McQuay WGS130AA: WGS140AW

Questions and Answers:

S
Seth SmithAug 22, 2025
What to do if motor overload relays or circuit breakers open in McQuay WGS130AA: WGS140AW Chiller?
- S
  Shane RiveraAug 22, 2025
  If the motor overload relays or circuit breakers are open on your McQuay Chiller, consider these potential causes: * Check for low voltage during high load conditions, and examine the supply voltage for excessive line drop. * Inspect for defective or grounded wiring in the motor or power circuits. Replace the compressor-motor if necessary. * Ensure all power wiring connections are tight. * Address high condensing temperature by following corrective steps for high discharge pressure. * Check the supply voltage for a power line fault causing unbalanced voltage. Notify the power company and do not start the chiller until the fault is corrected. * Provide ventilation to reduce heat if there's a high ambient temperature around the overload relay.
S
Summer FowlerAug 25, 2025
What causes low discharge pressure in a McQuay WGS130AA: WGS140AW Chiller?
- M
  Ms. Lauren Kirby MDAug 26, 2025
  If the McQuay Chiller has low discharge pressure, here are a few things to check: * Examine the condenser control operation for faulty temperature regulation. * Check for leaks and add refrigerant if there is insufficient refrigerant in the system. * Refer to the corrective steps for low suction pressure. * Compare the condenser rating table against the operation if the condenser is too large. * Check the condenser rating tables against the operation if there are low ambient conditions.
M
matthew87Aug 28, 2025
What should I do if my McQuay WGS130AA: WGS140AW Chiller has low suction pressure?
- L
  linjasonAug 28, 2025
  If your McQuay Chiller is experiencing low suction pressure, consider the following: * Check for refrigerant leaks and add refrigerant if necessary. * Clean the evaporator chemically if it's dirty. * Replace the cartridge(s) if the liquid line filter-drier is clogged. * Check and reset the expansion valve for proper superheat, replacing it if necessary. * Check the means for regulating condensing temperature if the condensing temperature is too low. * Refer to the corrective steps for failure of the compressor to unload. * Adjust the flow if there is insufficient water flow.
R
Robert KeithAug 30, 2025
Why is my McQuay Chiller compressor noisy or vibrating?
- E
  Ernest WrightAug 30, 2025
  If your McQuay Chiller's compressor is noisy or vibrating, here's what you can check: * Examine the superheat setting of the expansion valve to prevent refrigerant flooding into the compressor. * Relocate, add, or remove hangers to ensure proper piping support on the suction or liquid line. * If the compressor is worn, consider replacing it.
C
Carlos FullerSep 2, 2025
What causes little or no oil pressure in a McQuay WGS130AA: WGS140AW Chiller?
- S
  Sarah StewartSep 2, 2025
  If your McQuay Chiller shows little or no oil pressure, here's what to investigate: * Clean the suction oil strainer if it's clogged. * Check the sump heater, reset the expansion valve for higher superheat, and check the liquid line solenoid valve operation if there's excessive liquid in the crankcase. * Add oil if the oil level is low. * Adjust the expansion valve if there's flooding of refrigerant into the crankcase.
M
Mrs. Jacqueline WernerSep 5, 2025
Why is the suction pressure high in my McQuay WGS130AA: WGS140AW?
- R
  Richard Tate MDSep 5, 2025
  If your McQuay Chiller is experiencing high suction pressure, consider the following: * Reduce the load or add additional equipment if there is an excessive load. * Check the remote bulb and regulate superheat if the expansion valve is overfeeding.
L
Lawrence SheppardSep 7, 2025
Why does my McQuay WGS130AA: WGS140AW Chiller compressor lose oil?
- S
  Stephanie CunninghamSep 7, 2025
  If the compressor in your McQuay Chiller is losing oil, here are a few things to check: * Check for leaks and repair them. Add refrigerant if there is a lack of refrigerant. * Check riser sizes if the velocity in risers is too low (for A-C models only). * Check the pitch of lines and refrigerant velocities to identify oil trapped in the line.
A
Antonio JohnsonSep 12, 2025
What to do if freeze protection opens in McQuay WGS130AA: WGS140AW Chiller?
- M
  Mark AndersonSep 12, 2025
  If the freeze protection is opening on your McQuay Chiller, here's what to check: * Reset the thermostat to 42°F (6°C) or above if it's set too low. * Adjust the flow if there is low water flow. * Refer to the section on “Low Suction Pressure.”
W
wadeanthonySep 13, 2025
What causes the compressor thermal switch to open in a McQuay WGS130AA: WGS140AW?
- B
  brent43Sep 13, 2025
  If the compressor thermal switch is open on your McQuay Chiller, consider these potential causes: * Add facilities so that conditions are within allowable limits if operating beyond design conditions. * Open the valve if the discharge valve is partially shut.

McQuay WGS130AA: WGS140AW Specifications

General

Model	WGS130AA: WGS140AW
Category	Chiller
Cooling Capacity	130 - 140 tons
Refrigerant Type	R-134a
Compressor Type	Screw
Full Load Amps	160-180 A
Sound Pressure Level	78 dBA
Power Supply	460V/3/60Hz

Summary

Introduction

General Description

Provides a general overview of the McQuay Model WGS water chillers and their availability.

Nomenclature

Explains the meaning of the model designation for WGS chillers.

Definitions

Key Terms and Concepts

Defines various technical terms and parameters used throughout the manual, covering operation and control.

Wiring Diagrams

Field Wiring Diagrams

Illustrates the field wiring connections for the WGS 130AW – 190AW packaged chiller.

Wiring Diagrams

Field Wiring Diagrams (Remote Air-cooled)

Illustrates the field wiring connections for the WGS 130AA – 190AA chiller with remote condenser.

Control Panel Layout

Outer (Microprocessor) Panel

Details the components and layout of the outer control panel.

Control Panel Layout

Inner (Power) Panel

Details the components and layout of the inner power panel.

Control Panel Layout

Circuit BreakerFuse Panel

Illustrates the circuit breaker and fuse panel within the control enclosure.

MicroTech II Controller

System Architecture

Describes the distributed control system architecture of the MicroTech II.

PLAN Addressing

Explains the pLAN (proprietary local area network) addressing scheme.

MicroTech II Controller

General Description

Details the benefits and features of the MicroTech II controller's design.

Operator-Friendly Features

Highlights operator-friendly aspects like units of measure, distributed control, and alarms.

MicroTech II Controller

Unit Enable Selection

Explains how to enable or disable chiller operation via local keypad or digital input.

Unit Mode Selection

Describes how to select operating modes such as cooling, ice, or test.

Keypad and Display

Details the layout and functionality of the controller's keypad and display.

Sequence of Operation

Compressor Operations

Covers compressor heaters, startup staging, and automatic pumpdown sequences.

Water and Tower Controls

Explains control of chilled water pumps, condenser water pumps, and cooling tower.

Sequence of Operation

Start-Up Logic

Details low ambient start logic and remote condenser EXV operation.

Unit Controller Sequence of Operation

Circuit Controller Sequence of Operation

Start-Up and Shutdown

Pre Start-up Procedures

Outlines the necessary steps and precautions before initial unit start-up.

Start-Up and Shutdown

Start-up Procedures

Details steps for starting the unit after normal or temporary shutdowns.

Shutdown Procedures

Covers procedures for weekend, temporary, and extended unit shutdowns.

Start-Up and Shutdown

Start-up after Extended Shutdown

Provides instructions for restarting the unit after an extended shutdown period.

Evaporator Pressure Drop Data

Condenser Pressure Drop Data

Unit Controller

Unit Inputs and Outputs

Lists and describes analog and digital inputs and outputs for the unit controller.

Unit Setpoints

Explains setpoint types, default values, and adjustment parameters.

Unit Controller

Unit Controller Setpoints

Details the available setpoints for the unit controller, including default and range values.

Unit Controller

Auto Adjusted Setpoint Ranges

Describes setpoints with adjusted ranges based on operating modes.

Circuit Controller

Circuit Inputs and Outputs

Lists and describes analog and digital inputs and outputs for the circuit controller.

Circuit Controller

Circuit Setpoint Table

Details setpoints specific to each circuit, including default values and ranges.

Circuit Controller

EXV and Sensor Setpoints

Covers setpoints for EXV control, sensors, and fan operation.

RLAFLA Values

Provides Running Load Amps (RLA) and Full Load Amps (FLA) for compressor input.

Alarms and Events

Unit Stop Alarms Overview

Introduces unit stop alarms and covers flow loss alarms for evaporator and condenser.

Alarms and Events

Specific Sensor and System Faults

Details alarms related to freeze protection, sensor faults, and pLAN failure.

Alarms and Events

Unit and Circuit Events

Covers unit events, circuit stop alarms, and low evaporator pressure conditions.

Alarms and Events

Compressor and Pressure Related Alarms

Lists alarms for high lift pressure, discharge temperature, oil level, and pressure issues.

Alarms and Events

Pressure and Lift Events

Details events related to pressure changes, lift pressure, and evaporator pressure.

Alarms and Events

Oil, Pumpdown, and Fault Events

Covers events for oil level, pumpdown failures, power loss, freeze protection, VFD, and slide errors.

Alarm Logging

Explains how alarms are stored and viewed in the active and history buffers.

Unit Controller Functions

Calculations

Details calculations for LWT slope, pulldown rate, and unit capacity.

Unit Controller Functions

Unit Enable and Control Source

Explains unit enable settings and how the control source determines operation.

Unit Controller Functions

Unit Mode Selection and Sources

Details unit mode selection options and how sources affect mode changes.

Unit Controller Functions

Unit Test Mode and States

Describes unit test mode, operational states, and state transitions.

Unit Controller Functions

Evaporator Pump Control

Details the state transitions and control logic for the evaporator pump.

Unit Controller Functions

Pump Control and Staging

Explains pump selection, primary/standby staging, and auto control logic.

Leaving Water Temperature (LWT) Reset

Describes how the LWT setpoint is adjusted based on reset types like NONE or RETURN.

Unit Controller Functions

LWT Reset Types

Details Return Reset parameters and the 4-20 mA reset type.

Unit Controller Functions

OAT Reset and Capacity Overrides

Explains OAT reset, planned unit capacity overrides, and soft loading functions.

Unit Controller Functions

Demand and Network Limits

Covers capacity limitations via demand limit signals and network control.

Condenser Pump and Tower Control

Condenser Water Pump State Control

Details the state transitions for controlling the condenser water pump.

Condenser Pump and Tower Control

Cooling Tower Control: Fans

Explains tower fan control logic, staging, and related parameters.

Condenser Pump and Tower Control

Cooling Tower Bypass Valve

Details the control of the cooling tower bypass valve, including initial position.

Initial Valve Position

Describes the initial position of the bypass valve based on entering condenser water temperature.

Condenser Pump and Tower Control

Operation After Start and Valve Modes

Covers valve control after start, including setpoint and stage modes.

Cooling Tower Fan VFD

Explains the operation and configuration of variable frequency drives for condenser fans.

Evaporative Condenser Control

Discusses the use of WGS-A chillers with evaporative condensers and control responsibilities.

Evaporative Condenser Control

Circuit Controller Functions

Refrigerant Calculations

Provides tables for converting pressure to saturated temperature for refrigerant circuits.

Operating and Test Modes

Explains circuit operating modes and the procedure for entering circuit test mode.

Circuit Controller Functions

Compressor Staging and Control

Details compressor staging, start/stop timing, and full load indication logic.

Circuit Controller Functions

Compressor StartStop Timing and Capacity Control

Covers start/stop timing for cool/ice modes and compressor capacity control methods.

Circuit Controller Functions

Load Balancing and Low OAT Logic

Explains load balancing in cool mode and low OAT start logic for air-cooled operation.

Circuit Controller Functions

Internal Capacity Overrides

Details overrides for evaporator pressure, lift pressure, and temperature limits.

Circuit Controller Functions

Unit Capacity Overrides and Pumpdown

Explains unit capacity overrides and the pumpdown process.

Slide Positioning

Slide Position Indicator and Calibration

Describes slide position indicators and the procedure for calibration.

Slide Positioning

Calibration Procedure

Provides a detailed step-by-step guide for calibrating the slide indicator.

Slide Positioning

Manual Slide Control and Pulse

Explains manual slide control mode and the slide pulse output function.

Expansion Valve Control

Preopen Function

Details the EXV preopen function for startup and condenser operation.

Pressure Control

Describes EXV control in pressure control mode, including target calculation.

Expansion Valve Control

Superheat Control and Closed State

Explains superheat control and the closed state for the EXV.

EXV State Transitions

Illustrates state transitions between EXV control modes for water-cooled condensers.

Expansion Valve Control

EXV State Transitions - Aircooled

Illustrates EXV state transitions for air-cooled condensers with high evaporator pressure.

Expansion Valve Control

EXV Control Range

Shows the EXV control range for different compressor sizes and capacities.

Circuit Controller Functions

Oil Heater and Starter Communications

Covers oil heater control and Modbus communication with the compressor starter.

Starter Faults

Describes how starter faults are viewed and implemented as alarms.

Starter Communications

Starter Fault Codes

Lists starter fault codes and their corresponding alarm triggers.

Condenser Fan Control

Fan Staging

Explains fan staging logic, accumulators, and deadbands for condenser fans.

Condenser Fan Control

Condenser Fan VFD and Digital Outputs

Covers VFD operation, digital outputs for alarms, pumps, and fans.

Using the Controller

Display and Keypad Layout

Details the controller's display, keypad layout, arrow key functions, and navigation.

Using the Controller

ENTER Key and Changing Setpoints

Explains the ENTER key function and how to change setpoints via menus.

Using the Controller

Security and Editing

Covers password entry, editing setpoints, and clearing alarms.

Menu Descriptions

Unit Controller Menus

Describes the unit controller's menu structure, including shortcut menus.

Menu Descriptions

Unit Controller Menu Matrix

Provides a matrix layout for navigating unit controller screens.

Screen Definitions - MENU

Details the top-level and menu structure for screen navigation.

Menu Descriptions

Screen Definitions - VIEW

Explains the structure and content of the VIEW menu screens.

View Unit Status

Describes how to view the current operational status of the unit.

Menu Descriptions

View Unit Status Details

Provides further details on unit status indicators like softload and demand limits.

View Unit Temperature

Shows how to display evaporator and condenser water temperatures.

Menu Descriptions

View Circuit Status

Details how to view the status, current, voltage, and power information for each circuit.

View Refrigerant

Explains how to view refrigerant pressures for each circuit.

Menu Descriptions

View Fans and Tower

Describes how to view fan status and tower operating parameters.

Screen Definitions - ALARM

Alarm Logging Details

Explains the display of alarm logs, event logs, and alarm clearing procedures.

Screen Definitions - SET

Unit Set Points Configuration

Details unit enable, mode, and basic setpoint configurations.

Screen Definitions - SET

Unit Set Points Configuration (continued)

Covers further unit setpoints like pulldown, timers, watercooled settings, and reset types.

Screen Definitions - SET

Unit Set Points Configuration (continued)

Details clock, units, protocol settings, and compressor set points.

Compressor Set Points

Covers setpoints for compressor mode, slide control, and starter parameters.

Screen Definitions - SET

Compressor Set Points (continued)

Details compressor set points including pumpdown, load stage, and discharge temperature.

Alarm Set Points

Defines alarm limits for evaporator pressure, oil delay, and discharge temperature.

Screen Definitions - SET

Alarm Set Points (continued)

Details alarm limits for freeze protection, flow proof, and condenser settings.

Tower Setpoints Overview

Introduces tower setpoints available for water-cooled configurations.

Tower Setpoints

Tower Fan Control Settings

Details settings for tower control, stages, and fan deadbands.

Tower Setpoints

Valve Control Settings

Covers settings for valve control, including setpoints, range, and type.

Screen Definitions - TEST

Test Mode Circuit Operations

Details test mode operations for slide, oil heater, EXV, and condenser fans.

Circuit Controller

Circuit Controller Shortcut Menus

Hierarchical structure of shortcut menus for the circuit controller.

Circuit Controller Menu Matrix

Provides a matrix for navigating circuit controller screens.

Screen Definitions - MENU

Explains the top-level and menu structure for circuit controller screen navigation.

Circuit Controller

Screen Definitions - VIEW

Details the structure and content of the circuit controller's VIEW menu screens.

View Unit Status

Shows how to view the status of the unit, including pump states.

Circuit Controller

View Circuit Status

Provides details on viewing circuit status, hours, starts, current, and voltage.

Circuit Controller

View Refrigerant

Explains how to view refrigerant saturation temperatures and suction/discharge temps.

Circuit Controller

Fan and EXV Set Points

Covers fan set points and EXV set points, including manual control.

Sensor Offsets

Details how to set offsets for pressure, temperature, and slide position sensors.

Circuit Controller

Screen Definitions - TEST

Defines the test mode screens for circuit operations.

Editing Review and Security

Alarms and Security

Covers editing review, alarm logging, and security password management.

BAS Interface

Unit Controller Settings and Connections

Details BAS interface options, unit controller settings, and chiller connections.

Unit Troubleshooting Chart

Compressor Not Running Issues

Lists causes and corrective steps for compressor not running, noisy, or vibrating.

Unit Troubleshooting Chart

Refrigerant and Oil Related Issues

Troubleshoots low suction pressure, oil issues, and refrigerant leaks.

Electrical and Freeze Protection Issues

Addresses electrical faults, overloads, and freeze protection issues.

Related product manuals

McQuay WGS130AA: WGS140AW

Table of Contents

Questions and Answers:

McQuay WGS130AA: WGS140AW Specifications

Summary

Introduction

General Description

Nomenclature

Definitions

Key Terms and Concepts

Wiring Diagrams

Field Wiring Diagrams

Wiring Diagrams

Field Wiring Diagrams (Remote Air-cooled)

Control Panel Layout

Outer (Microprocessor) Panel

Control Panel Layout

Inner (Power) Panel

Control Panel Layout

Circuit BreakerFuse Panel

MicroTech II Controller

System Architecture

PLAN Addressing

MicroTech II Controller

General Description

Operator-Friendly Features

MicroTech II Controller

Unit Enable Selection

Unit Mode Selection

Keypad and Display

Sequence of Operation

Compressor Operations

Water and Tower Controls

Sequence of Operation

Start-Up Logic

Unit Controller Sequence of Operation

Unit Controller Sequence of Operation

Unit Controller Sequence of Operation

Circuit Controller Sequence of Operation

Circuit Controller Sequence of Operation

Start-Up and Shutdown

Pre Start-up Procedures

Start-Up and Shutdown

Start-up Procedures

Shutdown Procedures

Start-Up and Shutdown

Start-up after Extended Shutdown

Evaporator Pressure Drop Data

Condenser Pressure Drop Data

Unit Controller

Unit Inputs and Outputs

Unit Setpoints

Unit Controller

Unit Controller Setpoints

Unit Controller

Auto Adjusted Setpoint Ranges

Circuit Controller

Circuit Inputs and Outputs

Circuit Controller

Circuit Setpoint Table

Circuit Controller

EXV and Sensor Setpoints

RLAFLA Values

Alarms and Events

Unit Stop Alarms Overview

Alarms and Events

Specific Sensor and System Faults

Alarms and Events

Unit and Circuit Events

Alarms and Events

Compressor and Pressure Related Alarms

Alarms and Events

Pressure and Lift Events

Alarms and Events

Oil, Pumpdown, and Fault Events

Alarm Logging

Unit Controller Functions

Calculations

Unit Controller Functions

Unit Enable and Control Source