YORK INTERNATIONAL
18
FORM 160.54-O2(1102)
FORM 160.54-O2(1102)
19
YORK INTERNATIONAL
OIL PUMP
For normal operation, the oil pump should operate at
all times during chiller operation.
On shutdown of the system for any reason, the oil
pump operates and continues to run for 150 seconds.
The system cannot restart during that time interval.
OIL HEATER
During long idle periods, the oil in the compressor oil
reservoir tends to absorb as much refrigerant as it can
hold, depending upon the temperature of the oil and
the pressure in the reservoir. As the oil temperature is
lowered, the amount of refrigerant absorbed will be
increased. If the quantity of refrigerant in the oil be-
comes excessive, violent oil foaming will result as the
pressure within the system is lowered on starting. This
foaming is caused by refrigerant boiling out of the oil
as the pressure is lowered. If this foam reaches the oil
pump suction, the bearing oil pressure will fluctuate
with possible temporary loss of lubrication, causing
the oil pressure safety cutout to actuate and stop the
system. See “Control Center” Form 160.54-O1.
MOTOR DRIVELINE
The compressor motor is an open-drip-proof, squir-
rel cage, induction type constructed to YORK design
specifications. 60 hertz motors operate at 3570 rpm.
50 hertz motors operate at 2975 rpm.
The open motor is provided with a D-flange, cast iron
adapter mounted to the compressor and supported by
a motor support.
Motor drive shaft is directly connected to the com-
pressor shaft with a flexible disc coupling. This cou-
pling has all metal construction with no wearing parts
to assure long life, and no lubrication requirements to
provide low maintenance.
For units utilizing remote Electro-Mechanical starters,
a terminal box is provided for field connected con-
duit. Motor terminals are brought through the motor
casing into the terminal box. Jumpers are furnished
for three-lead type of starting. Motor terminal lugs are
not furnished. Overload/overcurrent transformers are
furnished with all units.
HEAT EXCHANGERS
Evaporator and condenser shells are fabricated from
rolled carbon steel plates with fusion welded seams.
Heat exchanger tubes are internally enhanced type.
The evaporator is a shell and tube, flooded type heat
exchanger. A distributor trough provides uniform
distribution of refrigerant over the entire shell length.
Stainless steel mesh eliminators or suction baffles are
located above the tube bundle to prevent liquid refrig-
erant carryover into the compressor. A 2" liquid level
sight glass is located on the side of the shell to aid in
determining proper refrigerant charge. The evaporator
shell contains dual refrigerant relief valves.
The condenser is a shell and tube type, with a dis-
charge gas baffle to prevent direct high velocity
impingement on the tubes. A separate subcooler is
located in the condenser to enhance performance.
Dual refrigerant relief valves are located on condenser
shells with optional isolation refrigerant isolation
valves.
The removable compact 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 provide the required pass
arrangements. Stub-out water nozzle connections
with Victaulic grooves are welded to the water boxes.
These nozzle connections are suitable for Victaulic
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
Refrigerant flow to the evaporator is controlled by a
variable orifice.
A level sensor senses the refrigerant level in the
condenser and outputs an analog voltage to the Mi-
croboard that represents this level (0% = empty; 100%
= full). Under program control, the Microboard modu-
lates a variable orifice to control the condenser refrig-
erant level to a programmed setpoint. Other setpoints
affect the control sensitivity and response. These
setpoints must be entered at chiller commissioning by
a qualified service technician. Only a qualified service
technician may modify these settings.
3