McQuay WGS190AW User Manual

64 WGS 130A to 190A OM WGS-5
 EXV State = Pressure AND Discharge Superheat >= 22 degrees F for at least 3 minutes
 Discharge Temperature <= 180F
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 for each size compressor at minimum and maximum
capacity. The minimum and maximum values vary linearly with slide position, defining a
new EXV control range for every change in slide position.
Compressor Size
EXV Slide %
167
179 197
Min 0 250 250 250
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.
Max EXV
@ 100%
100
Max EXV
@ 0%
Min EXV
@ 0%
EXV Control Range
0
Slide Position (%)
EXV
Steps
Min EXV
@ 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 set point is forced to
auto.
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.

McQuay WGS190AW Specifications

General

Brand	McQuay
Model	WGS190AW
Category	Chiller
Language	English