MILLENNIUM CENTRIFUGAL LIQUID CHILLERS OPERATING & MAINTENANCE Supersedes: Nothing 1096 FORM 160.48-O1 MODEL YT G0 A1 B1 thru YT L6 D8 F2 (STYLE H) HCFC-123 (cooling only) WITH MICROCOMPUTER CONTROL CENTERS PART #371-01200-002, #371-01200-007 & 371-01200-014 FOR ELECTRO-MECHANICAL STARTER, SOLID STATE STARTER & VARIABLE SPEED DRIVE 26874A WARNING SYSTEM CONTAINS REFRIGERANT UNDER PRESSURE. SERIOUS INJURY COULD RESULT IF PROPER PROCEDURES ARE NOT FOLLOWED WHEN SERVICING SYSTEM.
TABLE OF CONTENTS Section 1: Description of System and Operational Fundamentals .......................... 4 Section 2: MicroComputer Control Center ................................................................. 6 Introduction ................................................................................................... 6 Control Center .............................................................................................. 7 Operation ..........................................................
FORM 160.48-O1 26874A FIG. 1 - YT CHILLER WITH ELECTRO-MECHANICAL STARTER 28009A FIG.
SECTION 1 DESCRIPTION OF SYSTEM AND OPERATIONAL FUNDAMENTALS SYSTEM OPERATION DESCRIPTION YORK Millenium chillers are commonly applied to large air conditioning systems, but may be used on other applications. The unit consists of an open motor mounted to a compressor (with integral speed increasing gears) condenser with purge unit, sub-cooler, cooler and flow control chamber. The chiller is controlled by a modern state of the art MicroComputer Control Center which monitors its operation.
FORM 160.48-O1 7619A(D) FIG. 3 (DETAIL A) - COMPRESSOR PREROTATION VANES COMPRESSOR DISCHARGE SUCTION DISCHARGE BAFFLE COOLER CONDENSER ELIMINATOR SUB-COOLER FLOW CONTROL CHAMBER FLOW CONTROL OIL COOLER LD00478A FIG.
28050A FIG. 4 - MICROCOMPUTER CONTROL CENTER AND KEYPAD LD00457 Section 2 MICROCOMPUTER CONTROL CENTER 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. INTRODUCTION The YORK MicroComputer Control Center is a microprocessor based control system for centrifugal chillers.
FORM 160.48-O1 The system setpoints (see Fig. 4) are operator entered on the front control center “Setpoints” keypad. These set points can also be displayed on the 40 character alphanumeric display.
OPERATION DISPLAYING SYSTEM PARAMETERS The “Display” keys are used to display selected monitored parameters as follows: (Refer to Fig. 4) • Press and release the appropriate “DISPLAY” key the message will be displayed for 2 seconds. - or• Press and hold the appropriate “DISPLAY” key - the message will be displayed and updated every 0.5 seconds until the “DISPLAY” key is released.
FORM 160.48-O1 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 Solid State Starter, this key produces the following message: SOLID STATE STARTER NOT INSTALLED In program mode, this key is used to display the applicable line voltage range (200-208 VAC, 220-240 VAC, 380 VAC, 400 VAC, 415 VAC, 440-480 VAC, 500-600 VAC, Supply Voltage Range Disabled).
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 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. The maximum permitted motor current is in terms of % FLA.
FORM 160.48-O1 MON XX:XX AM HIGH LINE VOLTAGE is displayed. The high line voltage check is disabled along with the low line voltage check if desired. Refer to the following chart for thresholds. 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. press and release the “DISPLAY HOLD” key.
produce the following message: To Display REMOTE RESET TEMP RANGE Setpoint: TODAY IS DAY XX:XX AM/PM 1/1/89 To Display DAILY SCHEDULE Setpoints: Use “REMOTE RESET TEMP RANGE” setpoint key as described above to produce the following message: REMOTE RESETTEMP RANGE = 10 °F - or - • Press and hold the “DAILY SCHEDULE” setpoint key. The chiller start and stop times for each day of the week are sequentially displayed, beginning with Sunday and ending with Holiday.
FORM 160.48-O1 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 follows to enter system setpoints. (Refer to Fig. 6) 1. Press “ACCESS CODE” key. 2. This is displayed: 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. NOTE: If digits other than 9 6 7 5 are entered, Y O R K is still displayed.
To enter CHILLED LIQUID TEMP Setpoint: (Refer to Fig. 7) 1. Press and release “CHILLED LIQUIDTEMP” 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 any Energy Management System is applied, this value must be entered into the Energy Management System. Refer to previous explanation or REMOTE/RESET TEMP RANGE, page 10. 2. Use “ENTRY” keys to enter desired value. 3.
FORM 160.48-O1 To Enter PULL DOWN DEMAND Setpoint: (Refer to Fig. 9) 1. Press and release “PULL DOWN DEMAND” setpoint key. The following program prompt message is displayed: SETPOINT = XXX MIN @ XXX % FLA, XX MIN LEFT 2. Use “Entry” keys to enter desired values. For explanation, see PULL DOWN DEMAND, page 10. Note that ‘XX min left’ is not an operator entered value. 3. Press and release “ENTER” key. This message is displayed: LD0457 PROGRAM MODE, SELECT SETPOINT FIG.
To Enter DAILY SCHEDULE Setpoint: (Refer to Fig. 11) 1. Press and release “DAILY SCHEDULE” setpoint key. The following program prompt message is displayed: Press “ADVANCE DAY/SCROLL” key. The display will advance to the next consecutive day and the previous day will be automatically entered. DAY START XX:XX AM/PM STOP XX:XX AM/PM 2. Press “ADVANCE DAY/SCROLL” key until the day you wish to program appears on the display. 3. Use “Entry” keys to enter desired start time.
FORM 160.48-O1 To Enter REMOTE/RESET TEMP RANGE Setpoint: (Refer to Fig. 13) 1. Press and release “REMOTE/RESET TEMP RANGE” setpoint key. The following program prompt message is displayed: REMOTE/RESET TEMP RANGE = XX °F 2. Use “Entry” keys to enter desired value (10 or 20). 3. Press and release “ENTER” key. The following message is displayed. PROGRAM MODE, SELECT SETPOINT LD00457 FIG. 13 - KEYPAD - PROGRAMMING “REMOTE RESET TEMP RANGE” SETPOINT To Enter DATA LOGGER Setpoint: Refer to Form 160.48-NO1.
SERVICE KEYS FIG. 15 - KEYPAD - SERVICE KEYS LOCATION The “SERVICE” keys are provided for the service technician’s use when performing routine maintenance or when troubleshooting the system. The “WARNING RESET” and “PREROTATIONVANES” keys are enabled in “SERVICE” mode only. The remainder of the Service keys are enabled in “SERVICE”, “LOCAL” or “REMOTE” mode. PREROTATION VANES KEYS OPEN - Press and release this key to drive the prerotation vanes open.
FORM 160.48-O1 trol circuitry is automatically placed in “AUTO” mode and the vanes operate to control the leaving chilled water temperature to the programmed setpoint. (This function applies to non-Variable Speed Drive applications only.) CLOSE - Press and release this key to drive the prerotation vanes closed. If the chiller is running, SYSTEM RUN –VANES CLOSING is displayed. If chiller is not running, No. 3 PURGE PRESSURE = XX.X PSIA No.
and it says that there have been 7 purges in the “Last Hour”, that means that there have been 7 exhausts since 8:11 AM. If you do this at 2:57 PM, it means that there have been 7 exhausts since 1:57 PM, etc. The purge count is reset to zero by: A. Clearing the excess purge message. B. Moving the Micro Board program jumper J-57 (CLK ON/OFF) from “CLK OFF” to CLOCK ON” position. C. Starting the chiller. The purge count is frozen by the following: A. When the chiller is not running. B.
FORM 160.48-O1 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. 11. Press “ADVANCE DAY” key to scroll to desired mode. Each time this key is pressed, a different mode is displayed as above: 7. Press “PROGRAM” key. 12. When the desired mode is displayed, press “ENTER” key. 8. This message is displayed: 13. This message is displayed: PROGRAM MODE, SELECT SETPOINT PROGRAM MODE, SELECT SETPOINT 9.
Therefore: (100%) (50% x 200) = 100A = Vanes stop opening (104%) (50% x 200) = 104A = Vanes driven toward close position SYSTEM RUN – AUTO VANES Displayed when the chiller is running, the MicroComputer Control Center is in “SERVICE” mode, and the vanes are operating in “AUTO” mode.
FORM 160.48-O1 WARNING: HIGH PURGE PRESSURE If the purge transducer output is indicating a pressure greater than 95 PSIA (for 255 continuous sec.) the above warning message is displayed alternately with the normal foreground message. When the pressure decreases to less than 95 PSIA, the message is automatically cleared.
MON XX:XX AM – SYSTEM CYCLING – AUTOSTART 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. MON XX:XX AM – MULTI UNIT CYCLING – AUTOSTART Lead/Lag sequence control accessory has shut down the chiller. MON XX:XX AM – POWER FAILURE – AUTOSTART The chiller is shut down because there has been a power interruption or failure. The chiller will automatically restart when power is restored.
FORM 160.48-O1 rator Pressure (LEP, not included with standard Control Center) safety contacts have opened. The brine LEP safety is located external to the Control Center. Safety cutout 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.
FLA for 10 seconds minimum anytime when the compressor-start signal is not energized. To restart the chiller, press “COMPRESSOR” switch to “STOP/RESET” a position and then to the “START” position. MON XX:XX AM – PROGRAM INITIATED RESET The chiller is shut down because the 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.
FORM 160.48-O1 MON XX:XX AM – HIGH LINEVOLTAGE (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 8. The system will automatically restart when all phases of line voltage decrease to the maximum allowable line voltage to start the chiller.
SECTION 3 SYSTEM OPERATING PROCEDURES 28050A FIG. 17 - MICROCOMPUTER CONTROL CENTER AND KEYPAD LD00457 WARNING OIL HEATERS If the oil heater is de-energized during a shutdown period, it must be energized for 12 hours prior to starting compressor, or remove all oil and recharge compressor with new oil. (See “Oil Charging Procedure”, page 44.
FORM 160.48-O1 START-UP PROCEDURE Pre-Starting Prior to starting the chiller observe the MicroComputer Control Center. Make sure the display reads 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 12:00A.M. Daily Schedule = None Holiday = None Remote Reset Temp.
FIG. 18 - CHILLER STARTING SEQUENCE & SHUTDOWN SEQUENCE 3. The 1R-1 contacts of the 1R start relay will remain open for the first 30 seconds of oil pump operation. These contacts will close, starting the compressor motor and the condenser water pump at the end of the 30 second period. 4. The oil pump will start to circulate oil for a 30 second pre-run to establish oil flow and adequate lubrication to all bearings, gears, and rotating surfaces within the compressor.
FORM 160.48-O1 tain the leaving chilled liquid temperature setpoint. The prerotation vanes are modulated by an actuator under the control of the microprocessor board or logic section of the Variable Speed Drive. The vane control routine employs proportional plus derivative (rate) control action. A drop in chilled liquid temperature will cause the actuator to close the prerotation vanes (and also decreases the speed of the motor if equipped with a Variable Speed Drive) to decrease chiller capacity.
LD00467 23889A *NOTE: These items can be printed by an electronic printer connected to J-11 of the Micro Board and pressing the PRINT key on the Micro Board or automatically using the Data Logger feature. FIG. 20 - LIQUID CHILLER LOG SHEETS - FORM 160.44-F6 An optional status printer is available for this purpose or Fig. 20 shows a log sheet used by YORK personnel for recording test data on chillers. It is available from the factory in pads of 50 sheets each under Form No. 160.
FORM 160.48-O1 (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. Verify proper water treatment. 10.
this unit is to automatically remove the mixture of noncondensable gases and refrigerant from the top of the condenser, expel the noncondensables to the atmosphere and return the refrigerant to the system. IMPORTANT The purge unit operates continuously when the system is in operation. The Turboguard purge unit includes a display message on the control center display. The message reads WARNING: EXCESS PURGE if an excessive air leak is present within the chiller.
FORM 160.48-O1 for 150 seconds (6 min. if Micro Board jumper JP-4 removed). The compressor, condenser water, and cooling tower fans will stop automatically. The oil pump will continue to run for a period of 150 seconds. The oil pump will then stop automatically. Once stopped, the SYSTEM COASTDOWN display will be replaced by 2.
compressor load with quiet operation. Gears are integrally assembled in the compressor rotor support and are oil film lubricated. Each gear is individually mounted in journal bearings with individual thrust bearings to insure proper balance of forces from the impeller and motor. LUBRICATION SYSTEM - YORK lubricating oil is force fed to all bearings and filtered by an externally mounted 15 micron replaceable cartridge oil filter equipped with service valves.
FORM 160.48-O1 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 all times during the chiller operation. Manual pump operation may be used to establish stable oil pressure before starting.
FIG.
FORM 160.48-O1 SOLID STATE STARTER (OPTIONAL) The Solid State Starter is a reduced-voltage liquid cooled starter that controls and maintains a constant current flow to the motor during start-up. The starter is mounted on the chiller. The power wiring from the starter to the motor and from the starter control transformer to the Control Center is factory wired and tested. Available for 200-600V-3Ph-60/50Hz power; 2 or 3 barrel lug connections per phase are provided on the starter.
CHECK VALVE PURGE TANK FLOAT SWITCH ASS’Y FILTER DRIER PUMP 2627046A(D) 2626874A(D) FIG. 23 - PUMP ASSISTED TURBOGUARD PURGE UNIT COMPONENTS NOTE: If digits other than the correct digits were entered in step No. 4, day INVALID ACCESS CODE is displayed when the “ENTER” key is pressed. If this occurs, enter the correct access code and proceed. f.
FORM 160.48-O1 3. Using “entry” keys enter the appropriate access code per above description. 4. As each digit is entered, the characters Y O R K are displayed. NOTE: If digits other than the correct digits are entered, Y O R K is still displayed. 5. Press the “ENTER” key. NOTE: If digits other than the correct digits 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 and proceed. 6.
Purge Count Following a 1 hour bypass at start, purge exhausts are counted and displayed in the above messages while the chiller is running. With the exception of the first hour after the bypass, the value displayed is the number of exhausts that have occurred in the “Last Hour”. For example, if you walk up to the control panel at 9:11 AM and press the “DISPLAY DATA” service key and it says that there have been 7 purges in the “Last Hour”, that means that there have been 7 exhausts since 8:11 AM.
FORM 160.48-O1 FIG. 24 - SCHEMATIC OPERATIONAL DIAGRAM LD00471 ➧ ➧ LD00469 22621A(D) FIG. 25 - OIL RETURN SYSTEM FIG.
CHARGING THE UNIT WITH OIL THE OIL CHARGE The nominal oil charge for the compressor is: 10 gal. “B” and “C” compressor; 15 gal. “E” and “F’ compressor. New oil YORK Refrigeration Type “C” 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. 07010654.
FORM 160.
SECTION 6 TROUBLE SHOOTING TABLE 1 - CAUSES OF NORMAL AND SAFETY SYSTEM SHUTDOWNS IN ACCORDANCE WITH THE MICROCOMPUTER CONTROL CENTER DISPLAY SHUTDOWN CAUSE CONTROL CENTER DISPLAY CONTROL CENTER DISPLAY METHOD OF RESTART OPERATING POINT ON RISE ON FALL DAY OF WEEK TIME OF DAY MON. 10:00 AM Low Water Temperature Autostart Low Water (LWT) Chilled water setpoint 4°F below chilled water setpoint MON.
FORM 160.48-O1 TABLE 1 - CAUSES OF NORMAL AND SAFETY SYSTEM SHUTDOWNS IN ACCORDANCE WITH THE MICROCOMPUTER CONTROL CENTER DISPLAY - CONTINUED PROGRAMMED SETPOINTS BY OPERATOR START-UP OF SYSTEM AFTER SHUTDOWN PROBABLE CAUSE AND SERVICE REQUIRED 4°F below chilled water setpoint (If set to 40°F would be 36°F.) (36°F minimum) Automatic Restart when water reaches setpoint. If system is running and setpoint is increased 4°F, system will continue to run, as LWT cutout shifts to a fixed 36°F for 10 minutes.
TABLE 1 - CAUSES OF NORMAL AND SAFETY SYSTEM SHUTDOWNS IN ACCORDANCE WITH THE MICROCOMPUTER CONTROL CENTER DISPLAY - CONTINUED SHUTDOWN CAUsE CONTROL CENTER DISPLAY DAY OF WEEK TIME OF DAY MON. 10:00 AM CAUSE OF SHUTDOWN METHOD OF RESTART Oil Pressure Transducer Error Vane Motor Switch Open MON. 10:00 AM Starter Malfunction Detected MON.
FORM 160.48-O1 TABLE 1 - CAUSES OF NORMAL AND SAFETY SYSTEM SHUTDOWNS IN ACCORDANCE WITH THE MICROCOMPUTER CONTROL CENTER DISPLAY - CONTINUED PROGRAMMED SETPOINTS BY OPERATOR START-UP OF SYSTEM AFTER SHUTDOWN PROBABLE CAUSE AND SERVICE REQUIRED Will start at 59 PSID when compressor switch is placed to STOP/RESET and then START. This Shutdown is provided to check on Oil pressure Transducers for failure in the high state. Replace Oil Pressure Transducer in oil sump or compressor.
TABLE 2 - OPERATING ANALYSIS CHART RESULTS POSSIBLE CAUSE REMEDY 1. SYMPTOM: ABNORMALLY HIGH DISCHARGE PRESSURE Temperature difference between liquid refrigerant out and water off condenser higher than normal. Air in condenser. Purge unit operates automatically to take care of this condition. Test for air leaks if display WARNING – EXCESS PURGE reads: High discharge pressure. Condenser tubes dirty or scaled. Clean condenser tubes. Check water conditioning. High condenser water temperature.
FORM 160.48-O1 TABLE 2 - OPERATING ANALYSIS CHART - CONTINUED RESULTS POSSIBLE CAUSE REMEDY 6. SYMPTOM: UNUSUALLY HIGH OIL PRESSURE DEVELOPS WHEN OIL PUMP RUNS Unusually high oil pressure is displayed when the oil pressure display key is pressed when the oil pump is running. High oil pressure. Transducer defective. Relief valve is misadjsuted. Replace low or high oil pressure transducer. Adjust external relief valve. 7.
SECTION 7 MAINTENANCE RENEWAL PARTS For any required Renewal Parts refer to Forms listed on page 2. CHECKING SYSTEM FOR LEAKS LEAK TESTING DURING OPERATION To test with R-22, proceed as follows: The refrigerant side of the system is carefully pressure tested and evacuated at the factory. 1. With no pressure in the system, charge R-22 gas into the system through the charging valve to a pressure of 2 PSIG.
FORM 160.48-O1 FIG. 28 - EVACUATION OF CHILLER LD00473 TABLE 3 - SYSTEM PRESSURES *GAUGE BOILING ABSOLUTE TEMPERATURES INCHES OF MERCURY (HG) BELOW ONE STANDARD ATMOSPHERE 0 PSIA MILLIMETERS OF MERCURY (HG) MICRONS OF WATER °F 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 50,000 101 28.94* .481 25 25,000 78 29.53* .192 10 10,000 52 29.67* .122 6.3 6,300 40 29.72* .
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. Close the system charging valve and the stop valve between the vacuum indicator and the vacuum pump. (See Fig. 28) Then disconnect the vacuum pump leaving the vacuum indicator in place. 6.
FORM 160.48-O1 down 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.
MEGGING THE MOTOR While the main disconnect switch and compressor motor starter and Variable Speed Drive both open, meg the motor as follows: 1. Using a megohm meter (megger), meg between phases and each phase to ground (See Fig. 30); these readings are to be interpreted using the graph shown in Fig. 31. 2. If readings fall to the left of the applicable curve, remove external leads from the motor and repeat test.
FORM 160.48-O1 FIG.
Condenser 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. 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.
FORM 160.48-O1 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 torch will assure that any leakage will travel through the tube to the torch. 6. If any of the tube sheet joints are leaking, the leak should be detected by the test torch.
COOLER AND CONDENSER Annually The major portion of maintenance on the condenser and cooler will deal with the maintaining of the water side of the condenser and cooler in a clean condition. 1. Clean and inspect all valves which are part of the purge unit system. 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.
