Oil Heater; Motor Driveline; Heat Exchangers - Johnson Controls YORK YK Style G OPTIVIEW Operation And Maintenance

FORM 160.75-O1 (211)

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 sys-
tem. Refer to Optiview™ Control Center – Operation
and Maintenance (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 compres-
sor shaft with a flexible disc coupling. This coupling
has all metal construction with no wearing parts to as-
sure long life, and no lubrication requirements to pro-
vide low maintenance.
For units utilizing remote Electro-Mechanical starters,
a terminal box is provided for field connected conduit.
Motor terminals are brought through the motor cas-
ing into the terminal box. Jumpers are furnished for
three-lead type of starting. Motor terminal lugs are not
furnished. Overload/over current transformers are fur-
nished 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 type with customer
process fluid flowing inside the tubes and refriger-
ant removing heat on the shell side via evaporation.
Evaporator codes A* to K* utilize a hybrid falling film
design. It contains a balance of flooded and falling film
technology to optimize efficiency, minimize refriger-
JOHNSON CONTROLS
SECTION 3 - SYSTEM COMPONENTS DESCRIPTION
ant charge, and maintain reliable control. A specifically
designed spray distributor provides uniform distribu-
tion of refrigerant over the entire length to yield opti-
mum heat transfer. The hybrid falling film evaporator
design has suction baffles around the sides and above
the falling film section to prevent liquid refrigerant car-
ryover into the compressor.
Evaporators codes M* thru Z* are flooded type, with a
liquid inlet distributor trough underneath the tube bun-
dle which provides uniform distribution of refrigerant
over the entire shell length to yield optimum heat trans-
fer. Flooded evaporator designs have a suction baffle
on M* shells with H9 compressors and an aluminum
mesh eliminator on K* - Z* shells with K compressors
located above the tube bundle to prevent liquid refrig-
erant carryover into the compressor.
A 1-1/2" (38 mm) liquid level sight glass is conve-
niently located on the side of the shell to aid in deter-
mining proper refrigerant charge. The evaporator shell
contains a dual refrigerant relief valve arrangement set
at 180 psig (12.4 barg) on H and K compressor models;
235 psig (16.2 barg) on P and Q compressor models;
or single-relief valve arrangement, if the chiller is sup-
plied with optional refrigerant isolation valves. A 1"
(25.4 mm) refrigerant charging valve is provided. 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
refrigerant gas flow properly for most efficient heat
transfer. An optional cast steel condenser inlet diffuser
may be offered, on "M" and larger condensers, in lieu
of the baffle, to provide dynamic pressure recovery and
enhanced chiller efficiency. An integral sub-cooler is
located at the bottom of the condenser shell providing
highly effective liquid refrigerant subcooling to pro-
vide the highest cycle efficiency. The condenser con-
tains dual refrigerant relief valves set at 235 psig (16.2
barg).
The removable waterboxes are fabricated of steel. The
design working pressure is 150 psig (10.3 barg) and
the boxes are tested at 225 psig (15.5 barg). Integral
steel water baffles are located and welded within the
waterbox to provide the required pass arrangements.
Stub-out water nozzle connections with ANSI/AWWA
C-606 grooves are welded to the waterboxes. These
nozzle connections are suitable for ANSI/AWWA
C-606 couplings, welding or flanges, and are capped
for shipment. Plugged 3/4" (19 mm) drain and vent
connections are provided in each waterbox.
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