigerant velocities.

1. Check supply voltage for excess i ve l i ne drop.

2. Replace compressor-motor.

3. Check all connections and tighten.

4. See corrective steps for hi gh di scharge pressure.

5. Check Supply voltage. Notify power company. Do not start until fault is corrected.

6. Provide ventilation to reduce heat.

1. A dd facilities so that conditions are within allowable limits.

2. Open valve.

1. Reset to 42°F (6°C) or above.

2. Adjust flow.

3. See “Low Suction Pressure.”

OM WGS-1 WGS 130A to 190A 89

This document contains the most current product information as of this printing. For the most up-todate product information on this unit and others, please go to www.mcquay.com.

Post Office 2510, Staunton, Virginia 24402 USA • (800) 432-1342 • www.mcquay.com OM WGS (6/04)

McQuay WGS 130AA Installation Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Introduction

General Description

Nomenclature

Definitions

Active Setpoint

Active Capacity Limit

Condenser Recirc Timer

Condenser Saturated Temperature Target

CPU Error

Dead Band

Discharge Superheat

Error

Evaporator Approach

Evap Recirc Timer

High Saturated Condenser – Hold Value

High Saturated Condenser – Unload Value

High Superheat Error

Light load Stg Dn Point

Load Limit

Load Balance

Low Ambient Lockout

Low Pressure Hold Setpoint

Low/High Superheat Error

LWT Error

LWT Slope

Maximum Saturated Condenser Temperature

Offset

pLAN

Rapid Stop

Refrigerant Saturated Te mperature

Soft Load

Suction Superheat

Stage Up/Down Accumulator

Stageup/Stagedown Delta-T

Stage Up Delay

Startup Delta-T

Stop Delta-T

Wiring Diagrams

Control Panel Layout

System A rchitecture

PLAN A ddressing

General Description

Units of measure

Distributed Control

Operator-friendly

Staging

Equipment Protection

Unit Enable Selection

Unit Mode Selection

Keypad/Display

Sequence of Operation

Compressor Heaters

Startup/Compressor Staging

Automatic Pumpdown

Chilled Water and Condenser Water Pumps

Cooling Tower Control

Condenser Fan Control

Start-Up and Shutdown

Pre Start-up

Start-up

Weekend or Temporary Shutdown

Start-up after Temporary Shutdown

Extended Shutdown

Start-up after Extended Shutdown

Unit Controller

Unit Inputs/Outputs

Unit Setpoints

Auto A dj usted Ranges

Circuit Controller

Circuit Inputs and Outputs

Circuit Setpoint Table

Alarms, Warnings, Events

Stop Alarms (Shutdown)

Events (Limit)

Clearing Alarms

Unit Controller Functions