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JOHNSON CONTROLS
cooler is provided as standard. No auxiliary water pip-
ing is required. An oil eductor automatically removes oil
which may have migrated to the evaporator and returns
it to the compressor.
MOTOR DRIVELINE
The compressor motor is an open drip-proof, squirrel
cage, induction type constructed to Johnson Controls
design specifications. 60 Hertz motors operate at 3750
RpM; 50 Hertz motors operate at 2975 RpM. The open
motor is provided with a D-Flange and is factory-mounted
to a cast-iron adaptor mounted on the compressor. This
unique design allows the motor to be rigidly coupled to
the compressor to provide factory alignment of motor and
compressor shafts.
Motor drive shaft is directly connected to the compressor
shaft with a flexible disc coupling. Coupling has all metal
construction with no wearing parts to assure long life.
Additionally, no lubrication is required – providing low
maintenance.
For units utilizing remote electro-mechanical starters,
a large steel terminal box with gasketed front access
cover is provided for field connected conduit. There are
six terminals (three for medium voltage) brought through
the motor casing into the terminal box. Jumpers are fur-
nished for three-lead type of starting. Motor terminal lugs
are not furnished. Overload/overcurrent transformers are
furnished with all units. For units furnished with factory-
packaged Solid State Starters, refer to the Accessories
and Modifications section (page 17).
HEAT EXCHANGERS
Shells
evaporator and condenser shells are fabricated from
rolled carbon steel plates with fusion welded seams.
Carbon steel tube sheets, drilled and reamed to accom-
modate the tubes, are welded to the end of each shell.
Intermediate tube supports are fabricated from carbon
steel plates, drilled and reamed to eliminate sharp edges,
and spaced no more than four feet apart. The refrigerant
side of each shell is designed, tested, and stamped in
accordance with ASMe Boiler and pressure Vessel Code,
Section VIII – Division I, or other pressure vessel code
as appropriate.
Tubes
Heat exchanger tubes are state-of-the-art, high efficiency,
externally and internally enhanced type to provide op-
timum performance. Tubes in both the evaporator and
condenser are 3/4” O.D. copper alloy and utilize the
“skip-fin” design, providing a smooth internal and external
surface at each intermediate tube support. This provides
extra wall thickness (up to twice as thick) and non-work
hardened copper at the support location, extending the
life of the heat exchangers. each tube is roller expanded
into the tube sheets providing a leak-proof seal, and is
individually replaceable.
Evaporator
The evaporator is a shell and tube, flooded type heat ex
-
changer. A distributor trough provides uniform distribution
of refrigerant over the entire shell length to yield optimum
heat transfer. A suction baffle or aluminum mesh elimina
-
tors are located above the tube bundle to prevent liquid
refrigerant carryover into the compressor. A 1-1/2” liquid
level sight glass is conveniently located on the side of the
shell to aid in determining proper refrigerant charge. The
evaporator shell contains a dual refrigerant relief valve
arrangement set at 180 pSIG (1241 kpa); or single-relief
valve arrangement, if the chiller is supplied with the op-
tional refrigerant isolation valves. A 1” refrigerant charging
valve is provided.
Condenser
The condenser is a shell and tube type, with a discharge
gas baffle to prevent direct high velocity impingement on
the tubes. The baffle is also used to distribute the refrig-
erant gas flow properly for most efficient heat transfer.
An integral sub-cooler is located at the bottom of the
condenser shell providing highly effective liquid refriger-
ant subcooling to provide the highest cycle efficiency. The
condenser contains dual refrigerant relief valves set at
235 pSIG (1620 kpa).
water Boxes
The removable water boxes are fabricated of steel. The
design working pressure is 150 pSIG (1034 kpa) and the
boxes are tested at 225 pSIG (1551 kpa). Integral steel
water baffles are located and welded within the water box
to provide the required pass arrangements. Stub-out water
nozzle connections with ANSI/AwwA C-606 grooves are
welded to the water boxes. These nozzle connections
are suitable for ANSI/AwwA C-606 couplings welding or
flanges, and are capped for shipment. Plugged 3/4” drain
and vent connections are provided in each water box.
REFRIGERANT FLOw CONTROL
The YS Chiller is equipped with a refrigerant metering
device consisting of a fixed orifice and bypass solenoid
valve, which automatically adjusts to all real-world operat
-
ing conditions. This control ensures proper refrigerant flow
to the evaporator over a wide range of operating condi-
tions, including thermal storage applications and chilled
water reset. Valve operation is programmable and can
be customized for a specific application via the control
panel keyboard.
Mechanical Specifications
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