York MILLENNIUM YG Series Manual

27704A
OPERATING & MAINTENANCE
MILLENNIUM TM
CENTRIFUGAL LIQUID CHILLERS
Supersedes: 160.60-O1 (1296) Form 160.60-O1 (1197)
MODEL YG & YB
(DESIGN LEVEL A)
YG
YB
WARNING
SYSTEM CONTAINS REFRIGERANT UNDER PRESSURE.
SERIOUS INJURY COULD RESULT IF PROPER PROCEDURES ARE NOT FOLLOWED WHEN
SERVICING SYSTEM. ALL SERVICE WORK SHALL BE PERFORMED BY A QUALIFIED SERVICE
TECHNICIAN IN ACCORDANCE WITH YORK INSTALLATION/OPERATION MANUAL.
28699A

2 YORK INTERNATIONAL
ECP = Engine Control Panel
PLC = Programmable Logic Control
EIS = Electronic Ignition System
ECS = Engine Control Switch
SCM = Status Control Module
ABBREVIATIONS
The abbreviations below are used in this manual.
EMS = Energy Management System
PWM = Pulse Width Modulation
RTC = Real Time Clock
PRV = Prerotation Vane
LWT = Low Water Temperature
HOT = High Oil Temperature
OP = Oil Pressure
LCWT = Leaving Chilled Water Temp.
ECWT = Entering Condensing Water
Temp.
YB MC MC G4  G3406 A
Model Design Level
Cooler Code Engine Size
Condenser Code Power Supply - for 60 Hz
5 for 50 Hz
Compressor Code
NOMENCLATURE
The model number denotes the following characteristics of the unit:
YG NB NB G4  G3408 A
Model Design Level
Cooler Gas Engine Drive Package
Condenser Power Supply - for 60 Hz
Compressor

YORK INTERNATIONAL 3
FORM 160.60-O1
TABLE OF CONTENTS
SECTION 1
Description of System and Fundamentals of Operation ....................................... 10
Capacity Control (Also see page 57) ........................ 11 Quick Shutdowns (Also see page 49) ................... 13
Caterpillar Engine Control Panel ............................... 11 Safety Shutdowns (Also see page 53) .................. 14
SECTION 2
MicroComputer Control Center ......................................................... 17
Introduction .............................................................. 18 Manual Operation ................................................. 34
Micro Panel Control Center ...................................... 19 Fixed Operation .................................................... 34
Operation ................................................................. 19 Manual Speed or Manual Vane Control Selection .. 34
Out of Range Values for R134a (Also see pg 51) ...... 19 Prerotation Vanes and Engine Speed Keys........... 35
Selecting Engine Type .............................................. 20 Calibration Procedures .......................................... 36
System Setpoints .................................................... 23 PRV Motor Wiring Checkout .................................36
Displaying System Setpoints ................................... 24 Operating Modes .................................................. 37
Data Logger Setpoints.............................................. 26 Compressor Switch and Emergency Stop Switch . 38
Programming the MicroComputer Control Center ...... 27 Display Messages ................................................ 38
Programming System Setpoints............................... 27 System Shutdown Messages ............................... 40
Service Keys ............................................................ 32 Engine Related Display Messages .......................44
Automatic Operation ................................................ 32 Engine Related Shutdown Messages .................... 46
SECTION 3
System Operating Procedures ........................................................ 48
Start-Up Procedure (Also see page 50) .................... 48 Chiller Operating Thresholds (Also see page 19) ... 51
Start Sequence (Also see pages 50 & 57)................ 49 Chiller Operation ................................................... 52
Shutdown Sequence ................................................ 49 Safety Shutdowns (Also see page 14) .................. 53
Quick Safety Shutdown (Also see page 13) ............. 49 Cycling Shutdowns ............................................... 54
Timing Chart for System (Also see page 57) ............ 50
SECTION 4
System Components Description........................................................... 55
Photo of YG Components ........................................ 55 Engine Vibration Sensor ....................................... 59
Photo of YB Components ......................................... 56 Gear Oil Temp Switch Connections....................... 60
Start Sequence (Also see pages 49 & 50)................ 57
SECTION 5
Operation Maintenance.............................................................. 61
SECTION 6
Troubleshooting (Problems and Solutions) ................................................ 62
SECTION 7
Maintenance ......................................................................... 66
SECTION 8
Preventative Maintenance ........................................................... 71

4 YORK INTERNATIONAL
QUICK REFERENCE TO FIGURES
FIG. NO. DESCRIPTION PAGE NO.
1YG Gas Engine Drive Chiller ................................................................................... 10
1A YB Gas Engine Drive Chiller ................................................................................... 10
2Engine Speed Control Block Diagram ..................................................................... 11
2A Engine Control Panel .............................................................................................. 15
3Engine Control Panel .............................................................................................. 16
4MicroComputer Control Center and Keypad ............................................................ 17
5System Parameters  Out of Range Readings ........................................................ 19
6Manifold Pressure vs. Engine Speed ....................................................................... 21-23
7Keypad  Programming System Setpoints ............................................................. 27
8Keypad  Programming Leaving Chilled Water Temp Setpoint .............................. 28
9Keypad  Programming Engine Load Limit Setpoint ............................................. 28
10 Keypad  Programming Pulldown Demand Setpoint ............................................. 29
11 Keypad  Programming Clock Setpoint ................................................................ 29
12 Keypad  Programming Daily Schedule Setpoint .................................................. 30
13 Keypad  Programming Holiday Setpoint .............................................................. 31
14 Keypad  Programming Remote Reset Temp Range............................................. 31
15 Keypad  Service Keys Location ............................................................................ 32
16 MicroComputer Control Center  Location of Real Time Clock U16 ......................... 43
17 Chiller Start Sequence & Shutdown Sequence Timing Diagram ............................. 50
18 YG Chiller System Components ............................................................................. 55
18A YB Chiller System Components ............................................................................. 56
19 Saturation Curve ..................................................................................................... 67
QUICK REFERENCE TO TABLES
TABLE NO. DESCRIPTION PAGE NO.
1Operational Thresholds Chart .................................................................................. 51
2Causes of Normal & Safety System Shutdowns in Accordance
with the MicroComputer Control Center ................................................................. 62-63
3Operating Analysis Chart ........................................................................................ 64-65
4System Pressures .................................................................................................. 67
5Refrigerant Charge YB / YG Models........................................................................ 68

YORK INTERNATIONAL 5
FORM 160.60-O1
QUICK REFERENCE  DISPLAY MESSAGES
Following is a list of display messages showing the display and the page it can be found on to help you troubleshoot the
YORK panel faster.
Display Page No.
SYSTEM RUN – LEAVING TEMP CONTROL ...................................................................................................................................................... 38
SYSTEM RUN – ENGINE LOAD LIMIT IN EFFECT ............................................................................................................................................. 38
SYSTEM RUN – AUTO SPEED/AUTO VANES .................................................................................................................................................... 38
SYSTEM RUN – VANES OPENING ....................................................................................................................................................................... 38
SYSTEM RUN – VANES CLOSING ....................................................................................................................................................................... 38
SYSTEM RUN – AUTO SPEED/AUTO VANES .................................................................................................................................................... 38
SYSTEM RUN – VANES HOLDING ....................................................................................................................................................................... 38
SYSTEM RUN – LOW PRESSURE LIMIT IN EFFECT ........................................................................................................................................ 38
SYSTEM RUN – HIGH PRESSURE LIMIT IN EFFECT ........................................................................................................................................ 39
SYSTEM RUN – PRESS STATUS ........................................................................................................................................................................ 39
WARNING: COND OR EVAP TRANSDUCER ERROR ......................................................................................................................................... 39
WARNING – PRV POT OR SWITCH ERROR ....................................................................................................................................................... 39
SYSTEM RUN – LEAVING TEMP CONTROL ...................................................................................................................................................... 39
SYSTEM RUN – SETPOINT OVERRIDE .............................................................................................................................................................. 39
REPLACE RTC , U16 – REPROGRAM SETPOINTS ........................................................................................................................................... 39
SYSTEM READY TO START ................................................................................................................................................................................ 39
SYSTEM SHUTDOWN – PRESS STATUS .......................................................................................................................................................... 39
MACH = X.XX; MACH’S X.XX ............................................................................................................................................................................... 39
ENGINE RPM = XXXX; RPMS = XXXX................................................................................................................................................................. 39
DELTA P OVER P = X.XX; PRV = XXX% ............................................................................................................................................................ 39
COMP. COASTDOWN; ENG SHTDN-PRESS STATUS...................................................................................................................................... 40
COMPR. COASTDN; ENG COOLDN-PRESS STATUS ...................................................................................................................................... 40
COMPR SHUTDOWN – ENGINE COOLDOWN..................................................................................................................................................... 40
MON 10:00 AM – LOW WATER TEMP – AUTOSTART...................................................................................................................................... 40

6 YORK INTERNATIONAL
MON XX:XX AM – FLOW SWITCH........................................................................................................................................................................ 40
MON XX:XX AM – SYSTEM CYCLING – AUTOSTART ..................................................................................................................................... 40
MON XX:XX AM – MULTI UNIT CYCLING – AUTOSTART ............................................................................................................................... 40
MON XX:XX AM – POWER FAILURE.................................................................................................................................................................... 40
MON XX:XX AM – INTERNAL CLOCK – AUTOSTART...................................................................................................................................... 40
REMOTE STOP....................................................................................................................................................................................................... 40
MON XX:XX AM – LOW EVAP PRESSURE ......................................................................................................................................................... 40
MON XX:XX AM – LOW EVAP PRESSURE – BRINE .......................................................................................................................................... 40
MON XX:XX AM – LOW OIL PRESSURE ............................................................................................................................................................. 40
MON XX:XX AM – HIGH PRESSURE .................................................................................................................................................................... 41
MON XX:XX AM – EVAP TRANS OR PROBE ERROR ....................................................................................................................................... 41
MON XX:XX AM – HIGH DISCHARGE TEMP ....................................................................................................................................................... 41
MON XX:XX AM – HIGH OIL TEMP ...................................................................................................................................................................... 41
MON XX:XX AM – HIGH OIL PRESSURE............................................................................................................................................................. 41
MON XX:XX AM – FAULTY COND PRESSURE XDCR....................................................................................................................................... 41
MON XX:XX AM – FAULTY OIL PRESSURE XDCR ........................................................................................................................................... 41
VANE MOTOR SWITCH OPEN ............................................................................................................................................................................. 41
SYSTEM READY TO START – PRESS STATUS............................................................................................................................................... 41
START SEQUENCE INITIATED ............................................................................................................................................................................ 41
START SEQ. INITIATED – COMPRESSOR PRELUBE ...................................................................................................................................... 41
MON 9:30 AM LOW OIL TEMPERATURE – AUTOSTART ................................................................................................................................. 41
MON XX:XXX AM – LOW OIL TEMP DIFF – AUTOSTART ............................................................................................................................... 42
DAY – TIME – OIL PRESSURE XDCR ERROR .................................................................................................................................................... 42
MON XX:XX AM FAULTY DISCHARGE TEMP SENSOR ................................................................................................................................... 42
MON XX:XX AM – PROX SENSOR SAFETY SHUTDOWN................................................................................................................................ 42
FAULTY PROXIMITY PROBE ............................................................................................................................................................................... 42
MON XX:XX AM – HIGH SPEED DRAIN TEMP .................................................................................................................................................... 42
MON XX:XX AM – OPEN DRAIN TEMP THERMOCOUPLE ............................................................................................................................... 42
MON XX:XX AM – DC UNDER VOLTAGE ............................................................................................................................................................ 43
MON XX:XX AM – AUX SAFETY SHUTDOWN ................................................................................................................................................... 43

YORK INTERNATIONAL 7
FORM 160.60-O1
WARNING – PRV POT OR SWITCH ERROR ....................................................................................................................................................... 43
WARNING CONDENSER TRANSDUCER OR PROBE ERROR ........................................................................................................................... 43
REPLACE RTC.U16 – REPROGRAM SETPOINTS .............................................................................................................................................. 43
ENGINE RELATED DISPLAY MESSAGES (Displayed on YORK Micro Panel)
ENGINE START SIGNAL........................................................................................................................................................................................ 44
ENGINE WARMUP ................................................................................................................................................................................................... 44
START SEQ. INITIATED – COMPRESSOR PRELUBE ...................................................................................................................................... 44
SYSTEM RUN; STOP SEQUENCE INITIATED .................................................................................................................................................... 44
WARNING – HIGH ENGINE VIBRATION DETECTED .......................................................................................................................................... 44
WARNING – COMPRESSOR SERVICE TIME ELAPSED .................................................................................................................................... 44
COMPR. COASTDOWN: ENGINE COOLDOWN .................................................................................................................................................. 44
COMPR. SHUTDOWN: ENGINE COOLDOWN ..................................................................................................................................................... 44
MANUAL ENGINE CYCLING................................................................................................................................................................................... 44
COMPRESSOR ROTATION FAULT ..................................................................................................................................................................... 44
COMPR. COASTDN; ENGINE SHTDN – PRESS STATUS ................................................................................................................................ 44
DAY TIME COMPRESSOR ROTATION FAULT .................................................................................................................................................. 44
WARNING – ENGINE SERVICE TIME ELAPSED .................................................................................................................................................. 44
SUN 12:00 AM GENSET OVERRIDE...................................................................................................................................................................... 44
LOW GEAR OIL TEMPERATURE SENSOR ......................................................................................................................................................... 45
SUN 12:00 AM LOW GEAR OIL TEMP – AUTO START ..................................................................................................................................... 45
LOW GEAR OIL TEMP SENSE FAULT................................................................................................................................................................. 45
SUN 12:00 AM LOW GEAR OIL TEMPS SENS FAULT ....................................................................................................................................... 45
ENGINE VIBRATION = X.XX IN/SEC [0.40/0.65/0/60] .......................................................................................................................................... 45
WARNING – HIGH ENGINE VIBRATION DETECTED .......................................................................................................................................... 45
ENGINE VIBRATION LEVEL = X.XX IN/SEC ....................................................................................................................................................... 45
ENGINE VIBRATION SENSOR .............................................................................................................................................................................. 45
GEAR LUBE PUMP.................................................................................................................................................................................................. 45
ENGINE RELATED SHUTDOWN MESSAGES (Displayed on YORK Micro Panel)
COMPRESSOR OVERSPEED................................................................................................................................................................................ 46
SURGE SAFETY...................................................................................................................................................................................................... 46
SURGE SAFETY SHUTDOWN .............................................................................................................................................................................. 46

8 YORK INTERNATIONAL
PLC FAILURE .......................................................................................................................................................................................................... 46
ENGINE OVERSPEED ............................................................................................................................................................................................. 46
ENGINE OVERLOAD ............................................................................................................................................................................................... 46
ENGINE CRANKING FAULT ................................................................................................................................................................................... 46
LOW GEAR OIL TEMPERATURE SWITCH .......................................................................................................................................................... 46
SUN 12:00 AM LOW GEAR OIL TEMP SENS FAULT.......................................................................................................................................... 46
HIGH AFTER COOLER WATER TEMPERATURE................................................................................................................................................ 46
ENGINE FAULT ....................................................................................................................................................................................................... 46
CLUTCH FAILURE .................................................................................................................................................................................................. 46
LOW ENGINE OIL PRESSURE .............................................................................................................................................................................. 47
HIGH ENGINE JACKET TEMP................................................................................................................................................................................ 47
SURFACE SPEED CONTROL: ACTIVE ............................................................................................................................................................... 47
SURFACE SPEED CONTROL: NOT ACTIVE ...................................................................................................................................................... 47
HIGH ENGINE GLYCOL TEMP ............................................................................................................................................................................... 47
COMPR COASTDN; ENGINE SHTDN – PRESS STATUS ................................................................................................................................. 47
DAY TIME HIGH ENGINE GLYCOL TEMP ............................................................................................................................................................ 47
COMPR SHTDN; ENGINE COOLDN – PRESS STATUS .................................................................................................................................... 47
SUN 12:00 AM HIGH ENGINE VIBRATION FAULT .............................................................................................................................................. 47

YORK INTERNATIONAL 9
FORM 160.60-O1
STANDARD DISPLAY MODE KEY MESSAGES
SETPOINT KEY MESSAGE
Chilled Liquid Temp LEAVING SETPOINT = XX.X°F
% Engine Load Limit ENGlNE LOAD LIMIT = XXX%
Pulldown Demand SETPOINT = XXXMIN @ XXX% LOAD, XXX MIN LEFT
Clock TODAY IS SUN 12:00AM XX/XX/XX
Service Interval ENGlNE SETPOINT = XXXX HRS, XXXX HRS REM
COMPRESSOR SETP = XXXX HRS, XXXX HRS REM
Daily Schedule SUN START = 00:00 AM, STOP = 00:00 AM
MON START = 00:00 AM, STOP = 00:00 AM
TUES START = 00:00 AM, STOP = 00:00 AM
WED START = 00:00 AM, STOP = 00:00 AM
THURS START = 00:00 AM, STOP = 00:00 AM
FRI START = 00:00 AM, STOP = 00:00 AM
SAT START = 00:00 AM, STOP = 00:00 AM
HOLIDAY START = 00:00 AM, STOP = 00:00 AM
Holiday S M T W T F S HOLIDAY NOTED BY *
Remote Reset Temp. Range REMOTE TEMP RESET RANGE = 00°F
Data Logger WTO AUTO PRINT INTERVAL = NOT PROGRAMMED
DISPLAY KEY MESSAGE
Chilled Liquid Temps CHILLED LEAVING=XXX.X°F; RETURN=XXX.X°F
Refrigerant Pressures EVAP = XXXX.X PSIG; COND = XXXX.X PSIG
Comp Oil Pressure OIL PRESSURE = XXX.X PSID
Engine Data ENGINE OIL PRESSURE = XXX.X PSIG
ENGINE MANIFOLD PRESSURE = XX.X PSIA
ENGINE JACKET WATER TEMP = XXX.X°F
AC INLET WATER TEMPERATURE = XXX°F
Engine RPM / % Vanes ENGINE SPEED = XXXX RPM; VANES = XXX%
Condenser Liquid Temps COND LEAVING = XXX.X°F; RETURN = XXX.X°F
Print PRINT ENABLE
PRINT REQUEST IN PROGRESS
Chiller Data SAT TEMPS EVAP = XXX .X°F, COND = XXX.X°F
DISCHARGE TEMP = XXX.X°F, OIL TEMP = XXX.X°F
HOP = XXXX.X PSIG; LOP = XXXX.X PSIG
PROXIMITY SENS-POS:XX MILS; REF:XX MILS
HIGH SPEED DRAIN TEMP = XXX.X°F
DELTA P OVER P = X.XX; PRV = XXX%
ENGINE RPM = XXXX; RPMS = XXXX
MACH = X.XX; MACHS = X.XX
REFRIG. LEVEL
Operating Hours/Start Counter OPER. HOURS =XXXXX; START COUNTER = XXXXX
% Engine Load G3516 ENGINE LOADING = XXX%
ENGINE LOAD - > (30 - 39%): XXXX.X HOURS
ENGINE LOAD - > (40 - 49%): XXXX.X HOURS
ENGINE LOAD - > (50 - 59%): XXXX.X HOURS
ENGINE LOAD - > (60 - 69%): XXXX.X HOURS
ENGlNE LOAD - > (70 - 79%): XXXX.X HOURS
ENCilNE LOAD - > (80 - 89%): XXXX.X HOURS
ENGINE LOAD - > (90 - 100%): XXXX.X HOURS

10 YORK INTERNATIONAL
SECTION 1
DESCRIPTION OF SYSTEM AND
FUNDAMENTALS OF OPERATION
FIG. 1  MODEL YG GAS ENGINE DRIVE CHILLER
SYSTEM OPERATING DESCRIPTION (See Fig. 1 or 1A)
The YORK Gas Engine Drive Centrifugal Chiller consists
of two packages; a shell package and a drive line pack-
age. The shell package includes an evaporator and con-
denser with internal subcooler. The drive line package
includes a compressor, compressor lubrication sys-
27704A
GAS ENGINE
ENGINE
CONTROL
PANEL
YORK MICROCOMPUTER
CONTROL CENTER
COMPRESSOR AC DISTRIBUTION
PANEL
OIL SUMP CONDENSER
COOLER
SUCTION
LINE
DISCHARGE
LINE
FIG. 1A  MODEL YB GAS ENGINE DRIVE CHILLER
YORK POWER PANEL
YORK MICRO PANEL
ENGINE JACKET WATER
LOCATION WHEN INSTALLED CATERPILLAR
CONTROL
PANEL
1T 3KVA
TRANSFORMER BATTERY
CHARGER
RT4 LEAVING
COND. WATER
SENSOR
RT5 ENTERING
COND. WATER
SENSOR
RT9 ENTERING
CHILLED
WATER SENSOR
RT1 LEAVING
CHILLED
WATER SENSOR
28699A
tem, natural gas engine, clutch, speed increaser, torsional
vibration reducing coupling, power panel, engine PLC
panel, and chiller control panel.
The YORK Gas Engine Drive Centrifugal Chiller is com-
monly applied to large air conditioning systems, but may
be used on other applications.

YORK INTERNATIONAL 11
FORM 160.60-O1
The desired engine speed will be obtained from a three
dimensional equation which will represent the compres-
sor surge surface. The prerotation vane position and head
(P Cond. minus P Evap. divided by P Evap.) are the two
independent variables, which upon inserting into the equa-
tion, will yield a machine number. The machine number
will then be used to calculate the desired engine speed.
Each engine speed data point calculated will be set at a
marginal value above its associated compressor surge
point. This adjusted surface will provide a boundary on
which high efficiency chiller operation may be achieved
and below which surge may occur. Therefore, engine
speed must always be set on or above this adjusted sur-
face during system run.
You should note that automatic vane control will operate
in the background as it has on previous products and will
be inhibited only as required. At system start-up, the
engine will be brought up to full speed. Only after full
speed has been reached and leaving chilled water
temperature is close to setpoint (LCHWT) will the
engine speed slowly approach the surface speed.
Since PRV position and head are dynamic, the surface
speed must be calculated on a continuous basis.
Fig. 2 is a simple block diagram of the engine speed control:
Capacity control is achieved by use of prerotation vanes
and impeller speed control. Prerotation vane position and
engine speed are automatically controlled by the YORK
Micro Panel to maintain leaving chilled liquid tempera-
ture at the desired setpoint without overloading the en-
gine. Engine speed is set to optimize energy efficiency.
The unit will be capable of operating with lower tempera-
ture cooling tower water during part load operation. At
operating conditions requiring less than full impeller speed,
engine speed is reduced to improve efficiency.
CATERPILLAR ENGINE CONTROL PANEL
OPERATION
General
The Gas Engine Control Panel (referred to as ECP-En-
gine Control Panel) is designed for operation and protec-
LD02532
The chiller is controlled by a modern state-of-the-art
MicroComputer Control Center which monitors its
operation. The control center is programmed by the
operator to suit job specifications. Automatic timed
start-ups and shutdowns are also programmed to suit
nighttime, weekends, and holidays. The operating sta-
tus, temperatures, pressures and other information
pertinent to operation of the chiller are automatically dis-
played and read on a 40 character alphanumeric mes-
sage display. Other displays can be observed by press-
ing the keys as labeled on the control center.
In operation, a liquid (water or brine to be chilled) flows
through the cooler, where boiling refrigerant absorbs heat
from the water. 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 boiling
action in the cooler, 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 re-
frigerant vapor, causing it to condense. The condenser
water is supplied to the chiller from an external source,
usually a cooling tower. The condensed refrigerant flows
from the condenser (with integral sub-cooler) into the flow
control chamber, where the flow restrictor meters the flow
of liquid refrigerant to the cooler to complete the refriger-
ant circuit.
The major components of a unit are selected to handle
the refrigerant which would be evaporated at full load de-
sign 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 (Also see page 57)
The YG capacity control will employ the present form of
automatic vane control presently utilized on the centrifu-
gal chillers. In addition to this, the unit will control capac-
ity by varying the engine speed.
FIG. 2  ENGINE SPEED CONTROL
S
E
C
T
1

12 YORK INTERNATIONAL
tion of the natural gas engine and drive components. (See
Figs. 2A and 3, pages 15 & 16) The major components of
this panel consist of a Status Control Module (SCM),
Programmable Logic Controller (PLC) processor, Engine
Control Switches and an Electronic Governor.
The main purpose of the ECP is to integrate the YORK
Micro Panel controls with the Caterpillar Engine controls
(primarily Status Control Module). The ECP is not
intended to be the primary controller for the chiller sys-
tem. The YORK Micro Panel acts as the system con-
troller, providing start/stop initiation logic, clutch en-
gage/disengage initiation and speed control via a 4-
20mA speed reference signal based on system (en-
gine and chiller) parameters.
In addition to integrating the YORK Controls with the Cat-
erpillar Engine Controls, the ECP serves as the primary
control and protection system for the drive line engine,
clutch and gearbox. Engine protection and shutdown are
provided by the Caterpillar Status Control Module for Elec-
tronic Ignition Engines (EIS). This module provides
Overspeed, Overcrank, Low Lube Oil Pressure, High
Jacket Water Temperature, Emergency Stop and Auxil-
iary (PLC initiated) Quick Safety Shutdown protection
with LED indication of shutdown conditions. In addition,
this module displays Engine Hours, Engine Speed, En-
gine Jacket Water Temperature, Engine Oil Pressure and
Battery Voltage on an LCD digital display.
The drive line clutch and gearbox control/protection/indica-
tion is provided by the Drive Line PLC processor. The PLC
provides gear box lubrication control/protection, clutch fail-
ure protection and additional drive line related protection.
LED indication is provided for by Caterpillar modules for drive
line related alarms and shutdowns: (See Fig. 2A and 3)
Alarms include:
 High Jacket Water Temperature Alarm
 Low Engine Oil Pressure Alarm
 System Not in Auto Alarm
 Low Gear Box Oil Pressure Alarm
 High Drive Line Vibration Alarm (Optional)
 Electronic Ignition System Alarm
 Low Battery Voltage Alarm
 High Inlet Manifold Temp Alarm (Optional)
Drive Line Safety Shutdowns include (in addition to
SCM shutdowns):
 Low Jacket Water Level Shutdown
 High Gear Box Oil Temperature Shutdown
 High Drive Line Vibration Shutdown (Optional)
 PLC Failure Shutdown
 Low Gear Box Oil Pressure Shutdown
 Electronic Ignition System Shutdown
 Clutch Failure Shutdown
 Sensor Failure Shutdown consisting of:
1. Low Oil Pressure Warning Switch, Fail
2. Low Oil Pressure Shutdown Switch, Fail
3. High Gear Oil Temperature Switch, Fail
4. Clutch Engaged Pressure Switch, Fail
ENGINE CONTROL SWITCHES AND MANUAL
ENGINE RUN
Four engine control switches are located on the inside of the
ECP door. (See Fig. 3) This is by design to further empha-
size that YORKs Micro Panel is the primary system control.
However, the engine can be run de-clutched from the com-
pressor under manual control for engine set-up and trouble-
shooting, if correct procedures are followed. The following
guidelines should be followed to manually run the engine:
NOTE: It is recommended that the clutch air supply be
disconnected and visual inspection made of the
clutch friction shoes to confirm that the clutch is
disengaged before manually running the engine.
1. Engine Control Switch
The Engine Control Switch is a three (3) position main-
tained switch. Following is the functional description
of each position.
Left  OFF/RESET: This position is to be used when
a system safety shutdown has occurred or it is in-
tended that the system should not be run at that time.
Placing the Engine Control Switch (ECS) in this posi-
tion will reset engine shutdown and alarms if all en-
gine shutdown conditions are no longer present.
Center  AUTO: This position is the normal posi-
tion to run the engine as part of the Chiller System.
This is the position the switch has to be in for the
system to run.
Right  ENG MAINT: This position is to be used when
it is intended to run the engine as a stand alone compo-
nent ONLY. When this position is selected the Engine
Maintenance Control Switch becomes active.
2. Engine Maintenance Control Switch
The Engine Maintenance Control Switch is a two (2)
position maintained switch. Following is the functional
description of each position. This switch is only ac-
tive when the Engine Control Switch is in the ENG
MAINT position.
Left  STOP:
Right  Start/Run: This position should be selected if
it is intended to run the engine stand alone at either Idle
or Rated speed only. Selecting this position will imme-
diately pre-lube (if equipped) and start the engine.
3. Engine Maintenance Speed Control Switch
The Engine Maintenance Speed Control Switch is a
three (3) position maintained switch. Following is the
functional description of each position. This switch is
only active when the Engine Control Switch is in the
ENG MAINT position.

YORK INTERNATIONAL 13
FORM 160.60-O1
Left  PURGE: This position should be selected to
purge the engine of unburned gas.
Center  IDLE: This position should be selected if it
is desired to run the engine manually at Idle speed.
Right  RATED: This position should be selected if it
is desired to run the engine manually at Rated speed.
NOTE: NEVER MANUALLY ENGAGE THE CLUTCH
TO ATTEMPT TO RUN THE SYSTEM WITH-
OUT THE YORK MICRO PANEL CON-
TROLS. THIS WILL RESULT IN COMPRES-
SOR DAMAGE AND POSSIBLE PERSONAL
INJURY.
4. Electronic Ignition System Diagnostic Reset: This
switch is used to clear EIS alarms as described in
the following section.
RESETTING SYSTEM UNDER ALARM/SAFETY
SHUTDOWN CONDITIONS
1. Alarms  Engine Control Panel
The following procedure must be followed to clear
ENGINE related alarm conditions:
A. Alarm conditions will flash the appropriate Alarm
LED and sound the horn on the Alarm Module
until the Alarm Silence button is pressed to ac-
knowledge the alarm condition. At this time, the
LED will stay on continuously and the horn will
turn off.
B. If the alarm condition clears itself after the Alarm
Silence button is pressed, the LED will extinguish,
indicating the alarm condition has returned to nor-
mal operating state.
C. If the Alarm condition does not clear itself, the
LED will remain on continuously until the cause of
the condition is removed.
NOTE: Electronic Ignition System (EIS) Alarms are
the one exception to the above procedure.
The DIAGNOSTIC RESET push-button must
also be pressed in addition to the above pro-
cedure.
2. Purging the Gas Engine
Safety shutdown is any normal shutdown that occurs
during start-up or while in operation that causes the
system to disengage the clutch (stops the compres-
sor), closes the inlet vanes, and allows the compres-
sor lubrication pump to run for two (2) minutes; and
allows the gearbox lubrication pump to run during the
four (4) minute coastdown (engine cooldown) cycle.
When the safety occurrence failure has been satis-
fied, the system can be restarted. (i.e. flow switch).
Emergency stop (E stop) is any failure that shuts
down the system immediately without letting the sys-
tem go through a normal shutdown procedure as de-
scribed above. Before attempting to re-start the
system the engine must be purged of any raw
gas or ignition by-products that may have been
trapped in the engine/exhaust to prevent any
possibility of damage/injury caused by ignition
on start-up. (See purge procedure page 14.)
Below is a list of quick shutdowns which require a
purge:
Quick Shutdown (Also see page 49)
 Flow Switch
 Low Evap Press
 Low Oil Press
 High Press
 Evap Transducer or Probe Error
 High Discharge Temp
 High Oil Temp
 High Oil Pressure
 Faulty Cond Pressure XDCR
 Faulty Oil Pressure XDCR
 Oil Pressure XDRC Error
 Prox Sensor Safety Shutdown
 High Speed Drain Temp
 Aux Safety Shutdown
 Compressor Overspeed
 Surge Safety
 PLC Failure
 Engine Overload
 Engine Overspeed
 Engine Fault
 Clutch Failure
 Low Oil Pressure
 High Engine Jacket Temp
 Low Evap Pressure Brine
 Open Drain Temp Thermocouple
Quick Shutdown  YORK supplies a contact closure
which tells the Caterpillar Panel it is an emergency and
cuts the fuel and ignition. The YORK panel de-clutches.
COMP COASTDOWN – ENGINE SHUTDOWN
This shutdown occurs very quickly to avoid potential equip-
ment damage.
NOTE: In a Quick Shutdown, the engine panel must
be manually reset. This is due to the emer-
gency stop on the engine.
A. Clutch Engage Failure Shutdown
If the clutch of the chiller driveline does not en-
gage, a fault has occurred, and the engine will
shut down. Before attempting to re-start the en-
gine/chiller, a trained operator or YORK/Caterpil-
lar Technician should troubleshoot the system and
correct the problem.
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14 YORK INTERNATIONAL
B. PLC Failure Shutdown
The PLC (Program Logic Control) has been pro-
grammed to output a signal to a watchdog timer.
If the PLC fails to output this pulse to the watch-
dog timer, the engine will shut down to assure
that the engine does not run out of control.
C. Sensor Failure Shutdown
If any of the sensors fail, the engine control panel
and engine ignition system can no longer control
and monitor the engine. The engine is set to shut
down if this occurs to assure that the engine will
not fault, and further endanger the engine and op-
erator personnel.
D. Safety Shutdown  Emergency Stops  Purge
Procedure (Also see page 53)
Safety shutdowns can be intiated by the Engine
Control Panel (ECP) or by the YORK Micro Panel.
Safety shutdowns also require both panels to be
reset. The followign procedure should be followed
to reset the system after a safety shutdown:
NOTE: The system will run through a safety
shutdown sequence when a safety shut-
down has occurred. The sequence will
include running the Compressor Lubri-
cation Pump and the Gear Box Lubrica-
tion Pump for up to four (4) minutes.
The following procedure will not be able
to completely be carried out until the sys-
tem has run through this shutdown se-
quence. Wait for the sequence to com-
plete before executing the following
procedure (with exception A) to al-
low for proper lubrication of the com-
pressor and the gearbox.
1. Press the ALARM SILENCE push-button on
the ECP to turn the horn off.
2. Move the ENGINE CONTROL SWITCHto
the OFF/RESET position to reset the ECP.
Leave the ENGINE CONTROL SWITCH in
this position until this procedure is complete.
3. Press the DIAGNOSTIC RESET if the safety
shutdown was initiated by the EIS system or
caused an EIS SHUTDOWN DIAGNOSTIC.
4. Place the START/RUN/STOP toggle switch on
the YORK Micro Panel to the STOP position.
5. Press the WARNING RESET push-button on
the YORK Micro Panel to reset the system.
NOTE: If the compressor lubrication pump
is still running, the system will not reset.
6. Place the engine control switch in the EN-
GINE MAINTENANCE mode, and turn the
ENGINE MAINTENANCE SPEED CONTROL
switch to the PURGE position.
7. Turn the ENGINE MAINTENANCE CONTROL
switch to the START/RUN position and hold
for fifteen (15) seconds. Return the switch to
the STOP position.
8. Repeat steps 1 through 5 to reset the system.
9. Place the ENGINE CONTROL SWITCH
(ECP) back in the AUTO position and close
the door.
10. The system should now be reset.
3. Safety Shutdowns  Emergency Stops (Also see
page 53)
Safety shutdowns can be initiated by the Engine Con-
trol Panel (ECP) or by the YORK Micro Panel. Safety
Shutdowns will also require both panels to be reset.
Safety Shutdowns are distinguished from standard
shutdowns in that the shutdown occurs very quickly
to avoid potential equipment damage. The following
procedure should be followed to reset the system af-
ter a safety shutdown:
NOTE: The system will run through Safety Shut-
down sequence when a safety shutdown has
occurred. The sequence will include running
the Compressor Lubrication Pump and the
Gear Box Lubrication Pump for up to four
minutes. The procedure will not be able to
completely be carried out until the system
has run through this shutdown sequence.
WAIT FOR THE SEQUENCE TO COM-
PLETE BEFORE FOLLOWING THE BE-
LOW PROCEDURE (WITH THE EXCEP-
TION OF A) TO ALLOW FOR PROPER
LUBRICATION OF THE COMPRESSOR
AND GEAR BOX. DO NOT CYCLE
POWER TO CLEAR FAULTS.
1. Press the ALARM SILENCE push-button on the
ECP to turn the horn off.
2. Move the Engine Control Switch to the OFF/
RESET position to reset the ECP. Leave the
Engine Control Switch in this position until this
procedure is complete.
3. Press the DIAGNOSTIC RESET if the Safety Shut-
down was initiated by the EIS system or caused
an EIS Shutdown Diagnostic.
4. Place the START/RUN/STOP toggle switch on the
YORK Micro Panel to the STOP position.
5. Press the WARNING RESET push-button on the
Micro Panel to reset the system. Must be in
SERVICE Mode (page 37).
NOTE: If the Compressor Lubrication Pump is
still running, the system will not reset.
6. Place the Engine Control Switch (ECS) back in
the AUTO position and close the door.
7. The system should now be reset.
8. Push START/RUN/STOP toggle switch on YORK
Micro Panel to START to restart the chiller.

YORK INTERNATIONAL 15
FORM 160.60-O1
EMERGENCY STOP
LD00155
Alarms include:
 High Engine Coolant Temp Alarm
 High Drive-Line Vibration Alarm
 Low Engine Oil Pressure Alarm
 Electronic Ignition System Alarm
 System Not in Auto Alarm
 Low Battery Voltage Alarm
 Low Gear Box Oil Pressure Alarm
 High Air Inlet Manifold Temp Alarm
Safety Shutdowns include:
 Low Engine Coolant Level Shutdown
 Low Gear Box Oil Pressure Shutdown
 High Gear Box Oil Temperature Shutdown
 Electronic Ignition System Shutdown
 High Drive Line Vibration Shutdown
 Clutch Engage Failure Shutdown
 PLC Failure Shutdown
 Sensor Failure Shutdown consisting of:
1. Low Oil Pressure Warning Switch, Fail
2. Low Oil Pressure Shutdown Switch, Fail
3. High Gear Oil Temperature Switch, Fail
4. Clutch Engaged Pressure Switch, Fail
FIG. 2A  ENGINE CONTROL PANEL (ECP)
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16 YORK INTERNATIONAL
EMERGENCY STOP
LD00155
LD00156
Alarms include:
 High Engine Coolant Temp Alarm
 High Drive-Line Vibration Alarm (Optional)
 Low Engine Oil Pressure Alarm
 Electronic Ignition System Alarm
 System Not in Auto Alarm
 Low Battery Voltage Alarm
 Low Gear Box Oil Pressure Alarm
 High Air Inlet Manifold Temp Alarm (Optional)
Safety Shutdowns include:
 Low Engine Coolant Level Shutdown
 Low Gear Box Oil Pressure Shutdown
 High Gear Box Oil Temperature Shutdown
 Electronic Ignition System Shutdown
 Clutch Engage Failure Shutdown
 PLC Failure Shutdown
 Sensor Failure Shutdown consisting of:
1. Low Oil Pressure Warning Switch, Fail
2. Low Oil Pressure Shutdown Switch, Fail
3. High Gear Oil Temperature Switch, Fail
4. Clutch Engaged Pressure Switch, Fail
FIG. 3  ENGINE CONTROL PANEL (ECP) (Contd) ENGINE CONTROL SWITCHES
YG PANEL
YB PANEL
LD02533

YORK INTERNATIONAL 17
FORM 160.60-O1
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LD00157
27592A
SECTION 2
MICROCOMPUTER CONTROL CENTER
FIG. 4  MICROCOMPUTER CONTROL CENTER AND KEYPAD
WARNING
This equipment generates, uses and can radiate radio frequency energy and if not installed and used in
accordance with the instructions manual, may cause interference to radio communications. Operation of this
equipment in a residential area is likely to cause interference in which case the user at his own expense
will be required to take whatever action may be required to correct the interference.
Additionally, any electronic equipment can generate EMI (electromagnetic interference) which, depending
upon the installation and magnitude, may affect other electronic equipment. The amount of EMI generated
is determined by the source inductance, load inductance, and circuit impedances. Responsibility for
assuring the satisfactory operation of other equipment included in the same power source as the YORK
equipment rests solely with the user. YORK disclaims any liability resulting from any interference or for the
correction thereof. Ear protection should be worn when machine is running.

18 YORK INTERNATIONAL
*These keys provide a print-out when the customer connects a compatible printer to the Micro Board RS-232 serial port. (See Form 160.60-N2.)
The YORK MicroComputer Control Center is a micro-
processor based control system for R-134A centrifugal
chillers. It controls the leaving chilled water temperature
via prerotation vane and engine speed control and has
the ability to limit engine loading via control of the
prerotation vanes.
A keypad mounted on the front of the Control Center (See
Fig. 4) allows the operator to display system operating
parameters on a 40 character alphanumeric display that
is part of the keypad. These readings are displayed via
Display keypad as follows: (In the English mode; tem-
peratures in °F, pressures in PSIG; in the metric mode,
temperatures in °C, pressures in kPa).
 CHILLED LIQUID TEMPERATURES  LEAVING AND
RETURN
 REFRIGERANT PRESSURES  EVAPORATOR AND
CONDENSER
 DIFFERENTIAL COMPRESSOR OIL PRESSURE
 CONDENSER LIQUID TEMPERATURES  LEAVING
AND RETURN
 PRINT*
 HISTORY PRINT*
 SATURATION TEMPERATURES  EVAPORATOR
AND CONDENSER
 DISCHARGE TEMPERATURE
 COMPRESSOR OIL TEMPERATURE
 HIGH & LOW OIL PRESSURE TRANSDUCER
PRESSURE
 ENGINE RPM % VANES
 % ENGINE LOADING
 % OPERATING HOURS/START COUNTER
 ENGINE DATA
 CHILLER DATA
The system setpoints (See Fig. 5) are operator entered
on the front control center SETPOINTS keypad. These
setpoints can also be displayed on the 40 character al-
phanumeric display. The system setpoints are:
 CHILLED LIQUID TEMPERATURE (LCWT)
 % ENGINE LOAD LIMIT
 PULLDOWN DEMAND LIMIT
 CLOCK (TIME-OF-DAY)
 DAILY SCHEDULE (7 DAY TIME-CLOCK
PROGRAMMING)
 HOLIDAY
 REMOTE RESET TEMPERATURE RANGE
 DATA LOGGER
 SERVICE INTERVAL
The cause of all system shutdowns (safety or cycling) is
preserved (until the system is reset or restarts) in the
MicroComputers memory for subsequent viewing on the
keypad display. The operator is continually advised of
system operating conditions by various background and
warning messages. The keypad contains special service
keys for use by the service technician when performing
system troubleshooting.
The MicroComputer Control Center is designed to be com-
patible with most energy management systems (EMS)
in use today. The standard design allows for the following
EMS interface:
1. Remote Start
2. Remote Stop
3. Remote LCWT Setpoint (Pulse Width Modulated
signal)
4. Remote Engine Load Limit Setpoint (Pulse Width
Modulated signal)
5. A Remote Mode Ready to Start Status Contacts
6. Safety Shutdown Status Contacts
7. Cycling Shutdown Status Contacts
8. System Run Contacts
As an enhancement to the standard EMS features, an
optional card file with plug-in printed circuit boards is avail-
able. These optional cards will accept a remote LCWT 0°
to 10°F or 0° to 20°F setpoint offset and/or remote engine
load limit setpoint interface from three user input choices:
1. 4-20mA
2. 0-10VDC
3. contact closures
INTRODUCTION

YORK INTERNATIONAL 19
FORM 160.60-O1
MICRO PANEL CONTROL CENTER
The Control Center front panel layout consists of five key
groups, one switch, and 1 line by 40 character alphanu-
meric vacuum fluorescent display: (See Fig. 4)
CHARACTER DISPLAY  The alphanumeric vacuum fluo-
rescent display is located to the right of the STA-
TUS key. All messages, parameters, setpoints, and data
can be viewed at this location. The main communica-
tions between the operator or service technician and the
MicroComputer Control Center occur on this display.
DISPLAY  Provides a direct read-out of each monitored
parameter on the alphanumeric display.
ENTRY  These keys are used to enter the values for the
operator programmed setpoints. These keys are used in
conjunction with the SETPOINT keys while in program
mode.
SETPOINTS  These keys are used as follows:
1. To view each setpoint, in any Mode, or
2. To select the individual setpoints that are programmed
by the operator in PROGRAM mode only.
Pressing the appropriate key enables the operator to pro-
gram that setpoint by pressing the ENTRY keys.
SERVICE  Included in this group of keys are those func-
tions that are only relevant to servicing the chiller.
Typically, these keys would not be used for daily chiller
operation.
ACCESS CODE  Permits operator to access the
program.
PROGRAM  Permits operator to program the Control
Center.
MODE  Permits operator to check what mode the
Control Center is presently in (LOCAL, REMOTE or
SERVICE).
1. Service  allows manual PRV or engine speed
control with visual display readout of operation.
Also allows manual engine speed control with
visual display readout of engine speed.
2. Local  allows manual chiller start from the COM-
PRESSOR switch on Control Center front.
3. Program  allows operator programming of system
setpoints.
4. Remote  allows remote start, remote stop of com-
pressor and remote reset of LCWT and % engine load
limit.
COMPRESSOR  START, RUN, STOP/RESET
SWITCH  This 3 position rocker switch is used to start
(except in REMOTE mode), stop/run/reset the system.
OPERATION
DISPLAYING SYSTEM PARAMETERS
The DISPLAY keys are used to display selected moni-
tored parameters as follows: (Refer to Fig. 4)
 Press and release the appropriate DISPLAY key 
the message will be displayed for 2 seconds.
- or -
 Press and hold the appropriate DISPLAY key  the
message will be displayed and updated every 0.5 sec-
onds until the DISPLAY key is released.
- or -
 Press and release appropriate DISPLAY key, then press
and release the DISPLAY HOLD key  the message
will be displayed and updated every 2 seconds until the
DISPLAY HOLD key is again pressed and released, or
10 miutes have elapsed, whichever comes first.
NOTE: If the display actually displays Xs, then the moni-
tored parameter is out of normal operating range
(Ref. Fig. 5). If the English/Metric jumper is
installed on the Micro Board, all temperatures
are displayed in degrees Fahrenheit (°F) and all
pressures are displayed in pounds per square
inch gauge (PSIG) except oil pressure which is
displayed in pounds per square inch differential
(PSID). If the English/Metric jumper is not in-
stalled, all temperatures are displayed in degrees
Centigrade (°C) and all pressures are displayed
in Kilo-Pascals (kPa).
OUT OF RANGE VALUES FOR YG & YB CHILLER VARIABLES (R134A)
VARIABLE DISPLAY -> X’S WHEN,
EVAP PRESSURE (WATER & BRINE) <= 6.8 PSIG OR >= 77.4 PSIG
COND PRESSURE <= 6.8 PSIG OR >= 315.0 PSIG
HOP TRANSDUCER PRESSURE >= 315.0 PSIG
LOP TRANSDUCER PRESSURE >= 315.0 PSIG
DISCHARGE TEMPERATURE <= 20.3°F OR >= 226.4°F
OIL TEMPERATURE <= 20.3°F OR >= 226.4°F
LEAVING COND WATER TEMP. <= 8.4°F OR >= 134.1°F
ENTERING COND WATER TEMP. <= 8.4°F OR >= 134.1°F
LEAVING CHILLED WATER TEMP. >= 81.1°F
ENTERING CHILLED WATER TEMP. <= 0.1°F OR >= 93.0°F
FIG. 5  SYSTEM PARAMETERS  OUT OF RANGE
READINGS (Also see page 51)
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20 YORK INTERNATIONAL
To Display CHILLED LIQUID TEMPS:
Press CHILLED LIQUID TEMPS display key as
described on page 19 to produce the following alphanu-
meric display message:
CHILLED LEAVING = XXX.X °F, RETURN = XXX.X °F
To Display REFRIGERANT PRESSURE:
Use REFRIGERANT PRESSURE display key as
described on page 19 to produce the following alphanu-
meric display message:
EVAP = XXXX.X PSIG. COND = XXXX.X PSIG
To Display COMPRESSOR OIL PRESSURE:
Use COMPRESSOR OIL PRESSURE display key as
described on page 19 to produce the following alphanu-
meric display message:
OIL PRESSURE = XXXX.X PSID
The differential pressure displayed is the pressure differ-
ence between the high side oil pressure transducer (out-
put of oil filter) and the low side oil pressure transducer
(compressor housing). Displayed value includes offset
pressure derived from auto-zeroing during START SE-
QUENCE INITIATED. If either transducer is out-of-range,
XX.X is displayed. Oil pressure is calculated as follows:
____PSID = (HOP  LOP)  OFFSET PRESSURE
OFFSET PRESSURE  Pressure differential between the
HOP transducer and LOP transducer outputs during a 10
second period beginning 3 seconds after the start of COM-
PRESSOR START SEQUENCE INITIATED. During this
time the tranducers will be sensing the same pressure
and their outputs should indicate the same pressure.
However, due to accuracy tolerances in tranducer de-
sign, differences can exist. Therefore, to compensate for
differences between transducers and assure differential
pressure sensing accuracy, the OFFSET PRESSURE is
subtracted algebraically from the differential pressure. The
offset pressure calculation will not be performed if either
transducer is out-of-range. The offset value will be taken
as 0 psi in this instance.
To Display ENGINE DATA:
Press the ENGINE DATA display key as described on
page 19 to produce the following alphanumeric display
message:
ENGINE OIL PRESSURE = XXX.X PSIG
ENGINE MANIFOLD PRESSURE = XX.X PSIG
ENGINE JACKET WATER TEMPERATURE = XXX.X°F
AC INLET WATER TEMPERATURE = XXX°F
To Display ENGINE RPM% VANES:
Press the ENGINE RPM% VANES key as described on
page 19 to produce the following alphanumeric display
message:
ENGINE SPEED = XXXX RPM, VANES = XXX %
To Display CONDENSER LIQUID TEMPERATURES:
Use the CONDENSER LIQUID TEMPS display key as
described above to produce the following alphanumeric
display message:
COND LEAVING = XXX.X°F. RETURN = XXX.X°F
NOTE: If the condenser liquid thermistors are not con-
nected, or both termistors are out of range the
display will blank when this key is pressed.
To initiate a PRINT to the Printer:
Press the PRINT key to initiate a printout to an optional
printer. When the key is pressed, this message is displayed:
PRINT REQUEST IN PROGRESS...
Refer to MicroComputer Control Center - System Status
Printers Instruction (Form 160.60-N2) for details of the
optional printers.
SELECTING ENGINE TYPE
The engine type displayed with the % ENGINE LOAD-
ING KEY is a result of program jumper configurations
performed only by a qualified YORK service technician.
Refer to YORK service manual form no. 160.60-M1.
To Display % ENGINE LOADING:
Press the % ENGINE LOADING display key to dis-
play ENGINE LOADING as a percent and loading history
messages, as hours. The messages are as follows: (see
graph below)
G3512 ENGINE LOADING = XXX%
ENGINE LOAD (30 - 39%): XXXX.X HOURS*
ENGINE LOAD (40 - 49%): XXXX.X HOURS*
ENGINE LOAD (50 - 59%): XXXX.X HOURS*
ENGINE LOAD (60 - 69%): XXXX.X HOURS*
ENGINE LOAD (70 - 79%): XXXX.X HOURS*
ENGINE LOAD (80 - 89%): XXXX.X HOURS*
ENGINE LOAD (90 -100%): XXXX.X HOURS*
* Keeping the Engine Loading key depressed will allow you to see
these messages.