Specifications

13
JOHNSON CONTROLS
Form 201.28-NM1.EN.PED/CE (0211)
2
SECTION 2 - PRODUCT DESCRIPTION
YORK YVAA R134a chillers are designed for water
or glycol cooling. All units are designed to be located
outside on the roof of a building or at ground level.
The units are completely assembled with all
interconnecting 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 each of the
two independent refrigerant circuits. After assembly, an
operational test is performed with water flowing through
the cooler to ensure that each refrigerant circuit operates
correctly.
The unit structure is manufactured from heavy gauge,
galvanized steel. Many external structural parts are coated
with “Champagne” baked-on enamel powder paint. This
provides a finish which, when subjected to ASTM B117,
1000 hour, 5% salt spray conditions, shows breakdown
of less than 1/8" either side of a scribed line (equivalent
to ASTM D1654 rating of “6”).
All exposed power wiring is routed through liquid-tight,
non-metallic conduit.
GENERAL SYSTEM DESCRIPTION
The YVAA Chiller combines the best of modern screw
compressor design with the latest technology in variable
speed drives. The result is superior control and efficiency
in real world conditions. The VSD enables slowing the
speed of the compressor to match the load on the system
resulting in precise chilled liquid control, minimized
sound, maximum energy efficiency, and reduced cost of
ownership. The VSD also provides soft starts with no
electrical inrush. The lack of heat build-up on start also
enables required off time between starts to be reduced to
a period of two minutes.
The YVAA Air-Cooled Screw Chiller utilizes many
components, which are the same or nearly the same as
a standard screw chiller of a similar size. This includes
modular frame rails, condenser, fans, compressors and
evaporator.
The chiller consists of two screw compressors in a
corresponding number of separate refrigerant circuits, a
hybrid falling film evaporator, an air-cooled condenser,
receiver/flash tanks, feed valves, oil separators, and
compressor mufflers. Oil separators utilize no moving
parts and are rated for a 27.9 barg (405 PSIG) design
working pressure. Oil cooling is accomplished by
refrigerant leaving the eductor flashing in the suction
line which cools the oil, motor and compressor.
FIGURE 1 - YVAA AIR-COOLED SCREW LIQUID CHILLER WITH VARIABLE SPEED DRIVE
LD15045