McQuay WGS190AW

98 pages

To Next Page

To Next Page

Loading...

Operating Manual

OM WGS-5

Group: Chiller

Part Number: 331373701

Effective: November 2008

Supersedes: OM WGS-4

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 WGSD30101H

Table of Contents

Questions and Answers:

S
Shari SchultzAug 22, 2025
What to do if motor overload relays or circuit breakers open in McQuay Chiller?
- P
  Phillip Graham MDAug 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.
A
Andrew ReynoldsAug 26, 2025
What causes low discharge pressure in a McQuay Chiller?
- S
  Stephanie MolinaAug 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
mariahadamsAug 28, 2025
What should I do if my McQuay WGS190AW Chiller has low suction pressure?
- D
  Danny SmithAug 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.
C
Christine SparksAug 30, 2025
Why is my McQuay WGS190AW Chiller compressor noisy or vibrating?
- M
  maria40Aug 31, 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.
B
Benjamin QuinnSep 2, 2025
What causes little or no oil pressure in a McQuay WGS190AW Chiller?
- S
  samuel28Sep 3, 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.
P
Pamela BraySep 5, 2025
Why is the suction pressure high in my McQuay Chiller?
- C
  Caroline HillSep 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.
D
David SmithSep 8, 2025
Why does my McQuay WGS190AW compressor lose oil?
- E
  Elizabeth FowlerSep 8, 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.
K
Kim LaneSep 12, 2025
What to do if freeze protection opens in McQuay WGS190AW?
- C
  Christine VillarrealSep 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.”
J
Jorge NguyenSep 13, 2025
What causes the compressor thermal switch to open in a McQuay Chiller?
- M
  Melissa HollandSep 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 WGS190AW Specifications

General

Tonnage	190 tons
Refrigerant Type	R-134a
Compressor Type	Screw
Power Supply	460V/3Ph/60Hz
Length	5000 mm
Width	2000 mm

Summary

Wiring Diagrams

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

Control Panel Layout

Figure 3, Outer (Microprocessor) Panel

Figure 4, Inner (Power) Panel (Optional Single-Point Power with Disconnect Switches Shown)

Figure 5, Circuit BreakerFuse Panel

MicroTech II Controller

System Architecture

Overview of the distributed control system comprising Unit and Circuit controllers.

Sequence of Operation

StartupCompressor Staging

Describes the process of starting compressors and staging them based on conditions.

Automatic Pumpdown

Explains the automatic pumpdown procedure when a circuit shuts down.

Unit Controller Sequence of Operation

Unit power up

Describes the steps involved when the unit is powered on.

Is there enough load to start chiller?

Determines if sufficient load exists to initiate chiller operation.

Circuit Controller Sequence of Operation

Start Compressor

Details the sequence for starting a compressor within a circuit.

Run Compressor

Describes how a running compressor operates and adjusts capacity.

Start-Up and Shutdown Procedures

Pre Start-up

Essential steps to perform before initial unit startup.

Start-up

Procedures for starting the chiller unit.

Extended Shutdown

Unit Controller

Unit InputsOutputs

Unit Setpoints

Parameters retained during power-off that can be adjusted.

Circuit Controller

Circuit Inputs and Outputs

Circuit Setpoint Table

Table listing adjustable setpoints for each compressor circuit.

Alarms and Events

Unit Stop Alarms

Conditions requiring manual reset that shut down the chiller.

Circuit Stop Alarms

Conditions requiring manual reset that shut down a specific circuit.

Clearing Alarms

Procedures for clearing active alarms from the unit controller.

Unit Enable

Planned Unit Capacity Overrides

Planned Unit Capacity Overrides

Condenser Pump and Tower Control

Cooling Tower Control

Circuit Controller

Circuit Controller Functions

Overview of the functions and calculations performed by the circuit controller.

Compressor Control

Details on how compressors are staged, started, stopped, and controlled.

Internal Capacity Overrides

Low Evaporator Pressure

Overrides that limit capacity due to low evaporator pressure.

Slide Positioning

Slide Calibration Procedure

Step-by-step procedure for calibrating the slide position indicator.

Expansion Valve Control

Pressure Control

Superheat Control

Starter Communications

Table 21, Starter Fault Codes

Lists starter fault codes and their corresponding alarms.

Condenser Fan Control

Fan Stages

Using the Controller

Changing Setpoints

Security

Entering Passwords

Editing Setpoints

Screen Definitions - SET

Unit Set Points

Compressor Set Points

Sensor Offsets

Alarm Set Points

Tower Setpoints

Editing Review

Alarms

Security

BAS Interface

BAS Interface

Unit Troubleshooting Chart

Compressor Will Not Run

Diagnoses and corrective steps for a non-operational compressor.

Compressor Noisy or Vibrating

Diagnoses and corrective steps for abnormal compressor noise or vibration.

High Discharge Pressure

Diagnoses and corrective steps for high discharge pressure issues.

Low Discharge Pressure

Diagnoses and corrective steps for low discharge pressure issues.

Low Suction Pressure

Diagnoses and corrective steps for low suction pressure issues.

Related product manuals

McQuay WGS160AW

Preview: McQuay WGS130AA: WGS140AW

McQuay WGS130AA: WGS140AW

Preview: McQuay WMC

Preview: McQuay WDC

McQuay WHR Series

Preview: McQuay WMC-B 145S

McQuay WMC-B 145S