Johnson Controls YEWS Series, Installation, Operation And Maintanance Instructions

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position and provide a capacity control within 25%~100%
by using one continuous function slide valves.
The capacity control valve at the minimum load position
when it starts up will ensure compressor starting at the
minimum motor load.
2.3 Oil separator and oil sump
YEWS system uses two stage oil separation designs, the
first stage is the compressor built-in oil separator, and the
second stage is the condenser internal oil separator. For
YEWS H serie units, all models has the oil sump located
in the first stage oil separator, the oil level should be
visible in the sight glass on compressor; but for YEWS P
serie units, the oil sump is located in the second stage oil
separator, there should be no visible oil level in the
compressor sight glass (the oil will be piped to the oil
sump inside the condenser).
All lubricant must flow through a renewable filter before
it is supplied to compressor to lubricate the bearings and
the rotors.
After lubricating the bearings, the oil is injected through
an orifice loacted in the closed thread near the suction end
of the rotors. The oil is automatically injected because of
the pressure difference between the discharge pressure and
the pressure at the suction end of the rotors. This
lubricates the rotors as well as provides an oil seal against
leakage around the rotors to assure refrigerant
compression (volumetric efficiency).
For YEWS P serie units, a photoelectric type oil level
switch is used
，
and an oil heater are locaded on the oil
sump.
2.4 Refrigerant Circuits
The refrigerant circuit has a compressor, oil separator,
evaporator, condenser and a liquid line. Liquid line
components include: a manual shut-off valve, throttle
device , liquid injection piping (just for HP and ITS).
2.5 Condenser
The water-cooled condenser is a cleanable shell and tube
type, with 19mm thermally enhanced seamless copper
tubes and a builtin subcooler.
The design working pressure is 1.0MPa (gauge) on the
waterside. Flange connection HG20615 is provided for
water piping. The condenser shell is equipped with a
relief valve whose active pressure is 20.7 Bar. The
condenser is manufactured and tested according to China
National Standard GB151.
For HP unit, the external surface of the condenser shell
should be covered with 19mm-thick flexible closed-cell
foam for heat insulation purpose.
2.6 Evaporator
The evaporator is a shell and tube, falling film type heat
exchanger equipped with a relief valve whose active
pressure is 20.7 Bar.
The evaporator is manufactured and tested according to
China National Standard GB151.
The external surface of the evaporator shell is covered
with 19mm-thick flexible closed-cell foam for AC&HP
unit and 38mm us used for ITS unit. The water box
connection is equipped with HG20615 flanges for easier
connecting.
2.7 Power and Control Panel
All controls are factory-wired and function tested. The
panel enclosures are designed according to IP22 and are
manufactured from powder-painted steel.
The panel is divided into power supply section, control
section and start section. Power supply section and
control section have separated hinged, latched, and gasket
sealed doors.
The power panel contains: compressor starting contactor,
control wiring, compressor contacting solenoid and
YEWS-E Water Cooling Screw Chiller/Heat Pump