York MaxE YK Manual

OPERATING & MAINTENANCE
MAXETM
CENTRIFUGAL LIQUID CHILLERS
Supersedes: 160.73-O2 (1202) Form 160.73-O2 (605)
MODEL YK (STYLE F)
R-134a COOLING ONLY
WITH OPTIVIEWTM CONTROL CENTER
FOR ELECTRO-MECHANICAL STARTER,
SOLID STATE STARTER & VARIABLE SPEED DRIVE
00611VIP
LDO5842

YORK INTERNATIONAL
FORM 160.73-O2 (605)
2
This equipment is a relatively complicated apparatus.
During installation, operation, maintenance or service,
individuals may be exposed to certain components or
conditions including, but not limited to: refrigerants,
oils, materials under pressure, rotating components, and
both high and low voltage. Each of these items has the
potential, if misused or handled improperly, to cause
bodily injury or death. It is the obligation and respon-
sibility of operating/service personnel to identify and
recognize these inherent hazards, protect themselves,
and proceed safely in completing their tasks. Failure
to comply with any of these requirements could result
in serious damage to the equipment and the property
IMPORTANT!
READ BEFORE PROCEEDING!
GENERAL SAFETY GUIDELINES
in which it is situated, as well as severe personal in-
jury or death to themselves and people at the site.
This document is intended for use by owner-authorized
operating/service personnel. It is expected that this in-
dividual possesses independent training that will enable
them to perform their assigned tasks properly and safely.
It is essential that, prior to performing any task on this
equipment, this individual shall have read and under-
stood this document and any referenced materials. This
individual shall also be familiar with and comply with
all applicable governmental standards and regulations
pertaining to the task in question.
SAFETY SYMBOLS
The following symbols are used in this document to alert the reader to areas of potential hazard:
WARNING indicates a potentially
hazardous situation which, if not
avoided, could result in death or se-
rious injury.
DANGER indicates an imminently
hazardous situation which, if not
avoided, will result in death or serious
injury.
CAUTION identifies a hazard which
could lead to damage to the machine,
damage to other equipment and/or
environmental pollution. Usually an
instruction will be given, together with
a brief explanation.
External wiring, unless specified as an optional connection in the manufacturer’s product
line, is NOT to be connected inside the micro panel cabinet. Devices such as relays, switches,
transducers and controls may NOT be installed inside the micro panel. NO external wiring
is allowed to be run through the micro panel. All wiring must be in accordance with YORK’s
published specifications and must be performed ONLY by qualified YORK personnel. YORK
will not be responsible for damages/problems resulting from improper connections to the
controls or application of improper control signals. Failure to follow this will void the
manufacturer’s warranty and cause serious damage to property or injury to persons.
NOTE is used to highlight additional
information which may be helpful to
you.

FORM 160.73-O2 (605)
3
YORK INTERNATIONAL
CHANGEABILITY OF THIS DOCUMENT
It is the responsibility of operating/service personnel
as to the applicability of these documents to the equip-
ment in question. If there is any question in the mind
of operating/service personnel as to the applicability of
these documents, then, prior to working on the equipment,
they should verify with the owner whether the equipment
has been modified and if current literature is available.
DESIGN LEVEL (F)
POWERSUPPLY
– for 60 Hz
5 for 50 Hz
COMPRESSOR CODE
H4, H5, H6, H7, H8, H9, J1,
J2, J3, J4, J5, P1, P2, P3,
P4, P5, P6, P7, P8, P9, Q7
CONDENSER CODE
AA, AB, AC, AD, BA, BB, BC, BD, CD, CE, CF, CG, CH,
DE, DF, DG, DH, EB, EC, ED, EK, EL, EM, FA, FB, FC,
FD, FK, Fl, FM, GB, GC, GD, GJ, GK, GL, GM, HB, HC,
HD, HK, HL, HM, JB, JC, JD, KJ, KK, KL, KM, TB, TC, TD
, VB, VC, VD, XA, XB, XC, XD
EVAPORATOR CODE
AA, AB, AC, AD, BA, BB, BC, BD, CD, CE, CF, CG, CH, DE, DF, DG,
DH, EB, EK, EL, EM, FB, FC, FD, FK, FL, FM, GB, GC, GD, GF, GH,
GJ, GK, GL, GM, HB, HC, HF, HH, HK, HL, HM, JF, JG, JH, KD, KJ,
KK, KL, KM, LK, LL, LM, TB, TC, TD, TF, TG, TH, VF, VH, WF, WH, XF, XH
NOMENCLATURE
YK CB CB P6 – CM F
MOTOR CODE
60 Hz 50 Hz
CH CX 5CE 5CT
CJ CY 5CF 5CU
CK CZ 5CG 5CV
CL CA 5CH 5CW
CM CB 5CI 5CX
CN DA 5CJ 5DA
CP DB 5CK 5DB
CR DC 5CL 5DC
CS DD 5CM 5DD
CT DE 5CN 5DE
CU DF 5CO 5DF
CV DH 5CP 5DG
CW DJ 5CQ 5DH
CF CG 5CR 5OJ
5CS
In complying with YORK’s policy for continuous prod-
uct improvement, the information contained in this doc-
ument is subject to change without notice. While YORK
makes no commitment to update or provide current
information automatically to the manual owner, that in-
formation, if applicable, can be obtained by contacting
the nearest YORK Applied Systems Service office.
REFERENCE INSTRUCTIONS
DESCRIPTION FORM NO.
SOLID STATE STARTER (MOD “B”) – OPERATION & MAINTENANCE 160.00-O2
VARIABLE SPEED DRIVE – OPERATION 160.00-O1
VARIABLE SPEED DRIVE – SERVICE INSTRUCTIONS 160.00-M1
INSTALLATION 160.73-N1
OPTIVIEW CONTROL CENTER - SERVICE INSTRUCTIONS 160-54-M1
WIRING DIAGRAM – UNIT WITH ELECTRO-MECHANICAL STARTER 160.73-PW1
WIRING DIAGRAM – UNIT WITH MOD “A” SOLID STATE STARTER 160.73-PW2
WIRING DIAGRAM – UNIT WITH VARIABLE SPEED DRIVE 160.73-PW3
RENEWAL PARTS – UNIT 160.73-RP4
RENEWAL PARTS – OPTIVIEW CONTROL CENTER 160.54-RP1
OPTIVIEW™ PANEL - OPERATION & MAINTENANCE 160.54.O1
MODEL

YORK INTERNATIONAL
FORM 160.73-O2 (605)
4
SECTION 1 Description of System and Fundamentals of Operation............................... 6
SECTION 2 System Operating Procedures ...................................................................... 9
SECTION 3System Components Description ............................................................... 15
SECTION 4Operational Maintenance ........................................................................... 21
SECTION 5Troubleshooting.......................................................................................... 23
SECTION 6Maintenance ............................................................................................... 25
SECTION 7Preventive Maintenance ............................................................................. 34
TABLE OF CONTENTS

FORM 160.73-O2 (605)
5
YORK INTERNATIONAL
LIST OF FIGURES
FIG. 1 – MODEL YK MAXETM CHILLER................................... 6
DETAIL A – COMPRESSOR PREROTATION
VANES.................................................................. 7
FIG. 2 – REFRIGERANT FLOW-THROUGH CHILLER ........... 8
FIG. 3 – OIL LEVEL INDICATOR LABEL.................................. 9
FIG. 4 – CHILLER STARTING SEQUENCE &
SHUTDOWN SEQUENCE
(EM STARTER & SOLID STATE STARTER)...... 10
FIG. 5 – CHILLER STARTING SEQUENCE &
SHUTDOWN SEQUENCE
(VARIABLE SPEED DRIVE)................................11
FIG. 6 – LIQUID CHILLER LOG SHEETS.............................. 12
FIG. 7 – SYSTEM COMPONENTS ........................................ 15
FIG. 8 – SCHEMATIC DRAWING (YK) COMPRESSOR
LUBRICATION SYSTEM.................................... 16
FIG. 9 – OIL RETURN SYSTEM ............................................ 21
FIG. 10 – CHARGING OIL RESERVOIR WITH OIL............... 22
FIG. 11 – EVACUATION OF CHILLER................................... 25
FIG. 12 – SATURATION CURVE............................................ 27
FIG. 13 – DIAGRAM - MEGGING MOTOR WINDINGS......... 29
FIG. 14 – MOTOR STATOR TEMPERATURE &
INSULATION RESISTANCE .............................. 30

YORK INTERNATIONAL
FORM 160.73-O2 (605)
6
electro-mechanical starter, YORK Solid State Starter
(optional), or Variable Speed Drive (optional).
In operation, a liquid (water or brine to be chilled)
flows through the evaporator, where boiling refrigerant
absorbs heat from the liquid. The chilled liquid is then
piped to fan coil units or other air conditioning terminal
units, where it flows through finned coils, absorbing heat
from the air. The warmed liquid is then returned to the
chiller to complete the chilled liquid circuit.
The refrigerant vapor, which is produced by the boil-
ing action in the evaporator, flows to the compressor
where the rotating impeller increases its pressure and
temperature and discharges it into the condenser. Water
flowing through the condenser tubes absorbs heat from
the refrigerant vapor, causing it to condense. The con-
denser water is supplied to the chiller from an external
SECTION 1
DESCRIPTION OF SYSTEM AND FUNDAMENTALS OF OPERATION
00116vip
CONDENSER
CONTROL
CENTER
COMPRESSOR
MOTOR
EVAPORATOR
FIG. 1 – MODEL YK MAXETM CHILLER
SYSTEM OPERATION DESCRIPTION (SEE FIG. 2)
The YORK Model YK MaxETM Chiller is commonly ap-
plied to large air conditioning systems, but may be used on
other applications. The chiller consists of an open motor
mounted to a compressor (with integral speed increasing
gears), condenser, evaporator and variable flow control.
The chiller is controlled by a modern state of the art Mi-
crocomputer Control Center that monitors its operation.
The Control Center is programmed by the operator to suit
job specifications. Automatic timed start-ups and shut-
downs are also programmable to suit nighttime, week-
ends, and holidays. The operating status, temperatures,
pressures, and other information pertinent to operation
of the chiller are automatically displayed and read on a
graphic display. Other displays can be observed by press-
ing the keys as labeled on the Control Center. The chiller
with the OptiView Control Center is compatible with an

FORM 160.73-O2 (605)
7
YORK INTERNATIONAL
1
source, usually a cooling tower. The condensed refrig-
erant drains from the condenser into the liquid return
line, where the variable orifice meters the flow of liquid
refrigerant to the evaporator to complete the refrigerant
circuit.
7619A(D)
DETAIL A – COMPRESSOR PREROTATION VANES
Description of System and Fundamentals of Operation
The major components of a chiller are selected to handle
the refrigerant, which would be evaporated at full load
design conditions. However, most systems will be called
upon to deliver full load capacity for only a relatively
small part of the time the unit is in operation.
CAPACITY CONTROL
The major components of a chiller are selected for full
load capacities, therefore capacity must be controlled to
maintain a constant chilled liquid temperature leaving
the evaporator. Prerotation vanes (PRV), located at the
entrance to the compressor impeller, compensate for
variation in load (See Detail A).
The position of these vanes is automatically controlled
through a lever arm attached to an electric motor located
outside the compressor housing. The automatic adjust-
ment of the vane position in effect provides the perfor-
mance of many different compressors to match various
load conditions from full load with vanes wide open to
minimum load with vanes completely closed.

YORK INTERNATIONAL
FORM 160.73-O2 (605)
8
FIG. 2 – REFRIGERANT FLOW-THRU CHILLER
PREROTATION VANES
(See Detail A)
SUCTION
EVAPORATOR
ELIMINATOR
OIL COOLER
LD00924
FLOW CONTROL
ORIFICE
SUB-COOLER
CONDENSER
DISCHARGE
BAFFLE
DISCHARGE
COMPRESSOR

FORM 160.73-O2 (605)
9
YORK INTERNATIONAL
CHECKING THE OIL LEVEL
IN THE OIL RESERVOIR
Proper operating oil level – During operation, the oil
level should fall to the “Operating Range” identified on
the vertical oil level indicator label. See Figure 3.
• If the oil level during operation is in the “Over
Full” region of the oil level indicator, oil should be
removed from the oil reservoir, This reduces the oil
level to the “Operating Range”.
• If the oil level during operation is in
the “Low Oil” region of the oil level
indicator, oil should be added to the
oil reservoir. (See “Oil Charging Pro-
cedure”, page 22)
START-UP PROCEDURE
Pre-Starting
Prior to starting the chiller, observe the OptiView
Control Center. Make sure the display reads SYSTEM
READY TO START.
To pre-start the chiller, use the following procedure:
1. Oil Heater – The oil heater must be energized for
12 hours prior to starting the chiller.
2. Prior to start, the clock must be programmed for the
proper day and time. Any setpoints which are desired
to be changed may be programmed. All Control Cen-
ter setpoints should be programmed before the chiller
is started. (Refer to Form 160.54-O1).
Vent any air from the chiller water
boxes prior to starting the water
pumps. Failure to do so will result in
pass baffle damage.
START-UP
1. If the chilled water pump is manually operated, start
the pump. The Control Center will not allow the
chiller to start unless chilled liquid flow is established
through the unit. (A field supplied chilled water flow
switch is required.) If the chilled liquid pump is wired
to the Microcomputer Control Center the pump will
automatically start, therefore, this step is not neces-
sary.
System Operating Procedures
SECTION 2
SYSTEM OPERATING PROCEDURES
OIL HEATERS
If the oil heater is de-energized during a shutdown period,
it must be energized for 12 hours prior to starting com-
pressor, or remove all oil and recharge compressor with
new oil. (See “Oil Charging Procedure”, page 22.)
OIL HEATER OPERATION
The oil heater operation is controlled by the OptiView™
Control Center. The heater is turned on and off to main-
tain the oil temperature differential to a value 50°F
(27.8°C) above the condenser saturation temperature.
This is the target value and if the oil temperature falls to
4°F (2.2°C) or more below the target, the heater is turned
on. It is turned off when the oil temperature increases to
3°F (1.7°C) above the target value.
If the target value is greater than 160°F (71°C), the target
defaults to 160°F (71°C). If the target value is less than
110°F (43.3°C), it defaults to 110°F (43.3°C).
To prevent overheating of the oil in the event of a con-
trol center component failure, the oil heater thermostat
(1HTR) is set to open at 180°F (82°C). FIG. 3 – OIL LEVEL INDICATOR
LD08647
Comply with EPA and Local regu-
lations when removing or disposing
of Refrigeration System oil!

YORK INTERNATIONAL
FORM 160.73-O2 (605)
10
2. To start the chiller, press the COMPRESSOR
START switch. This switch will automatically
spring return to the RUN position. (If the unit was
previously started, press the STOP/RESET side
of the COMPRESSOR switch and then press the
START side of the switch to start the chiller.) When
the start switch is energized, the Control Center is
placed in an operating mode and any malfunction
will be noted by messages on a graphic display.
Any malfunctions which occur during
STOP/RESET are also displayed.
When the chiller is shut down, the prerotation vanes will
close automatically to prevent loading the compressor
on start-up.
When the chiller starts to operate, the following au-
tomatic sequences are initiated: (Refer to Fig. 4 & 5,
“Chiller Starting & Shutdown Sequence Chart”.)
1. The OptiView Control Center display message will
read SYSTEM PRELUBE for the first 50 seconds
of the starting sequence.
2. The oil pump will start to circulate oil for a 50 second
pre-run to establish oil flow and adequate lubrication
to all bearings, gears, and rotating surfaces within
the compressor.
The high and low oil pressure transducers (OP) and
the oil temperature sensor (RT3) will sense any mal-
function in the lubrication system.
3. The anti-recycle timer (non-VSD Chillers only)
software function will operate after the 50 seconds
of pre-run time. At this time, the timer will be initi-
ated and will run for 30 minutes after the compressor
starts. If the chiller shuts down during this period of
time, it cannot be started until the timer completes
the 30 minute cycle.
4. The chilled liquid pump contacts will close, start-
ing the chilled liquid pump, to allow liquid flow
through the evaporator when the COMPRESSOR
start switch is energized.
5. After the first 50 seconds of operation, the com-
pressor will start.
6. For display messages and information pertaining to
the operation of the OptiView™ Control Center, refer
to Form 160.54-O1.
FIG. 4 – CHILLER STARTING SEQUENCE & SHUTDOWN SEQUENCE
(EM STARTER & SOLID STATE STARTER)
LD04040
** NOT FOR ALL SHUTDOWNS. REFER TO “DISPLAY MES-
SAGES” SECTION OF THIS MANUAL.

FORM 160.73-O2 (605)
11
YORK INTERNATIONAL
2
FIG. 5 – CHILLER STARTING SEQUENCE & SHUTDOWN SEQUENCE
(VARIABLE SPEED DRIVE)
LD04130
CHILLER OPERATION
After the compressor reaches its operating speed, the
Prerotation Vanes will begin to open under the control
of the Microprocessor Board which senses the leaving
chilled liquid temperature. The unit capacity will vary to
maintain the leaving CHILLED LIQUID TEMPERA-
TURE setpoint. The Prerotation Vanes are modulated
by an actuator under the control of the Microprocessor
Board. The vane control routine employs proportional
plus derivative (rate) control action. A drop in chilled
liquid temperature will cause the actuator to close the
Prerotation Vanes to decrease chiller capacity. When
the chilled liquid temperature rises, the actuator will
open the Prerotation Vanes to increase the capacity of
the chiller.
However, the current draw (amperes) by the compressor
motor cannot exceed the setting of the % CURRENT
LIMIT at any time during the unit operation, since the
Microcomputer Control Center 40 to 100% three-phase
peak current limit software function, plus the 3-phase
100% solid state overload current limiter (CM-2), on
Electro-Mechanical Starter applications, or the Solid
State Starter current Limit function will override the
temperature control function and prevent the Prerotation
Vanes from opening beyond the % CURRENT LIMIT
setting.
** NOT FOR ALL SHUTDOWNS. REFER TO “DISPLAY MES-
SAGES” SECTION OF THIS MANUAL.
System Operating Procedures
If the load continues to decrease, after the Prerotation Vanes
are entirely closed, the chiller will be shut down by the
Leaving Chilled Liquid – Low Temperature Control.
CONDENSER WATER TEMPERATURE CONTROL
The YORK MaxETM chiller is designed to use less power
by taking advantage of lower than design temperatures
that are naturally produced by cooling towers throughout
the operating year. Exact control of condenser water
such as a cooling tower bypass, is not necessary for
most installations. The chiller requires only that the
minimum condenser water temperature be no lower
than the value
determined by referring to the formula below:
where:
ECWT = Entering Condensing Water Temperature
LCWT = Leaving Chilled Water Temperature
C Range = Condensing water temperature range at the
given load condition.
Min. ECWT = LCWT – C RANGE + 17ºF
Min. ECWT = LCWT – C RANGE + 9.4ºC

YORK INTERNATIONAL
FORM 160.73-O2 (605)
12
OPERATING INSPECTIONS – See Section 2
By following a regular inspection using the display
readings of the Microcomputer Control Center, and
maintenance procedure, the operator will avoid serious
operating difficulty. The following list of inspections
and procedures should be used as a guide.
Daily
1. Check OptiView™ Control Center displays.
2. If the compressor is in operation, check the bearing
oil pressure on the SYSTEM Screen. Also check
the oil level in the oil reservoir. Operating oil level
should be operating range of oil indicator. Drain or
add oil if necessary.
3. Check entering and leaving condenser water pressure
and temperatures for comparison with job design
conditions. Condenser water temperatures can be
checked on the SYSTEM Screen.
4. Check the entering and leaving chilled liquid tem-
peratures and evaporator pressure for comparison
with job design conditions on the SYSTEM
Screen.
5. Check the condenser saturation temperature (based
upon condenser pressure sensed by the condenser
transducer) on the SYSTEM Screen.
6. Check the compressor discharge temperature on
the SYSTEM Screen. During normal operation
discharge temperature should not exceed 220°F
(104°C).
At start-up, the entering condenser water temperature
may be as much as 25°F (14°C) colder than the standby
return chilled water temperature. Cooling tower fan
cycling will normally provide adequate control of the
entering condenser water temperature on most instal-
lations.
OPERATING LOG SHEET
A permanent daily record of system operating conditions
(temperatures and pressures) recorded at regular inter-
vals throughout each 24 hour operating period should
be kept.
An optional status printer is available for this purpose
or Fig. 6 shows a log sheet used by YORK Personnel
for recording test data on chiller systems. It is available
from the factory in pads of 50 sheets each under Form
160.44-F7 and may be obtained through the nearest
YORK office. Automatic data logging is possible by
connecting the optional printer and programming the
DATA LOGGER function.
An accurate record of readings serves as a valuable
reference for operating the system. Readings taken
when a system is newly installed will establish normal
conditions with which to compare later readings.
For example, an increase in condenser approach
temperature (condenser temperature minus leaving
condenser water temperature) may be an indication of
dirty condenser tubes.
FIG. 6 – LIQUID CHILLER LOG SHEETS
*NOTE: These items can be printed by an electronic printer connected to the Microboard
and pressing the PRINT key on the Keypad, or automatically using the Data Logger feature.
LD00467
23889A

FORM 160.73-O2 (605)
13
YORK INTERNATIONAL
2
7. Check the compressor motor current on the SYSTEM
Screen.
8. Check for any signs of dirty or fouled condenser
tubes. (The temperature difference between water
leaving condenser and saturated condensing tem-
perature should not exceed the difference recorded
for a new unit by more than 4°F, 2.2°C).
Weekly
1. Check the refrigerant charge. (See “Checking The
Refrigerant Charge”, page 28.)
Monthly
1. Leak check the entire chiller.
Quarterly
1. Perform chemical analysis of oil.
Semi-Annually (or more often as required)
1. Change and inspect compressor oil filter element.
2. Oil return system.
a. Change dehydrator.
b. Check nozzle of eductor for foreign particles.
3. Check controls and safety cutouts.
Annually (more often if necessary)
If quarterly inspection indicates oil is
fine, replacing the oil is not necessary.
1. Drain and replace the oil in the compressor oil sump.
(See “Oil Charging Procedure” page 22.)
2. Evaporator and Condenser.
a. Inspect and clean water strainers.
b. Inspect and clean tubes as required.
c. Inspect end sheets.
3. Compressor Drive Motor (See motor manufacturers
maintenance and service instruction supplied with
unit)
a. Clean air passages and windings per manufac-
turers instructions.
b. Meg motor windings – See Fig. 13 for details.
c. Lubricate per motor manufacturer recommenda-
tions.
4. Inspect and service electrical components as necessary.
5. Perform refrigerant analysis.
NEED FOR MAINTENANCE OR SERVICE
If the system is malfunctioning in any manner or the
unit is stopped by one of the safety controls, consult
the “Operation Analysis Chart”, (Table 1), pages 23
and 24 of this instruction. After consulting this chart,
if you are unable to make the proper repairs or adjust-
ments to start the compressor or the particular trouble
continues to hinder the performance of the unit, please
call the nearest YORK District Office. Failure to report
constant troubles could damage the unit and increase
the cost of repairs.
STOPPING THE SYSTEM
The Optiview™ Control Center can be programmed to
start and stop automatically (maximum, once each day)
whenever desired. Refer to Form 160.54-O1. To stop the
chiller, proceed as follows:
1. Push the COMPRESSOR STOP/RESET switch.
The compressor will stop automatically. The oil
pump will continue to run for coastdown period.
The oil pump will then stop automatically.
2. Stop the chilled water pump (if not wired into the
Microcomputer Control Center, in which case it will
shut off automatically simultaneously with the oil
pump.) (The actual water pump contact operation is
dependent upon the position of Microboard jumper
J54.)
3. Open the switch to the cooling tower fan motors, if
used.
4. The compressor sump oil heater is energized when
the unit is stopped.
PROLONGED SHUTDOWN
If the chiller is to be shut down for an extended period of
time (for example, over the winter season), the following
paragraphs outline the procedure to be followed.
1. Test all system joints for refrigerant leaks with a
System Operating Procedures

YORK INTERNATIONAL
FORM 160.73-O2 (605)
14
leak detector. If any leaks are found, they should be
repaired before allowing the system to stand for a
long period of time.
During long idle periods, the tightness of the system
should be checked periodically.
2. If freezing temperatures are encountered while the
system is idle, carefully drain the cooling water from
the cooling tower, condenser, condenser pump, and
the chilled water system-chilled water pump and
coils.
Open the drains on the evaporator and condenser
liquid heads to assure complete drainage. (If a Vari-
able Speed Drive, drain its water cooling system. If
Solid State Starter. drain water from starter cooling
loop.)
3. On the SETUP Screen, disable the clock. This con-
serves the battery.
4. Open the main disconnect switches to the compressor
motor, condenser water pump and the chilled water
pump. Open the 115 volt circuit to the Control Cen-
ter.

FORM 160.73-O2 (605)
15
YORK INTERNATIONAL
SECTION 3
SYSTEM COMPONENTS DESCRIPTION
MOTOR
EVAPORATOR
COMPRESSOR
SUCTION
DUAL RELIEF
VALVES
SIGHT
GLASS
VARIABLE SPEED
OIL PUMP CONTROL
BOX
REFRIGERANT
CHARGING VALVE
00611vip
FRONT VIEW
FIG. 7 – SYSTEM COMPONENTS
OPTIVIEW CONTROL
CENTER
3

YORK INTERNATIONAL
FORM 160.73-O2 (605)
16
FIG. 7 – SYSTEM COMPONENTS (CONT’D)
28778A
DISCHARGE LINE
OIL COOLER
OIL RESERVOIR
PUMP
REAR VIEW
System Components Description

FORM 160.73-O2 (605)
17
YORK INTERNATIONAL
GENERAL
The YORK Model YK MaxETM Centrifugal Liquid
Chiller is completely factory-packaged including evapo-
rator, condenser, compressor, motor, lubrication system,
OptiView Control Center, and all interconnecting unit
piping and wiring.
COMPRESSOR
The compressor is a single-stage centrifugal type pow-
ered by an open-drive electric motor.
The rotor assembly consists of a heat-treated alloy steel
drive shaft and impeller shaft with a cast aluminum,
fully shrouded impeller. The impeller is designed for bal-
anced thrust and is dynamically balanced and over-speed
tested. The inserted type journal and thrust bearings are
fabricated of aluminum alloy. Single helical gears with
crowned teeth are designed so that more than one tooth
is in contact at all times. Gears are integrally assembled
in the compressor rotor support and are film lubricated.
Each gear is individually mounted in its own journal
and thrust bearings.
The open-drive compressor shaft seal is a double bellows
cartridge style with ceramic internal and atmospheric
seal faces. The seal is oil-flooded at all times and is
pressure-lubricated during operation.
CAPACITY CONTROL
Prerotation vanes (PRV) modulate chiller capac-
ity from 100% to as low as 15% of design for
normal air conditioning applications. Operation
is by an external, electric PRV actuator which
automatically controls the vane position to main-
tain a constant leaving chilled liquid temperature.
COMPRESSOR LUBRICATION SYSTEM
(See Fig. 8)
The chiller lubrication system consists of the oil pump,
oil filter, oil cooler and all interconnecting oil piping
and passages. There are main points within the motor-
compressor which must be supplied with forced lubri-
cation as follows:
1. Compressor Drive Shaft (Low Speed)
a. Shaft seal.
b. Front and rear journal bearings – one on each
side of driving gear.
c. Low speed thrust bearing (forward and reverse).
2. Compressor Driven Shaft (High Speed)
a. Forward and reverse high speed thrust
bearing.
b. Two journal bearings.
3. Speed Increasing Gears
a. Meshing surfaces of drive and pinion gear teeth.
To provide the required amount of oil under the nec-
essary pressure to properly lubricate these parts, a motor
driven submersible oil pump is located in a remote oil
sump.
Upon pressing of the COMPRESSOR START switch
on the Control Center, the oil pump is immediately
energized. After a 50 second pre-lube period, the com-
pressor motor will start. The oil pump will continue to
run during the entire operation of the compressor, and
for 150 seconds during compressor coastdown.
The submerged oil pump takes suction from the sur-
rounding oil and discharges it to the oil cooler where heat
is rejected. The oil flows from the oil cooler to the oil
filter. The oil leaves the filter and flows to the emergency
oil reservoir where it is distributed to the compressor
bearings. The oil lubricates the compressor rotating
components and is returned to the oil sump.
There is an emergency oil reservoir located at the
highest point in the lubrication system internally in
the compressor. It provides an oil supply to the various
bearings and gears in the event of a system shutdown
due to power failure. The reservoir, located on the top of
the compressor, allows the oil to be distributed through
the passages by gravity flow, thus providing necessary
lubrication during the compressor coastdown.
3

YORK INTERNATIONAL
FORM 160.73-O2 (605)
18
LOW SPEED
GEAR REAR
BEARING
DOUBLE
BELLOWS
SHAFT SEAL
FIG. 8 – SCHEMATIC DRAWING – (YK) COMPRESSOR LUBRICATION SYSTEM LD08577
System Components Description

FORM 160.73-O2 (605)
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 sys-
tem 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, squirrel
cage, induction type constructed to YORK design spec-
ifications. 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 compressor
shaft with a flexible disc coupling. This coupling 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 conduit.
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 fur-
nished. 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 discharge
gas baffle to prevent direct high velocity impingement
on the tubes. A separate subcooler is located in the con-
denser 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 con-
denser and outputs an analog voltage to the Microboard
that represents this level (0% = empty; 100% = full).
Under program control, the Microboard modulates a
variable orifice to control the condenser refrigerant level
to a programmed setpoint. Other setpoints affect the
control sensitivity and response. These setpoints must
be entered at chiller commissioning by a qualified ser-
vice technician. Only a qualified service technician may
modify these settings.
3

YORK INTERNATIONAL
FORM 160.73-O2 (605)
20
While the chiller is shut down, the orifice will be in the
fully open position causing the sensed level to be ap-
proximately 0%. When the chiller is started, after the
vane motor end switch (VMS) opens when entering
SYSTEM RUN, if actual level is less than the level
setpoint, a linearly increasing ramp is applied to the
level setpoint. This ramp causes the setpoint to go from
the initial refrigerant level (approximately 0%) to the
programmed setpoint over a period of 15 minutes.
If the actual level is greater than the setpoint when the
VMS opens, there is no pulldown period, it immediately
begins to control to the programmed setpoint.
While the chiller is running, the refrigerant level is nor-
mally controlled to the level setpoint. However, anytime
the vanes fully close (VMS closes), normal level control
is terminated, any refrigerant level setpoint pulldown in
effect is cancelled and the outputs to the level control
will be opposite that which is supplied to the vane motor
(i.e., when a close pulse is applied to the vane motor, an
open pulse is applied to the level control, etc.). When the
VMS opens, if the refrigerant level is less than the level
setpoint, a refrigerant level setpoint pulldown is initiated
as described above. Otherwise, the level is controlled to
the programmed setpoint.
OPTIONAL SERVICE ISOLATION VALVES
If your chiller is equipped with optional service isolation
valves on the discharge and liquid line, these valves
must remain open during operation. These valves are
used for isolating the refrigerant charge in either the
evaporator or condenser to allow service access to the
system. A refrigerant pump-out unit will be required to
isolate the refrigerant.
Isolation of the refrigerant in this sys-
tem must be performed by a qualified
service technician.
OPTIONAL HOT GAS BYPASS
Hot gas bypass is optional and is used to eliminate
compressor surge during light load or high head op-
eration. The OptiView control panel will automatically
modulate the hot gas valve open and closed as required.
Adjustment of the hot gas control valve must be per-
formed by a qualified service technician following the
Hot Gas Set-up procedure.
Changes in chilled water flow will
require readjustment of the hot gas
control to insure proper operation.
OTIVIEW CONTROL CENTER
(See Section 2)
The OptiView Control Center is factory-mounted, wired
and tested. The electronic panel automatically controls
the operation of the unit in meeting system cooling re-
quirements while minimizing energy usage. For detailed
information on the Control Center, refer to “Section 2”
of this manual.
SOLID STATE STARTER (Optional)
The Solid State Starter is a reduced voltage starter
that controls and maintains a constant current flow to
the motor during start-up. It is mounted on the chiller.
Power and control wiring between the starter and chiller
are factory installed. Available for 380-600 volts, the
starter enclosure is NEMA-1 with a hinged access door
with lock and key. Electrical lugs for incoming power
wiring are provided.
VARIABLE SPEED DRIVE (Optional)
A 460V – 3-Ph – 60/50 Hz Variable Speed Drive can
be factory packaged with the chiller. It is designed to
vary the compressor motor speed and prerotation vane
position by controlling the frequency and voltage of
the electrical power to the motor. Operational informa-
tion is contained in Form 160.00-O1. The control logic
automatically adjusts motor speed and compressor pre-
rotation vane position for maximum part load efficiency
by analyzing information fed to it by sensors located
throughout the chiller.
System Components Description