York YCWS0313SC, Installation, Operation And Maintenance Manual, Page: 13 / 104

FORM 201.24-NM2
13
YORK INTERNATIONAL
INTRODUCTION
YORK YCWS chillers are designed for water or wa-
ter-glycol cooling.
All models are designed for indoor installation. The
units are completely assembled with all interconnect-
ing refrigerant piping and internal wiring, ready for field
installation.
The unit consists of 2 screw compressors in a corre-
sponding number of separate refrigerant circuits, a shell
and tube DX evaporator, a water cooled condenser and
oil separators for each circuit.
Before delivery, the unit is pressure tested, evacuated,
and fully charged with refrigerant and oil in each of
the independent refrigerant circuits. After assembly, an
operational test is performed with water flowing
through the cooler to ensure that each refrigerant cir-
cuit operates correctly.
The unit framework is fabricated using heavy-gauge
galvanized steel which is zinc phosphate pre-treated
and powder coated to minimize corrosion.
Compressor
Twin helical semi-hermetic screw compressors, are
provided to ensure high operational efficiencies and
reliable performance. Capacity control is achieved
through a single slide valve. The compressor is a posi-
tive displacement type characterized by two helically
grooved rotors which are manufactured from forged
steel. The 50 Hz motor operates at 2950 rpm to direct
drive the male rotor which in turn drives the female
rotor on a light film of oil.
Each compressor is direct drive, semi-hermetic, rotary
twin screw type and includes the following items:
Two screw rotors, with asymmetric profiles, manufac-
tured from forged steel.
A cast iron compressor housing precision machined to
provide optimal clearance for the rotors.
An internal discharge check valve to prevent rotor back-
spin during shutdown.
An acoustically tuned, internal discharge muffler to
minimize noise, while optimizing flow for maximum
performance.
Discharge and suction shut-off service valves.
A reliable suction gas cooled high efficiency, accessible
hermetic motor with redundant overload protection us-
ing both thermistor and current overload protection.
A suction gas screen and serviceable, 0.5 micron full
flow oil filter within the compressor housing.
Refrigerant gas is injected into the void created by the
unmeshing of the five lobed male and seven lobed fe-
male rotor. Further meshing of the rotors closes the rotor
threads to the suction port and progressively compresses
the gas in an axial direction to the discharge port. The
SECTION 2
PRODUCT DESCRIPTION
1 COMPRESSOR
2 COOLER
3 CONDENSER
4 POWER SECTION - SYSTEM 1
5 COMMON INPUT SECTION
6 POWER SECTION - SYSTEM 2
7 CONTROL PANEL
FIG. 1 – YCWS WATER COOLED LIQUID CHILLER
2
00546VIP
3
2
1
7
6 5 4