York YK Manual page 101

Guide Specifications (Cont'd)
JOHNSON CONTROLS
optimal relationship between compressor speed and inlet pre-rotation vane position for
maximum energy efficiency. Control shall automatically compensate for adverse operat-
ing conditions, such as fouled tubes, and adjust to prior operation after correction of these
conditions.
The unit shall be capable of continuous, reliable operation with low ECWT at all load
conditions as outlined on the equipment schedule. An external electric actuator shall au-
tomatically control pre-rotation vane position.
LUBRICATION SYSTEM
Lubrication oil shall be force-fed to all compressor bearings, gears, and rotating surfaces
by an external variable speed oil pump. The oil pump shall vary oil flow to the com-
pressor based on operating and stand-by conditions, ensuring adequate lubrication at all
times. The oil pump shall operate prior to start-up, during compressor operation and dur-
ing coastdown. Compressor shall have an auxiliary reservoir to provide lubrication during
coastdown in the event of a power failure.
An oil reservoir, separate from the compressor, shall contain the submersible 2 HP oil
pump and a 3000 watt oil heater, thermostatically controlled to remove refrigerant from the
oil. The oil reservoir shall be listed as part of the chiller by a nationally recognized testing
laboratory and shall be factory air strength tested at 1.1 times design working pressure.
Oil shall be filtered by an externally-mounted 1/2 micron replaceable cartridge oil filter
equipped with service valves. Oil cooling shall be done via refrigerant cooled oil cooler,
with all piping factory-installed. Oil side of the oil cooler shall be provided with service
valves. An automatic oil return system to recover any oil that may have migrated to the
evaporator shall be provided. Oil piping shall be completely factory-installed and tested.
WATER-COOLED OIL COOLER
Optional condenser water-cooled oil cooler is offered for units with Q3 compressors only.
The four tube pass and one shell pass oil cooler is by API Basco, Model 05036 (shell di-
ameter 5" OD, tube length 36"). The shell is steel pipe or tubing and tube sheets are steel
to ASME specification. Bafflers are precision hot-rolled, punched, carbon steel to assure
effective circulation by providing minimum clearances between the tubes and tube holes.
The cooler is a straight-tube type and has 180 plain copper tubes of 1/4" OD with 24 BWG.
The heat exchanger has either cast iron bonnets to be used for 150 psig (10.3 barg) con-
denser waterboxes or carbon steel bonnets to be used for 300 psig (20.6 barg) condenser
waterboxes. Condenser water is the cooling medium and water circulation is obtained by
the water pressure drop across the condenser shell. The minimum requirement of 7 to 8
gpm (0.4 to 0.5 l/s) water for this oil cooler is provided at a pressure drop as low as 3 ft.
with the Q3 piping arrangement.
MOTOR DRIVELINE
The compressor motor shall be an open drip proof, squirrel cage, induction type operating
at 3570 rpm for 60Hz operation and 2975 rpm for 50 Hz operation.
The open motor shall be provided with a D-flange. The D-flange is bolted to a cast iron
adaptor mounted on the compressor. This allows the motor to be rigidly coupled to the
compressor to provide factory alignment of motor and compressor shafts.
FORM 160.75-EG1 (519)
101