York YVWA, Installation Operation & Maintenance

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JOHNSON CONTROLS
15
FORM 201.30-ICOM1 (519)
ISSUE DATE: 05/22/2019
2
SECTION 2 - PRODUCT DESCRIPTION
COMPONENTS
The YVWA chiller, as shown in
Figure 2 on page 16
and Figure 3 on page 17, consists of:
• One screw compressors with a muffler
• A hybrid falling film evaporator
• A water-cooled condenser
• One economizer heat exchanger
• One oil separator
• VSD
• Control panel
The oil separator utilizes no moving parts. Oil cooling
is accomplished by refrigerant leaving the eductor and
flashing in the suction line, which cools the oil, motor,
and compressor.
An integral liquid cooled, transistorized, pulse-width
modulated (PWM) VSD is controlled by the micropro-
cessor control panel to start/stop, and select compres-
sor speed. Power factor is 95% at part or full load.
The chiller microprocessor communicates with the
VSD logic board via a 3-wire RS-485 opto-coupled
data link. The VSD logic board runs the compressor
to the speed requested by the chiller microprocessor to
meet the load as shown in Figure 4 on page 18.
YORK YVWA chillers are designed for water or gly-
col cooling. All units are designed to be located in an
equipment room unless the unit was ordered specially
for outside applications.
The units are completely assembled with all intercon-
necting refrigerant piping and internal wiring, ready
for field installation.
Prior to delivery, the unit is:
• Pressure tested,
• Evacuated, and
• Fully charged with refrigerant and oil in the re-
frigerant circuit.
All exposed power wiring is routed through liquid-
tight, non-metallic conduit.
The YVWA chiller combines the modern screw com-
pressor design with the latest Variable Speed Drive
(VSD) technology. The VSD enables the compressor
speed to match the system load, and provides soft starts
with no electrical inrush. The lack of heat buildup on
start-up also reduces required off time between starts
to two minutes.