York YK M3, MH, M3 G4, HC User Manual

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MILLENNIUM

CENTRIFUGAL LIQUID CHILLERS

OPERATING & MAINTENANCE

MODEL YK M3 M3 G4 THRU YK S6 S4 J2 (STYLE C)

R-22 (COOLING ONLY)

MODEL YK LB LB G4 THRU YK SE SC J4 (STYLE C)

R-134a (COOLING ONLY)

WITH MICROCOMPUTER CONTROL CENTER

PART #371-01200-010, 371-01200-011 & 371-01200-015

FOR ELECTRO-MECHANICAL STARTER,

SOLID STATE STARTER & VARIABLE SPEED DRIVE

Supersedes: Nothing

Form 160.49-O2 (1296)

ARNINGARNING

ARNING

ARNINGARNING

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 Y ORK INSTALLATION/OPERA TION MANUAL.

27385A

ABLE OF CONTENTSABLE OF CONTENTS

ABLE OF CONTENTS

ABLE OF CONTENTSABLE OF CONTENTS

Page

SECTION 1 – Description of System and

Fundamentals of Operation ......................................... 4

SECTION 2 – MicroComputer Control Center ...................................... 6

SECTION 3 – System Operating Procedures ..................................... 30

SECTION 4 – System Component Description .................................. 37

SECTION 5 – Operational Maintenance ............................................. 42

SECTION 6 – Trouble Shooting........................................................... 44

SECTION 7 – Maintenance ................................................................. 49

SECTION 8 – Preventive Maintenance............................................... 58

REFERENCE INSTRREFERENCE INSTR

REFERENCE INSTR

REFERENCE INSTRREFERENCE INSTR

DESCRIPTION FORM NO.

Solid State Starter – Operation & Maintenance 160.46-OM3.1 V ariable Speed Drive – Operation 160.00-O1 Installation 160.49-N5 Installation and Operation of Printers 160.49-N7 Wiring Diagram – Unit with Electro-Mechanical Starter 160.49-PW7 Wiring Diagram – Field Connections (E-M Starter) 160.49-PW10 Wiring Diagram – Field Control Modifications 160.49-PW13 Wiring Diagram – Control Center with SS Starter 160.49-PW8 Wiring Diagram – Field Connections (SS Starter) 160.49-PW11 Wiring Diagram – Solid State Starter 160.49-PW14 Wiring Diagram – Unit with Solid State Starter 160.49-PW8 Wiring Diagram – Unit with Variable Speed Drive 160.49-PW9 Wiring Diagram – Field Connections (V.S.D.) 160.49-PW12 Wiring Diagram – Variable Speed Drive 160.49-PW15

UCTIONSUCTIONS

UCTIONS

UCTIONSUCTIONS

2 YORK INTERNA TIONAL

R-22 UNITS

YK N2 N1 H1 – CX C

CONDENSER CODE M3, M4, N3, N4, P3, P4, Q3, Q4, R3, R4, S3, S4

COOLER CODE M3, M4, N3, N4, P3, P4, P5, P6, Q3, Q4, Q5, Q6, R3, R4, R5, R6, S5, S6

NOMENCLATURE

DESIGN LEVEL (C)

POWER SUPPLY – for 60 HZ 5 for 50 HZ

COMPRESSOR CODE G4, H0, H1, H2, J1, J2

FORM 160.49-O2

MOT OR 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 5OF CV DH 5CP 5OG CW DJ 5CQ 5OH

5CR 5OJ 5CS

MODEL

R-134a

YK NB PB H1 – CX C

CONDENSER CODE LB, LC, MB , MC, NB, NC, PB, PC, QB, QC, RB, RC, SB, SC

COOLER CODE LB, LC, MB , MC , NB, NC, PB , PC, PD , PE, QB, QC, QD, QE, RB, RC, RD , RE, SD, SE

DESIGN LEVEL (C)

POWER SUPPLY – for 60 HZ 5 for 50 HZ

COMPRESSOR CODE G4, H0, H1, H2, J1, J2, J3, J4

MOT OR 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

5CR 5OJ 5CS

MODEL

Y ORK INTERNA TIONAL 3

CONTROL CENTER

SECTION 1

DESCRIPTION OF SYSTEM AND FUNDAMENTALS OF OPERA TION

COMPRESSOR

MOTOR

PRE-ROT ATION

DISCHARGE LINE

27385A

COOLER

VANE ACTUA T OR

FIG. 1 – MODEL YK MILLENNIUM CHILLER

SYSTEM OPERATION DESCRIPTION (See Fig. 2)

The YORK Model YK Millennium Chiller is commonly applied 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, cooler and flow control chamber.

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 startups and shutdowns are also programmed to suit nighttime, weekends, and holidays. The operating status, temperatures, pressures, and other inf ormation pertinent to operation of the chiller are automatically displayed and read on a 40 character alphanumeric message display. Other displays can be observed by pressing the keys as labeled on the Control Center. The chiller with the MicroComputer Control Center is applied with an electro-mechanical starter, YORK Solid State Starter (optional), or Variable Speed Drive (optional).

OIL RESERVOIR/ PUMP

CONDENSER

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. W ater flowing through the condenser tubes absorbs heat from the refrigerant vapor, causing it to condense. The condenser water is supplied to the chiller from an external source, usually a cooling tower . The condensed refrigerant drains from the condenser into the flow control chamber, where the flow restrictor meters the flow of liquid refrigerant to the cooler to complete the refrigerant circuit.

The major components of a chiller are selected to handle the refrigerant which would be evaporated at full load

27382A

4 YORK INTERNA TIONAL

7619A(D)

DET AIL A – COMPRESSOR PRER O TATION V ANES

FORM 160.49-O2

design conditions. Howev er, 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 cooler. Prerotation vanes (PRV), located at the entrance to the compressor impeller, compensate f or variation in load (See Fig. 2. 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 adjustment of the vane position in effect provides the performance of many different compressors to match various load conditions from full load with vanes wide open to minimum load with vanes completely closed.

COMPRESSOR

DISCHARGE

DISCHARGE BAFFLE

CONDENSER

SUB-COOLER

FLOW CONTROL ORIFICE

PREROT A TION V ANES (See Detail A)

SUCTION

COOLER

ELIMINA TOR

LD00924

FIG. 2 – REFRIGERANT FLOW-THRU CHILLER

Y ORK INTERNA TIONAL 5

OIL COOLER

SECTION 2

MICROCOMPUTER CONTROL CENTER

26879A

LD00953

FIG. 3 – MICROCOMPUTER CONTR OL CENTER AND KEYPAD

NOTE: This instruction covers operation of chillers equipped with Electro-Mechanical or Solid State Starters. If chiller

is equipped with Variable Speed Drive, Form 160.00-O1 is to be used in conjunction with this manual.

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 whatev er action ma y be required to correct the interf erence .

Additionally , any electronic equipment can generate EMI (electromagnetic interf erence) 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.

6 YORK INTERNA TIONAL

INTRODUCTION

FORM 160.49-O2

The YORK MicroComputer Control Center is a microprocessor based control system for R-22 or R134a centrifugal chillers. It controls the lea ving chilled water temperature via pre-rotation vane control and has the ability to limit motor current via control of the pre-rotation vanes. Further, it is compatible with YORK Solid State Starter (optional), Variable Speed Drive (optional), and electromechanical starter applications.

A keypad mounted on the front of the Control Center (see Fig. 3) allo ws the operator to displa y 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; temperatures in °F, pressures in (PSIG) (in the metric mode, temperatures in °C, Pressures in KP a).

If unit is equipped with EPROM version C.02F(T).12 or later, the Control Center can be equipped with an optional Chinese language display, either as a field retrofit or factory supplied option on new units. This display mounts on the control center door, directly above the standard display. Both the standard and Chinese display will be present, providing displa y messages simultaneously in both English and Chinese language.

The system setpoints (see Fig. 3) are operator entered on the front control center Setpoints keypad. These setpoints can also be displayed on the 40 char acter alphanumeric display. The system setpoints are:

• CHILLED LIQUID TEMPERATURE (LCWT)

• % CURRENT LIMIT

• PULLDOWN DEMAND LIMIT

• CLOCK (TIME-OF-DAY)

• DAILY SCHEDULE (7 DAY TIME-CLOCK PROGRAMMING)

• HOLIDAY

• REMOTE RESET TEMPERATURE RANGE

• DATA LOGGER

• CONDENSER REFRIGERANT LEVEL

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 Control Center must be configured for Chinese display by a qualified service technician. Instructions are contained in YORK service manual, Form 160.49-M3.

• CHILLED LIQUID TEMPERATURES – LEAVING AND RETURN

• REFRIGERANT PRESSURES – EVAPORATOR AND CONDENSER

• DIFFERENTIAL OIL PRESSURE

• CONDENSER LIQUID TEMPERATURES – OPTIONAL FIELD INSTALLED – LEAVING AND RETURN

• OPTIONS

• PRINT *

• HISTORY PRINT *

• MOTOR CURRENT IN % OF FULL LOAD AMPS

• SA TURA TION TEMPERA TURES – EV APORATOR AND CONDENSER

• DISCHARGE TEMPERATURE

• OIL TEMPERATURE

• HIGH & LOW OIL PRESSURE TRANSDUCER PRESSURE

• SOLID ST ATE STARTER MOTOR CURRENT / VOLTS (When Supplied)

• CONDENSER REFRIGERANT LEVEL

The MicroComputer Control Center is designed to be compatible 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 Current 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

As an enhancement to the standard EMS features, an optional card file with plug-in printed circuit boards is available. These optional cards will accept a remote LCWT 0 to 10°F or 0 to 20°F setpoint offset and/or remote current limit setpoint interface from three user input choices.

1. 4-20mA

2. 0-10VDC

* These ke ys provide a print-out when the customer connects a com-

patible printer to the Micro Board RS-232 serial port. (See Form

160.49-N7.)

Y ORK INTERNA TIONAL 7

3. Contact Closures

CONTROL CENTER

The Control Center front panel layout consists of five key groups, one switch and a 1 line by 40 character alphanumeric vacuum fluorescent display: (see Fig. 3.)

CHARACTERISTIC DISPLAY – The alphanumeric vacuum fluorescent display is located to the right of the ST ATUS key . All messages, parameters, set points, and data can be viewed at this location. The main communications between the operator or service technician and the MicroComputer Control Center occurs on this display.

DISPLAY – Provide a direct readout of each monitored parameter on the alphanumeric display.

ENTRY – These keys are used to enter the values for the operator programmed setpoints. These k eys are used in conjunction with the Setpoint keys while in PRO-

GRAM 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 prog rammed by the operator in PR OGRAM mode only.

Pressing the appropriate key enables the operator to program that setpoint pressing the Entry keys.

SERVICE– Included in this group of keys are those functions 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 – P ermits operator to check what mode the Control Center is presently in (LOCAL, REMOTE or SER- VICE).

1. Service – allows manual PRV control with visual display readout of PRV operation.

2. Local – allows manual compressor start from the COMPRESSOR switch on the Control Center front.

3. Program – allows operator programming of system setpoints.

4. Remote – allows remote start, remote stop of compressor and remote reset of LCWT and % current limit.

COMPRESSOR-START, RUN, STOP/RESET SWITCH – This 3-position rocker s witch is used to start (except in REMO TE mode), stop/run/reset the system.

OPERATION

DISPLA YING SYSTEM PARAMETERS

The Display keys are used to display selected monitored parameters as follows: (Refer to Fig. 3.)

• Press and release the appropriate Display ke y – the message will be displayed f or 2 seconds.

– or –

• Press and hold the appropriate Display key – the message will be displayed and updated every 0.5 seconds until the Display ke y is released.

– or –

• Press and release appropriate Display key , then press and release the DISPLAY HOLD key – the message

8 YORK INTERNA TIONAL

will be displayed and updated every 2 seconds until the DISPLAY HOLD key is again pressed and re- leased, or 10 minutes have elapsed, whiche ver comes first.

NOTE: If the display actually displays X’s, then the

monitored parameter is out of normal operating range (refer to Fig. 4). If the “English/Metric” jumper is installed on the Micro Board, all temperatures are displayed in degrees F ahrenheit (°F) and all pressures are displayed in pounds per sq. inch gauge (PSIG) except oil pressure which is displayed in pounds per sq. inch diff erential (PSID). If the “English/Metric” jumper is not installed, all temperatures are displayed in degrees Centigrade (°C) and all pressures are displayed in Kilo-Pascals (kPa).

FORM 160.49-O2

DISPLAY

READS

CONDENSER PRESS. = < 6.8 PSIG, or > 300 PSIG XX.X PSIG EVAPORATOR PRESS. = < 50 PSIG, or > 125 PSIG XX.X PSIG EVAP. PRESS. (BRINE) = < 25 PSIG, or > 100 PSIG XX.X PSIG HOP TRANSDUCER = < 59.1 PSIG, or > 314.9 PSIG XX.X PSIG LOP TRANSDUCER = < 23.2 PSIG, or > 271.8 PSIG XX.X PSIG DISCHARGE TEMP. = < 20.3°F; > 226.4°F XXX.X°F OIL TEMP. = < 20.3°F; > 226.4°F XXX.X°F

LEAVING CONDENSER WATER TEMP. ENTERING CONDENSER WATER TEMP.

LEAVING EVAPORATOR = < 0°F XX.X°F WATER TEMP. = > 81.1°F XX.X°F

ENTERING EVAPORATOR = < .1°F XX.X°F WATER TEMP. = > 93°F XX.X°F

= < 8.4°F; > 134.1°F XXX.X°F

FIG. 4 – SYSTEM PARAMETERS – OUT OF

RANGE READINGS

To Display CHILLED LIQUID TEMPERATURES:

______ PSID = (HOP – LP) – OFFSET PRESSURE OFFSET PRESSURE: Pressure differential between

the HOP transducer and LOP transducer outputs during a 3 second period beginning 10 seconds after the start of “START SEQUENCE INITIATED”. During this time, the transducers will be sensing the same pressure and their outputs should indicate the same pressure. However, due to accuracy tolerances in transducer design, differences can exist. Therefore, to compensate for differences between transducers and assure differential pressure sensing accuracy, the OFF- SET 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 OPTIONS:

This key is not used.

NO OPTIONS INSTALLED

is displayed when this key is pressed.

Press CHILLED LIQUID TEMPS displa y key as de- scribed on page 7 to produce the following alphanumeric display message:

CHILLED LEA VING = XXX.X°F, RETURN = XXX.X°F

To Display REFRIGERANT PRESSURE:

Use REFRIGERANT PRESSURE display key as described on page 7 to produce the following alphanumeric display message:

EV AP = XXX.X PSIG; COND = XXX.X PSIG

To Display OIL PRESSURE:

Use OIL PRESSURE display key as described on page 7 to produce the following alphanumeric display message:

OIL PRESSURE = XXXX.X PSID

The differential pressure displayed is the pressure difference between the high side oil pressure transducer (output of oil filter) and the low side oil pressure transducer (compressor housing). Displayed value includes offset pressure derived from auto-zeroing during “START SEQUENCE INITIATED”. If either transducer is out-of-range, XX.X is displayed. Oil pressure is calculated as follows:

To Display SSS MOT OR CURRENT / VOLTS: (Solid State Starter Applications Only)

If chiller is equipped with a Y ORK Solid State Starter, use SSS MOTOR CURRENT / VOLTS key to dis- play 3-phase compressor motor current and 3-phase Solid State Starter input line voltage.

Continuously pressing this key will display the motor current and line voltage alternately. When used with the DISPLAY HOLD key, motor current and line voltage will alternately be displayed each time this key is pressed. The messages are as follows:

A AMPS = XXXX; B AMPS = XXXX; C AMPS = XXXX V A-B = XXXX; V B-C = XXXX; V C-A = XXXX

If chiller is not equipped with a Solid State Starter, this key produces the following message:

SOLID STATE STARTER NOT INSTALLED

In PROGRAM mode, this k ey is used to displa y the applicable line voltage range (200-208VAC, 220240V AC , 380VAC, 400V A C , 415V A C , 440-480V A C, 500-600V AC, Supply V oltage Range Disab led). The correct line voltage range is programmed at the YORK factory and is checked by the service technician at start-up. For security reasons, a special access code is required to program the line voltage range. The line voltage range is used to determine a low line voltage threshold for cycling shutdown. Refer to “System Setpoints” for Trip/Reset values.

Y ORK INTERNA TIONAL 9

To Display CONDENSER LIQUID TEMPERATURES

(Field Installed Option Package):

Use CONDENSER LIQUID TEMPS display key as described above to produce the follo wing alphan umeric display message:

Computer Control Center”, page 14. However, the purpose of the OPERATING HOURS key is to display the total accumulated chiller run time. Therefore, the operating hours should not be arbitrarily reset.

SYSTEM SETPOINTS

COND LEAVING = XXX.X°F; RETURN = XXX.X°F

NOTE: If the condenser liquid thermistors are not con-

nected, or both thermistors are “out of range”, the display will blank when this k e y is pressed.

To Initiate a PRINT to Printer:

Press the PRINT key to initiate a printout to an optional printer. When the key is pressed,

PRINT ENABLE

is displayed.

Refer to “MicroComputer Control Center – System Status Printers” instruction, Form 160.49-N7 for details of the optional printers.

To Display MOTOR CURRENT:

Press the % MOTOR CURRENT display key as described above to display motor current as a percent of Full Load Amps (FLA). The message is as follows:

MOTOR CURRENT = XXX% FLA

The system setpoints may be programmed by the system operator. The Setpoints keys are located on the Control Center keypad (see Fig. 3). To program, see “Programming System Setpoints”, page 14. The following is a description of these setpoints (with the English/ Metric jumper installed on the Micro Board):

CHILLED LIQUID TEMP – This key displays the leaving chilled water temperature (LCWT) setpoint in degrees Fahrenheit. If not progr ammed, the default value is 45°F. See “Programming System Setpoints”, page 15).

NOTE: If an Energy Management System is interfaced

to the Control Center for the purpose of remote LCWT setpoint reset, then the operator-programmed chilled liquid temperature will be the base or lowest setpoint av ailable to the Energy Management System (EMS). This chilled liquid temperature value must also be entered into the EMS. Further, any subsequent change to this value must also be entered into the EMS.

% CURRENT LIMIT – This key displays the maximum value of motor current permitted by its programmed setting. The value is in terms of percent of Full Load Amps (FLA). If not programmed, the def ault value is 100%. (See “Programming System Setpoints”, page 15.)

NOTE: • Liquid-Cooled Solid State Starter Applications

– the % Motor Current displayed is the highest of three line currents divided by the programmed chiller FLA value x 100%.

• Electro-Mechanical Starter Applications – the % Motor Current displayed is the highest of the three line currents.

If chiller is equipped with a YORK Solid State Starter, the system FLA is also displayed. This value is programmed by the f actory and should nev er be changed. The Micro Board uses this value to calculate and display the % motor current parameter that is displayed when the % MOT OR CURRENT display ke y is pressed. Also, proper current limit control depends on the correctly programmed FLA value. For security reasons, a special access code is required to program the FLA value. It should only be changed by a service technician.

To Display OPERATING HOURS and STARTS COUNTER:

Use the OPERA TING HOURS ke y as described on page 8, to produce the following message:

OPER. HOURS = XXXXX; START COUNTER = XXXXX

PULL DOWN DEMAND – This function is used to provide energy savings following the chiller start-up. This key displays a programmable motor current limit and a programmable period of time. Operation is as follows: Whenever the system starts, the Pull Down Demand Limit is maintained for the programmed time, then the current limit control returns to % current limit setpoint.

NOTE: The operating hours and starts counter can be

reset to zero. Ref er to “Progr amming the Micro-

The maximum permitted motor current is in terms of % FLA. The duration of time that the current is limited is in

10 YORK INTERNA TIONAL

FORM 160.49-O2

terms of minutes (to a maximum of 255). If not programmed, the default value is 100% FLA for 00 minutes. (See “Programming Systems Setpoints”, page 16.) Thus, no pull down demand limit is imposed following system start, and the % current limit setpoint is used.

CLOCK – This key displa ys the day of the week, time of day and calendar date. If not programmed, the default value is

SUNDAY 12:00 AM 1/1/92 .

(See “Programming System Setpoints”, page 16.)

DAIL Y SCHEDULE – This key displays the programmed daily start and stop times, from Sunday thru Saturday plus Holiday. If desired, the Control Center can be programmed to automatically start and stop the chiller as desired. This schedule will repeat on a 7-day calendar basis. If the Daily Schedule is not progr ammed, the default value is 00:00 AM start and stop times for all da ys of the week and the holiday. (Note that the system will not automatically start and stop on a daily basis with these default values because 00:00 is an “Impossible” time for the Micro Board. See “Programming System Setpoints”, page 17.) Finally, one or more days in the week can be designated as a holiday (see description under HOLIDAY setpoint) and the Control Center can be programmed (usually Daily Schedule setpoint) to automatically start and stop the chiller on those days so designated. The operator can override the time clock at any time using the COMPRESSOR switch.

For additional information on remote LCWT reset, refer to Form 160.49-PW13.

NOTE: If an Energy Management System is interfaced

to the Control Center for the purpose of remote LCWT setpoint reset, then the operator programmed REMOTE RESET TEMP RANGE value determines the maximum value of temperature reset controlled by the Energy Management System.

DATE LOGGER – This key is used when an optional printer is connected to the MicroComputer Control Center. Refer to Form 160.49-N7 for operation instructions.

SSS MOT OR CURRENT/VOLTS – This key is used on Solid State Starter applications only. Although this is a display key, it is used to program the applicable AC power line voltage range (380VAC, 400VAC, 415VAC, 440-480VAC, 550-600VAC). The MicroComputer Control Center uses this entry to determine the under-voltage and overvoltage shutdown threshold. For each line voltage category, there is an undervoltage and overvoltage shutdown threshold. If the AC po wer line v oltage exceeds these thresholds for 20 continuous seconds, the chiller shuts down and displays

MON 10:00 AM LOW LINE VOLTAGE

– or –

Note that if only a start time is entered for a particular day, the compressor will not automatically stop until a scheduled stop time is encountered on a subsequent day.

HOLIDAY – This key indicates which da ys in the upcoming week are holidays. On those designated days, the chiller will automatically start and stop via the holiday start and stop times programmed in the DAIL Y SCHED- ULE setpoint. It will do this one time only and the f ollowing week will rev ert to the normal daily schedule for that day.

REMOTE / RESET TEMP RANGE – This key displays the maximum offset of remote LCWT setpoint reset. This offset is either 10° or 20°F as programmed. When in the REMOTE mode, this v alue is added to the operator programmed CHILLED LIQUID TEMP setpoint and the sum equals the temperature range in which the LCWT can be reset. For example, if the operator programmed CHILLED LIQUID TEMP setpoint is programmed with a value of 10°F, then the CHILLED LIQUID TEMP setpoint can be remotely reset over a range of 46°F to 56°F (46 + 10 = 56). If not prog rammed, the default value for this parameter is 20°F.

MON 10:00 AM HIGH LINE V OLTAGE

This overvoltage and undervoltage protection can be disabled. Ref er to chart below:

LOW / HIGH LINE VOLTAGE TRIP / RESET VALUES

COMPRESSOR

MOT OR

SUPPL Y VOL TA GE

RANGE – (V)

380 305 331 415 414 400 320 349 436 435

415 335 362 454 453 440-480 370 400 524 523 550-600 460 502 655 654

Supply V oltage

Range Disabled

LOW LINE VOL TAGE HIGH LINE V O LTAGE

OPERA TING POINT OPERATING POINT

CUTOUT -(V) CUTIN-(V) CUTOUT -(V) CUTIN-(V)

(

ON FALL) (ON RISE) (ON RISE) (ON FALL)

NONE 0 NONE 0

For security reasons, a special access code is required to program the supply voltage range. The supply voltage range is programmed at the factory and should only be changed by a service technician.

Y ORK INTERNA TIONAL 11

DISPLAYING SYSTEM SETPOINTS

The currently programmed Setpoint values can be viewed at any time (see page 22) in SER VICE, LOCAL or REMOTE operating mode as follo ws:

• Press and release the appropriate Setpoint key – the message will be displayed f or 2 seconds.

– or –

If chiller is equipped with a YORK Solid State Starter, the message is:

CURRENT LIMIT = XXX % FLA; *MTR CUR = 000 FLA

NOTE: On Solid State Starter applications, this value is

programmed at the YORK factory . A special access code is required.

• Press and hold the appropriate Setpoint key – the message will be displayed as long as the key is pressed.

– or –

• Press and release the appropriate Setpoint key , then press and release the DISPLA Y HOLD k ey . The message will be displayed until the DISPLAY HOLD key is again pressed and released, or 10 minutes have elapsed, whichever comes first.

To Display CHILLED LIQUID TEMP Setpoint:

Use CHILLED LIQUID TEMP setpoint key as de- scribed on page 10 to produce the following message:

LEAVING SETPOINT = XX.X °F

NOTE: The value displayed is the actual LCWT setpoint.

For example , the value display ed in LOCAL

PROGRAM modes is that which is oper ator programmed. The v alue displayed in the REMOTE mode is that base setpoint with added temperature reset by an Energy Management System, via remote LCWT setpoint (PWM signal) if a remote reset signal was received within 30 minutes.

To Display PULL DOWN DEMAND Setpoint:

Use PULL DOWN DEMAND setpoint key as de- scribed on page 10 to produce the following message:

SETPOINT = XXX MIN @ XX % FLA XXX MIN LEFT

To Display CLOCK Setpoint (Time of Day):

Use CLOCK setpoint key as described above to produce the following message:

TODAY IS DAY XX:XX AM/PM 1/1/92

To Display DAILY SCHEDULE Setpoints:

• Press and hold the DAILY SCHEDULE setpoint key. The chiller start and stop times for each day of the

week are sequentially display ed, beginning with Sunday and ending with Holida y. The displa y will continuously scroll until the DAILY SCHEDULE key is re- leased.

– or –

• Press and release the DAIL Y SCHEDULE setpoint k ey . Then press and release the DISPLA Y HOLD k ey . The

To Display % CURRENT LIMIT Setpoint:

Use % CURRENT LIMIT setpoint key as described above to produce the f ollowing message:

CURRENT LIMIT = XXX % FLA

chiller start and stop times for each day of the week are sequentially displayed beginning with Sunda y and ending with Holiday . The display will continuously scroll until the DISPLAY HOLD key is again pressed and released, or 10 minutes have elapsed, whichever comes first.

NOTE: The value display ed is the actual % current limit

setpoint. For example, the value displayed in LOCAL or PROGRAM mode is that which is operator programmed. The value displayed in the REMOTE mode is that which has been pro- grammed by the Energy Management System via the remote current limit setpoint input.

The display message for DAILY SCHEDULE will scroll in the following sequence:

SUN START = 08:30 AM STOP = 06:00 PM MON START = 05:00 AM STOP = 07:00 PM

12 YORK INTERNA TIONAL

TUE START = 05:00 AM STOP = 07:00 PM

FORM 160.49-O2

WED START = 05:00 AM STOP = 07:00 PM THU START = 05:00 AM STOP = 07:00 PM FRI START = 05:00 AM STOP = 07:00 PM SAT STAR T = 05:00 AM STOP = 01:00 PM HOL START = 00:00 AM STOP = 00:00 PM

To Display HOLIDAY Setpoints:

Use HOLIDAY setpoint key as described in the be- ginning of this section to produce the following message:

S_ M_ T_ W_ T_ F_ S_ HOLIDAY NOTED BY *

NOTE: On the days that are designated by an *, the

chiller will automatically start and stop per the holiday schedule established in D AIL Y SCHED- ULE setpoints.

To Display UNDERVOLTAGE setpoints: (Solid State Starter Applications Only)

Press SSS MOTOR CURRENT/V OL TS key in PRO- GRAM mode to display the selected voltage range. One of the following messages will be displa yed.

SUPPLY VOLTAGE RANGE 380

– or –

SUPPLY VOLTAGE RANGE 400

– or –

SUPPLY VOLTAGE RANGE 415

– or –

SUPPLY VOLTAGE RANGE 440-480

– or –

SUPPLY VOLTAGE RANGE 550-600

– or –

To Display REMOTE RESET TEMP RANGE Setpoint:

Use REMOTE RESET TEMP RANGE setpoint ke y as described above to produce the following message:

REMOTE RESET TEMP RANGE = 10°F

– or –

REMOTE RESET TEMP RANGE = 20°F

To Display DATA LOGGER setpoints:

Refer to Y ORK, F orm 160.49-N7 for operation of this key .

SUPPLY VOLTAGE RANGE DISABLED

A special access code is required to program the Supply Voltage Range. The Supply Voltage Range is programmed at the factory and check ed at system start-up. (Note to service technician: Refer to programming instructions in Service Instruction, Form 160.49-M3.)

Y ORK INTERNA TIONAL 13

PROGRAMMING

THE MICROCOMPUTER CONTROL CENTER

PROGRAMMING SYSTEM SETPOINTS

The system setpoints can be entered at any time . . . . .

even when the system is running. Proceed as f ollows to enter system setpoints. (Ref er to Fig. 5.)

1. Press ACCESS CODE key .

ENTER VALID ACCESS CODE _ _ _ _

3. Using ENTRY keys, enter 9 6 7 5.

4. As each digit is entered, the characters Y O R K are displayed.

is displayed.

NOTE: If digits other than 9 6 7 5 are entered,

YORKis still displayed.

NOTE: For ease in remembering the code, note that

the letters YORKcorrespond to the digits 9675on a telephone dial

5. Press ENTER key. NOTE: If digits other than 9675 w ere entered in step

No. 4,

INVALID ACCESS CODE

is displayed when the ENTER key is pressed. If this occurs, enter the correct access code (9675) and proceed.

ACCESS TO PROGRAM KEY AUTHORIZED

is displayed.

NOTE: Unless terminated by pressing the ACCESS

CODE key again, the operator will have access to the PROGRAM key for 10 minutes. When 10 minutes have elapsed, access to PROGRAM key will be automatically disab led and the operator must return to step No. 1 to gain access.

7. Press PROGRAM key .

PROGRAM MODE, SELECT SETPOINT

is displayed.

LD00954

FIG. 5 – KEYPAD – PROGRAMMING SYSTEM

SETPOINTS

9. Enter setpoints as detailed below. If you make a mistake when entering a value, press CANCEL k ey and then ENTER key . The display will re vert to the default values and the cursor will return to the first changeable digit. You can then proceed to enter the correct values. If the entered v alue exceeds acceptab le limits,

OUT OF RANGE – TRY AGAIN!

message will be displayed for 2 seconds, then the

PROGRAM MODE, SELECT SETPOINT

message will re-

appear.

10.When all the desired setpoints have been entered, press the ACCESS CODE key to exit PROGRAM mode and terminate access to PROGRAM mode.

ACCESS TO PROGRAM MODE DISABLED

is displayed. The Control Center will automatically return to LO-

CAL, REMOTE or SERVICE mode . . . . whichever

was last selected.

14 YORK INTERNA TIONAL

To enter CHILLED LIQUID TEMP Setpoint: (Refer to Fig. 6.)

1. Press and release CHILLED LIQUID TEMP setpoint key. The following program prompt message will be displayed:

LEAVING SETPOINT = XX.X °F (BASE)

(BASE) refers to the base or lowest setpoint available to an Energy Management System. If an y Energy Management System is applied, this value must be entered into the Energy Management System. Refer to previous explanation or REMO TE/RESET TEMP RANGE, page 11.

FORM 160.49-O2

2. Use ENTRY keys to enter desired v alue.

3. Press and release ENTER key.

PROGRAM MODE, SELECT SETPOINT

message is displayed.

To Enter % CURRENT LIMIT Setpoint: (Electro-Mechanical Starter , ref er to Fig. 7)

1. Press and release % CURRENT LIMIT setpoint key . The following program prompt message is displa yed:

CURRENT LIMIT = XXX% FLA

2. Use ENTRY k e ys to enter desired v alue .

3. Press and release ENTER key.

PROGRAM MODE, SELECT SETPOINT

message is displayed.

LD00955

FIG. 6 – KEYPAD – PROGRAMMING “LEAVING

CHILLED WATER TEMP” SETPOINT

3. Press and release ENTER key.

PROGRAM MODE, SELECT SETPOINT

message is displayed.

(Solid State Starter, ref er to Fig. 7)

1. Press and release % CURRENT LIMIT setpoint key . The following program prompt message is displa yed:

CURRENT LIMIT = XXX% FLA; MTR CUR = _ _ _ FLA

2. Use ENTRY k e ys to enter desired v alue . NOTE: Motor Current FLA value is entered by Y ORK

LD00956

factory and checked at system start-up. It cannot be changed without special access code. (Note to service technician: refer to

FIG. 7 – KEYPAD – PROGRAMMING “% CURRENT

LIMIT” SETPOINT

“Programming Instructions” in Service instruction, Form 160.49-M3.

Y ORK INTERNA TIONAL 15

To Enter PULL DOWN DEMAND Setpoint: (Refer to Fig. 8.)

1. Press and release PULL DOWN DEMAND setpoint key. The following program prompt message is displayed:

SETPOINT = XXX MIN @ XXX % FLA, XXX MIN LEFT

2. Use Entry keys to enter desired values. For explanation, see PULL DOWN DEMAND, page 12. Note that “XX min left” is not an operator entered v alue .

3. Press and release ENTER key.

PROGRAM MODE, SELECT SETPOINT

message is displayed.

LD00957

FIG. 8 – KEYPAD – PROGRAMMING “PULL DO WN

DEMAND” SETPOINT

To Enter CLOCK Setpoint: (Refer to Fig. 9.)

1. Assure Micro Board Program jumper J57 is in “CLKON” position.

2. Press and release CLOCK setpoint key. The f ollo w- ing program prompt message is displayed:

TOD AY IS MON 10:30 PM 1/1/92

3. Press ADVANCE DAY / SCROLL key until the pro- gram per day of week appears on the display.

4. Use Entry keys to enter proper time of day.

5. Press AM/PM key to change the AM to PM or vice versa.

6. Use Entr y keys to enter proper calendar date, (MONTH/DA Y/YR). If month and da y are single digit entries, precede the entry with “0”. For example, 02/04/88.

7. Press and release ENTER key.

PROGRAM MODE, SELECT SETPOINT

message is displayed.

LD00958

FIG. 9 – KEYPAD – PROGRAMMING “CLOCK”

SETPOINT

16 YORK INTERNA TIONAL

FORM 160.49-O2

To Enter DAILY SCHEDULE Setpoint: (Refer to Fig. 10.)

1. Press and release DAILY SCHEDULE setpoint key. The following prompt message is displa yed:

SUN START = XX:XX AM, STOP = XX:XX AM

2. If the displayed start and stop time is not the desired schedule, enter the desired start and stop times as follows:

a. If you do not want the chiller to automatically start

and stop on this day, press CANCEL key.

b. Use the Entry keys to enter desired hours and

minutes start time.

c. If necessary, press the AM/PM ke y to change “AM”

to “PM” or vice versa.

d. Use the Entry keys to enter desired hours and

minutes stop time.

e. If necessary , press the AM/PM key to change “AM”

to “PM” or vice versa.

3. Press and release ADV ANCE D A Y/SCROLL ke y. The following prompt message is displa yed:

6. Use the ADV ANCE DAY / SCROLL key with proce- dure in Step 2. To enter start and stop times for remainder of the week plus a holiday schedule if required.

7. Press the ENTER key.

PROGRAM MODE, SELECT SETPOINT

is displayed.

MON START = XX:XX AM, STOP = XX:XX AM

4. Enter the desired start and stop time per Step 2.

5. Press and release ADV ANCE D A Y/SCROLL ke y. The following prompt message is displa yed:

REPEAT MON SCHEDULE MON-FRI? YES = 1; NO = 0

a. If you press the 1 Entry key, Monday’s start and

stop time will be automatically entered for Tuesday through F riday.

– or –

b. If you press the 0 Entry key, Tuesday through Fri-

day can be programmed with different start and stop times.

LD00959

FIG. 10 – KEYPAD – PROGRAMMING “DAIL Y

SCHEDULE” SETPOINT

Y ORK INTERNA TIONAL 17

To Enter HOLIDAY Setpoint: (Refer to Fig. 11.)

1. Press and release HOLIDAY setpoint key. The fol- lowing program prompt message is display ed:

S_ M_ T_ W_ T_ F_ S_ HOLIDAY NOTED BY

2. Press and release ADV ANCE DAY/SCR OLL k ey to move cursor to the day that y ou wish to designate as a holiday .

3. Press and release r entry key. An r will appear next to the selected day.

4. After you have placed an r n ext to each of the da ys that you wish to designate a holiday, press ENTER key

PROGRAM MODE, SELECT SETPOINT

message is displayed. T o cancel all of the designated holidays: perform Step

1, press CANCEL key, and then press ENTER key.

PROGRAM MODE, SELECT SETPOINT

message is displayed. To cancel one of the designated holidays: perform

Step 1, press ADVANCE DAY / SCROLL key until the cursor appears to the right of the desired day, press the r key, then press the ENTER key.

LD00961

FIG. 11 – KEYPAD – PROGRAMMING “HOLIDAY”

SETPOINT

To Enter REMOTE/ RESET TEMP RANGE Setpoint: (Refer to Fig. 12.)

1. Press and release REMOTE/RESET TEMP RANGE setpoint key . The following program prompt message is displayed:

REMOTE TEMP SETPOINT RANGE = XX °F

2. Use Entry keys desired value (10 or 20).

3. Press and release ENTER key.

PROGRAM MODE, SELECT SETPOINT

message is displayed.

To Enter DA TA LOGGER Setpoint: Refer to F orm 160.49-N7 for operation of this k e y.

LD00962

FIG. 12 – KEYPAD – PROGRAMMING “REMO T E

RESET” TEMP RANGE

18 YORK INTERNA TIONAL

SERVICE KEYS

FORM 160.49-O2

LD00963

FIG. 13 – KEYPAD – SERVICE KEYS LOCATION

The Service keys are provided for the service technician’s use when perf orming routine maintenance or when troubleshooting the system. The W ARNING RESET and PRE-ROT A TION VANES keys are enab led in SERVICE mode only. The remainder of the Service keys are enabled in SERVICE, LOCAL or REMOTE mode.

PRE-ROTATION VANES KEYS

If chiller is equipped with the REFRIGERANT LEVEL CONTROL (and EPROM v ersion C.02F(T).13 or later), the pre-rotation vanes keys can be used to manually control the refrigerant level variable orifice or the prerotation vanes. The procedure to select either manual vane or manual variable orifice control is contained in “Special Setpoints and Programming Procedures” section of Service manual, Form 160.49-M3 and must be performed by a qualified service technician only.

OPEN – Press and release this key to drive the prerotation vanes open. If the chiller is running,

SYSTEM RUN – VANES OPENING

not running,

SYS READY TO START – VANES OPENING

is displayed. If chiller is

displayed. The vanes will continue to open until the CLOSE, HOLD, or AUTO (if temperature error requires it) keys are pressed and released.

HOLD – Press and release this key to hold the prerotation vanes in their present position. If the chiller is

running,

SYSTEM RUN – VANES HOLDING

is displayed.

If chiller is not running,

SYS READ Y TO START – VANES HOLDING

is displayed. The

vanes will remain stationary until the OPEN, HOLD, or

AUTO keys are pressed and released.

AUTO – Press and release this key to put the pre-rota-

tion vanes under LCWT control as long as the current limit setpoint is not reached, which causes the current limit function to override the LCWT control. If system is running,

SYSTEM RUN – AUTO VANES

is displayed. The actual opening and closing of the vanes is indicated on the display. When the v anes are opening,

SYSTEM RUN – VANES OPENING

are closing,

SYSTEM RUN – VANES CLOSING

is displayed. If the vanes

is displayed. Whenever the Control Center is in LOCAL, REMOTE or PROGRAM mode, the vane control circuitry is automatically placed in AUTO mode and the vanes operate to control the leaving chilled water temperature to the programmed setpoint.

CLOSE – Press and release this key to drive the pre-

rotation vanes closed. If the chiller is running,

SYSTEM RUN – VANES CLOSING

not running,

SYS READY TO START – VANES CLOSING

is displayed. If chiller is

displayed. When the vanes are full closed,

SYS READ Y TO ST A RT – VANES CLOSED

is displayed. The

vanes will continue to close until the OPEN, HOLD, or AUTO keys are pressed.

Y ORK INTERNA TIONAL 19

OTHER SER VICE KEYS WARNING RESET – Press and release this key to re-

set any “WARNING” or “STATUS” message that can be reset with this key, unless the condition still exists. To reset any cycling or warning message, place the Control Center in SERVICE mode and press WARNING RESET key. To reset any safety shutdown message, press WARNING RESET key in SERVICE mode with the COMPRESSOR switch in the STOP/RESET posi- tion.

MANUAL OIL PUMP – This key is operational in any mode. Press and release this key to run the oil pump. Press and release the key again to stop the oil pump . A 10-minute maximum is imposed on the running of the oil pump (i.e., the oil pump will automatically shut off after 10 minutes). If a longer running time is desired, the ke y must be pressed again. The manual oil pump feature is disabled during “START SEQUENCE INITIALIZED” to allow for auto-zeroing of oil pressure tr ansducers .

DISPLAY DATA – This key is operational in any three of the Control Center modes of operation (SERVICE, LOCAL or REMOTE). It is used to display certain sys- tem operating parameters that are relevant to troubleshooting the chiller system.

Press and the DISPLAY DATA key. The following mes- sages will sequentially scroll on the display. Each message will be displayed f or 2 seconds.

procedure to select manual refrigerant level control is in Service manual, Form 160.49-M3 and should be performed only by a qualified service technician.

NO. 2

PULLDN LEVEL = XXX%; SETP = XXX%; ACTUAL = XXX%

– Displayed when there is a refrigerant level setpoint pulldown (ramp) in effect. PULLDN LEVEL is the refrig- erant level setpoint that is presently in effect. SETP is the refrigerant level setpoint that has been programmed by the service technician and ACTU AL is the refrigerant level in the condenser. The pulldown period is 15 minutes in duration. During the pulldown period, a linearly increasing ramp is applied to the level setpoint. This causes the setpoint to increase from 0% to the programmed value ov er a period of 15 minutes. After the 15 minutes have elapsed, the setpoint remains the programmed value and this message is replaced by the message

ACTUAL = XXX%; LEVEL SETP = XXX%

described below. A refrigerant level setpoint pulldown is put into eff ect when

the vanes are driven from a fully closed to an open position, if the actual refrigerant level is less than the level setpoint when the vane motor end switch (VMS) opens. If the actual level is greater than the setpoint when the VMS opens, the level is controlled to the programmed setpoint. Whenever the vanes go to the fully closed position (VMS closed), any pulldown that is in effect is cancelled.

Messages 1 and 2 are only displayed if unit is equipped with EPROM version C .02F(T).13 or later and Refrigerant Level Control has been enabled by a qualified service technician using the “Special Setpoints and Programming” procedures section of Service manual, F orm

160.49-M3. NO. 1

MANUAL V ANE OPERATION ALLOWED

– Displayed when the

PRE-ROTATION VANES ser vice keys have been se-

lected for manual VANE control. This allo ws these k eys to manually control the vanes in Service mode. The pro- cedure to select manual vanes control is in Service manual, Form 160.49-M3 and should be performed only by a qualified service technician.

– or –

NO. 1

MANUAL LEVEL CONTROL ALLO WED

– Displayed when the

PRE-ROTATION VANES keys have been selected for

manual REFRIGERANT LEVEL control. This allows these keys to manually control the refrigerant le vel control variable orifice in Service mode. When manual refrigerant level control is selected, the pre-rotation v anes Service keys cannot be used to control the vanes. The

– or –

NO. 2

ACTUAL LEVEL = XXX%; LEVEL SETP = XXX%

– Displays the actual refrigerant level in the condenser and the refrigerant level setpoint progr ammed by the service technician. This message replaces the previous message after a refrigerant level setpoint pulldown period terminates.

NO. 3

SAT TEMPS EVAP = XX.X°F; COND = XX.X°F

– This is the refrigerant saturation temperatures for the e vaporator and condenser.

NO. 4

DISCHARGE TEMP = XXX.X°F; OIL TEMP = XXX.X°F

NO. 5

HOP = XX.X PSIG; LOP = XX.X PSIG

– This is the low oil pressure (LOP) as measured at the oil sump and the high oil pressure (HOP) as measured at the compressor bearing input.

20 YORK INTERNA TIONAL

FORM 160.49-O2

NO. 6

ACTU AL POS = XX MILS; REF = YY MILS

– ACTU AL POS is the distance between the high speed thrust collar and the proximity probe that is used to measure the position. REF is the reference position established at time of compressor manufacture.

NO. 7

HIGH SPEED DRAIN TEMP = XXX.X °F

– Temperature of oil

in high speed drain line.

OPERATING MODES

The MicroComputer Control Center can be operated in four different operating modes as f ollo ws:

SERVICE – enables all the Service keys except DIS- PLAY DATA, MANUAL OIL PUMP, and HISTORY PRINT, which are enabled in all modes. See “Service

Keys”, page 20. LOCAL – This is the normal operating mode. The com-

pressor can be started and stopped from the Control Center. Also , the Display and Setpoints parameters can be displayed.

T o hold any of the abo ve messages, press the DISPLAY DAT A key, then press the DISPLAY HOLD key. The message will be displayed and updated every 2 seconds until the DISPLAY DATA key is pressed again, whereupon the next message is displayed. T o return to the normal foreground messages, press the DISPLAY

HOLD key.

HISTOR Y PRINT – This key is used to initiate a history

print to the optional printer. Refer to F orm 160.49-N7 for operation of this key.

• If the Control Center is in LOCAL mode,

LOCAL OPERATING MODE IN EFFECT

is displayed.

• If the Control Center is in REMOTE mode,

REMOTE OPERATING MODE IN EFFECT

is displayed.

• If the Control Center is in SERVICE mode,

SERVICE OPERATING MODE IN EFFECT

is displayed.

To change operating mode, proceed as follows:

1. Press ACCESS CODE key .

PROGRAM – Allows the operator to program the Set- points parameters, and change operating modes.

REMOTE – In this mode, the Control Center will ac-

cept control signals from a remote device (i.e., Energy Management System) or cycling input. The control signal inputs are:

1. Remote Start

2. Remote Stop

3. Remote LCWT Setpoint

4. Remove Current Limit Setpoint

NOTE: The compressor can be stopped by the COM-

PRESSOR switch, regardless of the operating mode. The switch must be in RUN position to enable REMOTE mode. The operator cannot locally start the compressor using the COM- PRESSOR s witch when in the REMOTE mode .

To determine which operating mode the Control Center is presently in, simply press the MODE key .

ENTER VALID ACCESS CODE _ _ _ _

is displayed.

3. Using Entry keys, enter 9 6 7 5.

4. As each digit is entered, the characters Y O R K are displayed.

NOTE: If digits other than 9 6 7 5 are entered, YO RK

is still displayed.

5. Press ENTER key. NOTE: If digits other than 9 6 7 5 were entered in

step No. 4,

INVALID ACCESS CODE

is displayed when the ENTER key is pressed. If this occurs, enter the correct access code (9675) and proceed.

ACCESS TO PR OGRAM KEY A UTHORIZED

is displayed.

NOTE: Unless terminated by pressing the ACCESS

CODE key again, the operator will have access to the PROGRAM key for 10 minutes. When 10 minutes have elapsed, access to PROGRAM key will be automatically disabled and the operator must return to step No. 1 to gain access.

Y ORK INTERNA TIONAL 21

7. Press PROGRAM key.

PROGRAM MODE, SELECT SETPOINT

is displayed.

11.Press ADV ANCE D A Y k ey to scroll to desired mode. Each time this key is pressed, a different mode is displayed as above:

9. Press MODE key.

10.The mode that has been previously selected will be displayed as follows:

LOCAL MODE SELECTED

– or –

SERVICE MODE SELECTED

– or –

REMOTE MODE SELECTED

COMPRESSOR SWITCH

(See Fig. 13, page 19.) This rocker switch is used to locally operate the com-

pressor. It is used to star t, run and stop the compressor. Also, it resets the Control Center after a safety shutdown.

To START* chiller compressor in LOCAL mode:

12.When the desired mode is displayed, press EN- TER key.

13.

PROGRAM MODE, SELECT SETPOINT

14.Press A CCESS CODE key to e xit PROGRAM mode and terminate access to PROGRAM mode.

15.

ACCESS TO PROGRAM MODE DISABLED

To RESET Control Center:

Following a safety shutdown, the operator is required to reset the Control Center prior to restarting the system. Move switch from RUN to STOP/ RESET position.

is displayed.

Move COMPRESSOR switch from STOP/RESET to START position. Switch will spring-return to RUN position.

To STOP compressor:

Move switch from RUN to STOP/RESET position.

DISPLAY MESSAGES

The following display ed messages will be automatically displayed unless the operator is requesting additional information via the keypad.

SYSTEM RUN - CURRENT LIMIT IN EFFECT

Displayed when the chiller is running, and the motor current is equal-to or greater-than the operator-programmed “XXX % FLA” current limit value. When the motor current reaches 100% of this value, the prerotation vanes are not permitted to open further. If the current continues to rise to 104% of this value, the vanes will be driven closed – not fully closed; only far enough to allow the current to decrease to a value less

*NOTE:The operator cannot start the compressor (us-

ing this switch) when the Control Center is in REMOTE mode.

than 104% of the operator-programmed “XXX % FLA” current limit.

For example: With the operator-programmed “% CURRENT LIMIT”

set at 50% and the FLA of the chiller equal to 200A, the current limit circuit would perform as follows:

(100%) (50% x FLA) = Vanes inhibited from opening further.

(104%) (50% x FLA) = Vanes driven toward close position.

22 YORK INTERNA TIONAL

FORM 160.49-O2

Therefore:

(100%) (50% x 200) = 100A = Vanes stop opening

(104%) (50% x 200) = 104A = Vanes driven toward close position.

SYSTEM RUN – A UT O VANES

Displayed when the chiller is running, the MicroComputer Control Center is in SERVICE mode, and the vanes are operating in AUTO mode.

SYSTEM RUN – VANES OPENING

Displayed when the chiller is running, the MicroComputer Control Center is in SERVICE mode with:

• The vanes operating in AUTO mode and opening to maintain the leaving chilled water temperature setpoint.

– or –

•The operator has pressed the vanes OPEN key on the keypad.

SYS READY TO START – VANES HOLDING

Displayed when the chiller is running and the operator has pressed the vanes HOLD key on the keypad.

SYSTEM RUN – LEVEL VAL VE OPENING

Displayed as a foreground message when manual refrigerant level control has been selected using the “Special Setpoints Procedure” in Service manual, Form

160.49-M3 and operating in SER VICE mode. Indicates an “OPEN” command is being output to the variable orifice. Manual level control should be selected only by a qualified service technician.

SYSTEM RUN – LEVEL VAL VE CLOSING

Displayed as a foreground message when manual refrigerant level control has been selected using the “Special Setpoints Procedure” in Service manual, Form

160.49-M3 and operating in SER VICE mode. Indicates a “CLOSE” command is being output to the variable orifice. Manual level control should be selected only by a qualified service technician.

SYSTEM RUN – A UTO LEVEL CONTROL

SYSTEM RUN – VANES CLOSING

Displayed when the chiller is running, the MicroComputer Control Center is in SERVICE mode with:

•The vanes operating in AUTO mode and closing to maintain the leaving chilled water temperature setpoint.

– or –

• The operator has pressed the vanes CLOSE key on the keypad.

SYSTEM RUN - VANES HOLDING

Displayed when the chiller is running, the MicroComputer Control Center is in SERVICE mode, and the operator has pressed the vanes HOLD key.

SYS READY TO START – VANES OPENING

Displayed when the chiller is running and the operator has pressed the vanes OPEN key on the keypad.

Displayed as a foreground message when manual refrigerant level control has been selected using the “Special Setpoints Procedure” in Service manual, Form

160.49-M3 and operating in SER VICE mode. Indicates that neither a “CLOSE” nor “OPEN” command is being output to the variable orifice but is in “AUTO” mode. Manual lev el control should be selected only by a qualified service technician.

SYSTEM RUN – LOW PRESSURE LIMIT IN EFFECT

Displayed when the chiller is running and the evaporator pressure falls to 56.2 PSIG (R-22); 27 PSIG (R134a). Simultaneously, the pre-rotation vanes will be prevented from further opening. This action maintains chiller operation to prevent low-evaporator-pressure shutdown at 54.3 PSIG (R-22); 25 PSIG (R-134a). When the evaporator pressure rises to 57.5 PSIG (R-

22); 28 PSIG (R-134a), the vanes will be permitted to open. Low pressure limit feature is not used when program jumper (JP3) is cut (Brine application).

SYSTEM RUN – HIGH PRESSURE LIMIT IN EFFECT

SYS READ Y TO ST A RT – VANES CLOSING

Displayed when the chiller is running and the condenser pressure rises to 246.3 PSIG (R-22); 162.5 PSIG (R-

Displayed when the chiller is not running and the operator has pressed the vanes CLOSE key on the keypad.

Y ORK INTERNA TIONAL 23

134a). Simultaneously, the pre-rotation vanes will be inhibited from further opening. This action occurs to prevent system shutdown on high condenser pressure

at 265 PSIG (R-22); 180 PSIG (R-134a). When the condenser pressure falls to 245 PSIG (R-22); 160 PSIG (R-134a), the vanes will be permitted to open.

SYSTEM RUN – PRESSURE STATUS

Displayed when the chiller is running. It instr ucts the operator to press the STATUS key, whereupon one of the following messages will be displayed:

•

WARNING: COND OR EVA P TRANSDUCER ERR OR

Indicates a probable condenser or evaporator transducer problem, because the output is unreasonable. The microprocessor arrives at this conclusion by subtracting the evaporator transducer output from the condenser transducer output. The result must be zero or some positive number. If the result is a negative number, it concludes that there is a probable condenser or evaporator transducer problem. This function is inhibited for the first 10 minutes of chiller run-time, and is checked every 10 minutes thereafter. Message is reset by pressing the WARNING RE- SET key in the Service mode.

NOTE: If the STATUS key is arbitrarily pressed, with- out the operator being prompted by the

PRESS STATUS

message, the following message shall be displayed.

NO MALFUNCTION DETECTED

W ARNING – REFRIGERANT LEVEL OUT OF RANGE

Displayed when the refrigerant lev el sensor output goes to > 4.4VDC. While this is displayed, the variable orifice is driven open until the level is within range. This message is automatically cleared when output is within range.

SYSTEM RUN – LEA VING TEMP CONTROL

Displayed while the chiller is running. Indicates that the pre-rotation vanes are being controlled by the leaving chilled water temperature (LCWT). This is the normal mode of chiller operation. Thus, if the LCWT is above the setpoint, but pulling down rapidly, the vanes will pulse closed as the LCW nears the setpoint.

initial start-up). The status message consists of the day and time of shutdown, cause of shutdown, and type of restart required. Upon pressing STATUS key, System Shutdown Message will be display ed for 2 seconds and then return to

SYSTEM SHUTDOWN – PRESS STATUS

Display can be held indefinitely by depressing DIS- PLAY key. For examples of System Shutdown Messages, see below.

SYSTEM SHUTDOWN MESSAGES

Day of Week Cause of Shutdown

Time of Day Type of Restart

MON 10:00 AM – LOW WATER TEMP – AUTOSTART

Chiller was shut down on Monday at 10:00 AM because the LCWT has decreased to a value that is 4°F below the operator-programmed chilled liquid temperature setpoint. Ho w ever, if the setpoint is less than 40°F , the chiller will always shut down at 36°F. Further, if the chiller is running and the setpoint is changed, the (Low Water Temperature) cutout will be 36°F for 10 minutes in order to eliminate nuisance trips. Finally, for brine chilling applications, the LWT cutout is always 4°F below the setpoint. (The water jumper on the Micro Board must be removed for a brine unit.)

MON XX:XX AM – FLOW SWITCH – A UTOSTART

Chiller is shut down because a chilled-liquid flow switch has opened. The flow switch must open for a minimum of 2 seconds in order to cause a shutdown. The flow switch is checked 25 seconds into “Start Sequence Initiated” and continuously thereafter.

MON XX:XX AM – SYSTEM CYCLING – AUT OSTART

A remote command (computer relay contact or manual switch) connected to the Remote/Local cycling input of the digital input board has shut down the chiller.

SYSTEM READ Y TO START

MON XX:XX AM – MUL TI UNIT CYCLING – AUTOST AR T

Indicates that the system is not running, but will start upon application of a start signal.

Lead/Lag sequence control accessory has shut down the chiller.

SYSTEM SHUTDOWN – PRESS STA TUS

MON XX:XX AM – POWER FAILURE – AUTOST AR T

Displayed when chiller is shut down on a cycling shutdown, safety shutdown (oper ator must move the COM- PRESSOR switch to STOP/RESET in order to restart) or operator-initiated shutdown (within 30 minutes of

The chiller is shut down because there has been a power interruption or failure. The chiller will automatically restart when power is restored. This message

24 YORK INTERNA TIONAL

FORM 160.49-O2

will be displayed if the Micro Board is configured for AUTO-RESTART AFTER POWER FAILURE. The Micro Board is factory set for manual restart after power failure. To convert it to auto-restar t after power failure, remove one of the two-pin program jumpers from the cloth bag located inside the Control Center and place it on the terminals labeled “Auto R” (J60) on the Micro Board.

MON XX:XX AM – POWER F AILURE

The chiller is shut down because there has been a power interruption or failure. When power is restored, the chiller can be restarted by pressing the COMPRES-

SOR switch to STOP/RESET position and then to START position. This message will be displayed if the Micro Board is configured for MANU AL RESTART AFTER POWER FAILURE. The Micro Board is factory

set for manual restart after power failure. This has been accomplished by removing the two-pin jumper from the terminals labeled “Auto R” (J60) on the Micro Board.

AC UNDERVOLTAGE – AUTOSTART

The chiller is shut down because the MicroComputer Control Center was in RUN mode, displaying

SYSTEM RUN – LEAVING TEMP CONTROL

, but the motor current was less than 10% FLA for 25 continuous seconds. This is indicative of an AC undervoltage condition that has caused the start relay (1R) in the MicroComputer Control Center to de-energize. This condition is checked when the MicroComputer Control Center goes into RUN mode (after 30 second pre-lube). This condition can be caused by failure of any component that would cause a loss of the start signal from the Control Center. In essence, this check assures that the compressor is running when the Control Center is displaying

SYSTEM RUN – LEAVING TEMP CONTROL .

This check is not performed when program jumper JP4 is removed (Steam Turbine applications).

when Control Center is in REMOTE mode.

ANTI-RECYCLE, XX MIN LEFT

The chiller may not restart more frequently than every 30 minutes. Displayed when chiller is shut down and there is time remaining on the anti-recycle timer. In normal operation, chiller cannot be restarted until

ANTI-RECYCLE, 00 MIN LEFT

is displayed. How eve r, when servicing the chiller, it may be desirable to inhibit this 30-minute timer. If so, simply install a jumper plug in the unmarked terminals of the Micro Board directly under Auto-Restart jack.

This feature eliminated when program jumper JP4 is removed (Steam Turbine applications).

WARNING: Remove this jumper after servicing. Failure to do this voids the Warranty.

MON XX:XX AM – LOW EVAP PRESSURE

The chiller is shut down because the evaporator pressure has decreased to 54.3 PSIG (R-22); 25.0 PSIG (R-134a). The chiller will be allowed to star t when the pressure increases to 54.4 PSIG (R-22); 25.1 PSIG (R-134a). To restart chiller, press the COMPRESSOR switch to the STOP/RESET position and then to the START position.

MON XX:XX AM – LOW EVAP PRESSURE – BRINE

The chiller is shut down because the brine Low Evaporator Pressure (LEP, not included with standard Control Center) safety contacts have opened. The brine LEP safety is located external to the Control Center. Safety cut-out settings will vary with the brine application. To restart the chiller, wait until the safety contacts close, press the COMPRESSOR switch to the STOP/ RESET position and then to the START position.

MON XX:XX AM – INTERNAL CLOCK – AUT OSTART

The operator-programmed daily stop schedule has shut down the chiller. The chiller will automatically restart when the operator-programmed daily start schedule indicates a start. It can be overriddden by pressing the COMPRESSOR switch to the START position.

MON XX:XX AM – LOW OIL PRESSURE

The chiller is shut down because the oil pressure has decreased to 15 PSID while running, or never achiev ed 25 PSID prior to compressor start dur ing the oil pump pre-lube run. The chiller will be allowed to restart when the pressure increases to 25 PSID. Differential pressure is sensed by two pressure transducers. To re-

REMOTE STOP

This message will be displayed when a remote device

start chiller, press COMPRESSOR switch to STOP/ RESET position and then to the START position.

(typically an Energy Management System) has commanded the chiller to shut down. The chiller will restart

MON XX:XX AM – HIGH PRESSURE

upon application of a separate start signal from the remote device. This message will only be displayed

Y ORK INTERNA TIONAL 25

The chiller is shut down because condenser pressure

has increased to 265 PSIG (R-22); 180 PSIG (R-134a). System will be allowed to restart when pressure decreases to 205 PSIG (R-22); 120 PSIG (R-134a). Pressure is sensed by a High Pressure (HP) safety control that is located on a mounting bracket above the oilpump starter located on the condenser. This message is prompted by the opening of the HP safety control contacts. To restart chiller, press COMPRESSOR switch to the STOP/RESET position and then to the START position.

Solid State Starter application, the shutdown could have been caused by any of the following reasons. The appropriate light on the Solid State Starter Logic Board will be illuminated.

• Phase rotation/loss

• Trigger Board out of lock (OOL)

• Power Fault

• Half Phase

MON XX:XX AM – EV AP TRANS OR PROBE ERR OR

The chiller is shut down because the leaving chilled water temperature minus the ev aporator saturation temperature is outside the range of –2.5°F to +25°F continuously for 10 minutes. To restar t the chiller, press

COMPRESSOR switch to STOP/RESET switch to STOP/RESET position and then to STAR T position. On

Brine applications (program jumper JP3 removed), this check is not performed when the ev aporator transducer is reading a pressure below its “out-of-range” threshold.

On Steam Turbine applications (Micro Board program jumper JP4 removed), with EPROM version C.02F (T).12 or later, this check is bypassed for the first 20 minutes of chiller run time and then performed at the regular 10 minute intervals thereafter. This is to allow for the additional time required to decrease the evaporator pressure due to the longer acceleration time of the steam turbine.

MON XX:XX AM – MOTOR CONTROLLER – EXT. RESET

The chiller is shut down because a current module (CM-2 Electro-Mechanical starter application), or the YORK Solid State Starter or the Var iable Speed Drive initiated a shutdown. To restar t system, reset the external device that caused the shutdown. The chiller will then automatically restart.

NOTE: The following motor controller shutdowns do not require an external reset to restart chiller.

Solid State Starter 110°F start inhibit. Anytime the chiller has been shut down for any reason, this message will be displayed until the SCR heatsink temperatures decrease to below 110°F.

MON XX:XX AM – POWER F AULT – AUTOSTART

The chiller is shut down because of a Solid State Starter or current module (CM-2 Electro-Mechanical starter application) “Power Fault” shutdown. The chiller will automatically restart. This function is sensed by the motor controller input to the digital input board. A powerfault shutdown is initiated by the motor controller contacts (CM-1) opening and reclosing in one second. If

MON XX:XX AM – HIGH DISCHARGE TEMP

The chiller is shut down because the discharge temperature has increased to 220°F. The system will be allowed to restart when the temperature has decreased to 219°F. Temperature is sensed by a thermistor RT2. To restar t the chiller, press COMPRESSOR switch to STOP/RESET position and then to the START posi- tion.

MON XX:XX AM – HIGH OIL TEMP

The chiller is shut down because the oil temperature has increased to 180°F. The system will be allowed to restart when the temperature decreases to 179°F. The temperature is sensed by thermistor RT3. To restart the chiller, press COMPRESSOR switch to STOP/RE- SET position and then to the START position.

MON XX:XX AM – OIL PRESSURE TRANSDUCER

The chiller is shut down because the oil pressure has increased to 125 PSID (during the first 7 minutes of compressor operation) 60 PSID (after the first minutes of compressor operation). The chiller will be allowed to restart when the oil pressure decreases to 59 PSID. T o restart the chiller, press COMPRESSOR switch to STOP/RESET position and then to the START position.

MON XX:XX AM – FAULTY COND PRESSURE XDCR

The chiller is shut down because the condenser transducer is indicating a pressure of less than 24.2 PSIG (R-22), 6.8 PSIG (R-134a); or a pressure greater than 300 PSIG (R-22 or R-134a). This is generally indicative of a defective condenser transducer or the transducer has been disconnected. After the problem has been corrected, the chiller can be restarted. To restart, press COMPRESSOR switch to STOP/RESET posi- tion and then to START position.

MON XX:XX AM – F A ULTY OIL PRESSURE XDCR

The chiller is shut down because either the high side or low side oil pressure transducer was out-of-range (displaying x’s) while chiller was running. To restar t

26 YORK INTERNA TIONAL

FORM 160.49-O2

chiller, press COMPRESSOR switch to STOP/RESET position and then to START position.

VANE MOTOR SWITCH OPEN

The chiller is shut down because a system-start sequence has been initiated, but the pre-rotation vanes are not fully closed.

MON XX:XX AM – STARTER MALFUNCTION DETECTED

The chiller is shut down because the Control Center has detected a motor-current value greater than 15% FLA for 10 seconds minimum anytime when the compressor-start signal is not energized. To restart the chiller, press COMPRESSOR switch to STOP/RESET position and then to the START position.

MON XX:XX AM – PROGRAM INITIATED RESET

The chiller is shut down because Micro Board did not receive a hardware-generated interrupt on schedule. Typical is an Analog/Digital Converter interrupt. This message is indicative of a Micro Board hardware failure or electrical noise on Micro Board. The chiller will automatically restart. This message indicates that the watchdog timer-circuit has reset the microprocessor. This occurs when the time needed to step through program is longer than allowable, thus the software program is initialized at its beginning.

SYSTEM READY TO START – PRESS STATUS

jumper on the Micro Board as follows:

FUNCTION JUMPER POSITION

50 Sec. Oil Pump Prerun Installed

180 Sec. Oil Pump Prerun Cut

SYSTEM COASTDOWN

Displayed while motor is decelerating after a chiller shutdown. The oil pump is running during this period. The duration of this period is 150 seconds.

If unit is configured for a Steam Turbine application (program jumper JP4 removed), this period is e xtended to allow for a longer coastdown time. EPROM version C.02F(T).11 provides a 6 minute coastdown period. EPROM version C.02F(T).12 or later provides a 10 minute coastdown period.

MON XX:XX AM – MTR PHASE CURRENT UNBALANCE

(Solid State Starter applications only)

The chiller is shut down because the compressor-motor current was unbalanced while the chiller was running. The current balance is only checked after the motor has been running for a minimum of 45 seconds and the motor current is 80% FLA or greater. If the current in any phase deviates from the average (

a + b3+ c

) current by greater than 30% for a minimum of 45 consecutive seconds, a shutdown is initiated. To restart the system, press the COMPRESSOR switch to STOP/RE- SET position and then to the START position. An ex- ample of the conditions for shutdown is as follows:

The chiller was shut down on a safety shutdown and will start upon application of a local or remote start signal. Since the message states that the chiller is “Ready to Start”, it means that the shutdown no longer exists and the Control Center has been manually reset. When the STATUS key is pressed, a message is displayed that describes the reason for shutdown. The message will be displayed for 2 seconds and then return to

SYSTEM READ Y TO START – PRESS STATUS

. Those messages that could be displayed are any of the previously described safety-shutdown messages or warning messages. They can be cleared from the display by entering Service mode and pressing WARN- ING RESET key. Or, the message will be cleared by initiating a compressor start.

START SEQUENCE INITIA TED

Indicates that the Micro Board has received a local or remote start signal and has initiated the chiller star tup routine.

This is the compressor pre-lube period. The duration of this period is controlled by the “Prerun” (JP6) wire

IF:

I∅ A = 200A I∅B = 200A I∅C = 118A

THEN:

IAV =

200 + 200 + 118

3 IAV = 173A IACCEPTABLE = 173 ± 30% = 121A or 225A

THEREFORE:

Since I∅C = 118A which is less than the acceptable 121A, the chiller would shut down if this unbalance exists for 45 consecutive seconds.

MON XX:XX AM – LOW LINE VOLTAGE

(Solid State Starter applications only)

Chiller is shut down because the voltage in any phase of line voltage has decreased below the under-voltage-shutdown threshold for 20 consecutive seconds,

Y ORK INTERNA TIONAL 27

or failed to achieve the minimum required starting linevoltage. Refer to explanation under “System Setpoints – SSS Motor Current/Volts”, page 11. The system will automatically restart when all phases of line voltage increase to the minimum required starting voltage.

MON XX:XX AM

–

HIGH LINE VOLTAGE

(Solid State Starter applications only)

Chiller is shut down because the voltage in any phase of line voltage has increased above the over-voltage threshold for 20 consecutive seconds. Refer to explanation under “System Setpoints – SSS Motor Current/ Volts”, page 11. The system will automatically restart when all phases of line voltage decrease to the maximum allowable line voltage to start the chiller.

MON 09:30 AM – LOW OIL TEMPERATURE – AUT OSTART

The chiller is running and the oil temperature (as indicated by thermistor RT3) falls below 55°F, the chiller will shut down and display this message. The chiller will automatically restart when the oil temperature increases to >71°F AND is greater than the condenser saturated temperature by 20°F or 30°F depending upon how long the chiller was shut down. Refer to the message “

MON XX:XX AM LOW OIL TEMP DIFF – AUTOSTART

MON XX:XX AM – LOW OIL TEMP DIFF – AUTOSTA RT

”.

Indicates the chiller is shut down for one of the following reasons:

1. The chiller has been shut down for 30 minutes or less and the oil temperature minus the condenser saturation temperature is less than 30°F.

– or –

2. The chiller has been shut down for more than 30 minutes and the oil temperature minus the condenser saturation temperature is less than 40°F.

– or –

3. Following a power failure, the oil temperature minus the condenser saturation temperature is less than 40°F.

DAY – TIME – OIL PRESSURE XDCR ERROR

Indicates the chiller has shut down because the difference between the High Side Oil Pressure Transducer Output and the Low Side T ransducer Output was g reater than 15.0 PSID during the “Transducer Auto-Zeroing Sequence” that occurs 10 seconds after a chiller start is initiated. Message is displayed immediately after the Auto-Zeroing sequence has completed. This indicates that one of the transduce outputs is incorrect, possibly due to an incorrect or defective transducer. To restar t the chiller, press COMPRESSOR switch to STOP/ RESET position and then to START position.

MON XX:XX AM – F A ULTY DISCHARGE TEMP SENSOR

Whenever the discharge temperature falls below 30°F, or the discharge temperature sensor is disconnected from the Micro Board, the preceding message will appear. To restar t the system when the discharge temperature rises or the sensor has been connected, press the COMPRESSOR switch to the STOP/RESET posi- tion and then to the START position.

MON XX:XX AM – PRO X SENSOR SAFETY SHUTDO WN

The chiller is shut down because the “Proximity/Temperature Sensor” has detected that the distance between the compressor high speed thrust collar and the sensor probe has increased > 10 mils or decreased > 20 mils (25 mils with EPROM version C.02F(T).12 or later) from the “Reference Position”.

NOTE: With EPROM version C.02F (T).11, if the ref-

erence position is < 42 mils, the minimum allowed distance is 22 mils. With EPROM version C.02F(T).12 or later, if the reference position is < 44 mils, the minimum allowed distance is 19 mils.

IMPORTANT: If the chiller has shut down displaying this message, it cannot be restarted until a qualified service technician performs a visual inspection of the high speed thrust bearing and performs a special reset procedure. This special reset procedure is detailed in YORK Ser vice manual, Form 160.49-M3. Failure to perform the visual inspection prior to restarting the chiller could result in severe compressor damage!!!

The chiller will restart automatically after the condition clears if the COMPRESSOR switch is in the RUN po-

DAY – TIME – F AULTY PROXIMITY PROBE

sition.

The chiller has shut down because the “Pro ximity/Tem-

NOTE: This check is made only when the chiller is

shut down. It is not checked when the chiller is running or in “Start Sequence Initiated”.

perature Sensor” has detected that the distance between the compressor high speed thrust collar and the sensor probe has decreased to ≤ 17 mils.

28 YORK INTERNA TIONAL

FORM 160.49-O2

IMPORTANT!!!: Although this message is generally indicative of a defective proximity probe, it is possible that the compressor has been damaged. If the high speed thrust bearing is not inspected by a qualified service technician prior to star ting the chiller, fur ther severe compressor damage could result. The chiller cannot be restarted until the “Special Reset Procedure” inYORK Service manual, Form 160.49-M3 is performed by a qualified service technician.

MON XX:XX AM – HIGH SPEED DRAIN TEMP

The chiller has shut down because the “Pro ximity/Temperature Sensor” has detected the temperature of the high speed drain line has reached 250.0°F or greater.

IMPORTANT: If the chiller has shut down displaying this message, it cannot be restarted until a qualified service technician performs visual inspection of the high speed thrust bearing and performs a special reset procedure. This special reset procedure is detailed in YORK Service manual, Form 160.49-M3. Failure to perform the visual inspection prior to restarting the chiller could result in severe compressor damage!!!

MICRO BOARD

U16 RTC IC CHIP REAL TIME CLOCK

24673A

FIG. 14 – MICROCOMPUTER CONTROL CENTER

LOCATION OF REAL TIME CLOCK U16 RTC IC CHIP

MON XX:XX AM – OPEN DRAIN TEMP THERMOCOUPLE

The chiller is shut down because the “Proximity/Temperature Sensor” thermocouple or high speed drain temperature wiring between the “Proximity/Temperature Sensor” module and the MicroComputer Control Center has been disconnected or has a poor electrical connection.

IMPORTANT: Open thermocouple shutdowns would typically indicate hardware or wiring defects and should not result in any damage to the compressor high speed thrust bearing. Therefore, a bearing inspection is not required. However, due to the critical nature of these circuits, anytime this shutdown occurs, a special reset procedure must be performed by a qualified service technician before the chiller can be restarted. This procedure is detailed in Service manual, Form

160.49-M3.

MON XX:XX AM – DC UNDERV OLTAGE

The “Proximity/Temperature Sensor” module becomes unstable in operation when the +24VDC supply decreases to +17VDC. Therefore, the Micro Board monitors the +24VDC supply and when it decreases to +19VDC, it shuts down the chiller and displays this message, preventing invalid “Proximity Sensor Safety” or “High Speed Drain Temp” safety shutdowns. The chiller will automatically restart when the voltage increases to greater than +19.7 VDC.

MON XX:XX AM – AUX SAFETY SHUTDOWN

The system is shut down because an external device, connected to digital input board TB1-31 (A uxiliary Safety Shutdown Input), has initiated a system shutdown. This input is a general purpose input that can be used to annunciate a user-defined safety shutdown. To restar t chiller, press COMPRESSOR switch to STOP-RESET position and then to START position.

REPLACE RTC. U16 – REPROGRAM SETPOINTS

Indicates that the battery located inside the REAL- TIME CLOCK IC chip (U16 on the Micro Board) is defective. This batter y provides back-up power to the RTC memory (RAM) in the event of a utility AC power failure. This assures the system setpoints will be maintained. If this message appears , the R TC IC chip (U16) on the Micro Board must be replaced. If there had been a power failure while this message is displayed, the setpoints will have been lost and must be reprogrammed. Order a replacement RTC IC chip (YORK part number 031-00955-000) from the YORK Parts Distribution Center. With AC power removed from system, locate RTC chip U16 on the Micro Board and remove existing RTC chip from socket and discard. Observe anti-static precautions and install new RTC chip in socket. Assure proper IC orientation – orientation notch must be UP. (Refer to Fig. 14.)

Y ORK INTERNA TIONAL 29

SECTION 3

SYSTEM OPERA TING PROCEDURES

WARNING

OIL HEATERS

If the oil heater is de-energized during a shutdown period, they must be energized f or 12 hours prior to starting compressor, or remove all oil and recharge compressor with new oil. (See “Charging Unit With Oil”, page 43.)

NOTE: The oil heater is thermostatically controlled

and remains energized as long as the fused disconnect switch to the starter or turbo-modulator is energized.

START-UP PROCEDURE

PRE-STARTING Prior to starting the chiller, observe the MicroCom-

puter Control Center. Make sure the display reads

SYSTEM READY TO START

To pre-star t the chiller, use the following procedure:

1. Oil Heater – The oil heater must be energized for 12 hours prior to starting the chiller. The unit will not start if the oil is less than 71°F. If not possible the compressor oil should be drained and new oil must be charged into the oil sump. (See “Charging Unit With Oil”, page 43.)

2. Oil Pump – To check, press and release the MANUAL OIL PUMP key under Service on the Control Center. The oil pump will run for 10 minutes and shut down. Press and release the MANUAL OIL PUMP key to stop the operation of the oil pump for less than 10 minutes of operation.

3. Pre-Rotation Vanes – To perform this test the starter interlock terminals 3 and 4 must be jumpered to allow vanes to open (remove the jumper after test). Make sure the Control Center is in the SERVICE mode , then press the prerotation vanes OPEN and CLOSE keys to observe the operation of the prerotation vanes. The Control Center supplies a signal to operate the prerotation vanes. The movement of the vanes will be dis-

CHECKING THE OIL LEVEL IN THE OIL RESERVOIR

Proper operating oil level – the middle of the upper sight glass.

If the oil is excessively high after start-up, the excess oil may be drained from the oil filter drain valve while the compressor is running.

If oil level is low, oil should be added to the compressor. (See “Charging Unit With Oil”, page 43.)

played on the Control Center. The display readout is active whenever power is supplied to the Control Center. Return from the SERVICE mode to LOCAL, PROGRAM, or REMOTE mode to suit the method of operation selected for the chiller application. Refer to “Section 2”.

4. % Current Limit – Press the % CURRENT LIMIT setpoint key on the Control Center. The “Display” should read State Starter units only, the display is

CURRENT LIMIT = 100% FLA, MTR CUR = XXXX FLA

if the Control Center was not programmed. If the setpoint is not 100% and was predetermined for the job application the Control Center should be programmed to that specification. To program, refer to “Section 2”.

5. All Control Center setpoints should be programmed before the chiller is started. (Refer to “Section 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. If not programmed the “default” value setpoints are as follows:

LCWT = 45°F % Current Limit = 100% FLA Pulldown Demand = None Clock = Sun 12:00 A.M. Daily Schedule = None Holiday = None Remote Reset Temp. Range = 20°F Data Logger = No operation

CURRENT LIMIT = 100% FLA

on (Solid

)

30 YORK INTERNA TIONAL

FORM 160.49-O2

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 necessary.

2. To start the chiller, press the COMPRESSOR START switch. This s witch 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 ST ART 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 the 40 character alphanumeric display. (See Fig. 3.)

NOTE: 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 prerotation vanes are fully closed the “Display” will read

SYSTEM READ Y TO START – VANES CLOSED

when in SERVICE mode.

When the chiller starts to operate, the following automatic sequences are initiated: (Ref er to Fig. 15, “Chiller Starting & Shutdown Sequence Chart”.)

1. The MicroComputer Control center alphanumeric display message will read

START SEQUENCE INITIATED

for the first 50 seconds of the starting sequence, (3 minutes if Micro Board JP6 removed).

The high and low oil pressure transducers (OP) and the oil temperature sensor (RT3) will sense any malfunction in the lubrication system and activate one of the following display messages:

DAY 10:30 AM – LOW OIL PRESSURE

DAY 10:30 AM – HIGH OIL TEMPERATURE

DAY 10:30 AM – LOW OIL TEMP – AUTOSTART

DAY 11:30 AM – OIL PRESSURE TRANSDUCER

5. The anti-recycle timer software function will operate after the 50 seconds of pre-run time. At this time, the timer will be initiated 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.

6. The chilled liquid pump contacts will close star ting the chilled liquid pump to allow liquid flow through the cooler when the COMPRESSOR start switch is energized.

7. After the first 50 seconds of operation, the compressor will start and the Control Center display message will read

SYSTEM RUN – CURRENT LIMIT IN EFFECT

while the motor is accelerating to full speed. When the motor reaches full speed and the current falls below 100% FLA the message will read

SYSTEM RUN – LEAVING TEMP. CONTROL

8. For additional display messages and information pertaining to the operation of the MicroComputer Control Center, refer to “Section 2”.

9. Low Oil Temp. Differential.

2. The compressor vent line solenoid valve will open after the first 5.83 minutes of operation. The solenoid will close automatically after the compressor shuts down.

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

3. The 1R-1 contacts of the 1R start relay will remain open for the first 50 seconds of oil pump operation. These contacts will close, starting the compressor motor and the condenser water pump at the end of the 50 second period.

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

4. 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.

Y ORK INTERNA TIONAL 31

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.

SYSTEM ST ARTING & SHUTDO WN SEQUENCE

OPERA TOR INITIA TED

(NOTE 2)

NOTES: 1. REF. MICROBOARD PROGRAM JUMPER JP6

2. REF . MICR OBOARD PROGRAM JUMPER JP4

FIG. 15 – CHILLER STARTING SEQUENCE & SHUTDOWN SEQUENCE

However, the current draw (amperes) by the compressor motor cannot exceed the setting of the % CUR- RENT LIMIT at any time during the unit operation, since

This occurs when the leaving water temperature falls to 4°F below setpoint or 36°F, whichever is higher. The

LWT is part of the Micro Board. the MicroComputer Control Center 40 to 100% threephase peak current limit software function, plus the 3phase 100% solid state overload current limiter (CM-

2) on Electro-Mechanical Starter applications or the

NOTE: If the temperature setpoint has been repro-

grammed within the last 10 minutes, the LWT cutout is 36°F for 10 minutes.

Solid State Starter current Limit function will override the temperature control function and prevent the Prerotation Vanes from opening beyond the % CURRENT

Condenser Water T emperature Control LIMIT setting.

The YORK Millennium chiller is designed to use less If the load continues to decrease, after the Prerotation Vanes are entirely closed, the chiller will be shut down by the Low Water Temperature control (LWT) function which is displayed on the Control Center as:

power by taking advantage of lower than design tem-

peratures that are naturally produced by cooling tow-

ers throughout the operating year . Exact control of con-

denser water such as a cooling tower bypass, is not

necessary for most installations. The chiller requires

MON 10:30 AM – LOW WATER TEMPERATURE – AUTOSTART

only that the minimum condenser water temperature

LD00952

32 YORK INTERNA TIONAL

be no lower than the value determined by referring to the formula below:

Min. ECWT = LCHWT—C RANGE + 5 + (

where:

ECWT = entering condensing water temperature LCHWT = leaving chilled water temperature C RANGE = condensing water temperature range

15 x % LOAD

100

At start-up, the entering condenser water temperature may be as much as 25°F 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 installations.

CHECKING OPERATION

During operation, the following conditions should be periodically checked:

1. On starting, the prerotation vanes should remain closed until the compressor motor is up to speed on the run winding; then the vane motor should cause the vanes to modulate with load requirements.

FORM 160.49-O2

2. Be sure the oil pump is operating while unit is running.

3. Check Oil Pressure display. A gradual decrease in

)

bearing oil pressure of 5 to 10 psi (with constant suction and discharge pressures) may be an indication of a dirty filter. The filter should be replaced when pressure loss is 30% or more of the original pressure. The actual bearing oil pressure will vary with compressor suction and discharge pressures. When a new system is first operated under normal full load conditions, the bearing oil pressure should be recorded as a reference point with which to compare subsequent readings.

OPERATING LOG SHEET

A permanent daily record of system operating conditions (temperatures and pressures) recorded at regular intervals throughout each 24 hour operating period should be kept.

An optional status printer is available for this purpose or Fig. 16 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-F6 and may be obtained through the nearest

LD00467

*NOTE: These items can be printed by an electronic printer connected to TB8 of the Micro Board and pressing the PRINT key on the

Micro Board or automatically using the Data Logger feature.

23889A

FIG. 16 – LIQUID CHILLER LOG SHEETS

Y ORK INTERNA TIONAL 33

YORK office. Automatic data logging is possible by connecting the optional printer and programming the DATA LOGGER function; refer to Form 160.49-N7.

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.

OPERATING INSPECTIONS – See Section 2

By following a regular inspection using the displa y 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.

7. Check the compressor motor voltage and current (amps) at E-M starter (or Variable Speed Drive), or on the Control Center display for Solid State Starter units.

8. Check for any signs of dirty or fouled condenser tubes. (The temperature difference between water leaving condenser and liquid refrigerant leaving the condenser should not exceed the difference recorded for a new unit by more than 4°F.)

9. Press the STATUS key whenever the display indi- cates so. This allows any warning messages to be displayed.

Weekly

1. Check the refrigerant charge. (See “Checking The Refrigerant Charge”, page 52.)

Quarterly

Daily

1. Check MicroComputer Control Center displays.

2. If the compressor is in operation, check the bearing oil pressure by pressing OIL PRESSURE key to read the display on the Control Center . Also check the oil level in the oil reservoir. Operating oil level should be between the upper and lower sight glasses. 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 by pressing CONDENSER LIQUID TEMPERATURES display key.

4. Check the entering and leaving chilled liquid temperatures and evaporator pressure for comparison with job design conditions. This can be accomplished by pressing the CHILLED LIQUID TEMPS key and the REFRIGERANT PRESSURES key.

5. Check the condenser saturation temperature (based upon condenser pressure sensed by the condenser transducer). Press the DISPLAY DATA key. This key may be depressed repeatedly after depressing the DISPLAY HOLD key to display three different parameters.

6. Check the compressor discharge temperature. Press DATA DISPLAY key. During normal opera- tion discharge temperature should not exceed 220°F.

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)

1. Drain and replace the oil in the compressor oil sump. (See “Charging The Unit With Oil”, page 43.)

2. Cooler 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. 23 for details. c. Re-lubricate ball bearings.

34 YORK INTERNA TIONAL

FORM 160.49-O2

4. Inspect and ser vice electrical components as necessary.

5. Perform chemical analysis of system.

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”, pages 47 through 48 of this instruction. After consulting this chart, if you are unable to make the proper repairs or adjustments to start the compressor or the par ticular 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 considerably.

NORMAL AND SAFETY SYSTEM SHUTDOWNS

Normal and safety system shutdowns have been built into the chiller to protect it from damage during certain operating conditions. Theref ore, it should be understood that at certain pressures and temperatures the system will be stopped automatically by controls that respond to high temperatures, low temperatures, and low and high pressures, etc. Table 1 is an explanation of each specific shutdown. If the chiller shuts down on a “Safety” shutdown, the display will read

SYSTEM SHUTDOWN – PRESS STATUS

Upon pressing the ST ATUS k ey, the day-of-week, timeof-day and cause of shutdown is display ed. Safety shutdowns require the operator to manually reset the Control Center prior to restarting the chiller. When the display reads

START SEQUENCE INITIA TED

, the cause of the safety shutdown is automatically cleared from the memory.

SAFETY SHUTDOWNS

• Motor Phase Current Unbalance (Solid State Starter Unit only)

• Proximity sensor

• Faulty Prox. Probe

• Open Drain Ther mocouple

If the chiller shuts down on a “Cycling” shutdown the display will read

SYSTEM SHUTDOWN – PRESS STATUS

Upon pressing the ST ATUS key, the day-of-week, time- of-day and cause of shutdown are displayed. These shutdowns do not require the operator to manually reset the Control Center prior to re-starting the chiller. The chiller will automatically restart when the cycling condition is removed.

CYCLING SHUTDOWNS

• Power Failure (If auto re-start programming jumper is installed on the Micro Board)

• Low Water Temp

• Flow Switch

• System Cycling

• Multi-Unit Cycling

• Internal Clock

• Anti-Recycle

•Motor Controller (Manual reset of the CM-2 module on E-M starter units; the logic board of the Solid State Starter may be required)

• Power Fault

• Program Initiated Reset

• Low Oil Temp

• AC Undervoltage

• DC Undervoltage

• Low Line Voltage (Solid State Starter units only)

• High Line Voltage (Solid State Starter units only)

• Low Oil Temp. Differential

• Power Failure (If auto restart programming jumper is

STOPPING THE SYSTEM (See Fig. 3, page 6)

not installed on the Micro Board)

• Low Evaporator Pressure

•Low Oil Pressure

• High Condenser Pressure

The MicroComputer Control Center can be programmed to start and stop automatically (maximum, once each day) whenever desired. Refer to “Section 2”. To stop the chiller, proceed as follows:

• Evaporator Transducer or Probe Error

• High Discharge Temp

• High Oil Temp

• Oil Pressure Transducer

•Starter Malfunction Detected

• Faulty Discharge Temp Sensor

• Aux. Safety Shutdown

Y ORK INTERNA TIONAL 35

1. Push the COMPRESSOR STOP/RESET switch. The Control Center display will show

SYSTEM COASTDOWN

for 150 seconds. If unit is configured for a STEAM TURBINE application (program jumper JP4 removed), this period is e xtended to allow for a longer coastdown time. EPROM version C.02F(T).11 provides a 6 minute coastdown

period. EPROM version C.02F(T).12 or later provides a 10 minute coastdown period. The compressor, condenser water, and cooling tower fans will stop automatically. The oil pump will continue to run for coastdown period. The oil pump will then stop automatically. Once stopped, the

SYSTEM COASTDOWN SYSTEM READY TO START

display will be replaced by

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 postion of Micro Board jumper J54.)

3. Open the switch to the cooling tower fan motors, if used.

the cooling tower , condenser, condenser pump , and the chilled water system-chilled water pump and coils.

Open the drains on the cooler and condenser liquid heads to assure complete drainage. (If a Variable Speed Drive, drain its water cooling system. If Solid State Starter. dr ain water from starter cooling loop.)

3. Move jumper J-57 on the Micro Board from CLOCK ON position (CLKON) to CLOCK OFF position (CLKOFF) while 115VAC control power is applied. This conserves 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 Center.

4. The compressor sump oil heater (thermostatically controlled) 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 f ollowed.

1. Test all system joints for refrigerant leaks with a 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

START-UP AFTER PROLONGED SHUTDOWN

1. When putting the system into operation after prolonged shutdown (during the winter), remove all oil from the compressor. Install a new filter element and charge compressor with fresh oil. Move jumper J-57 on the Micro Board from CLOCK OFF position (CLKOFF) to CLOCK ON position (CLKON) and reset the clock. Energize the 115 volt circuit to the Control Center to energize the compressor sump oil heater for at least 12 hours.

2. Operate the Oil Pump (press and release the MAN- UAL OIL PUMP key) until steady oil pressure is established. Then press and release the OIL PUMP key to stop operation of the oil pump. If the water systems were drained, fill the condenser water circuit and chilled liquid circuit.

36 YORK INTERNA TIONAL

DUAL RELIEF VA LVES

SUCTION

SECTION 4

SYSTEM COMPONENTS DESCRIPTION

MICROCOMPUTER CONTROL CENTER

DISCHARGE

COMPRESSOR

FORM 160.49-O2

ADAPTER MOT OR SUPPORT & COVER

MOTOR

COOLER

OIL PUMP ST AR TER

SIGHT GLASSES

DISCHARGE LINE

DEHYDRA TOR

FRONT VIEW

27385A

REFRIGERANT CHARGING V ALVE

27382A

OIL RESERVOIR/ PUMP

CONDENSER

FIG. 17 – SYSTEM COMPONENTS

Y ORK INTERNA TIONAL 37

GENERAL

The YORK Model YK Millennium Centrifugal Liquid Chiller is completely factory-packaged including cooler , condenser, compressor, motor, lubrication system, MicroComputer Control Center, and all interconnecting unit piping and wiring.

The initial charge of refrigerant and oil is supplied for each unit. Oil is shipped in containers with the chiller. Refrigerant is shipped to the jobsite in cylinders at the time of installation.

The services of a YORK factory-trained, field service representative are included to supervise the final leak testing, charging and the initial start-up and concurrent operator instructions.

COMPRESSOR

The compressor is a single-stage centrifugal type powered 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 balanced 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 consists of a spring-loaded, precision carbon ring, high temperature elastomer “O” ring static seal, and stress-relieved, precision lapped collars. The seal is oil-flooded at all times and is pressure-lubricated during operation.

CAPACITY CONTROL

Prerotation vanes (PR V) modulate chiller capacity 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 maintain a constant leaving chilled liquid temperature.

pressor which must be supplied with forced lubrication 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 necessary pressure to properly lubricate these par ts, 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 delay to allow the system oil pressure to stabilize, the compressor 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 surrounding 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.

Since the emergency oil reservoir is at the highest point in the lubrication system, 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.

OIL PUMP

For normal operation, the oil pump should operate at

COMPRESSOR LUBRICATION SYSTEM

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-com-

38 YORK INTERNA TIONAL

(See Fig. 18)

all times during chiller operation. Manual pump operation may be used to establish stable oil pressure before starting. When depressed and released, the MANUAL OIL PUMP key will operate the oil pump for 10 minutes and then automatically shut off. To stop the

FORM 160.49-O2

FIG. 18 – SCHEMATIC DRAWING – (YK) COMPRESSOR LUBRICATION SYSTEM

Y ORK INTERNA TIONAL 39

LD00951

oil pump sooner, depress the MANUAL OIL PUMP key again.

On shutdown of the system for any reason, the oil pump operates and continues to run for 150 seconds. The system cannot restart during that time inter val.

OIL HEA TER

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 becomes 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, Section 2”.

To maintain the lowest possible concentration of refrigerant in the oil, the compressor oil reservoir is equipped with a 115 volt electric reservoir oil heater. The oil heater is thermostatically controlled at all times during compressor shutdown to maintain the sump oil at 145°F to 155°F. If the oil temperature falls below 55°F, the display will read

SYSTEM SHUTDOWN – PRESS STATUS

Pressing the ST ATUS key causes the message to read

DAY 10:00 AM – LOW OIL TEMP – A UT O START

. The system will be allowed to automatically restart when oil temperature rises to 30°F above condenser temperature.

Motor drive shaft is directly connected to the compressor shaft with a flexible disc coupling. 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 threelead type of starting. Motor terminal lugs are not furnished. Overload/overcurrent transformers are furnished with all units. For units furnished with factory packaged Solid State Starters, (optional) see right.

HEA T 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. Aluminum mesh eliminators are located above the tube bundle to prevent liquid refrigerant carryover into the compressor. Two 1-1/2" liquid level sight glasses are located on the side of the shell to aid in determining proper refrigerant charge. The evaporator shell contains a dual refrigerant relief valve.

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 condenser.

The removable compact water boxes are fabr icated of

MOT OR DRIVELINE

steel. The design working pressure is 150 psig and the boxes are tested at 225 psig. Integr al steel water baffles

The compressor motor is an open-drip-proof, squirrel cage, induction type constructed to Y ORK design specifications. 60 hertz motors operate at 3570 rpm. 50 hertz motors operate at 2975 rpm.

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

(For 60 hertz motors 1750 HP and smaller; and 50

vent connections are provided in each water box.

hertz motors 1400 HP and smaller) . . . the open motor is provided with a D-flange, factory mounted to a cast

REFRIGERANT FLOW CONTROL

iron adapter mounted on the compressor.

Refrigerant flow to the evaporator is controlled by a

(For 2000 HP 60 hertz motors; and 50 hertz motors

single fixed-orifice (or variable orifice). above 1400 HP) . . . a separate structural steel base is furnished to provide rigid mounting of the compressor and motor, independent of the evaporator shell, to ensure controlled alignment of the assembly. Motor is mounted with final alignment at start-up.

Chillers can be provided with a REFRIGERANT LEVEL

CONTROL (EPROM version C.02.F(T).13 or later sup-

ports this feature). A level sensor senses the refriger-

ant level in the condenser and outputs an analog volt-

40 YORK INTERNA TIONAL

FORM 160.49-O2

age to the Micro Board that represents this level (0% = empty; 100% = full). Under program control, the Micro Board 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 service technician. Only a qualified service technician may modify these settings. Manual operation of the refrigerant lev el control can be selected. This allows the prerotation v anes keypad k eys to manually control the variable orifice. This manual control can also be used to position the variable orifice in a fixed position. Instructions for selecting manual level control and entering the level control setpoints are contained in the “Special Setpoints and Programming Procedures” section of Service manual, Form

160.49-M3. While the chiller is shut down, the orifice will be in the

fully open position causing the sensed level to be approximately 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 . While this ramp is in effect,

PULLDN LEVEL = XXX%; SETP = XXX%; ACTUAL = XXX%

one of the scrolled messages under the DISPLA Y D A T A key. “PULLDN LEVEL” is the ramping setpoint that will ramp up to the programmed setpoint “SETP”. “SETP” is the level setpoint programmed by the service technician. “ACTUAL” is the present refrigerant level in the condenser. After the 15 minute pulldown period has elapsed, this message is replaced by

ACTUAL LEVEL = XXX%; LEVEL SETP = XXX%

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 normally 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.

If the refrigerant level sensor output e ver goes to greater than 4.4VDC, indicating a level greater than 100%,

WARNING-REFRIGERANT LEVEL OUT OF RANGE

is displayed and the level control actuator is driven open until the level has decreased to a level within range. When within range, the warning message is automatically cleared and normal control is resumed.

MICROCOMPUTER CONTROL CENTER (See Section 2)

The MicroComputer Control Center is factory mounted, wired and tested. The electronic panel automatically controls the operation of the unit in meeting system cooling requirements 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. Po wer 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 – 60/50Hz 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 information is contained in Form 160.00-O1. The control logic automatically adjusts motor speed and compressor prerotation vane position for maximum part load efficiency by analyzing information fed to it by sensors located throughout the chiller.

Y ORK INTERNA TIONAL 41

OIL RETURN SYSTEM

SECTION 5

OPERA TIONAL MAINTENANCE

The oil return system continuously maintains the proper oil level in the compressor oil sump. (See Figs. 18 &

19.) High pressure condenser gas flows continuously

through the eductor inducing the low pressure, oil rich liquid to flow from the ev aporator, through the dehydrator to the compressor sump.

CHANGING THE DEHYDRAT OR To change the dehydrator, use the f ollowing procedure:

1. Shut the stop valves on the condenser gas line, oil

return line to rotor support and inlet end of the dehydrator.

2. Remove the dehydrator. Refer to Fig. 19.

3. Assemble the new filter-drier.

4. Open condenser stop valve and check dehydrator connections for refrigerant leaks.

5. Open all the dehydrator stop valves to allow the liquid refrigerant to flow through the dehydrator and condenser-gas through the eductor.

LD00950

FIG. 19 – OIL RETURN SYSTEM 42 YORK INTERNA TIONAL

FORM 160.49-O2

THE OIL CHARGE

The nominal oil charge for the compressor is 20 gal., type “F” for R-22 application or type “K” for R-134a application.

New YORK Refrigeration oil must be used in the centrifugal compressor. Since oil absorbs moisture when exposed to the atmosphere, it should be kept tightly capped until used.

OIL CHARGING PROCEDURE

The oil should be charged into the oil reservoir using the YORK Oil Charging Pump – YORK Part No. 070-

10654. To charge oil into the oil reservoir, proceed as follows:

1. The unit must be shut down.

2. Immerse the suction connection of the oil charging pump in a clean container of new oil and connect the pump discharge connection to the oil charging valve (A) located on the remote oil reservoir cover

plate. (See Fig. 20.) Do not tighten the connection at the charging valve until after the air is forced out by pumping a few strokes of the oil pump. This fills the lines with oil and prevents air from being pumped into the system.

3. Open the oil charging valve and pump oil into the system until oil level in the compressor oil reservoir is about midway in the upper sight glass. Then, close the charging valve and disconnect the hand oil pump.

4. As soon as oil charging is complete, close the power supply to the starter to energize the oil heater. (See “Section 3, System Operating Procedures”.) This will keep the concentration of refrigerant in the oil to a minimum.

When the oil reservoir is initially charged with oil, the oil pump should be started manually to fill the lines, passages, oil cooler and oil filter. This will lower the oil level in the reservoir. It will then be necessary to add oil to bring the level back to the center of the upper sight glass.

OIL CHARGING VALVE

25721A

LD00472

FIG. 20 – CHARGING OIL RESERVOIR WITH OIL

Y ORK INTERNA TIONAL 43

44 YORK INTERNA TIONAL

TABLE 1 – CAUSES OF NORMAL AND SAFETY SYSTEM SHUTDOWNS IN ACCORDANCE WITH THE MICROCOMPUTER CONTROL,

CENTER DISPLAY

SHUTDOWN CA USE

CONTROL CENTER DISPLA Y

DA Y O F TIME OF CAUSE OF METHOD OF

WEEK DA Y SHUTDOWN REST ART ON ON

MON. 10:00 AM Low W ater Autostart Low Water Chilled 4°F below 4°F below chilled Automatic Restart System load is less

Temp. (LWT) water chiller water setpoint when water reaches than minimum

MON. 10:00 AM Flow Switch Autostart Flow Switch Automatic Restart Lack of water flow.

MON. 10:00 AM System Autostart A remote com- Automatic Restart Contact-connected to

Cycling mand (computer upon remote the Remote/Local

MON. 10:00 AM Multi-Unit Autostart (Optional) Lead- Automatic Restart Contact-connected to

MON. 10:00 AM Internal Autostart Internal Clock Daily Schedule Will automatically Pressing Compressor

Clock Programmed to restart when pro- Start Switch over-

MON. 10:00 AM AC under- Autostart <15% FLA for Cycling shutdown oc-

voltage 25 continuous curs when motor cur-

MON. 10:00 AM Power F ault A utostart CM-2 Current Will start automatic- Motor Controller con-

Remote Stop Energy manage- Start up by start Remote Stop Contact

MON. Anti-Recycle, Anti-Recycle Will not start Will restart when Min. Time between

20 Min. Left timer until 30 Min. time left = 00 Min. successive compres-

GOVERNING CONTROL FUNCTION

OPERA TING

DESCRIPTION

relay contact or command. cycling input of the manual switch) Digital input board

Lag Sequence upon remote the Multi-Unit cycling Control command. input of the Digital

seconds rent is >15% FLA for

Module or tically following tacts opening and Solid State coastdown closing in less than 3 Starter seconds due to a power

ment System signal from remote Closure

POINT

RISE F ALL

setpoint water (If set to 40°F setpoint; if system capacity

setpoint would be 36°F) is running and set-

PROGRAMMED START -UP OF PROBABLE CA USE

SETPOINTS SYSTEM AFTER AND SER VICE

BY OPERA TOR SHUTDOWN REQUIRED

(36°F minimum point is increased

4°F, system will continue to run, as LWT cutout shifts to a fixed 36°F for 10 minutes.

when water flow is Check operation of Restored to close chilled water pump flow switch.

input board

Shutdown Unit grammed schedule rides the program

permits

25 seconds during chiller operation

fault condition

start switch

timer is timed sor starts is 30 min.

TROUBLESHOOTING

SECTION 6

Y ORK INTERNA TIONAL 45

MON. 10:00 AM Low Evap. Low Evap. 54.3 54.4 T o restart, press See OPERATION

Pressure Pressure

PSIG (R-22) PSIG (R-22)

compressor switch ANALYSIS Table 2 T ransducer 25 25.1 from STOP/RESET Symptom 2 (LEP)

PSIG (R-134a) PSIG (R-134a)

to ST AR T position

MON. 10:00 AM Low Evap. LEP external Set to Job Set to Job To restart, press See OPERATION

Pressure control (Brine Spec. Spec. compressor switch ANAL YSIS Table 2 Brine units only) from STOP/RESET Symptom 2.

to ST AR T position

MON. 10:00 AM Low Oil Low Oil 25 1 5 Will restart when Refer to OPERA TION

Pressure Pressure PSID PSID pressure increases ANAL YSIS T able 2

Transducer to 25 PSID. To Symptoms 4, 5, 6, 7, (OP) restart, press com- 9, 10, 11

pressor switch from

STOP/REST AR T to

ST ART position.

MON. 10:00 AM High High Pressure 265 205 Will restart when See Operational

Pressure Safety Control

PSIG (R-22) PSIG (R-22)

Pressure falls to Analysis Table 2 (HP) 180 120 205 PSIG. To restart Symptom 1 High

PSIG (R-134a) PSIG (R-134a)

press compressor Discharge Pressure

switch from STOP/

RESET to START

position

MON. 10:00 AM Evap. T r ans. Evap. Pressure To restart press Defective Evap. Pressure

or Probe T ransducer or compressor switch T ransducer or Leaving Erro r Leaving Chilled from STOP/RESET Chilled Water thermistor

Water Thermis- to START position (RS1). LCWT minus satutor (RS1) ration temperature is less

than –2.5°F or greater than 25°F. Checked e very 10 minutes following a 10 min. bypass at start-up.

MON. 10:00 AM Motor Con- CM2 or Solid Reset the device CM2, or Solid State

troller – Ext. State Starter that caused the shut- Starter has shutdown Reset (RT2) down. Chiller will chiller

start automatically.

MON. 10:00 AM High Discharge Temp. 220°F 219°F T o restart press Condenser tubes dirty or

Discharge Thermistor compressor switch scaled or high condenser T emp. (RT2) from STOP/RESET water temperature. (See

to START position. Symptom 1, Table 1.)

MON. 10:00 AM High Oil Oil T emperature 170°F 169°F To restart press Dirty oil filter or restricted

Temp. Thermistor compressor switch oil cooler line. Change oil

(RT3) from STOP/RESET filter. Refer to OPERATION

to ST AR T position ANALYSIS T ab le 2,

Symptom 9.

MON. 10:00 AM Po we r Auto-Restart Micro Board 8.29VDC 7.84VDC Optional A UTO Will restart automa- Power F ailure.

Failure undervoltage Restart Plug is tically when voltage

circuit on 5V installed on reaches 8.29VDC. unregulated Micro Board An undervoltage supply circuit on the Micro

Board monitors the

5VC unregulated

supply for an under-

voltage condition.

MON. 10:00 AM Po we r Micro Board 8.29VDC 7.84VDC Auto restart plug To restart, press Pow e r Failure

Failure undervoltage is removed on compressor switch

circuit on 5V Micro Board to STOP-RESET unregulated Position and then to supply ST ART position

(Continued on page 46)

FORM 160.49-O2

46 YORK INTERNA TIONAL

TABLE 1 – CAUSES OF NORMAL AND SAFETY SYSTEM SHUTDOWNS IN ACCORDANCE WITH THE MICROCOMPUTER CONTROL,

CENTER DISPLAY

SHUTDOWN CA USE

CONTROL CENTER DISPLA Y

DAY OF TIME OF CAUSE OF METHOD OF

WEEK DA Y SHUTDOWN REST ART ON ON

MON. 10:00 AM Oil Pressure High Oil Press. 100 PSID (Dur- 59 Will start at 59 This Shutdown is provided

T ransducer T ransducer ing first 7 min. of PSID PSID when compr. to check on Oil Pressure Error Compr. Oper.) switch is placed to T ransducers for failure in

Vane Motor Autostart V ane Motor Restart automatically Vanes are set improperly , Switch Open Switch after Vane Motor arm reset vane linkage check

MON. 10:00 AM Starter Motor Current > Press compressor Chec k motor starter

Malfunction 15% for 10 swc. ST OP/RESET operation. Motor current Detected with Control Cen- switch and then value greater than 15%

MON. 10:00 AM Prog ra m Autostart Micro Board Watchdog timer circuit

Initiated has reset software proReset gram – Chiller will

Replace RTC RTC-IC chip Reprogram the Con- Weak battery IC chip trol Center Setponts Replace RTC-IC chip Reprogram & proceed with U16 Setpoints Normal Start-up

MON. 10:00 AM Low Oil Autostart Oil Temp. 71.0°F 55°F Press STOP/ Oil Temp . Thermistor

T emper ature Thermistor RESET switch & disconnected from

MON. 10:00 AM Faulty Dis- Discharge Temp. 30.0°F 29.9°F Press STOP/ Faulty Discharge Temp.

charge T emp. Thermistor START switch & Thermistor (RT2) or disSensor (RT2) discon- then START connected from Analog

MON. 100.00 AM Low Line SSS Logic See legend on wiring Chiller will automa- Low AC Line Voltage

Voltage (SSS Bo ar d diagram tically restart when Units only) all phases of line vol-

MON. 10:00 AM MTR Phase SSS Logic See “Section 2” Press STOP/START Motor Phase Current

Current Board switch then START Unbalance unbalance switch (SSS Units only)

GOVERNING CONTR OL FUNCTION

OPERA TING

DESCRIPTION

ter not calling for FLA motor to run

(RT3) then ST ART Analog Input Board.

nected or faulty switch Input Board. Connect or operating temp. replace open sensor. = 32°F

POINT

RISE F ALL

60 PSID (After STOP/RESET and the high state. Replace first 7 min. of then START Oil Press. Transducer in Compr. Oper.) oil sump or compressor

PROGRAMMED START -UP OF PROBABLE CA USE

SETPOINTS SYSTEM AFTER AND SER VICE

BY OPERAT OR SHUTDOWN REQUIRED

linkage is set pro- vane positions using perly. Press STOP/ the SERVICE key switch RESET and then and proper keys on the ST ART switch MicroComputer Control

Center

automatically restart.

switch Reconnect or replace

open sensor.

tage increase to the minimum required starting level.

FORM 160.49-O2

TABLE 2 – OPERATING ANALYSIS CHART

RESULTS POSSIBLE CAUSE REMEDY

1. SYMPTOM: ABNORMALLY HIGH DISCHARGE PRESSURE

Temperature difference between liquid Air in condenser. refrigerant out and water off condenser higher than normal.

High discharge pressure. Condenser tubes dirty or . Clean condenser tubes. Check water

scaled conditioning. High condenser water Reduce condenser water inlet

temperature. temperature. (Check cooling tower

and water circulation.)

Temperature difference between conden- Insufficient condensing Increase the quantity of water through ser water on and water off higher than water flow. the condenser to proper value. normal, with normal cooler pressure.

2. SYMPTOM: ABNORMALLY LOW SUCTION PRESSURE

Temperature difference between leaving Insufficient charge of Check for leaks and charge chilled water and refrigerant in cooler refrigerant. refrigerant into system. greater than normal with high discharge temperature.

Flow orifice blocked. Remove obstruction.

Temperature difference between leaving Cooler tubes dirty or Clean cooler tubes. chilled water and refrigerant in the cooler restricted. greater than normal with normal discharge temperature.

Temperature of chilled water too low with Insufficient load for Check prerotation vane motor operawith low motor amperes. system capacity. tion and setting of low water temper-

ature cutout.

3. SYMPTOM: HIGH COOLER PRESSURE

High chilled water temperature. Prerotation vanes fail to Check the prerotation vane motor

open. positioning circuit. System overload. Be sure the vanes are wide open

(without overloading the motor) until the load decreases.

4. SYMPTOM: NO OIL PRESSURE WHEN SYSTEM START BUTTON PUSHED

Low oil pressure displayed on control Oil pump running in wrong Check rotation of oil pump center; compressor will not start. direction. (Electrical Connections).

Oil pump not running. Check electrical connections to oil

pump and press manual reset on oil pump starter mounted on condenser shell.

5. SYMPTOM: COMPRESSOR STARTS, NORMAL OIL PRESSURE DEVELOPS, FLUCTUATES FOR

SHORT WHILE, THEN COMPRESSOR STOPS ON OIL PRESSURE CUTOUT

Oil pressure normal, fluctuates then Unusual starting conditions Drain the oil from the compressor and compressor stops on Oil Pressure exist, i.e., oil foaming in charge new oil into the compressor. Cutout. Display reading resevoir and piping due to (Refer to “Charging The System With

LOW OIL PRESSURE .

lowered system pressure. Oil”, page 39.) Burned out oil heater. Replace oil heater.

Y ORK INTERNA TIONAL 47

TABLE 2 – OPERATING ANALYSIS CHART (Continued)

RESULTS POSSIBLE CAUSE REMEDY

6. SYMPTOM: USUALLY HIGH OIL PRESSURE DEVELOPS WHEN OIL PUMP RUNS

Unusually high oil pressure is displayed High oil pressure. Trans- Replace low or high oil pressure when the oil pressure display key is ducer defective. Relief transducer. Adjust external relief pressed when the oil pump is running. valve is misadjusted. valve.

7. SYMPTOM: OIL PUMP VIBRATES OR IS NOISY

Oil pump vibrates or is extremely noisy Misalignment of pump or Correct condition or replace faulty with some oil pressure when pressing OIL PRESSURE display key.

NOTE: When oil pump is run without Oil not reaching pump Check oil supply and oil piping.

an oil supply it will vibrate and suction inlet in sufficient become extremely noisy. quantity.

Mounting bolts loose. Bent shaft. Worn pump parts.

part.

8. SYMPTOM: OIL PRESSURE GRADUALLY DECREASES (Noted by Observation of Daily Log Sheets)

Oil pressure (noted when pressing OIL Oil filter is dirty. Change oil filter. PRESSURE display key) drops to 70%

of oil pressure when compressor was Extreme bearing wear. Inspect compressor. originally star ted.

9. SYMPTOM: OIL PRESSURE SYSTEM CEASES TO RETURN AN OIL/REFRIGERANT SAMPLE

Oil refrigerant return not functioning. Filter-drier in oil return Replace old filter-drier with new.

system dirty. Jet or orifice of oil return Remove jet, inspect for dirt. Remov e

jet clogged. dirt using solvent and replace.

10. SYMPTOM: OIL PUMP FAILS TO DELIVER OIL PRESSURE

No oil pressure registers when pressing Faulty oil pressure Replace oil pressure transducer. OIL PRESSURE display key when oil pump runs.

transducer Faulty wiring/connectors.

11. SYMPTOM: REDUCED OIL PUMP CAPACITY

Oil pump pumping capacity. Excessive end clearance Inspect and replace worn parts.

pump. Other worn pump parts.

Partially blocked oil supply Check oil inlet for blockage. inlet.

48 YORK INTERNA TIONAL

SECTION 7

MAINTENANCE

FORM 160.49-O2

RENEW AL P ARTS

For any required Renewal Parts, refer to “Parts Lists” shown in “Reference Instructions”, page 2.

CHECKING SYSTEM FOR LEAKS

LEAK TESTING DURING OPERATION

The refrigerant side of the system is carefully pressure tested and evacuated at the factory.

After the system is in operation under load, the high pressure components should be carefully leak tested with a leak detector to be sure all joints are tight.

If any leaks are indicated, they must be repaired immediately. Usually, leaks can be stopped by tightening flare nuts or flange bolts. However, if it is necessary to repair a welded joint, the refrigerant charge must be removed. (See “Handling Refrigerant for Dismantling and Repair”, page 53.)

CONDUCTING R-22 PRESSURE TEST

With the R-22 charge removed and all known leaks repaired, the system should be charged with a small amount of R-22 mixed with dry nitrogen so that a ha-

lide torch or electronic leak detector can be used to detect any leaks too small to be found by the soap test.

To test with R-22, proceed as follows:

1. With no pressure in the system, charge R-22 gas into the system through the charging valve to a pressure of 2 psig.

2. Build up the system pressure with dr y nitrogen to approximately 10 psig. To be sure that the concentration of refrigerant has reached all part of the system, slightly open the oil charging valve and test for the presence of refrigerant with a leak detector.

3. Test around each joint and factory weld. It is important that this test be thoroughly and carefully done, spending as much time as necessary and using a good leak detector.

4. T o chec k for refrigerant leaks in the cooler and condenser, open the v ents in the cooler and condenser heads and test for the presence of refrigerant. If no refrigerant is present, the tubes and tube sheets may be considered tight. If refr igerant is detected at the vents, the heads must be removed, the leak located (by means of soap test or leak detector) and repaired.

EV ACU A TION AND DEHYDRATION OF UNIT

27385A(D)

LD00949

FIG. 21 – EVACUATION OF CHILLER

Y ORK INTERNA TIONAL 49

TABLE 3 – SYSTEM PRESSURES

*GAUGE ABSOLUTE

INCHES OF TEMPERATURES

MERCURY (HG) MILLIMETERS OF

BELOW ONE PSIA OF MERCURY MICRONS WATER

STANDARD (HG) °F

ATMOSPHERE

0 14.696 760. 760,000 212

10.24" 9.629 500. 500,000 192

22.05" 3.865 200. 200,000 151

25.98" 1.935 100. 100,000 124

27.95" .968 50. 50,000 10 1

28.94" .481 25. 25,000 78

29.53" .192 10. 10,000 52

29.67" .122 6.3 6,300 40

29.72" .099 5. 5,000 35

29.842" .039 2. 2,000 15

29.882" .019 1.0 1,000 +1

29.901" .010 .5 5 0 0 –11

29.917" .002 .1 1 0 0 –38

29.919" .001 .05 50 – 5 0

29.9206" .0002 .01 10 – 7 0

29.921" 0 0 0

*One standard atmosphere = 14.696 PSIA

= 760 mm Hg. absolute pressure at 32°F = 29.921 inches Hg. absolute at 32°F

NOTES: PSIA = Lbs. per sq. in. gauge pressure

= Pressure above atmosphere

PSIA = Lbs. per sq. in. absolute pressure

= Sum of gauge plus atmospheric pressure

BOILING

V ACUUM TESTING

After the pressure test has been completed, the vacuum test should be conducted as follows:

1. Connect a high capacity vacuum pump, with indicator, to the system charging valve as shown in Fig. 22 and start the pump. (See “Vacuum Deh ydration”.)

2. Open wide all system valves, including the purge and gauge valves. Be sure all valves to the atmosphere are closed.

3. Operate the vacuum pump in accordance with V ACUUM DEHYDRATION until a wet bulb temperature of +32°F or a pressure of 5 mm Hg is reached. See Table 3 for corresponding values of pressure.

4. To improve evacuation circulate hot water (not to exceed 125°F) through the cooler and condenser tubes to thoroughly dehydrate the shells. If a source of hot water is not readily available, a portable water heater should be employed. DO NOT USE STEAM. A suggested method is to connect a hose between the source of hot water under pressure and the cooler head drain connection, out the cooler

vent connection, into the condenser head drain and out the condenser vent. To avoid the possibility of causing leaks, the temperature should be brought up slowly so that the tubes and shell are heated evenly.

5. Close the system charging valve and the stop valve between the vacuum indicator and the vacuum pump. Then disconnect the vacuum pump leaving the vacuum indicator in place.

6. Hold the vacuum obtained in Step 3 in the system for 8 hours; the slightest rise in pressure indicates a leak or the presence of moisture, or both. If, after 8 hours the wet bulb temperature in the vacuum indicator has not risen above 40°F or a pressure of

6.3 mm Hg, the system may be considered tight.

NOTE: Be sure the vacuum indicator is valved off

while holding the system vacuum and be sure to open the valve between the vacuum indicator and the system when checking the vacuum after the 8 hour period.

7. If the vacuum does not hold for 8 hours within the limits specified in Step 6 above, the leak must be found and repaired.

50 YORK INTERNA TIONAL

VACUUM DEHYDRATION

To obtain a sufficiently dry system, the following instructions have been assembled to provide an effective method for evacuating and dehydrating a system in the field. Although there are several methods of dehydrating a system, we are recommending the following, as it produces one of the best results, and affords a means of obtaining accurate readings as to the extent of dehydration.

The equipment required to follow this method of dehydration consists of a wet bulb indicator or vacuum gauge, a chart showing the relation between dew point temperature and pressure in inches of mercury (vacuum), (see Table 3) and a vacuum pump capable of pumping a suitable vacuum on the system.

FORM 160.49-O2

LD00474

OPERATION Dehydration of a refrigerant system can be obtained

by this method because the water present in the system reacts much as a refrigerant would. By pulling down the pressure in the system to a point where its saturation temperature is considerably below that of room temperature, heat will flow from the room through the walls of the system and vaporize the water, allowing a large percentage of it to be removed by the vacuum pump. The length of time necessary for the dehydration of a system is dependent on the size or volume of the system, the capacity and efficiency of the vacuum pump, the room temperature and the quantity of water present in the system. By the use of the vacuum indicator as suggested, the test tube will be evacuated to the same pressure as the system, and the distilled water will be maintained at the same saturation temperature as any free water in the system, and this temperature can be observed on the thermometer.

If the system has been pressure tested and found to be tight prior to evacuation, then the saturation temperature recordings should follow a curve similar to the typical saturation curve shown as Fig. 22.

The temperature of the water in the test tube will drop as the pressure decreases, until the boiling point is reached, at which point the temperature will level off and remain at this level until all of the water in the shell is vaporized. When this final vaporization has taken place the pressure and temperature will continue to drop until eventually a temperature of 35°F or a pressure of 5 mm Hg. is reached.

FIG. 22 – SATURATION CURVE

When this point is reached, practically all of the air has been evacuated from the system, but there is still a small amount of moisture left. In order to provide a medium for carrying this residual moisture to the vacuum pump, nitrogen should be introduced into the system to bring it to atmospheric pressure and the indicator temperature will return to approximately ambient temperature. Close off the system again, and start the second evacuation.

The relatively small amount of moisture left will be carried out through the vacuum pump and the temperature or pressure shown by the indicator should drop uniformly until it reaches a temperature of 35°F or a pressure of 5 mm Hg.

When the vacuum indicator registers this temperature or pressure, it is a positive sign that the system is evacuated and dehydrated to the recommended limit. If this level cannot be reached, it is evident that there is a leak somewhere in the system. Any leaks must be corrected before the indicator can be pulled down to 35°F or 5 mm Hg. in the primary evacuation.

During the primar y pulldown, keep a careful watch on the wet bulb indicator temperature, and do not let it fall below 35°F. If the temperature is allowed to fall to 32°F, the water in the test tube will freeze, and the result will be a faulty temperature reading.

Y ORK INTERNA TIONAL 51

REFRIGERANT CHARGING

To avoid the possibility if freezing liquid within the cooler tubes when charging an evacuated system, only refrigerant vapor from the top of the drum or cylinder must be admitted to the system pressure until the system pressure is raised above the point corresponding to the freezing point of the cooler liquid. For water, the pressure corresponding to the freezing point is 57.5 PSIG for R22 or 8.54 PSIG for R-134a (at sea level).

While charging, every precaution must be taken to prevent moisture laden air from entering the system. Make up a suitable charging connection from new copper tubing to fit between the system charging valve and the fitting on the charging drum. This connection should be as short as possible but long enough to permit sufficient flexibility for changing drums. The charging connection should be purged each time a full container of refrigerant is connected and changing containers should be done as quickly as possible to minimize the loss of refrigerant.

Refrigerant may be furnished in drums containing either 30, 50, 125 or 1750 lbs. of refrigerant. These drums are not returnable and they should be stored for future use if it should ev er become necessary to remove refrigeration from the system.

TABLE 4 – REFRIGERANT CHARGE

R-22

SHELL CODES

COOLER COND.

M M 1,425 M N 1,600

N M 1,675 N N 1,800 N P 1,800 P N 1,875 P P 1,875

P Q 2,175 Q P 2,225 Q Q 2,500 Q R 2,800

R Q 3,050

R R 3,300

R S 3,500

S R 3,500

S S 3,500

LBS.

SHELL CODES

COOLER COND.

L L 1,150

L M 1,150 M L 1,400 M M 1,400 M N 1,585 N M 1,650 N N 1,805 N P 1,805 P N 1,900 P P 1,900 P Q 2,205 Q P 2,235 Q Q 2,515 Q R 2,800 R Q 3,075 R R 3,325 R S 3,450 S R 3,450 S S 3,575

R-134a

LBS.

CHECKING THE REFRIGERANT CHARGE

DURING UNIT SHUTDOWN

The refrigerant charge is specified for each chiller model (see Table 4). Charge the correct amount of refrigerant and record the level in the cooler sight glass.

The refrigerant charge should always be checked and trimmed when the system is shut down.

The refrigerant charge level must be checked after the pressure and temperature have equalized between the

52 YORK INTERNA TIONAL

condenser and cooler. This would be expected to be 4 hours or more after the compressor and water pumps are stopped. The level should be at the center of the sight glass + 1/4 inch.

Charge the refrigerant in accordance with the method shown under the “Refrigerant Charging”, above. The refrigerant level should be observed and the level recorded after initial charging.

HANDLING REFRIGERANT FOR

DISMANTLING AND REPAIRS

If it becomes necessary to open any part of the refr igerant system for repairs, it will be necessary to remove the charge before opening any part of the unit.

MEGGING THE MOTOR

FORM 160.49-O2

While the main disconnect switch and compressor motor starter are open, meg the motor as follows:

1. Using a megohm meter (megger), meg between phases and each phase to ground (see Fig. 23); these readings are to be interpreted using the graph shown in Fig. 24.

2. If readings fall below shaded area, remove e xternal leads from motor and repeat test.

NOTE: Motor is to be megged with the starter at

ambient temperature after 24 hours of idle standby.

LD00475

FIG. 23 – DIAGRAM, MEGGING MOTOR WINDINGS

Y ORK INTERNA TIONAL 53

54 YORK INTERNA TIONAL

FIG. 24 – MOTOR STATOR TEMPERATURE AND INSULATION RESISTANCES

Minimum Insulation Resistance vs. Temperature (per IEEE Std 43)

Open Motors

TEMPERA TURE – °F

LD00476

MEGOHMS

CONDENSERS AND COOLERS

FORM 160.49-O2

GENERAL

Maintenance of condenser and cooler shells is important to provide trouble free operation of the chiller. The water side of the tubes in the shell must be kept clean and free from scale. Proper maintenance such as tube cleaning, and testing for leaks, is covered on the following pages.

CHEMICALWATER TREATMENT

Since the mineral content of the water circulated through coolers and condensers varies with almost every source of supply, it is possible that the water being used may corrode the tubes or deposit heat resistant scale in them. Reliable water treatment companies are available in most larger cities to supply a water treating process which will greatly reduce the corrosive and scale forming properties of almost any type of water.

As a preventive measure against scale and corrosion and to prolong the life of cooler and condenser tubes, a chemical analysis of the water should be made preferably before the system is installed. A reliable water treatment company can be consulted to determine whether water treatment is necessary, and if so, to furnish the proper treatment for the particular water condition.

CLEANING COOLER AND CONDENSER TUBES

COOLER It is difficult to determine by any particular test whether

possible lack of perf ormance of the water cooler is due to fouled tubes alone or due to a combination of troubles. Trouble which may be due to fouled tubes is indicated when, over a period of time, the cooling capacity decreases and the split (temperature difference between water leaving the cooler and the refrigerant temperature in the cooler) increases. A gradual dropoff in cooling capacity can also be caused by a gradual leak of refrigerant from the system or by a combination of fouled tubes and shortage of refrigerant charge. An excessive quantity of oil in the cooler can also contribute to erratic performance.

CONDENSER

TUBE FOULING

Fouling of the tubes can be due to deposits of two types as follows:

1. Rust or sludge – which finds its way into the tubes and accumulates there. This material usually does not build up on the inner tube surfaces as scale, but does interfere with the heat transfer. Rust or sludge can generally be removed from the tubes by a thorough brushing process.

2. Scale – due to mineral deposits. These deposits, even though v ery thin and scarcely detectable upon physical inspection, are highly resistant to heat transfer. They can be removed most effectively by circulating an acid solution through the tubes.

TUBE CLEANING PROCEDURES

BRUSH CLEANING OF TUBES If the tube consists of dirt and sludge, it can usually be

removed by means of the brushing process. Drain the water sides of the circuit to be cleaned (cooling water or chilled water) remove the heads and thoroughly clean each tube with a soft bristle bronze brush. DO NOT USE A STEEL BRISTLE BRUSH. A steel br ush may damage the tubes.

Improved results can be obtained by admitting water into the tube during the cleaning process. This can be done by mounting the brush on a suitable length of 1/8" pipe with a few small holes at the brush end and connecting the other end by means of a hose to the water supply.

The tubes should always be brush cleaned before acid cleaning.

ACID CLEANING OF TUBES If the tubes are fouled with a hard scale deposit, they

must be acid cleaned. It is important that before acid cleaning, the tubes be cleaned by the brushing process described above. If the relatively loose foreign material is removed before the acid cleaning, the acid solution will have less material to dissolve and flush from the tubes with the result that a more satisfactory cleaning job will be accomplished with a probable saving of time.

In a condenser, trouble due to fouled tubes is usually indicated by a steady rise in head pressure, over a period of time, accompanied by a steady rise in condensing temperature, and noisy operation. These symptoms may also be due to foul gas buildup. Purging will remove the foul gas revealing the effect of fouling.

Y ORK INTERNA TIONAL 55

COMMERCIAL ACID CLEANING

In many major cities, commercial organizations now offer a specialized service of acid cleaning coolers and condensers. If acid cleaning is required, YORK

recommends the use of this type of organization. The Dow Industries Service Division of the Dow Chemical Company, Tulsa, Oklahoma, with branches in principal cities is one of the most reliable of these companies.

TESTING FOR COOLER AND CONDENSER TUBE LEAKS

Cooler and condenser tube leaks in R-22 or R-134a systems may result in refrigerant leaking into the water circuit, or water leaking into the shell depending on the pressure levels. If refrigerant is leaking into the water, it can be detected at the liquid head vents after a period of shutdown. If water is leaking into the refrigerant, system capacity and efficiency will drop off sharply. If a tube is leaking and water has entered the system, the cooler and condenser should be valved off from the rest of the water circuit and drained immediately to prevent severe rusting and corrosion. If a tube leak is indicated, the exact location of the leak may be determined as follows:

1. Remove the heads and listen at each section of tubes for a hissing sound that would indicate gas leakage. This will assist in locating the section of tubes to be further investigated. If the probable location of the leaky tubes has been determined, treat that section in the following manner (if the location is not definite, all the tubes will require investigations).

3. With nitrogen or dr y air, blow out the tubes to clear them of traces of refrigerant laden moisture from the circulation water . As soon as the tubes are clear, a cork should be driven into each end of the tube. Repeat this with all of the other tubes in the suspected section or if necessary, with all the tubes in the cooler or condenser. Allow the cooler or condenser to remain corked up to 12 to 24 hours before proceeding. Depending upon the amount of leakage, the corks may blow from the end of a tube, indicating the location of the leakage. If not, if will be necessary to make a very thorough test with the leak detector.

4. After the tubes have been corked for 12 to 24 hours, it is recommended that two men working at both ends of the cooler carefully test each tube – one man removing corks at one end and the other at the opposite end to remove corks and handle the leak detector. Star t with the top row of tubes in the section being investigated, remove the corks at the ends of one tube simultaneously and insert the exploring tube for 5 seconds – this should be long enough to draw into the detector any refrigerant gas that might have leaked through the tube walls. A fan placed at the end of the cooler opposite the detector will assure that any leakage will travel through the tube to the detector.

5. Mark any leaking tubes for later identification.

2. Wash off both tube heads and the ends of all tubes with water.

NOTE: Do not use carbon tetrachloride for this pur-

pose since its fumes give the same flame discoloration that the refrigerant does.

6. If any of the tube sheet joints are leaking, the leak should be indicated by the detector. If a tube sheet leak is suspected, its exact location may be found by using a soap solution. A continuous buildup of bubbles around a tube indicates a tube sheet leak.

56 YORK INTERNA TIONAL

COMPRESSOR

FORM 160.49-O2

Maintenance for the compressor assembly consists of checking the operation of the oil return system and changing the dehydrator, checking and changing the oil, checking and changing the oil filters, checking the operation of the oil heater, checking the operation of the oil pump, and observing the operation of the compressor.

Internal wearing of compressor par ts could be a serious problem caused by improper lubrication, brought

ELECTRICAL CONTROLS

For information covering the MicroComputer Control Center operation, refer to “Section 2”.

about by restricted oil lines, passages, or dirty oil filters. If the unit is shutting down on (HOT) High Oil Temperature or Low Oil Pressure (OP), change the oil filter element. Examine the oil filter element f or the presence of aluminum particles. If aluminum particles are noticeable and the same conditions continue to stop the unit operation after a new filter element is installed, notify the nearest YORK office to request the presence of a YORK Service man.

The operating points of the pressure and temperature cut outs are shown in the Wiring Diagrams. These diagrams also contain a starting and stopping sequence diagram.

Y ORK INTERNA TIONAL 57

SECTION 8

PREVENTIVE MAINTENANCE

It is the responsibility of the owner to provide the necessary daily, monthy and yearly maintenance requirements of the system.

IMPORTANT – If a unit failure occurs due to improper maintenance during the warranty period; YORK will not be liable for costs incurred to return the system to satisfactory operation.

In any operating system it is most important to provide a planned maintenance and inspection of its functioning parts to keep it operating at its peak efficiency. Therefore, the following maintenance should be performed when prescribed.

COMPRESSOR

1. Oil Filter – The oil filter must be changed when the oil pressure drops 30% or semi-annually if not required earlier.

When the oil filter is changed, it should be inspected thoroughly for any aluminum particles which would indicate possible bearing wear. If aluminum particles are found this should be brought to the attention of the nearest YORK office for their further investigation and recommendations.

2. Oil Changing – The oil in the compressor must be changed annually or earlier if it becomes dark or cloudy.

COOLER AND CONDENSER

The major portion of maintenance on the condenser and cooler will deal with the maintaining the water side of the condenser and cooler in a clean condition.

The use of untreated water in cooling towers, closed water systems, etc. frequently results in one or more of the following:

1. Scale Formation.

2. Corrosion or Rusting.

3. Slime and Algae Formation.

It is therefore to the benefit of the user to provide for proper water treatment to provide for a longer and more economical life of the equipment. The following recommendation should be followed in determining the condition of the water side of the condenser and cooler tubes.

1. The condenser tubes should be cleaned annually or earlier if conditions warrant. If the temperature difference between the water off the condenser and the condenser liquid temperature is more than 4° greater than the difference recorded on a new unit, it is a good indication that the condenser tubes require cleaning. They should be cleaned as instructed on pages 38 to 39 of this manual.

COMPRESSOR MOT OR

1. Check motor mounting screws frequently to insure tightness.

2. Meg motor windings annually to check for deterioration of windings.

PRESSURE TESTING

The unit should be pressure tested annually. Any leaks found must be repaired immediately. Air and moisture are the worst enemies of these systems and experience has shown that units which are maintained tight, are systems that provide trouble free efficient operation.

58 YORK INTERNA TIONAL

2. The cooler tubes under normal circumstances will not require cleaning. If ho we ver the temperature difference between the refrigerant and the chilled water increases slowly over the operating season, it is an indication that the cooler tubes may be fouling or that there may be a water by-pass in the water box requiring gasket relacement or refrigerant may have leaked from the chiller.

OIL RETURN SYSTEM

1. Change the dehydrator in the oil return system semiannually or earlier if the oil return system fails to operate.

2. When the dehydrator is changed, the nozzle of the

FORM 160.49-O2

eductor should be checked for any foreign particles that may be obstructing the jet.

ELECTRICAL CONTROLS

1. All electrical controls should be inspected for obvious malfunctions.

2. It is impor tant that the factory settings of controls (operation and safety) not be changed. If the settings are changed without YORK’s approval, the warranty will be jeopardized.

3. A 5-11 year life battery is part of the RTC-Real Time Clock. To replace, refer to page 29.

Y ORK INTERNA TIONAL 59

Form 160.49-O2 (1296) Supersedes: Nothing

York YK M3, MH, M3 G4, HC User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

CENTRIFUGAL LIQUID CHILLERS

OPERATING & MAINTENANCE

MODEL YK M3 M3 G4 THRU YK S6 S4 J2 (STYLE C)

MODEL YK LB LB G4 THRU YK SE SC J4 (STYLE C)

R-22 UNITS

NOMENCLATURE

R-134a

SECTION 1

DESCRIPTION OF SYSTEM AND FUNDAMENTALS OF OPERA TION

FIG. 1 – MODEL YK MILLENNIUM CHILLER

SYSTEM OPERATION DESCRIPTION (See Fig. 2)

DET AIL A – COMPRESSOR PRER O TATION V ANES

CAPACITY CONTROL

FIG. 2 – REFRIGERANT FLOW-THRU CHILLER

SECTION 2

MICROCOMPUTER CONTROL CENTER

FIG. 3 – MICROCOMPUTER CONTR OL CENTER AND KEYPAD

WARNING

INTRODUCTION

CONTROL CENTER

OPERATION

SYSTEM SETPOINTS

DISPLAYING SYSTEM SETPOINTS

PROGRAMMING

THE MICROCOMPUTER CONTROL CENTER

PROGRAMMING SYSTEM SETPOINTS

SERVICE KEYS

FIG. 13 – KEYPAD – SERVICE KEYS LOCATION

OPERATING MODES

COMPRESSOR SWITCH

DISPLAY MESSAGES

SECTION 3

SYSTEM OPERA TING PROCEDURES

WARNING

START-UP PROCEDURE

START-UP

CHILLER OPERATION

SYSTEM ST ARTING & SHUTDO WN SEQUENCE

FIG. 15 – CHILLER STARTING SEQUENCE & SHUTDOWN SEQUENCE

CHECKING OPERATION

OPERATING LOG SHEET

FIG. 16 – LIQUID CHILLER LOG SHEETS

OPERATING INSPECTIONS – See Section 2

NEED FOR MAINTENANCE OR SERVICE

NORMAL AND SAFETY SYSTEM SHUTDOWNS

SAFETY SHUTDOWNS

CYCLING SHUTDOWNS

PROLONGED SHUTDOWN

START-UP AFTER PROLONGED SHUTDOWN

SECTION 4

SYSTEM COMPONENTS DESCRIPTION

FRONT VIEW

FIG. 17 – SYSTEM COMPONENTS

GENERAL

COMPRESSOR

CAPACITY CONTROL

OIL PUMP

COMPRESSOR LUBRICATION SYSTEM

FIG. 18 – SCHEMATIC DRAWING – (YK) COMPRESSOR LUBRICATION SYSTEM

OIL HEA TER

HEA T EXCHANGERS

MOT OR DRIVELINE

REFRIGERANT FLOW CONTROL

OIL RETURN SYSTEM

SECTION 5

OPERA TIONAL MAINTENANCE

THE OIL CHARGE

OIL CHARGING PROCEDURE

FIG. 20 – CHARGING OIL RESERVOIR WITH OIL

SECTION 6

TABLE 2 – OPERATING ANALYSIS CHART

SECTION 7

MAINTENANCE

RENEW AL P ARTS

CHECKING SYSTEM FOR LEAKS

EV ACU A TION AND DEHYDRATION OF UNIT