Installation and Maintenance Manual IMM WMC-2 Group: Chiller Part Number: 331374601 Effective: March 2008 Supersedes: December 2007 Water-Cooled Centrifugal Chiller With Oil-Free Magnetic Bearing Compressors Model WMC-145S to 290D (50/60 Hertz) R-134a
Table of Contents Nomenclature................................................. 3 VFD Line Harmonics ................................... 25 Multiple Chiller Setup.................................. 28 Prestart System Checklist............................. 30 Installation .............................................4 Operation .............................................31 Receiving and Handling................................. 4 Operator Responsibilities .............................
Introduction General Description The McQuay Model WMC Centrifugal Water Chillers are complete, self-contained, automatically controlled, fluid-chilling units featuring oil-free, magnetic bearing compressors. Each unit is completely assembled and factory tested before shipment. The WMC chillers are equipped with two compressors operating in parallel with a single evaporator and single condenser. The model WMC 145S has a single compressor.
Installation Receiving and Handling The unit should be inspected immediately after receipt for possible damage. All McQuay centrifugal water chillers are shipped FOB factory and all claims for handling and shipping damage are the responsibility of the consignee. On units with factory-installed insulation, the insulation is removed from the vessel lifting hole (also used for transportation tie-downs) locations and are shipped loose. They should be glued in place after the unit is finally placed.
Location and Mounting Clearance The unit must be mounted on a level concrete or steel base and must be located to provide service clearance at one end of the unit for possible removal of evaporator and/or condenser tubes. Evaporator and condenser tubes are rolled into the tube sheets to permit replacement if necessary. The length of the vessel should be allowed at one end. Doors or removable wall sections can be utilized. Clearance at all sides, including the top, is 3 feet (1 meter). The U.S.
The piping should include thermometers at the inlet and outlet connections and air vents at the high points. The water heads can be interchanged (end for end) so that the water connections can be made at either end of the unit. If this is done, use new head gaskets and relocate the control sensors. In cases where the water pump noise can be objectionable, vibration isolation sections are recommended at both the inlet and outlet of the pump.
Cooling Towers The condenser water flow rate must be checked to be sure that it conforms to the system design. A tower bypass valve, controlled by the unit controller, is required to control the minimum condenser entering temperature. Unless the system and chiller unit are specifically designed for them, condenser bypass or variable condenser flow is not recommended, since low condenser flow rates can cause unstable operation and excessive tube fouling.
Field Insulation If the optional factory-installation of thermal insulation is not ordered, insulation should be field installed to reduce heat loss and prevent condensation from forming. Insulation should cover the evaporator barrel, tube sheet, and water heads, plus the suction line to the compressor flange and the compressor end bell opposite the suction connection.
Dimensions Figure 5, WMC IMM WMC-2 145S (NOTE: See page 14 for notes.
Figure 6, WMC 10 145D (See page 14 for notes.
Figure 7, WMC IMM WMC-2 150D, 2-Pass Evaporator, 2-Pass Condenser ( See page 14 for notes.
Figure 8, WM C 250D, 2-Pass Evaporator, 2-Pass Condenser (NOTE: See page 14 for notes.
Figure 9, WMC IMM WMC-2 290D, 2-Pass Evaporator, 2- Pass Condenser Centrifugal Chillers (See page 14 for notes.
Drawing Notes NOTES: 1. All dimensions are in Inches and [Millimeters] unless noted otherwise. 2. Final connections must allow for .500 inch +/- [12.7mm] manufacturing tolerances. 3. 1.00-inch FPT [25.4 mm] evaporator and condenser relief valves must be piped per ANSI / ASHRAE 15. Number of relief valves is 1 per evaporator and 2 per condenser. 4. .375 inch [9 mm] suction nozzle relief valve must be piped per ANSI / ASHRAE 15. 5. Clearances: Ends, Sides Electric Panels 6. 7. 8. 9. 10. 11. 12. 13. 14.
Mounting/Lifting Weights Figure 10 LB RB “A “B” RF LF Circuit #2 Circuit #1 Electric Panels Control Panel WMC Model Vessel Models (Size) 145S 145D 150D 250D 290D E2209/C2009 E2209/C2209 E2212/C2012 E2609/C2209 E2612/C2212 WMC Model Vessel Models (Size) 145S 145D 150D 250D 290D E2209/C2009 E2209/C2209 E2212/C2012 E2609/C2209 E2612/C2212 Shipping Weight, lbs (kg) LF 1238 (561) 1438 (652) 1619 (735) 1850 (839) 2793 (1242) RF 1146 (520) 1440 (653) 1750 (794) 1829 (830) 2105 (955) LB 1565 (710)
Pressure Drop Curves Figure 11, WMC 150, Evaporator Pressure Drops WMC Evap - Water Side Pressure Drop 90 E2212-B 1 pass E2212-B 2 pass E2209-B 1 pass 80 E2209-B 2 pass E2212-C 1 pass E2212-C 2 pass 70 E2212-C 3 pass E2209-C 1 pass E2209-C 2 pass 60 E2209-C 3 pass EPD - ft E2212-D 1 pass E2212-D 2 pass 50 E2212-D 3 pass E2209-D 1 pass E2209-D 2 pass 40 E2209-D 3 pass 30 20 10 0 0 200 400 600 800 1000 1200 1400 1600 1800 EGPM - gpm Figure 12, WMC 150, Condenser Pressure Drops WMC C
Relief Valves As a safety precaution and to meet code requirements, each chiller is equipped with pressure relief valves located on the condenser and evaporator for the purpose of relieving excessive refrigerant pressure (caused by equipment malfunction, fire, etc.) to the atmosphere. Most codes require that relief valves be vented to the outside of a building and this is a desirable practice for all installations. Relief piping connections to the relief valves must have flexible connectors.
Using the ASHRAE formula and basing calculations on the 225 psi design yields a conservative pipe size, which is summarized in Table 4. The table gives the pipe size required per relief valve. When valves are piped together, the common piping must follow the rules set out in the following paragraph on common piping. Table 4. Relief Valve Piping Sizes Equivalent length (ft) Pipe Size inch (NPT) Moody Factor 2.2 1 1/4 0.0209 18.5 1 1/2 0.0202 105.8 2 0.0190 296.7 2 1/2 0.0182 973.6 3 0.0173 4117.4 4 0.
Electrical Data Wiring, fuse and wire size must be in accordance with the National Electric Code (NEC). Important: The voltage to these units must be within ±10% of nameplate voltage, and the voltage unbalance between phases must not exceed 2%. Since a 2% voltage unbalance will cause a current unbalance of 6 to 10 times the voltage unbalance per NEMA MG-1, 1998 Standard, it is most important that the unbalance between phases be kept at a minimum.
WMC 145S, Single Compressor Table 6, Standard Single Point Connection, 1 Compressor Only RLA (Per Compressor) LRA Minimum Circuit Ampacity (MCA) Field Wire Quantity Wire GA Max Fuse Size 79 to 80 Amps 110 97 to 100 3 3 GA 175 Amps 81 to 88 Amps 110 101 to 110 3 2 GA 175 Amps 89 to 92 Amps 110 111 to 115 3 2 GA 200 Amps 93 to 99 Amps 110 116 to 123 3 1 GA 200 Amps 100 Amps 110 125 3 1 GA 225 Amps 101 to 104 Amps 132 126 to 130 3 1 GA 225 Amps 105 to 111 Amps 132 13
Single-point Connection, Optional Table 9, WMC 145D, 150D Electrical Data RLA (Per Compressor) LRA Minimum Circuit Ampacity (MCA) Field Wire Quantity Wire GA Max Fuse Size 52 to 53 Amps 72 117 to 120 3 1 GA 150 Amps 54 to 57 Amps 72 122 to 129 3 1 GA 175 Amps 58 to 61 Amps 72 131 to 138 3 1/0 175 Amps 62 to 65 Amps 72 140 to 147 3 1/0 200 Amps 68 to 69 Amps 94 153 to 156 3 2/0 200 Amps 70 to 76 Amps 94 158 to 171 3 2/0 225 Amps 77 to 85 Amps 94 174 to 192 3 3/0
Single Point Connection, Optional RLA (Per Compressor) LRA Minimum Circuit Ampacity (MCA) Quantity Field Wire 79 to 88 Amps 110 176 to 199 3 4/0 250 Amps 89 to 92 Amps 110 201 to 208 3 250 MCM 250 Amps 93 to 100 Amps 110 210 to 226 3 250 MCM 300 Amps 101 to 107 Amps 132 228 to 241 3 250 MCM 300 Amps 108 to 113 Amps 132 244 to 255 3 250 MCM 350 Amps 114 to 120 Amps 132 257 to 271 3 300 MCM 350 Amps 121 to 123 Amps 154 273 to 277 3 300 MCM 350 Amps 124 to 126 Amp
Figure 15, Field Wiring Diagram MICROTECH CONTROL BOX TERMINALS (115V) (24V) UTB1 GND PE 54 * REMOTE ON/OFF (NOTE 5) 85 POWER * NOTE 7 NEUTRAL * NOTE 10 * COOLING TOWER FOURTH STAGE STARTER MODE SWITCH 55 74 C4 * 70 80 H O 86 * NOTE 8 H A O 86 A EP2 86 C NOTE 11 * NOTE 10 * COOLING TOWER THIRD STAGE STARTER O C3 * NOTE 8 73 A H O EWI-1 76 O C2 75 A (NOTE 6) SWITCH DELTA P FLOW OR EVAP.
8. 9. 10. 11. 12. 13. Optional customer supplied 115 VAC, 25-VA maximum coil rated, chilled water pump relay (ep1 & 2) may be wired as shown. This option will cycle the chilled water pump in response to chiller demand. The condenser water pump must cycle with the unit. A customer supplied 115 VAC 25 VA maximum coil rated, condenser water pump relay (CP1 & 2) is to be wired as shown. Units with free-cooling must have condenser water above 60°F before starting.
1. Set the generator to always run five minutes longer than the unit start-to-start timer, which could be set from 15 to 60 minutes. The actual setting can be viewed on the operator interface panel on the Setpoint/Timer screen. 2. Configure the transfer switch, provided with the generator, to automatically shut down the chiller before transfer is made. This function can be accomplished through a BAS interface or with the “remote on/off” wiring connection shown in Figure 15.
1. 2. 3. 4. Keep the PCC as far from the drives (close to the power source) as possible. Increase the size (decrease the impedance) of the source transformer. Increase the capacity (decrease the impedance) of the busway or cables from the source to the PCC. Make sure that added reactance is "downstream" (closer to the VFD than the source) from the PCC. Line Reactors Five-percent line reactors are standard equipment on WMC chillers and located in each compressors power panel.
The filters are current-rated devices. In order to properly size a filter, it is necessary to know the operating voltage and the input current rating of the drive. No derating or re-rating is necessary when applying the filter at voltages that are less than or equal to the maximum voltage listed on the filter. The IEEE 519-1991 Standard The Institute of Electrical and Electronics Engineers (IEEE) has developed a standard that defines acceptable limits of system current and voltage distortion.
Multiple Chiller Setup WMC dual compressor units have their main control components factory wired to an internal network so that the components can communicate with each other, within the chiller itself. On multi-chiller WMC applications, two WMC chillers can be interconnected by simple field RS485 interconnecting wiring, the addition of an accessory communication isolation board(s) 485OPDR (McQuay P/N 330276202), and some MicroTech II control settings.
Figure 17, Communication Wiring Chiller A 485 OPDR C B A P P J10 J11 UCM BLU/WHT WHT/BLU SHIELD Chiller B (+) (-) J11 PORT MicroTech II Operator Interface Touch Screen (OITS) Settings Settings for any type of linked multiple compressor operation must be made to the MicroTech II controller. Settings on a dual compressor unit are made in the factory prior to shipment, but must be verified in the field before startup.
Operating Sequence For multiple-chiller, parallel operation, the MicroTech II controllers are tied together by a communications network and stage and control compressor loading among the chillers. Each compressor, single or dual compressor chiller, will stage on or off depending on the sequence number programmed into it. For example, if all are set to “1”, the automatic lead/lag will be in effect. When chiller #1 is fully loaded, the leaving chilled water temperature will rise slightly.
Operation Operator Responsibilities It is important that the operator become familiar with the equipment and the system before attempting to operate the chiller. During the initial startup of the chiller, the McQuay technician will be available to answer any questions and instruct in the proper operating procedures. It is recommended that the operator maintain an operating log for each individual chiller unit.
System Water Volume It is important to have adequate water volume in the system to provide an opportunity for the chiller to sense a load change, adjust to the change, and stabilize. As the expected load change becomes more rapid, a greater water volume is needed. The system water volume is the total amount of water in the evaporator, air handling products and associated piping.
Building Automation Systems All MicroTech II controllers with Open Choices™ are capable of BAS communications, providing easy integration and comprehensive monitoring, control, and two-way data exchange with open standard protocols such as LonTalk, Modbus or BACnet.
Protocols Supported Table 14, Standard Protocol Data Protocol Physical Layer Data Rate Controller Other BACnet/IP Ethernet 10 Base-T 10 Megabits/sec Color graphics SBC Reference ED 15057: BACnet PICS BACnet MSTP RS485 (TBD) pCO2 Unit Controller LonTalk FTT-10A 78kbits/sec pCO2 Unit Controller Reference ED 15057: BACnet PICS LONMARK Chiller Functional Profile Modbus RTU RS-485 (TBD) pCO2 Unit Controller NOTE: For additional information on the protocol data available through the BACn
Figure 19, Unit Control Panel SW1, Unit Switch SW12, Circ #1 Switch SW22, Circ #2 Switch Control Circuit Breaker Unit Terminal Board UTB1 Unit Controller Circuit # 1 Controller Circuit #1 Terminal Board, TB1 Circuit # 2 Controller Circuit #2 Terminal Board, TB2 MOD1, MOD2 Ground Capacity Control System The capacity of the chiller is controlled by: 1) Staging the compressors on and off; 2) By adjusting the capacity of each compressor by opening or closing the inlet vanes to control the quantity of r
The speed control and vane control work in conjunction. As load decreases, compressor speed is reduced as low as possible but above the point where stall might begin. If further capacity reduction is required, the guide vanes will close to whatever position is required to match the compressor capacity to the load. Surge and Stall Stall and surge are a characteristic of all centrifugal compressors.
when it is under control from a remote switch or BAS. When these buttons are pressed, the unit will cycle through its normal starting or stopping sequence, both compressors will be stopped and normal dual compressor starting procedure will be in effect. 2. Remote SWITCH, Selecting SWITCH in SP3 will put the unit under the control of a remote switch that must be wired into the control. See Field Wiring Diagram, page 23. 3.
Maintenance ! DANGER Wait 10 minutes after compressor shutdown before opening any compressor access panel. The DC link capacitors store enough energy to cause electrocution. Pressure/Temperature Chart R-134a Temperature Pressure Chart °F PSIG °F PSIG °F PSIG °F PSIG 6 9.7 46 41.1 86 97.0 126 187.3 8 10.8 48 43.2 88 100.6 128 192.9 10 12.0 50 45.4 90 104.3 130 198.7 12 13.2 52 47.7 92 108.1 132 204.5 14 14.4 54 50.0 94 112.0 134 210.5 16 15.7 56 52.
Electrical System Maintenance of the electrical system involves the general requirement of keeping contacts clean and connections tight and checking on specific items as follows: 1. The compressor current draw should be checked and compared to nameplate RLA value. Normally, the actual current will be lower, since the nameplate rating represents full load operation. Also check all pump and fan motor amperages, and compare with nameplate ratings. 2.
complete the pump down, condense the refrigerant, and pump it into the condenser or pumpout vessel using approved procedures. Pressure Testing No pressure testing is necessary unless some damage was incurred during shipment. Damage can be determined by a visual inspection of the exterior piping, checking that no breakage occurred or fittings loosened. Service gauges should show a positive pressure. If no pressure is evident on the gauges, a leak may have occurred, discharging the entire refrigerant charge.
pumps operating, liquid refrigerant will flow into the condenser. Approximately 75% of the total requirement estimated for the unit can be charged in this manner. 5. After 75% of the required charge has entered the condenser, reconnect the refrigerant drum and charging line to the service valve on the bottom of the evaporator. Again purge the connecting line, stand the drum with the connection up, and place the service valve in the open position.
Maintenance Schedule I. Compressor A. Performance Evaluation (Log & Analysis) * B. Motor • Ampere Balance (within 10%) • Terminal Check (tight connections, porcelain clean) • Motor Cooling (check temperature) C. Vane Operation • Compressor Loads: Operate Manual Switch Record Motor Amps • Compressor Unloads: Operate manual Switch Record Motor Amps • Vanes Will Hold (place manual switch in "hold") Observe Water Temp and Record Amps D. Internal Compressor Check II. Controls A.
Service Programs It is important that an air conditioning system receive adequate maintenance if the full equipment life and full system benefits are to be realized. Maintenance should be an ongoing program from the time the system is initially started. A full inspection should be made after 3 to 4 weeks of normal operation on a new installation and on a regular basis thereafter.
Centrifugal Chillers IMM WMC-2
This document contains the most current product information as of this printing. For the most up-todate product information, please go to www.mcquay.com. All McQuay equipment is sold pursuant to McQuay’s Standard Terms and Conditions of Sale and Limited Product Warranty. (800) 432-1342 • www.mcquay.
