Home

Centrifugal chiller McQuay WMC User manual

1. o irer se TOWER e Anote 10 F FIRST i CWL2 STAGE CF2 STARTER 2 81 COMMON PeT ALARM RELAY BONDENSER A NOTE 3 WATER O NOTE 3 83 NC PUMP D STARTERS POWER 52 NOTE 8 J A H COOLING TOWER BYPASS VALUE 7 L gt aa 0 10 VDC Tir 71 cpi 0 10 VDC J COOLING TOWER VFD 53 2 4 NOTE 10 F CWI 1 11 330617801 REV 00 Compressor terminal boxes are factory mounted and wired All line side wiring must be in accordance with the NEC and be made with copper wire and copper lugs only Power wiring between the terminal box and compressor terminals is factory installed Minimum wire size for 115 vac is 12 ga for a maximum length of 50 feet If greater than 50 feet refer to McQuay for recommended wire size minimum Wire size for 24 vac is 18 ga All wiring to be installed as NEC Class 1 wiring system All 24 vac wiring must be run in separate conduit from 115 vac wiring Wiring must be wired in accordance with NEC and connection to be made with copper wire and copper lugs only A customer furnished 24 or 120 vac power for alarm relay coil may be connected between UTB 1 terminals 84 power and 81 neutral of the control panel For normally open contacts wire between 82 amp 81 For normally closed wire between 83 amp 81 Maximum rating of the alarm relay coil is 25 VA Remote on
2. VIEW ALARMS SET SETPOINTS PASSWORD Alarm Log 01 SET UNIT SPs 1 SET COMP 1 SPs 1 SET COMP 2 SPs 1 SET ALARM LMTs 1 SET TOWER SPs 1 SET PASSWORD description Unit Enable OFF Demand Limit OFF Demand Limit OFF LowEvPrHold 33psi TowerControl type Enter HH MM SS Unit Mode COOL Minimum Amps 040 Minimum Amps 040 LowEvPrUnld 31psi Tower Stages 4 Password 00000 MM DD YY Source SWITCHES Maximum Amps 100 Maximum Amps 100 LowEvPrStop 29psi StageUP Dn 080 020 No Access Given Alarm Log 02 SET UNIT SPs 2 SET COMP SPs 2 SET COMP 2 SPs 2 SET ALARM LMTs 2 SET TOWER SPs 2 SET PASSWORD 2 description Available Modes StageMode Normal StageMode Normal HighCondPr 140psi Stage ON Tech Password HH MM SS COOL StageSequence 01 StageSequence 01 HiDschT Load 170 F 1 2 3 4 00000 00000 MM DD YY Select w Unit Off Max Compr ON 01 Max Compr ON 01 HiDschT Stop 190 F__ xxx_ xxx xxx xxx No Access Given Alarm Log 03 to 25 SET UNIT SPs 3 SET COMP SPs 3 SET COMP 2 SPs 3 SET ALARM LMTs 3 SET TOWER SPs 3 description Cool LWT 44 0 F StageDeltaT 1 0 F StageDeltaT 1 0 F WMC Compressor StageDiff type HH MM SS Stop Start 03min Stop Start 03 min Oilless Design StageUp 02 min MM DD YY Start Start 40 min Start Start 40 min blank mask page StageDown 05 min A SET UNIT SPs 4 SET COMP SPs 4 SETCOMP 2 SPs 4 SET ALARM LMTs 4 SET TOWER SPs 4 Leaving Wa
3. Operating Manual OM WMC 3 Group Chiller Part Number 331374701 Effective August 2007 Supersedes OM WMC 2 WMC Magnetic Bearing Compressor Chillers Model WMC 145S 290D 50 60 Hertz Model WMM 145S 60 Hertz OITS Software Version 2 01 01 Control Software Version WMCU3UU02B McQuay Air Conditioning Table of Contents Introduction cccssssssssssssssssssssssceceees 3 Features of the Control Panel 4 Definitions a sasssivecsasceenceadivssvenscceseastareceneed General Description ccscccssssceseeseed Control Panel svissvsscsssasisssomsdeasiaciscssnns 10 Use with On Site Generators 11 Sequence of Operation ccesceseee 12 Multi Chiller Setup ssesssesesosesocessossee 13 Operating Limits eee eeeeeeeeeeeees 14 Operating the Control System 15 Interface Panel On Off 15 Start Stop Unit sesiis eee cee cseecneeeeeeeeeee 15 Change Setpoint eee eeeeeeeeeeeeeeeeeees 15 Alarms hiiia an 15 Component Failure sseeseeeeeseeeereerrrrerrerrereeee 16 Component Description 0000000016 Faults Problems Warnings ccesceeeseeeeee 21 Unit Controller Functions c ccccccceceeeeees 22 Compressor Controller scsseeee 23 Compressor Controller Setpoints 24 Compressor Faults Problems Warnings 25 Compressor Controller Functions 00 0 2
4. Valve Type NC NO 44 OM WMC 3 Cooling TOWER Fan Settings Figure 23 Cooling TOWER Fan Setpoint Screen See page 46 for complete explanation ray Status AUTO Compressor Status SETPOINTS a F PSI air a CPIE Lift ooling Tower Control NONE No tower control Sage ONEM _ e 3 ON Lift EMP Fan amp bypass valve Stage ON et e 2 ON Lift control is based on Stage 1 ON Lift e 1 ON Lift entering condenser Stage 4 ON Temp temperature LIFT Control is based on Stage 3 ON Temp lift pressure Saas rere e 2 ON Temp Stage 1 ON Temp 1 ON Temp Stage Differential Lift cance W Stage Differential Temp Fan Stage Down Time Fan Stage Up Time Cooling Tower Stages Twr Bypass Valve Fan VFD Temp Cooling Tower Control ENTER HISTORY co SET Table 21 Tower Fan Settings ze e come 10 to 130 psi Lift pressure for fan stage 1 on 10 to 130 psi Lift pressure for fan stage 2 on 10 to 130 psi Lift pressure for fan stage 3 on 10 to 130 psi Lift pressure for fan stage 4 on 40 to 120 F Temperature for fan stage 1 on 40 to 120 F Temperature for fan stage 2 on eae zon Tere f e oor 40 to 120 F Temperature for fan stage 3 on Stage 1 On erp 40 to 120 F Temperature for fan stage 4 on Stage Differential Lift 1 0 to 20 0 psi Fan staging deadband with Setpoint 1 Lift Stage Differential o gt S S S S S E Fan staging deadband with Setpoint 1
5. WARNING Notification Only No Effect On Chiller Control ressor Shutdown or Start Aborted DOWNLOAD TRENDS or ALARMS SET The Alarm History lists the alarms with the most current on top with date stamp action taken and the cause of the alarm It is accessed from the history screen by pressing HISTORY again The alarms have a color code as follows Faults shutdowns Red Problems limit alarms Yellow e Warnings notifications Dark Blue Download Data This screen is also used to download the Trend History Figure 29 selected by date or the Alarm History shown above Download is via a USB port located in the control panel For Alarms press the ALARMS button on the screen then press the COPY to USB button e For Trend History select the desired History File by date using the PREV or NEXT buttons then press the COPY to USB button 54 OM WMC 3 ACTIVE ALARM Screen Figure 31 Active Alarms ACTIVE ALARMS Alarm Color Code FAULT Compressor Shutdown or Start Aborted Corrective Action Limits Operation In Some Way WARNING Notification Only No Effect On Chiller Control The Active Alarm screen is only accessible when an active alarm exists on the unit Pressing the red alarm signal on any screen will access this screen It can also be accessed from the SERVICE screen by pressing the dark blue button where the Alarm indicator normally appears There are no alarms active on
6. 090 F SET TOWER SPs Valve Control Min 010 Max 100 SET TOWER SPs 8 PD Control Loop Error Gain 25 Slope Gain 25 Tower fan control is active when the Tower Control setpoint is set to Temperature or Lift and the condenser pump is in the RUN state Staging is based on either Entering Condenser Water Temperature ECWT or Lift pressure as selected by the Tower Control setpoint Operation depends on the following parameters e Condenser pump state e ECWT OR Lift pressure e Stage up and stage down timer values e Tower setpoints Tower Control Tower Stages Stage Up Time Stage Down Time Stage Differential Temp OR Lift Stage 1 ON Temp OR Lift Stage 2 ON Temp OR Lift Stage 3 ON Temp OR Lift Stage 4 ON Temp OR Lift Stage Down Stage Up OM WMC 3 71 The stage up timer starts when the condenser pump starts The first stage turns ON when the following conditions are met e The stage up timer completes e The ECWT is gt Stage 1 ON Temp setpoint only if the Tower Control setpoint Temperature e The Lift pressure is gt Stage 1 ON Lift setpoint only if the Tower Control setpoint Lift e Bypass valve position is gt the Stage Up setpoint only if Valve VFD Control setpoint Valve Stage Additional stages can turn on up to the number specified by the Tower Stages setpoint when above conditions are met for the next stage plus the following condition e VED Speed is gt the Stage Up setpoi
7. LWT Setpoint plus Startup Delta T If there is no load based on the temperature the unit is in the state of Awaiting Load Interlock On If there is load the unit waits for the Evaporator Recirculation Timer period default value of 30 seconds and starts the Interlock Timer for 10 seconds Cond Condenser Pump Start After Interlock is confirmed the controller starts the Condenser Pump and checks for condenser flow before starting the first compressor Compressor Start Starting the compressor is accomplished by setting the Demand to 25 of the MAX KW setpoint When the actual rpm of the compressor exceeds 350 rpm the demand setting is allowed to be governed by the normal control logic Compressor Run The compressor that is running will signal all other compressors when it reaches full load Full load status is determined when any one of the following tests is true Percent RLA exceeds 100 or the Active Amp Limit from an external limiting source Evap Saturation pressure drops below the Evap Hold Loading pressure setpoint Actual compressor RPM exceeds 97 of Max RPM limit from compressor Lag Compressor Staging The Next On compressor will initiate the following staging sequence when it receives a Full Load indication from the Lead compressor or all other running compressors in the case of a four compressor two units setup The lag compressor will start Demand set to 25 of Max KW setpoint When t
8. 0 are slide and not rocker switches They are located on the upper left corner of the face of the controller They 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 Settings for multiple chiller installations are set in the field on the Operator Interface Touch Screen as follows Maximum Compressors ON SETPOINTS MODES screen Selection 10 2 for a WMC 4 for 2 WMCs Sequence and Staging SETPOINTS MODES screen Selection 11 amp 13 12 amp 14 Sequence sets the sequence in which compressors will start Setting all to 1 evokes the automatic lead lag feature and is the preferred setting Nominal Capacity SETPOINTS MOTOR screen Selection 10 The setting is the compressor design tons Compressors on dual units are always of equal capacity Communication Setup 1 With no communication connections between chillers disconnect control power and set the DIP switches as shown in Table 1 2 With all manual switches off turn on control power to each chiller and set each OITS address see Note 2 above 3 Verify correct nodes on each OITS Service Screen OM WMC 3 13 4 Connect chillers together PLAN RS485 between J6 connections on each unit s isolation boards The
9. IN OUT DELTA HtRc NA NA NA Cond NA VIEW UNIT REFRG 2 Suct Line 000 0 F Liquid Line 000 0 F Lift Press 000 0psi VIEW UNIT TOWER 2 Bypass Valve XXX VFD Speed XXX VIEW COMP Cond Press Evap Press Lift Press 2 psi 000 0 000 0 000 0 VIEW COMP 2 2 psi Cond Press 000 0 Evap Press 000 0 Lift Press 000 0 Start Start Tmr Clr Inhibits None VIEW UNIT WATER 3 Water Flow Rates Evap XXXXX GPM Cond XXXXX GPM VIEW COMP 3 psi WMC Compressor Oilless Design blank mask page VIEW COMP 2 3 psi WMC Compressor Oilless Design blank mask page VIEW COMP 4 F Cavity Temp 000 0 F Invert Temp 000 0 C Lift Temp 00 0 F VIEW COMP 2 4 F Cavity Temp 000 0 F Invert Temp 000 0 C Lift Temp 00 0 F VIEW COMP 5 F Temp SH Suction 000 0 00 0 Discharge 000 0 00 0 VIEW COMP 2 5 F Temp SH Suction 000 0 00 0 Discharge 000 0 00 0 VIEW COMP 6 psi F SatEvap 000 0 000 0 SatCond 000 0 000 0 VIEW COMP 2 6 psi F SatEvap 000 0 000 0 SatCond 000 0 000 0 The right half of the matrix is continued on next page VIEW COMP 7 Hours 00000 x10 Starts 00000 VIEW COMP 2 7 Hours 00000 x10 Starts 00000 NOTE There is a VIEW CONDENSER menu to the right of VIEW EVAPORATOR but omitted from this matrix due to space limitations 58 OM WMC 3 Table Continued
10. The system is password protected and only allows access by authorized personnel The operator must enter the password into the touch screen or one of the controller s keypad before any setpoints can be altered NOTE It is important to understand that the OITS is the operator interface device under normal conditions If and only if it is unavailable should the unit controller be used to change setpoints or operate the chiller Figure 2 Major Control Components Universal Comm Module OPERATOR Color Graphics INTERFACE Touch Screen Interface TOUCH SCREEN View Data Input Setpoints Stores History UNIT UNIT CONTROLLER OOOO Analog Inputs Analog Outputs Digital Inputs 1 COMPRESSOR Digital O CONTROLLER Onboard Analog Outputs 2 COMPRESSOR Control Digital Inputs OM WMC 3 CONTROLLER Digital Outputs Control Panel The unit and compressor controllers along with unit and compressor on off switches are mounted in the unit control panel which is mounted adjacent to the OITS panel See Figure 1 The switches are designated T for on and 0 for off The compressor on off switch should only be used when an immediate stop is required since the normal shut down sequence is bypassed The switch panel also has a Circuit Breaker that interrupts power to the cooling tower fans valves and evaporator and condenser pumps if any of these are tied into the MicroTech II controller for
11. buttons will forward to those respective screens SET Screens The set screens on the Interface Panel are used to input the many setpoints associated with equipment of this type MicroTech II provides an extremely simple method for accomplishing this NOTE If the Interface Panel is unavailable the unit controller can be used to change setpoints Appropriate setpoints are factory set and checked by McQuay Factory Service or Factory Authorized Service Company during commissioning However adjustments and changes are often required to meet job conditions Certain settings involving pumps and tower operation are field set Pressing the SET button found on almost every screen accesses the last SET screen used or the SERVICE screen whichever of the two was used last When in any SET screen pressing the SET button again will toggle to the SERVICE screen shown on page 52 OM WMC 3 39 Figure 19 A Typical SETPOINT Screen Unit Status Chiller A Unit Status Compressor Status S ETPOI NTS WATER 1 RUN Hold F PSI 2 OFF Awaiting Load Compressor ee _ Status Leaving Water Temp Cool Se ets control target for a mens evaporator leaving a pn Setpoint water temperature ee a Description PSUR SSS e 35 to 80 Deg F SEs eee ai cs 2 to 26 Deg C Rawea g Maximum Reset Delta T aem Settings Start Reset Delta T 0 0 Fes LWT Reset Type Startup DeltaT EH I Shutdown DeltaT a 6 Numeric ne Leaving Water Temp Heat aa Keypad
12. or 2 Primary 1 Standby e If 1 Only is selected only pump 1 will be started even in event of a failure e If 2 Only is selected only pump 2 will be started e If Auto is desired the unit will try to balance operating hours on each pump by starting the pump with the least amount of operating hours first In case of pump failure the unit will start the backup pump e In standby mode the primary pump will always be started first The standby pump will only be started if there is a failure indicated on the primary pump An Evaporator Water Pump output will be ON if the Evap State is set to START or RUN Both outputs will be OFF if the Evap State is set to OFF SET UNIT SPs 9 Templifier Scr Water No Start 070 F Delta Reset 055 F This menu does not apply to WMC chillers and should be ignored UNIT SPs 10 Yes Speed XXX Kw 076 0 VED settings are controlled by the compressor on board microprocessor and these settings are not used SET UNIT SPs 11 OM WMC 3 65 Max Wtr Flow Rates Evap WF 02400 GPM Cond WF 03000 GPM These settings are used to calibrate customer supplied flow switches SET UNIT SPs 12 STD Day Light Time dd mmm yyyy hh mm ss Day of week SET UNIT SPs 13 Display Format Units F psi IP Lang English SET UNIT SPs 14 Protocol Modbus Id 001 Units IP Baud Rate 19200 SET UNIT SPs 15 EX Val Std Values Pos 450 L76 0psi Enthalpy Sp 85 0 F This
13. 0 75 1 00 1 50 Multiple Compressor Staging This section defines which compressor is the next one to start or stop The next section defines when the start or stop is to occur Functions 1 Can start stop compressors according to an operator defined sequence 2 Can start compressors based on the number of starts run hours if starts are equal and stop on run hours 3 The above two modes can be combined so that there are two or more groups where all compressors in the first group are started based on number of starts hours before any in the second group etc Conversely all compressors in a group are stopped based on run hours before any in the preceding group etc 4 An efficiency priority mode can be selected for two or more chillers where one compressor is started on each chiller in the group before a second is started on any of them 5 A pump priority mode can be selected for one or more chillers where all compressors on a given chiller are started before going to the next chiller in the group 6 One or more compressor can be defined as standby where it is never used unless one of the normal compressors is unavailable Required Parameters 1 Sequence number setpoint SQ _SP for all compressors Possible settings 1 4 2 Compressor Staging Mode setpoint CSM_SP for all compressors Possible settings are 26 OM WMC 3 e NORMAL e EFFICIENCY PRIORITY e PUMP PRIORITY e STANDBY 3 Maxim
14. 25 vi SP15 Set the control gain for slope Default is 25 NOTE Setpoints 14 and 15 are site specific dealing with system fluid mass component size and other factors affecting the reaction of the system to control inputs These setpoints should be set by personnel experienced with setting up this type of control Figure 24 Bypass Valve Positions Initial Valve Position values are examples only Max Position Setpoint 90 F Min Position Setpoint 65 F Min Start Position Max Start Position Set Point 10 Set Point 90 See Figure 10 on page 31 for fan staging and bypass valve field wiring connection points 3 Tower staging with bypass valve controlled by fan stage VALVE STAGE This mode is similar to 2 above except that the bypass valve setpoint changes to be set at the same point of whatever fan stage is active rather than just maintaining a single minimum condenser EWT In this mode the valve controls between fan stages and tries to maintain the fan stage setting in effect When it is max open or max closed staging up or down and the temperature or lift moves to the next fan stage the valve will go the opposite max setting This mode reduces fan cycling This mode is programmed the same as Mode 2 above except that in SETPOINT TOWER SP2 VALVE STAGE is selected instead of VALVE SP and e SP6 Set the valve position open above which the first fan can stage on fan stage ON temperature and STAGE UP
15. 4 mA and 20 mA An example of this action is shown below LWT Reset Cool mode temperatures are examples only 54 0 Max Reset Delta T 10 0 F Cool LWT Set Point 44 0 F Oma 4ma 20 ma 22 OM WMC 3 Compressor Controller The compressor controller s primary function is controlling and protecting the compressor No setpoints are input to it There is one compressor controller for each compressor on the unit The compressor controller receives processes and sends data to the unit controller the compressor on board microprocessors and to external devices With some operator intervention the compressor controller can operate the compressor if the operator interface touch screen is unavailable Inputs and outputs are as follows Table 9 Compressor Controller Analog Inputs Description Signal Source Leaving Evaporator Water NTC Thermistor Temperature 10k 25 C 58 to 212 F Spare Motor Current 0 to 5 VDC 0 to 125 RLA Table 10 Compressor Controller Digital Inputs Description Manual Off 0 VAC Off 24 VAC Auto Spare Spare Spare Spare Spare Evaporator Water Flow Switch 0 VAC No Flow Condenser Water Flow Switch 0 VAC No Flow Spare o fo o sfols Table 11 Compressor Controller Analog Outputs Description Output Signal a o o Table 12 Compressor Controller Digital Outputs Description Output OFF Output
16. Delta Reset 055 F Ident Number 001 Ident Number 001 Ignore this menu Baud Rate 19200 Baud Rate 19200 SET UNIT SPs 10 SET COMP SPs 10 SET COMP 2 SPs 10 VFD YES Refrg Sat Pressure Refrg Sat Pressure Min Speed 015 KW Evp Offset 00 0 psi Evp Offset 00 0 psi Max Kw 076 0 Cnd Offset 00 0psi Cnd Offset 00 0psi Ignore this menu SET UNIT SPs 11 SET COMP SPs 11 SET COMP 2 SPs 11 Max Wtr Flow Rates ELWT Offset 0 0 F ELWT Offset 0 0 F Evap WF 02400GPM CondWF 03000GPM SET UNIT SPs 12 Time Day Mon Yr 24 hr time day of wk SET UNIT SPs 13 Display Format Units F psi IP Lang English SET UNIT SPs 14 Protocol MODBUS Id 001 Units IP Baud Rate 19200 SET UNIT SPs 15 Ex Val Std Values Pos 450 L76 0psi Enthalpy Sp 85 0 F Ignore this menu OM WMC 3 59 Selection can then be made by using the LEFT RIGHT keys to move between columns and the UP DOWN keys to move between rows If the VIEW COMP 2 3 screen is being viewed and the RIGHT arrow key is pressed the display will show VIEW EVAP If the LEFT arrow key is then pressed the display will show VIEW COMP 2 3 again not VIEW COMP 1 Attempts to scroll past the limits of the matrix are ignored Screen Definitions VIEW The following screens are shown in F psi When the Display Units setpoint is set to C kPa the units of measure on the OITS will change accordingly The unit and compressor controllers will always be
17. Enable OFF COOL SWITCHES Unit Enable settings can be OFF and ON as determined from the Unit Enable setpoint Unit Mode settings can be COOL or TEST as determined from the Unit Mode setpoint TEST mode is not be selectable from the 4x20 display keypad although it may be displayed if already set Source settings can be KEYPAD SWITCHES or NETWORK as determined from the Mode Source setpoint SET UNIT SPs 2 Available Modes COOL Select w Unit Off Available Modes settings for WMC chillers can be COOL The unit must be turned off to change this setpoint SPs 3 XX X F XX XF XX XF Ignore any setting other than COOL LWT should they appear on this menu SET UNIT SPs 4 Leaving Water Temp StartDelta 03 0 F StopDelta 03 0 F SET UNIT SPs 5 Reset Type none MaxResetDT XX X F 64 OM WMC 3 strtResetDT Xx X F Reset Type settings can be NONE RETURN or 4 20 as determined by the LWT Reset Type setpoint SET UNIT SPs 6 Soft Load OFF BeginAmpLimit 40 SoftLoadRamp 05min Soft Load settings can be OFF or ON as determined from the Soft Load setpoint SET UNIT SPs 7 Max Min LWT Rates Max 0 5 F min Min 0 1 F min Pump Selection SET UNIT SPs 8 EvapRecTmr X Xmin 1 ONLY 2 PRIM The Evaporator Water Pump outputs will be controlled in a Primary Standby manner according to the Evap Pump setpoint which may be set to 1 Only 2 Only Auto 1 Primary 2 Standby
18. LANGUAGE OSL Comp 1 O3L Unit DISPLAY UCM The SERVICE screen is accessed by pressing SET from any SET screen In other words it is the second SET screen While containing information and activity buttons for the service technician it also has valuable information for the operator The upper left corner contains compressor information such as number of starts and operating hours for each compressor Spare Capacity is used to set the compressor stopping increments The Active pLAN Nodes matrix shows active control components on the pLAN A B C D are individual chillers 1 and 2 are compressor controllers 5 is the unit controller and 7 is the interface panel pLAN Comm is used for setting up multiple chillers and is set at startup by the McQuay startup technician as is LOAD UCM CHANGE UNITS button allows selection of Inch Pounds or Metric units of measure on the OITS SELECT LANGUAGE allows toggling between the available languages The language can be set separately for display or history which is used for alarm and trend files The version numbers shown in the lower left corner are the controllers software identification The number in the upper right corner is the Operator Interface Panel software identification number These numbers may be required by McQuay to answer questions about unit operation or to assist in possible future upgrades of software The PASSWORD button is used to access the Keyboard screen to enter a passw
19. One is to scroll through the matrix from one screen to another using the four ARROW keys 2 Another way is to use shortcuts to work through the matrix hierarchy From any menu screen a Pressing the MENU key will take you to the top level of the hierarchy The display will show ALARM VIEW and SET as shown in Figure 6 One of these choices can then be selected by pressing the key connected to it via the pathway shown in the figure OM WMC 3 17 b Depending on the top level selected a second level of screens will appear For example selecting ALARM will go the next level of menus under ALARM ALARM LOG or ACTIVE ALARM Selecting VIEW will go the next level of menus VIEW COMPRESSOR STATUS VIEW UNIT STATUS VIEW EVAPORATOR or VIEW CONDENSER Selecting SET will go to a series of menus for looking at and changing setpoints c After selecting this second level the desired screen can be acquired using the arrow keys A typical final screen is shown below Pressing the MENU key from any menu screen will automatically return you to the MENU mode Figure 7 Typical Menu Display and Keypad Layout C JA VIEW UNIT STATUS Unit COOL MENU Key Compr 1 2 OFF OFF Evap Pump RUN MicroTech lI ARROW Keys ENTER Key Menu Screens A hierarchical menu structure is used to access the various screens Each menu screen can have one to four lines of information Optionally the last menu selection can access on
20. TIME from 1 to 60 minutes The default value of 5 minutes is probably a good starting point The value may need to be adjusted later depending on actual system operation vi If TEMP is selected in SP1 use 1 SP6 Select STAGE DIFFERENTIAL in degrees F start with default of 3 degrees F 2 SP8 11 Set the STAGE ON temperatures consistent with the temperature range over which the condenser EWT is desired to operate The default values of 70 F 75 F 80 F and 85 F are a good place to start in climates with moderate wet bulb temperatures The number of STAGE ON setpoints used must be the same as SP3 b If LIFT is selected in SP1 use 1 SP7 Select STAGE DIFFERENTIAL in PSI Start with default of 6 PSI it SP12 15 Start with default setpoints The number of STAGE ON setpoints used must be the same as SP3 See Figure 10 Field Wiring Diagram on page 31 for fan staging field wiring connection points 2 Tower Fan Staging With Bypass Valve Controlling Minimum EWT VALVE SP 1 TOWER SETPOINT Screen 46 OM WMC 3 a SP1 Select TEMP if control is based on condenser EWT or LIFT if based on compressor lift expressed in pressure b SP2 Select Valve SP for control of bypass valve based on temperature or lift c SP3 Select one to four fan outputs depending on the number of fan stages to be used More than one fan can be used per stage through the use of relays d SP4 Select STAGE UP TIME from 1 to 60 minutes The default v
21. TIMER must also be satisfied Default is 80 e SP7 Set the valve position closed below which the first fan can stage off the fan stage temperature and STAGE DOWN TIMER must also be satisfied Default is 20 4 Fan VFD no bypass valve VFD STAGE The fan VFD mode assumes the tower is driven by one large fan Set up is as above except in SETPOINT TOWER SP2 VALVE VFD is selected 48 OM WMC 3 MOTOR Setpoint Screen Figure 25 MOTOR Setpoint Screen Unit Status ChillerA SETPOINTS 1 RUN Hold OF PSI 2 OFF Awaiting Load Demand Limit Enable ON Limits RLA to a value set by the Demand Limit analog input where 4mA O RLA 20mMA 100 RLA FF The Demand Limit Nominal Capacity input is ignored Maximum LWT Rate Minimum LWT Rate Soft Load Ramp Time Initial Soft Load Limit Soft Load Enable Nameplate RLA Maximum Amps CANCEL Minimum Amps Demand Limit Enable Soft Load Ramp Time P ston pe oon ee come Nominal Capacity 0 to 9999 Tons Determines when to shut off a compressor 0 5 0 1 to 5 0 Inhibits loading if LWT change exceeds the setpoint Maximum LWT Rate ie ages F min value 3 Additional compressor can start if LWT change is Minimum LWT Rate F min below setpoint Time period to go from initial load point RLA set Soft Load Ramp Time i 1 to 60 min in SP 5 to 100 RLA Initial Soft Load Amp Limit 10 to 100 Initial amps as of RLA uses SP4 amp 6 Soft Load Enable OFF
22. Temp Time delay between stage up down event and next stage down Time delay between stage up down event and next stage up Number of fan stages used None No tower valve or VFD None Valve Valve Setpoint Valve controls to VALVE SP3 4 Setpoint Valve amp 5 6 Valve VFD Control Stage VFD Valve Stage Valve control setpoint changes to Stage Valve fan stage setpoint SP VFD Stage VFD Stage 1 fan is VFD controlled no valve Valve Setpoint VFD Stage Both valve and VFD None None No tower fan control Tower Control Temperature Temperature Fan and valve controlled by EWT Lift Lift Fan and valve controlled by lift pressure Stage Down Time i 1 to 60 min Stage Up Time i 1 to 60 min S 8 E Tower Stages 1to4 OM WMC 3 Explanation of Tower Control Settings The MicroTech II controller can control cooling tower fan stages a tower bypass valve and or a tower fan VED if the chiller has a dedicated cooling tower The Tower Bypass Valve position will always control the Tower Fan Staging if Valve Setpoint or Stage Setpoint is selected There are five possible tower control strategies as noted below and explained in detail later in this section They are selected from SETPOINT TOWER SP2 1 NONE Tower fan staging only which is not recommended In this mode the tower fan staging up to 4 stages is controlled by either the condenser Entering Water Temperature EWT or LIFT pressure difference between the con
23. Tower Control setpoint Lift e Slope Present CP Previous CP When the Error is gt the Valve Deadband Temp OR Lift as appropriate setpoint the valve position analog output of full scale is updated according to the following equation e New Position Old Position Increment 10 Valve Stage Mode This mode is only operational when the Valve VFD Control setpoint is set to Valve Stage In this mode the valve output is controlled as for Valve Setpoint mode above except that the active setpoint for the controlled parameter is selected according to the following table Table 25 Valve Staging Of Fans ON Active Setpoint Valve Setpoint Temp OR Lift as appropriate Stage 1 ON Temp OR Lift as appropriate Stage 2 ON Temp OR Lift as appropriate Stage 3 ON Temp OR Lift as appropriate Stage 4 ON Temp OR Lift as appropriate Cooling Tower Fan VFD Normal Operation When the Valve VFD Control setpoint is set to None Valve Setpoint OR Valve Stage this output is set to 0 Otherwise it shall be controlled in a manner identical to Valve Stage Mode above except that 1 it is kept at zero until the first fan stage is ON and 2 the following setpoints do not apply e Valve Control Range Min e Valve Control Range Max e Valve Type Editing Editing is accomplished by pressing the ENTER lower right key key until the desired field is selected This field is indicated by a blinking curs
24. menu is used for setting certain electronic expansion valves and does not apply to WMC chillers Set Compressor Setpoints NOTE In the following SET COMP screens the N field indicates which compressor 1 or 2 is being set There is basically a column of menu screens for each compressor SET COMP N SPs Demand Limit 01 Max Comprs ON 02 66 OM WMC 3 StageMode settings can be NORMAL HI EFF PUMP and STANDBY as determined by the Stage Mode setpoint NORMAL has the auto balance sequence that starts compressors with least starts and stops compressors with most hours in sequence providing all compressors have the same sequence number If they have different sequence numbers say 1 2 3 4 they will always start in that sequence That is sequence number will take precedence over auto balance sequencing HI EFF is used with multiple chillers and runs one compressor per chiller when ever possible PUMP starts all compressors on the same chiller first starting with the chiller with the compressor with the least starts or by sequence number if they are different STANDBY is used in multi compressor systems and reserves a compressor to come on only if there is a failure of another compressor in the system and the standby compressor capacity is required to maintain chilled water temperature StageSequence is set for each compressor e In NORMAL or STANDBY Mode all compressors can have the same number or a number from 1 u
25. oenen pe ie ommen 10 to 99 Control gain for temperature or lift slope 10 to 99 Control gain for temperature or lift error 0 to 100 Maximum valve position overrides all other settings 0 to 100 Minimum valve position overrides all other settings Temp Maximum Start 5 a Condenser EWT at which valve should be open to tower aa Initial valve position when condenser EWT is at or above O O Maximum Start Position 0 to 100 Setpoint 9 5 M Condenser EWT at which initial valve position is set to Temp Minimum Position e 0 to 100 F Setpoint 6 Minimum Start Position 0 to 100 ae Wnemcondenser EWS at or Valve position below which the fans can stage down Tower Setpoint 2 Valve Stage Down VFD speed below which the next fan speed can turn off Tower Setpoint 2 valve VFD Valve position above which the fans can stage up Tower Setpoint 2 Valve Stage Down VFD speed above which the next fan speed can turn on Tower Setpoint 2 valve VFD Valve Deadband Lift i 1 0 to 20 0 psi Control deadband Tower Setpoint 1 Lift Valve Deadband Temp 1 0 to 10 0 F Control deadband Tower Setpoint 1 Temp Valve Target Lift 3 F 10 to 130 psi Ee P Tower Setpoint 1 Lift Works Target for condenser EWT Tower Setpoint 1 Temp Works with Setpoint 4 Normally closed NC or normal open NO to tower Stage Down 0 to 100 Stage Up 0 to 100 Valve Setpoint Temp 40 to 120 F
26. screen is basically a compilation of the events that the chiller sequences through at startup A green light light gray in the figure indicates that a particular sequence requirement has been satisfied It is recommended that this screen be viewed during the start up sequence One can see the requirements light up as they are met and quickly see why a non start may have occurred For example The Evap Flow OK will light when the evaporator flow switch is closed by flow The bottom sections from RUN down are in effect during the shut down process The sequence transitions back to OFF at this point and the OFF light will be illuminated OM WMC 3 mit 37 Figure 16 View Compressor Input Output Status Pressing the I O button adjacent to the compressor on the VIEW MENU screen will access the screen shown in Figure 16 It is superimposed on the right side of COMPR I O the Detail View Screen It gives the status of the compressor digital inputs and outputs Many of these I Os also appear in the Compressor State screen since they are part of the start up sequence and define the compressor state at any given time Manual Switch WMC units will have two of any compressor screen Evap Water Flow Cond Water Flow A COMP button will appear in the lower left hand corner of the Detail View Screen This button will toggle compressor data from 1 compressor to 2 Digital Outputs compressor Circuit Breaker Trip Interlock Figure 17 Un
27. this demonstration screen Alarms are arranged in order of occurrence with the most recent on top Once the abnormal condition is corrected pressing the CLEAR key will clear the alarm The current active alarms there may be more than one are displayed Note that the alarms are color coded red for FAULT equipment protection control that causes a rapid compressor shutdown yellow for PROBLEM limit alarm that will inhibit loading or load or unload the compressor and blue for WARNING which is information only and takes no action Faults Problems and Warnings as detailed on pages 21 and 25 The date time and cause of the alarm are displayed After eliminating the cause of the alarm clear the alarm by pressing the CLEAR button This will clear the alarm from the register and allow the unit to restart after going through the start sequence The alarm notice will be deleted from the screen However if the cause of the alarm is not remedied the alarm is still active and the alarm message will remain open The unit will not begin its starting sequence OM WMC 3 55 Figure 32 Keyboard KEYBOARD Type password and press Enter or Cancel 18 Use Shift for Lock Space Second Character or Caps The keyboard is only used to enter the password when attempting to enter or change a setpoint Input the number 100 for operator 2001 for manager level and press Enter to enter the password The screen will automatically revert back
28. to the previous Set screen This screen will appear automatically when a password is required for changing a setpoint It can also be access from the service screen second set screen by pressing PASSWORD 56 OM WMC 3 Unit Controller Menu Screens The unit controller located in the control panel adjacent to the OITS is the only controller used by the unit operator In addition to unit functions most compressor parameters are viewable on it and all setpoints can be accessed from it Unit of Measure SI units of measure can be selected with the appropriate setpoint screen but will appear only on the OITS The controller LCD screens read only in inch pounds unit of measure Menu Structure Hierarchical A hierarchical menu structure is used to access the various screens Each menu screen can have one to four lines of information Optionally the last menu selection can access one of a set of screens that can be navigated with the UP DOWN arrow keys see the scrolled menu structure below Menu selection is initiated by pressing the MENU key which changes the display from a data screen to a menu screen Menu selections are then made using the arrow keys according to labels on the right side of the display the arrows are ignored When the last menu item is selected the display changes to the selected data screen An example follows showing the selection of the VIEW COMPRESSOR n screen Suppose the current screen is A
29. 6 Compressor On Board Controllers sesssesssosssocesooesooesssessseesssesss OU Interface Touch Screen ccccccssseees 32 Navigatlon aonais 32 Screen Descriptions eee eee cee eseeereeeeeeee 34 VIEW Screens i c8se s0ciecsedhssasestenesenetbeadvenenetes 34 SET SCPEEMNS eiaeia EE aE evens 39 SERVICE Screen ccecccsssecceceeeesssseececeeeees 52 HISTORY Screens ccccccsssseceeeeeeeessrseeeeees 53 Download Data c ccccccccsesssseceeeeesenseseeeeeees 54 ACTIVE ALARM Screen ccecsesseeeeeeeee 55 Unit Controller Menu Screens 57 Men Matti x csiciscccestisvcvsecsavevencenievntacevevetaebebee 58 Compressor Controller Menu Operator Interface Touch Screen eee 16 Unit Compressor Controller Description 16 Screens lt nissscscccessseooscdscnscseessevesnsosecoasorsooe 7D Navigating sersoriea orea Daos rRNR ER 17 Mena Matike iisiiess tintsb dees sei os ena 75 Unit Controller eesesesesossosorsesecceseeesoeses 19 BAS Interface esseeesoesesesesoesesosseseseceeeesee 77 Unit Controller Setpoints sseeeeeeeseeeeeeeeeeeees 19 MTD o amp D O bes BA C n et gu CERTIFIED w a LONMARK 3 3 c Muste O tiste O ARI Standard 550 590 Water Cooled Chiller www aridirectory org Manufactured in an ISO Certified Facility 2007 McQuay International Illustrations and data cover the McQuay International product at the time of publication and we reserve
30. 6 F the LWT error is 2 degrees LWT Slope The LWT slope is an indication of the trend of the chilled water temperature It is calculated by taking readings of the temperature every few seconds and subtracting them from the previous value over a rolling one minute interval ms Milli second Maximum Saturated Condenser Temperature The maximum saturated condenser temperature allowed is calculated based on the compressor operational envelope OAT Outside ambient air temperature Offset Offset is the difference between the actual value of a variable such as temperature or pressure and the reading shown on the microprocessor as a result of the sensor signal OITS Operator Interface Touch Screen one screen per unit provides operating data visually and accommodates setpoint entry pLAN Peco Local Area Network is the proprietary name of the network connecting the control elements Refrigerant Saturated Temperature Refrigerant saturated temperature is calculated from the pressure sensor readings The pressure is fitted to an R 134a temperature pressure curve to determine the saturated temperature Soft Load Soft Load is a control sub routine that allows the chiller to load up gradually It requires setpoint inputs of selecting it by Yes or No inputs by selecting the percent load to start ramping up and by selecting the time to ramp up to full load up to 60 minutes OM WMC 3 SP Setpoint Suction Superheat Suction superhe
31. Active Demand Limit variable Low Evaporator Pressure If the evaporator pressure drops below the Low Evaporator Pressure Inhibit setpoint the unit will inhibit capacity increase If the evaporator pressure drops below the Low Evaporator Pressure Unload setpoint the unit will begin capacity decrease 28 OM WMC 3 High Discharge Temperature Load If the discharge temperature rises above the High Discharge Temperature Load setpoint and the motor current is lt 50 RLA the unit will begin capacity increase Soft Load Soft Loading is a configurable function used at compressor startup to limit the maximum current draw on the compressor in a ramp up type manner It is only active on the first compressor to start The setpoints that control this function are e Soft Load ON OFF e Begin Amp Limit RLA e Maximum Amps RLA e Soft Load Ramp seconds The active soft load limit value in RLA increases linearly from the Begin Amp Limit setpoint to the Maximum Amps setpoint over the amount of time specified by the Soft Load Ramp setpoint If the amp draw rises above the currently active soft load limit value the unit will inhibit capacity increases If the amp draw rises to 5 or more above this value the unit will begin capacity decrease Maximum LWT Rate The maximum rate at which the leaving water temperature can drop chiller mode COOL is limited at all times by the Maximum Rate setpoint If the rate excee
32. EW UNIT TOWER 1 VIEW UNIT TOWER 1 Stages ON 2 of 4 Stages ON 2 of 4 Setpoint XXX F Setpoint XXXX psi The first Stages ON value is the number of fan stages ON The second number is the Tower Stages setpoint 0 if Tower Control None VIEW UNIT TOWER 2 Bypass Valve XXX VFD Speed The Bypass Valve value is None in place of XXX if the Valve VFD Control setpoint None or VFD Stage The VFD Speed value shall be None if the Valve VFD Control setpoint None Valve Setpoint or Valve Stage View Compressor Status NOTE In the following VIEW COMP screens the N field indicates which compressor 1 or 2 is being viewed There are two columns of menus the first for compressor 1 the second for 2 VIEW COMP N 1 State RUN RLA XXX Evap LWT 000 0 F State settings can be OFF START INTLOK HOLD LOAD UNLOAD SHUTDOWN STOP and ALARM as determined from the Comp State variable the Load and Unload outputs and the presence of a compressor shutdown alarm VIEW COMP N 2 psi Cond Press XXXX OM WMC 3 61 Evap Press XXXX Lift Press XXX VIEW COMP N 3 psi WMC Compressor Oilless Design blank menu VIEW COMPHN 4 F Cavity Temp XXX X F Invert Temp XXxX X C Lift Temp XX X F VIEW COMP N 5 F Temp SH Suction XXX X XX xX DischargeXXX X XX X VIEW COMP N 6 psi oF SatEvap XXX X XXX X SatCond XXX X XX X VIEW COMP N 7 Hours XXXXX Starts
33. EvPrStop 29psi SET PASSWORD Enter Password 00000 No Access Given SET COMP SPs_ 2 StageMode Normal StageSequence 01 Max Compr ON 01 SET ALARM LMTs 2 HighCondPr 140psi HiDschT Load 170 F HiDschT Stop 190 F SET PASSWORD 2 Tech Password 00000 00000 No Access Given SET COMP SPs 3 StageDeltaT 1 0 F Stop Start 03 min Start Start 40 min SET ALARM LMTs 3 WMC Compressor Oilless Design blank mask page SET COMP SPs 4 FullLoad 300sec Name Plate RLA 085 SET ALARM LMTs 4 Surge Slp Str 20 F Surge Tmp Run 06 F MtrCurThrshld 10 SET COMP SPs 5 Nom Capacity 0100T HotGasBypass 30 SET ALARM LMTs 5 Evap Freeze 34 0 F Cond Freeze 34 0 F SET COMP SPs 6 InterLokTmr 010sec UnloadTimer 030 sec SET COMP SPs 7 WMC Automatic Vane Control blank mask page SET COMP SPs 8 MAX KW 76 0 Lag Start 000Sec Step Down 060Sec SET COMP SPs 9 Protocol M BUS MSTR Ident Number 001 Baud Rate 19200 SET COMP SPs 10 Refrg Sat Pressure Evp Offset 00 0 psi Cnd Offset 00 0psi SET COMP SPs 11 ELWT Offset 0 0 F 76 OM WMC 3 BAS Interface The MicroTech II controller is available with the optional Open Choices feature an exclusive McQuay feature that provides easy integration with a building automation system BAS If the unit will be tied into a BAS the controller should have been purchased with t
34. GURE 22 POWER TIMERS ALARMS VALVE TOWER TOWER FANS MOTOR MODES PRESS VIEW PRESS ME LABELS WATER VIEW HOME SCREEN y MENU ON OFF BAR GRAPHS SCHEMATIC REEN VIEW i fones VIEW VIEW SCREEN V PRESS VIEW SEE FIGURE 12 SEE FIGURE 13 mi Apress VIEW SEE FIGURE 18 HISTORY HOME SCREEN HISTORY PRESS HISTORY TREND OR ALARM HISTORY COMPRESSOR STATE on SEE FIGURE 19 COMPRESSOR VO lt SEE FIGURE 20 UNIT O a EVAPORATOR CONDENSER SEE FIGURE 21 Pressing VIEW from any sub menu will toggle back to the home Pressing MENU when in any sub menu will return to the view Pressing SET or HISTORY will go to these groups of OM WMC 3 33 Screen Descriptions Figure 12 Home View Screen Unit Status Chiller A VIEW chiles Conta Compressor Status 1 RUN Hold OF _ PSI VIEW 2 OFF Awaiting Load Screens ACTIVE LWT WATER TEMPERATURES PERCENT View screens SETPOINT UNIT RLA are used for looking at unit status and conditions Home View Screen The Home View Screen shows the basic operating j condition of CONDENSER IO the chiller and R j is the screen that is normally left on
35. ITS is used per unit Selected information from the OITS panel can be down loaded via a USB port located in the unit control panel The OITS panel is mounted on a moveable arm to allow placement in a convenient position for the operator There is a screen saver programed into the system The screen is reactivated by touching it anywhere Unit Compressor Controller Description Hardware Structure The controllers are fitted with a microprocessor for running the control program There are terminals for connection to the controlled devices for example solenoid valves tower fans pumps The program and settings are saved permanently in FLASH memory preventing data loss in the event of power failure without requiring a back up battery Each controller connects to other controllers the on board compressor microprocessors and the OITS via a local communications network The unit controller can also have an optional module to provide communication for a BAS using standard open protocols 16 OM WMC 3 Keypad A 4 line by 20 character line liquid crystal display and 6 button keypad is mounted on the unit and compressor controllers Its layout is shown below Figure 6 Controller Keypad Red Alarm Light Behind MENU Key Key to Screen Pathway lt VIEW lt SET MicroTech II ARROW Keys 4 ENTER Key with Green Run Light Behind The four arrow keys UP DOWN LEFT RIGHT have three modes of use e Scroll between data scree
36. Leaving Water Temp Ice A A erwe Bem as Setpoint Action Setpoints Selection Initiate Setpoint Buttons Buttons Change Groups Button The above figure shows the Water screen with Leaving Water Temp setpoint selected The various setpoint groups are in a column on the right side of the screen Each button contains a number of setpoints grouped together by similar content The WATER button as shown contains various setpoints relating to water temperature setpoints NOTE Some setpoints that do not apply to a particular unit application may still be listed on the screen They will be inactive and can be ignored The numbered buttons in the second from right column are pressed to select a particular setpoint The selected setpoint will appear in blue on the screen and a description of it with the range of available settings will appear in the upper left hand box Procedure for Changing a Setpoint A list of setpoints their default value their available setting range and password authority are in Table 6 on page 20 for the unit and Table 13 on page 24 for the compressor 1 Press the applicable Setpoint Group A complete explanation of setpoint content of each group follows this section 2 Select the desired setpoint by pressing the numbered button 40 OM WMC 3 Press the CHANGE button indicating that you wish to change a setpoint value The KEYBOARD screen will be turned on automatically to facilitate entering the password e O
37. ON Circuit Breaker OFF Compressor Off Emer Solenoid Circuit Breaker ON Spare Spare Spare Spare Spare Spare Inter Lock Solenoid Comp Disabled OFF Comp Enabled ON Spare OO CO N Om om A oo Pe OM WMC 3 23 Compressor Controller Setpoints The following parameters in Table 13 are remembered during power off are factory set to the Default value and can be adjusted to any value in the Range column The Type column defines whether the setpoint is part of a coordinated set of duplicate setpoints in different controllers The possibilities are given below e N Normal setpoint Not copied from or to any other controller e D Duplicate setpoint Setpoint is duplicated same value in all compressor controllers on the same chiller e G Group setpoint Setpoint is duplicated same value in all compressor controllers on all chillers in a group e M Master setpoint Setpoint is copied to all controllers in the Sent To column e S Slave setpoint Setpoint is a copy of the master setpoint in the Unit controller At power up the slave controller checks if the master is operational and if so it sets its copy of the setpoint equal to the master s Otherwise the setpoint remains unchanged During normal operation any time the master setpoint changes the slave is updated as well The PW password column indicates the password that must be active in order to ch
38. ON Soft load on or off Uses SP6 amp 7 Nameplate RLA 52 to 113 Amps RLA value from compressor nameplate RLA above which loading is inhibited Load Limit SP 5 unloads compressor Minimum Amps 5 to 80 RLA below which unloading is inhibited ON sets RLA at 0 for 4 mA external signal and at Demand Limit Enable OFF ON 100 RLA for 20 mA signal OFF signal is ignored Maximum Amps 10 to 100 OM WMC 3 MODES Setpoints Figure 26 MODES Setpoint Screen 201 Al MB SETPOINTS COOL AUTO Remote Switch Compressor Status oO 1 RUN Hold F PSI 2 OFF Awalting Load Unit Enable OFF Compressors pumps amp fans are OFF AUTO Evap pump ts ON Compressors condenser pump amp fans will operate as needed to maintain water temperature 1 DOWN NOTE Gray setpoints are not used with WMC chillers Table 23 MODES Setpoint Settings _oesorpion no oean rona Comp 2 Stage 1 2 of 10 1 Sequence Compressors Comp 2 Stage Normal Efficiency Mode o roma Pump Standby Comp 1 Stage A 1 2 of Sequence Compressors Comp 1 Stage Normal Efficiency Max Comp ON ef 1 1 16 None Local BACnet BAS Protocol MODBUS LonWorks MODBUS Remote Cond Pump Evap Pump Pump 1 Only Pump 2 seo 1 Only Auto Lead 1 y Primary 2 Primary Only Auto Lead 1 Primary 2 Primary m g TIMERS 2 J Comments Sets sequence numbe
39. Operator level password is 100 e M Manager level password is 2001 e T Technician level password Press the appropriate numbers in the numeric keyboard to enter the password There is a small delay between pressing the keypad and recording the entry Be sure that an asterisk appears in the window before pressing the next number Press ENTER to return to the SETPOINT screen The password will remain open for 15 minutes after initiation and does not need to be re entered Press CHANGE again The right side of the screen will turn blue inactive The numeric keypad and action buttons in the lower left hand corner of the screen will be activated the background will turn green Setpoints with numeric values can be changed in two ways e Select the desired value by pressing the numbered buttons Press ENTER to enter the value or CANCEL to cancel the transaction e Press the UP or DOWN button to increase or decrease the value displayed Press ENTER to enter the value or CANCEL to cancel the transaction Some setpoints are text rather than numeric values For example LWT Reset Type can be None or 4 20 ma The selection can be made by toggling between choices using the UP or Down button If dashed lines appear in the setpoint window it indicates that you have toggled too far and need to reverse direction Press ENTER to enter the choice or CANCEL to cancel the transaction Once CHANGE is selected the CANCEL or ENTER buttons must be pressed before an
40. RY toggles between the Trend History screen and the Alarm History screen e SET toggles between the Setpoints screen that are used for changing setpoints and the Service screen Returning Pressing the VIEW button from any screen will return to this screen OM WMC 3 35 Figure 13 Detail View Screen Unit Status ChillerA COOL AUTO Remote Switch VI EW Chiller Control Compressor Status oO 1 RUN Hold F PSI 2 OFF Awaiting Load STATE A3 SUCTION TEMP 140 Maximum RPM 1 1 DISCHARGE TEMP 105 Actual RPM 36 Minimum APM po Power 100 RLA 90 ZAPM of Maximum gugu wr 4c 41 E 3 p j C ACTIVE LWT SETPDINT m m ae oe A SUCTION PRESS MOUT 4 e 83 LIFT PRESS 30 0 amp XvV POSITION Data for one compressor is shown at a time on this screen Pressing the COMPRESSOR button in the screen lower left hand corner will toggle between 1 and 2 compressor LIQUID LINE TEMP Pressing the VIEW button on the bottom of the Home View screen accesses the Detail View Screen shown above This screen gives additional information on the refrigerant pressures and temperatures Pressing the STATE button will bring up a display of the compressor state as described on page 37 Pressing the I O button displays the status of the compressor inputs and outputs as described in Figure 16 on the same page WMC units will have a COMP button that will toggle between the two compressors data allowing the STATE and I O detail screens
41. Superimposed on a chiller schematic drawing is Alarm A red ALARM light will appear to the right of the SET button should an alarm occur Pressing it will bring up the active alarm screen to view the alarm details Information e Chilled water setpoint ACTIVE LWT SETPOINT e Entering and leaving chilled water temperatures e Entering and leaving condenser water temperatures e Percent motor amps e UNIT STATUS is MODE followed by STATE followed by the SOURCE that is the device or signal that created the STATE The possible combinations are in the following table Table 16 UNIT STATUS Combinations mopes STATES SOURCES OFF Manual Switch SHUTDOWN Note 1 Remote Switch AUTO Local BAS Network Note 1 Shutdown is the state of shutting down vane close etc e COMPRESSOR STATUS is MODE followed by STATE followed by the SOURCE that is the device or signal that created the STATE The possible combinations are in the following table Table 17 COMPRESSOR STATUS Possibilities Complete STATUS Text in priority sequence OFF Manual Switch Reason for the compressor being off 34 OM WMC 3 OFF Compressor Alarm OFF Unit State OFF Evap Flow Re circulate OFF Start to Start Timer xxx OFF Stop to Start Timer xxx OFF Staging Next ON OFF Awaiting Load RUN Unload Vanes Max Amps RUN Hold Vanes Max Amps Overrides water temperat
42. Table 18 TIMER Setpoints No Default Range Comments 0 to 999 Time compressor must load without unloading before sec vanes are considered fully open 10 to 240 Maximum time allowed before interlock confirmation seconds from compressor Stop Start Timer 3 to 20 min eta when compressor stops to when it can 15 to 60 Time from when compressor starts to when it can start min again 0 2 to 5 min Time that evaporator pump must run before Full Load Timer Interlock Timer Start Start Timer Evap Recirculate Timer compressor start 42 OM WMC 3 ALARMS Setpoint Figure 21 ALARMS Setpoint Screen Unit Status ChillerA SETPOINTS Compressor Status 1 RUN Hold o E PSI 2 OFF Awaiting Load Low Evap Pressure Inhibit Sets the evaporator pressure yalue below which any capacily increase is inhibited Condenser Freeze Protect 20 to 45 PSI Evaporator Freeze Protect 138 to 310 kPa Motor Current Threshhold Surge Slope Limit Surge Temperature Limit High Discharge Temp Stop High Discharge Temp Load High Condenser Pressure Low Evap Pressure Stop Low Evap Pressure Unload Low Evap Pressure Inhibit HISTORY Table 19 ALARM Setpoints o 114 34 0 F 9 0 to 45 0 F Minimum cond sat temp to start pump Evaporator Freeze 10 34 0 F 9 0 to 45 0 F Minimum evap sat temp to start pump Motor Current Threshold 1 to 20 Min RLA to consider that the is motor off 9 1 20 de 1 to 99 Surge
43. XXXXX The following menus are found only on the compressor controllers and contain detailed information on the compressor operation used only by trained compressor technicians VIEW COMP N 8 WMC Compressor Rdy Mode3 Unit0O Float0 Auto Demand 000 0KW VIEW COMP N 9 RPM Min 00000 Act 00000 Max 00000 Des 00000 Ver 419 Serial 0000 VIEW COMP N 10 Alrms BearingF 00000A00000 Motor F 00000A00000 62 OM WMC 3 VIEW COMP N 11 Pwr L1 458V 000 0Amps L2 458V 000 0Amps L3 458V 000 0Amps VIEW COMP N 12 Bear FX 00000 RX 00000 FY 00000 RY 00000 Ax 00000 Ver3939 off VIEW COMP N 13 S Str UpTrp 0530 Vdrp 0000 DnTrp 0380 RxV 0654 Ver 00136 Ok SCR On VIEW COMP N 14 Psi IGV 020 0 DisC 082 6 024 9 Suct 081 9 o0000Alr Intr 000 0 VIEW COMP N 15 Temps Suct 89 4 Cav 093 9 SCR 090 8 Ent 077 4 Disc 090 7 Lev 077 4 VIEW COMP N 16 Motor S_SP 0017 Spdly 0000 Inv_Temp 031 0 deg C View Vessel Status VIEW EVAPORATOR XXX X F XX X F Press right arrow to view the condenser data VIEW CONDENSER Disch SH XXX X F Approach XX X F Subcooling XX X F OM WMC 3 63 View Alarms hh mm ss dd mmm yyyy ALARM LOG 02 to 25 Description hh mm ss dd mmm yyyy ACTIVE ALARM Time Date Fault Description Set Unit Setpoints The following screens are only shown in F psi Setpoint default vales and available setting range can be found in Table 6 on page 20 SET UNIT SPs 1 Unit
44. action taken by controller Any type will light the ALARM light Procedures for dealing with alarms are shown below 1 Press the alarm light button This will go directly to the ACTIVE ALARMS screen 2 The alarm description with date stamp will be shown 3 Press the ACKNOWLEDGE button to recognize the alarm OM WMC 3 15 4 Correct the condition causing the alarm 5 Press the CLEAR button to clear the alarm from the controller If the fault condition is not fixed the alarm will continue to be on and the unit will not be able to be restarted Component Failure Chiller Operation without the Operator Interface Panel The Interface Panel communicates with the unit and compressor controllers displaying data and transmitting touch screen inputs to the controllers It does no actual controlling and the chiller can operate without it Should the Touch Screen become inoperable no commands are necessary for continuing unit operation All normal inputs and outputs will remain functional The unit controller can be used to view operational data to clear alarms and to change setpoints if necessary Component Description Operator Interface Touch Screen The operator interface touch screen OITS is the primary device for entering commands and entries into the control system Settings can also be made directly into the unit controller The OITS can also display controller data and information on a series of graphic screens A single O
45. alue of 2 minutes is probably a good starting point The value may need to be adjusted later depending on actual system operation e SP5 Select STAGE DOWN TIME from 1 to 60 minutes The default value of 5 minutes is probably a good starting point The value may need to be adjusted later depending on actual system operation f If TEMP is selected in SP1 use i SP6 Select STAGE DIFFERENTIAL in degrees F start with default of 3 degrees F ii SP8 11 Set the STAGE ON temperatures consistent with the temperature range over which the condenser EWT is desired to operate The default values of 70 F 75 F 80 F and 85 F are a good place to start in climates with moderate wet bulb temperatures The number of STAGE ON setpoints used must be the same as SP3 g If LIFT is selected in SP1 use i SP7 Select STAGE DIFFERENTIAL in PSI Start with default of 6 PSI ii SP12 15 Start with default setpoints The number of STAGE ON setpoints used must be the same as SP3 2 VALVE SETPOINT Screen a SP1 Select NC or NO depending if valve is closed to tower with no control power or open to tower with no control power b If TEMP was selected for fan control above use i SP2 Set the VALVE TARGET setpoint usually 5 degrees below the minimum fan stage setpoint established in TOWER SP11 This keeps full flow through the tower until the last fan is staged off ii SP4 Set VALVE DEADBAND the default of 2 degrees F is a good place to start i
46. and related operating conditions are available from the display Data can be exported for archival purposes via a 3 5 inch floppy drive or other device depending on date of manufacture e Soft loading feature reduces electrical consumption and peak demand charges during system loop pulldown e Remote input signals for chilled water reset demand limiting and unit enable e Manual control mode allows the service technician to command the unit to different operating states Useful for system checkout e BAS communication capability via LONTALK Modbus or BACnet standard open protocols for most BAS manufacturers e Service Test mode for troubleshooting controller outputs e Pressure transducers for direct reading of system pressures e Preemptive control of low evaporator and high discharge pressure conditions to take corrective action prior to a fault trip 4 OM WMC 3 Definitions Active Setpoint The active setpoint is the parameter setting in effect at any given moment This variation can occur on setpoints that can be altered during normal operation Resetting the chilled water leaving temperature setpoint by one of several methods such as return water temperature is an example Active Capacity Limit The active capacity setpoint is the setting in effect at any given moment Any one of several external inputs can limit a compressor s capacity below its maximum value Active Amp Limit Active amp limit is the actual am
47. ange the setpoint Codes are as follows O Operator M Manager T Technician not available through the 4x20 display keypad The following table groups setpoints that relate to compressor operation and are stored for the most part in the compressor controllers All settings are made through the OITS indiscriminately as to whether they are unit or compressor Table 13 Compressor Controller Setpoints eference Motor Amps Demand Limit OFF OFF ON Minimum Amps 40 20 to 80 Maximum Amps 100 40 to 100 Soft Load OFF OFF ON Begin Amp Limit 40 20 to 100 Soft Load Ramp 5 min 1 to 60 min Maximum Rate 0 5 F min 0 1 to 5 0 F min Minimum Rate 0 1 F min 0 0 to 5 0 F min Staging ojojojlz o z z z S F A A o Normal Efficiency Pump Standby 1 2 of Compressors Maximum Compressors ON 16 1 16 Stage Delta T 1 0 0 5 5 0 Full Load 120 sec 30 to 300 sec Absolute Capacity 100 Tons 0 to 9999 Tons Timers Start Start 15 to 60 min Stop Start 3 to 20 min Source No Start 50 to 100 F Continued next page Mode Normal Sequence 1 aja zz Sz __ Description Default Range Type Pw Manual _ 24 OM WMC 3 Reference Alarms Evaporator Freeze 9 0 to 45 0 F Condenser Freeze 9 0 to 45 0 F Low Evap Pressure 10 to 45 psi Low Evap Pressure Inhibit 20 to 45 psi Low Evap Pressure Unload 20 to 45 psi Hig
48. at is calculated for each circuit using the following equation Suction Superheat Suction Temperature Evaporator Saturated Temperature Stageup Stagedown Delta T Staging is the act of starting or stopping a compressor or fan when another is still operating Startup and Stop is the act of starting the first compressor or fan and stopping the last compressor or fan The Delta T is the dead band on either side the setpoint in which no action is taken Stage Up Delay The time delay from the start of the first compressor to the start of the second Startup Delta T Number of degrees above the LWT setpoint required to start the first compressor Stop Delta T Number of degrees below the LWT setpoint required for the last compressor to stop VDC Volts Direct Current sometimes noted as vdc VFD Variable Frequency Drive a device located on the compressor used to vary the compressor speed OM WMC 3 7 General Description Major Components Figure 1 Major Component Location Compressor 2 Unit Control Panel Compressor 1 with with On Board On Board Controls Controls Evaporator Relief Valve Operator Interface Panel Condenser Optional Unit Circuit 1 Circuit 2 Relief Disconnect Power Panel Power Switch amp Single Panel Point Power Electronic Expansion Valve Connection General Description The centrifugal MicroTech II control system consists of microprocessor based controllers in the c
49. ators are used for temporary power when the utility power is lost Starting Stopping Procedure The stopping of the chiller in the event of a power failure is typically uneventful The chiller will sense a loss of voltage and the compressors will stop coasting down using power generated from their dynamic braking to maintain the bearing magnetic field The stop signal will initiate a three minute stop to start timer effectively preventing compressor restart for three minutes The timer is adjustable from three to fifteen minutes but the recommended and default value is three minutes This interval allows the generator sufficient time to get up to speed and stabilize The chiller will restart automatically when the start to start timer expires Transfer Back to Grid Power Proper transfer from stand by generator power back to grid power is essential to avoid compressor damage A WARNING Stop the chiller before transferring supply power from the generator back to the utility power grid Transferring power while the chiller is running can cause severe compressor damage The necessary procedure for reconnecting power from the generator back to the utility grid is show below These procedures are not peculiar to McQuay units only but should be observed for any chiller manufacturer 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 o
50. boards are not furnished separate RS485 isolators must be field supplied 5 Verify correct nodes on each OITS Service Screen See Figure 28 on page 52 Operating Limits Maximum standby ambient temperature 130 F 55 C Minimum operating ambient temperature standard 35 F 2 C Leaving chilled water temperature 38 F to 60 F 3 C to 15 C Maximum operating evaporator inlet fluid temperature 66 F 19 C Maximum startup evaporator inlet fluid temperature 90 F 32 C Maximum non operating inlet fluid temperature 100 F 38 C Minimum condenser water entering temperature 55 F 12 8 C Maximum condenser entering temperature 105F 40 6C Maximum condenser leaving temperature 115F 46 1C Low Condenser Water Temperature Operation When the ambient wet bulb temperature is lower than design the entering condenser water temperature can be allowed to fall to improve chiller performance This is especially true of an advanced design such as the McQuay WMC chiller that features variable compressor speed It is an engineering fact that as the compressor discharge pressure is reduced the amount of power to pump a given amount of gas also is reduced The reduction can result in significant energy savings However as with most centrifugal chiller applications a tower bypass valve must be installed and must be controlled by the chiller MicroTech II controller Figure 5 illustrates two temperature actuated tower bypass arrange
51. control of their operation If these components operate independently from the chiller control the breaker has no effect The unit controller s primary function is processing data relating to the entire chiller unit operation as compared to data relating to the compressor operation The unit controller processes information and sends data to the compressor Figure 3 Control Panel Interior Switch Panel and Switches See Below Unit Controller SWS Emergency Shutdown Switch Outside Panel Se 3 qi m USB Port Located on PC Located in this Area Compressor 1 Controller SS E Compressor 2 Controller controllers and devices and relays information to the OITS for graphic display It has a 4x20 LCD display and keys for accessing data and changing setpoints The controller LCD can display most of the same information as the OITS and can operate the chiller independently if the OITS is not available Figure 4 Switch Locations Compressor 1 Switch Compressor 2 Switch Unit Switch Circuit breaker 10 aims smsi dzzms OM WMC 3 Use with On Site Generators WMC chillers have their total tonnage divided between two compressors that start sequentially and they are operated with variable frequency drives These features make WMC chillers especially appropriate for use in applications where they may be required to run with on site electrical generators This is particularly true when the gener
52. denser and evaporator pressure Tower bypass or fan speed are not controlled 2 VALVE SP Tower staging with low limit controlled bypass valve In this mode the tower fans are controlled as in 1 plus a tower bypass valve is controlled to provide a minimum condenser EWT There is no interconnection between the fan control and the valve control 3 VALVE STAGE Tower staging with stage controlled bypass valve In this mode the bypass valve controls between fan stages to smooth the control and reduce fan cycling 4 VED STAGE In this mode a VFD controls the first fan Up to 3 more fans are staged on and off and there is no bypass valve 5 NMALVE VED Tower fan control with VFD plus bypass valve control 1 Tower Fan Staging Only NONE This is not a recommended control strategy The following settings are used for the Tower Fan Staging Only mode SP setpoint a TOWER SETPOINT Screen i SP1 Select TEMP if control is based on condenser EWT or LIFT if based on compressor lift expressed in degrees ii SP2 Select NONE for no bypass valve or fan VED control iii SP3 Select one to four fan outputs depending on the number of fan stages to be used More than one fan can be used per stage through the use of relays iv SP4 Select STAGE UP TIME from 1 to 60 minutes The default value of 2 minutes is probably a good starting point The value may need to be adjusted later depending on actual system operation v SP5 Select STAGE DOWN
53. ds this setpoint capacity increases is inhibited Demand Limit The maximum amp draw of the compressor can be limited by a 4 to 20 mA signal on the Demand Limit analog input This function is only enabled if the Demand Limit setpoint is set to ON The amp limit decreases linearly from the Maximum Amp Limit setpoint at 4 mA to the Minimum Amp Limit setpoint at 20mA If the amp draw rises above the limit value the unit will inhibit capacity increases If the amp draw rises to 5 or more above this value the unit will begin capacity decrease Network Limit The maximum amp draw of the compressor can be limited by a value sent through a BAS network connection and stored in the Network Limit variable If the amp draw rises above the limit value the unit will inhibit capacity increases If the amp draw rises to 5 or more above this value the unit will begin capacity decrease Minimum Amp Limit The minimum amp draw of the compressor can be limited by the Minimum Amps setpoint If the amp draw drops below the limit value the unit will inhibit capacity decrease Maximum Amp Limit The maximum amp draw of the compressor is always limited by the Maximum Amps setpoint This limit has priority over all other functions including manual capacity control If the amp draw rises above the limit value the unit will inhibit capacity increases If the amp draw rises to 5 or more above this value the unit will begin capacity decrease OM WMC 3 29 Compr
54. e 35 to 80 Deg F 2 to 26 Deg C Maximum Reset Delta T Start Reset Delta T LWT Reset Type Stage Delta T Startup Delta T Shutdown Delta T 6 Leaving Water Temp Heat Leaving Water Temp Cool Leaving Water Temp Ice HISTORY Table 24 WATER Setpoint Settings Default Range Comments Set the maximum reset that can occur in Max Reset Delta T 7 0 0 F 0 0 to 20 0 F M degrees F if LWT reset is selected or max reset at 20 mA input if 4 20 mA is selected in SP7 Start Reset Delta T 6 10 OF 0 0 to 20 0 F M ay evap delta T above which Return reset Select reset type NONE for none RETURN for LWT Reset Type 5 NONE NONE RETURN M resetting chilled water based on the entering 4 20mA water or 4 20 mA for external analog signal Stage Delta T 4 1 0 0 5 to 5 F Sets the temperature the leaving water must be 9 i above setpoint for next compressor to start Startup Delta T 0 0 to 10 0 F Degrees above setpoint for compressor to start Shutdown Delta T 0 0 to 3 0 F Degrees below setpoint for compressor to stop Cool LWT 44 0 F 40 0 to 80 0 F Evaporator LWT setpoint in COOL mode OM WMC 3 51 SERVICE Screen Figure 28 Service Screen COMPRESSOR 1 2 Hours 57 570 Stage Mode Sequence Spare Capacity 0 Active RLA pLAN Nodes 1234667 oe eoe o eeeeee elec aeeeeee eo eee eoe 0 er VERSION OSL Comp 2 SERVICE UNITS F PSI Uperating Manual SELECT LANGUAGE ENGLISH ma SET
55. e of a set of screens that can be navigated with the UP DOWN arrow keys see the scrolled menu structure below Menu selection is initiated by pressing the MENU key which changes the display from a data screen to a menu screen Menu selections are then made using the arrow keys according to labels on the right side of the display the arrows are ignored When the last menu item is selected the display changes to the selected data screen An example follows showing the selection of the VIEW COMPRESSOR n screen Suppose the initial screen is After pressing the MENU button the top level menu screen will show After pressing the VIEW menu button a menu screen will show COMPRESSOR UNIT After pressing the COMPRESSOR menu button the selected EVAPORATOR data screen will show CONDENSER n Where n is the number of the last viewed COMPRESSOR screen n data screen The arrow keys will automatically return to the y y screen n data scroll mode at this time Different compressor screens can then be selected with the UP DOWN arrow keys screen n data 18 OM WMC 3 Unit Controller Table 2 Unit Controller Analog Inputs Description Signal Source Reset of Leaving Water Temperature 4 20 mA Current 0 10 to 80 F Entering Evaporator Water 7 s a Temperature NTC Thermistor 10k 25 C 58 to 212 F Entering Condenser Water s Temperature NTC Thermistor 10k 25 C 58 to 212 F Leaving Condenser Wa
56. ed into the control panel see Figure 10 on page 31 3 BAS BAS input is field wired into a module that is factory installed on the unit controller Control Panel Switches The unit control panel located adjacent to the Interface Panel has switches inside the panel for stopping the entire unit or individual compressors When the UNIT switch is placed in the OFF position the chiller will shut down through the normal shutdown sequence whether one or two compressors are on The COMPRESSOR switches will immediately shut down the compressor without going through the shutdown sequence when placed in the OFF position It is equivalent to an emergency stop switch Change Setpoints Setpoints are easily changed on the Operator Interface Touch Screen OITS A complete description of the procedure begins on page 40 Setpoints can also be changed in the unit controller but this is not recommended except in an emergency when the OITS is unavailable Alarms A red ALARM light in the lower middle of any screen is illuminated if there is an alarm If the optional remote alarm is wired in it too will be energized There are three types of alarms e Fault equipment protection alarms that shut a unit or compressor off e Problem limit alarms that limit compressor loading in response to an out of normal condition If the condition that caused a limit alarm is corrected the alarm light will be cleared automatically e Warning notification only no
57. essor On Board Controllers Each compressor is equipped with microprocessor controllers and sensors that provide control and data acquisition The data is transmitted to other controllers and the OITS via the multi unit communication network The on board controllers consist of Compressor Controller the compressor controller is the central processor of the compressor It is continually updated with critical data from the motor bearing controller and external sensors An important function is to control the compressor speed and guide vanes operation in order to satisfy load requirements to avoid surge and to provide for optimum efficiency The controller monitors over 60 parameters including Refrigerant pressures and temperatures Line voltage Phase failure detection Motor temperature Silicone Rectifier SCR temperature Speed Line currents Guide vane position Soft Start Controller the soft start controller limits current inrush by temporarily inserting a charging resistor between the ac line and the DC bus It works in conjunction with the variable speed function Motor Bearing Controller the motor bearing system provides the measurements and control to calculate and maintain the desired shaft position An RS 485 link connects the bearing controller and the compressor controller Backplane although not a controller the backplane connects the on board control modules with the soft start controller power electronics motor cooling s
58. et Alarm Limits SET ALARM LMTS 1 LowEvP rHold 33psi LowEvPrUn1ld 31psi LowEvPrStop 29psi SET ALARM LMTS 2 HighCondPr 140psi HiDschT Load 170 F HiDschT Stop 190 F SET ALARM LMTS 3 WMC Compressor Oilless Design blank mask page SET ALARM LMTS 4 Surge Slp Str 20 F Surge Tmp Run 12 F Mt rCurrThrshld 05 CAUTION Only trained compressor technicians should set these setpoints SET ALARM LMTS 5 Evap Freeze 34 0 F Cond Freeze 34 0 F Set Tower Setpoints SET TOWER SPs 1 OM WMC 3 TowerControl None Tower Stages 2 StageUP DN 080 020 Tower control settings can be None Temp or Lift 70 OM WMC 3 Tower Control Temp None Tower Control Lift SET TOWER SPs 2 SET TOWER SPs 2 Stage ON Temp F Stage ON Lift psi 1 2 3 4 1 2 3 4 XXX XXX XXX XXX XXX XXX XXX XXX Tower Control Temp None Tower Control Lift psi SET TOWER SPs 3 StageDiff i XX Xpsi Stage Up XX min StageDown XX min SPs 4 Control ValveSP VFDStage Valve Type NC Valve VFD Control settings are None Valve Setpoint Valve Stage VFD Stage or ValveSP VFDStage Valve Type settings are NC normally closed to tower or NO normally open Tower Control Temp None Tower Control Lift SET TOWER SPs 5 SET TOWER SPs 5 Valve SP XXX F Valve SP XXX psi Valve DB XX X F Valve DB XXX Xpsi SET TOWER SPs 6 ValveStartPosition Min 010 060 F Max 100
59. fter pressing the MENU button the top level menu screen will show COMPRESSOR UNIT EVAPORATOR CONDENSER screen n data screen n data screen n data Where n is the number of the last viewed COMPRESSOR screen The arrow keys will automatically return to the scroll mode at this time Different compressor screens can then be selected with the UP DOWN arrow keys The complete menu structure follows Data screens are shown as data when a single screen is at the bottom of the menu structure and as data n when multiple screens are available using UP DOWN keys OM WMC 3 57 Menu Structure Scrolled As an alternate to selecting screens with the menu function it is be possible to scroll through all of them with the 4 arrow keys For this use the screens are arranged logically in a matrix as shown in Figure 33 Menu Matrix Figure 33 Unit Controller Menu Matrix COMP 1 OFF 2RUN Ev Cn Pmps OFF OFF View Unit Information VIEW UNIT WATER 1 F In Out Delta Evap 00 0 00 0 00 0 Cond 00 0 00 0 00 0 VIEW UNIT REFRG 1 psi F Sat Evap 000 0 000 0 Sat Cond 000 0 000 0 VIEW UNIT TOWER 1 Stages ON 0 of 2 Setpoint XXX F View Compressor Information VIEW COMP 31 1 State OFF RLA 000 Evap LWT 054 0 F VIEW COMP 2 1 State RUN RLA 095 Evap LWT 054 0 F View Evaporator VIEW EVAPORATOR SuctSH 000 0 F Approach 00 0 F See NOTE 1 VIEW UNIT WATER 2
60. h Discharge Temperature Shutdown 120 to 240 F High Discharge Temperature Load 120 to 240 F High Condenser Pressure 120 to 240 psi Motor Current Threshold 1 to 20 Surge High Suction SH Start 25 to 90 F Surge High Suction SH Run 5 to 45 F Service Vane Mode AUTO MANUAL Unload Timer 10 to 240 sec STOP Timer 1 to 240 sec These setpoints are normally viewed or changed on the OITS but can be changed on the unit controller if the OITS is not available Z z z ojz zjuj ojujujo A a a ala a a af aya Compressor Faults Problems Warnings Faults Equipment Protection Shutdowns Equipment protection faults cause rapid compressor shutdown The compressor is stopped immediately if the compressor was running The following table identifies each alarm gives the condition that causes the alarm to occur and states the action taken because of the alarm All equipment protection alarms require a manual reset Table 14 Compressor Controller Faults Equipment Protection Shutdowns Occurs When Action Taken Low Evaporator Pressure Evaporator Press lt Low Evap Pressure SP Rapid Stop High Condenser Pressure Cond Press gt High Condenser Pressure SP Rapid Stop Low Motor Current lt Motor Current Threshold with Compressor ON for 30 sec Rapid Stop High Discharge Temperature Temp gt High Discharge Temperature SP Rapid Stop Mechanical High Pressure Digital Input High P
61. he actual RPM exceeds 350 rpm the lead compressor will unload to 25 of the MAX KW setpoint The lead compressor will maintain this demand setting for a time period set by the Step Down timer found in Set COMP1 SPs 8 When the Step Down timer expires both compressors should be nearly matched in capacity and can began amp balancing to share the load equally Note If the Next On compressor is on another chiller the controller will start that chiller s evaporator and condenser pumps if they are separate from the lead unit s pumps Only compressors on the same unit will unload the lead compressor before starting the lag compressor Unloading compressors The setpoint of Nominal Capacity is used for defining the point to unload a compressor on a single or two chiller system With each compressor having its Nominal Capacity defined then the network which is load 12 OM WMC 3 balanced continues to unload at 0 2 tenths or more below setpoint Each compressor keeps computing the spare capacity of the network When the designated Next Off sees enough spare capacity it will turn off Then similarly in about 40 seconds a new compressor will be designated as the Next Off and the spare capacity will continue to be calculated between the remaining compressors Compressors continue to unload and stage off until there is only one compressor running It will shut off when the water temperature reaches the LWT Setpoint
62. he correct factory installed communication module The modules can also be added in the field during or after installation If an interface module was ordered one of the following BAS interface installation manuals was shipped with the unit Contact your local McQuay sales office for a replacement if necessary e IM 735 LONWORKS Communication Module Installation e IM 736 BACnet Communication Module Installation e IM 743 Modbus Communication Module Installation Connection to Chiller Connection to the chiller for all BAS protocols will be at the unit controller An interface card will have to be installed in the unit controller depending on the protocol being used OM WMC 3 77 This document contains the most current product information as of this printing For the most up to date 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 McQuay 800 432 1342 e www mcquay com OM WMC 3 8 07
63. in inch pounds View Unit Status VIEW UNIT STATUS 1 Unit COOL COMP 1 OFF 2 RUN Ev Cn Pmps STRT RUN Unit states can be OFF COOL SHUTDOWN and ALARM as determined from the Unit State variable the Unit Mode setpoint and the presence of a unit shutdown alarm Compressor states can be OFF START HOLD LOAD UNLOAD SHUTDN and ALARM as determined from the Comp State variable the Load and Unload outputs and the presence of a compressor shutdown alarm Evap and Cond Pump states can be OFF STRT start amp RUN VIEW UNIT STATUS 2 COMP 1 OFF Start Start Tmr Cir Inhibits None Inhibits are signals that prevent further loading such as Load Limit High Discharge Pressure etc VIEW UNIT STATUS 3 COMP 2 OFF Start Start Tmr Cir Inhibits None Inhibits are signals that prevent further loading such as Load Limit High Discharge Pressure etc View Water Status WATER F 1 Out Delta XX X XX X XX X XX X WATERY F 2 Out Delta XX X XX X This screen deals with a heat recovery option not currently available on WMC units vIEW UNIT WATERY F 3 60 OM WMC 3 Water Flow Rates Evap XXXXX GPM XXXXX GPM Q 0 3 Q li View Refrigerant Status VIEW UNIT REFRG 1 psi F Sat Evap XXX X XX X Sat Cond XXX X XX X VIEW UNIT REFRG 2 Suct Line XXX X F Liquid Line XXX X F Lift Press XXXX psi View Tower Status Tower Control Temp None Tower Control Lift VI
64. ing Tower VFD Speed 0 to 10 VDC 0 to 100 EXV signal to IB Valve Control Bd 0 to 10 VDC 0 to 100 Y3 Electronic Expansion Valve 0 to 10 VDC 0 to 100 Open Unit Controller Setpoints The following parameters are remembered during power off are factory set to the Default value and can be adjusted to any value in the Range column The Type column defines whether the setpoint is part of a coordinated set of duplicate setpoints in different controllers There are three possibilities as given below N Normal setpoint Not copied from or copied to any other controller M Master setpoint Setpoint is copied to all controllers in the Sent To column S Slave setpoint Setpoint is a copy of the master setpoint in the unit controller OM WMC 3 19 At power up the slave node checks if the master node is operational and if so it sets its copy of the setpoint equal to the master s Otherwise the setpoint remains unchanged During normal operation any time the master setpoint changes the slave is updated as well The PW password column indicates the password that must be active in order to change the setpoint Codes are as follows O Operator M Manager T Technician not available through the 4x20 display keypad The following table groups setpoints that relate to the entire unit operation and are stored for the most part in the unit controller All settings are made through the OITS indi
65. interface depending on date of manufacture e Entering and leaving chilled water temperature e Enter and leaving condenser water temperature e Saturated evaporator refrigerant temperature and pressure e Saturated condenser temperature and pressure e Outside air temperature optional e Suction line liquid line and discharge line temperatures calculated superheat for discharge and suction lines and calculated subcooling for liquid line e Automatic control of primary and standby evaporator and condenser pumps e Control of up to 4 stages of cooling tower fans plus modulating bypass valve and or tower fan VFD Although fan staging is available continuous modulated control of tower capacity is preferred and recommended e History trend feature that will constantly log chiller functions and setpoints The controller will store and display all accumulated data for recall in a graphic format on the screen Data can be downloaded for archival purposes e Three levels of security protection against unauthorized changing of setpoints and other control parameters e Plain language warning and fault diagnostics to inform operators of most warning or fault conditions Warnings problems and faults are time and date stamped for identification of when the fault condition occurred In addition the operating conditions that existed just prior to shutdown can be recalled to aid in resolving the cause of the problem e Twenty five previous faults
66. ion Taken No flow indicated for 5 sec with Evaporator Pump 1 ON AND the other pump is available per the Evap Pump SP Start pump 2 Manual AND has not faulted No flow indicated for 5 sec with Evaporator Pump 2 ON AND the other pump is available per the Evap Pump SP Start pump 1 Manual AND has not faulted No flow indicated for 5 sec with Condenser Pump 1 ON AND the other pump is available per the Evap Pump SP Start pump 2 Manual AND has not faulted No flow indicated for 5 sec with Condenser Pump 2 ON AND the other pump is available per the Evap Pump SP Start pump 1 Manual AND has not faulted Evaporator Pump 1 Fault Evaporator Pump 2 Fault Condenser Pump 1 Fault Condenser Pump 2 Fault Manual Reset mode goes back to Entering Evaporator Water Temperature Sensor fault AND leaving water reset is based on entering Reset mode is Sensor Fault water setto No Reset Entering Water Warnings The following alarms only generate a warning message to the operator Chiller operation is not affected OM WMC 3 21 Table 8 Unit Controller Warnings Entering Evaporator Temperature Sensor Fault Entering Condenser Temperature Sensor Fault Leaving Condenser Temperature Sensor Fault Liquid Line Refrigerant Temperature Sensor Fault Sensor is open or shorted Annunciation Automatic Sensor is open or shorted Annunciation Automatic Sensor is open
67. it Input Output Screen The screen shown in Figure 17 to the left gives the status of the unit controller digital unitvo inputs and outputs and analog outputs The unit controller in concerned with the UNIT I O operation of the entire unit and its I Os reflect this Note that operation of condenser and evaporator water pumps and tower operation constitute most of the data flow An Manual Switch illuminated block gray in the figure indicated that either an input or output signal Remote Start exists Mode Pressing the Evaporator or Condenser buttons on Detail View Screen will display pertinent vessel temperatures and pressures The screens are very simple self Evap Pump 1 explanatory and not shown here Evap Pump 2 Cond Pump 1 Cond Pump 2 Tower Fan 1 Tower Fan 2 Tower Fan 3 Tower Fan 4 Alarm Analog Outputs Bypass Valve 100 Tower Fan VFD 100 EXV Position 38 OM WMC 3 Figure 18 Labeled Bar Graphs COMPRESSOR EVAPORATOR CONDENSER kW 80 KAA 4110 EWT AT 60 EWT ATI LLT kilo atts Entering Water Temp Inlet Guide Vanes Liquid Line Temp The bar chart screen is accessed from the MENU screen Figure 14 by selecting Labeled Bar Graphs for the graphs with labels attached as shown above or select Bar Graphs for charts without labels Pressing COMP on the lower left corner of the screen will toggle between the unit s two compressors Pressing MENU HISTORY VIEW or SET
68. it board terminal blocks or power plugs while power is applied to the panel NOTICE This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with this instruction manual may cause interference to radio communications Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at the owner s own expense McQuay disclaims any liability resulting from any interference or for the correction thereof Temperature and humidity considerations The unit controllers are designed to operate within an ambient temperature range 20 F to 130 F 7 C to 54 C with a maximum relative humidity of 95 non condensing HAZARD IDENTIFICATION INFORMATION Z DANGER Dangers indicate a hazardous situation which will result in death or serious injury if not avoided A WARNING Warnings indicate potentially hazardous situations which can result in property damage severe personal injury or death if not avoided A CAUTION Cautions indicate potentially hazardous situations which can result in personal injury or equipment damage if not avoided OM WMC 3 Features of the Control Panel e Control of leaving chilled water within a 0 2 F 0 1 C tolerance e Display of the following temperatures and pressures on a 15 inch Super VGA touch screen operator
69. li SP8 Set MINIMUM VALVE POSITION when EWT is at or below SP9 Default is 0 iv SP9 Set the EWT at which the valve position will be at SP8 Default is 60 F v SP10 Set the initial valve position when EWT is at or above SP11 Default is 100 vi SP11 Set the EWT at which initial valve position is set to SP10 Default is 90 F vii SP12 Set the minimum position to which the valve can go Default is 10 viii SP13 Set the maximum position to which the valve can go Default is 100 ix SP14 Set the control gain for error Default is 25 x SP15 Set the control gain for slope Default is 25 A CAUTION Setpoints 14 and 15 are site specific dealing with system fluid mass component size and other factors affecting the reaction of the system to control inputs These setpoints should be set by personnel experienced with setting up this type of control to avoid possible equipment damage OM WMC 3 47 c If LIFT was selected for fan control use i SP3 Set the VALVE TARGET setpoint usually 30 psi below the minimum fan stage setpoint established in TOWER SP15 This keeps full flow through the tower until the last fan is staged off ii SP5 Set VALVE DEADBAND the default of 6 psi is a recommended initial setting iii SP12 Set the minimum position to which the valve can go Default is 10 iv SP13 Set the maximum position to which the valve can go Default is 100 v SP14 Set the control gain for error Default is
70. lowing matrix NOTE All relevant unit operating data and setpoint entry are available and performed on the unit controller and there is no need to consult the individual compressor controllers The following table is for general information only VIEW STATUS SCREENS VIEW UNIT STATUS 1 VIEW UNIT WATER 1 F VIEW UNIT REFRG 1 VIEW COMP 1 VIEW EVAPORATOR _ VIEW CONDENSER In Out Delta psi F State OFF SuctSH 000 0 F DischSH Evap 00 0 00 0 00 0 SatEvap 000 0 000 0 RLA 000 Approach 00 0 F 000 0 F Ev Cn Pmps OFF OFF Cond 00 0 00 0 00 0 Sat Cond 000 0 000 0 Evap LWT 054 0 F Approach 00 0 F Subcooling _00 0 F VIEW UNIT STATUS 2 VIEW UNIT REFRG 2 VIEW COMP 2 psi Comp OFF Suct Line 000 0 F Cond Press 000 0 Start Start Tmr Clr Liquid Line 000 0 F Evap Press 000 0 Inhibits None Lift Press 000 0psi Lift Press 000 0 VIEW COMP 8 psi WMC Compressor Oilless Design blank menu VIEW COMP 4 F Cavity Temp 000 0 F Invert Temp 000 0 C Lift Temp 00 0 F VIEW COMP 5 F Temp SH Suction 000 0 00 0 Discharge 000 0 00 0 VIEW COMP 6 psi F SatEvap 000 0 000 0 SatCond 000 0 000 0 VIEW COMP 7 Hours 00000 x10 Starts 00000 NOTE Right half of matrix continued on the next page OM WMC 3 75 SET SETPOINTS SET COMP 1 SPs 1 Demand Limit OFF Minimum Amps 040 Maximum Amps 100 SET ALARM LMTs 1 LowEvPrHold 33psi LowEvPrUnId 31 psi Low
71. ly from the keypad Systems available are e F psi unit controller compressor controller touch screen e C kPa touch screen only Security Two four digit passwords provide OPERATOR and MANAGER levels of access to changeable parameters Either password can be entered using the ENTER PASSWORD screen which can be accessed in one of three ways 1 The SET UNIT SPs menu 2 Scrolling to it last screen in the SET UNIT SPs column 3 By simply pressing the UP ARROW DOWN ARROW or DEFAULT keys while on the desired field on one of the SET screens The password can then be entered by pressing the ENTER key scrolling to the correct value with the UP and DOWN arrow keys and pressing ENTER again The length of the password shall not be indicated Once the correct password has been entered cases 1 and 2 above the PASSWORD screen shall show the active password level For case 3 above the previously selected screen shall reappear still in edit mode with the cursor on the previously selected field Once a password has been entered it shall remain valid for 15 minutes after the last key press It shall be possible to change the passwords through multi chiller communications Parameters and screens that require the MANAGER password shall not be displayed unless the MANAGER password is active 74 OM WMC 3 Compressor Controller Menu Screens Menu Matrix Each of the two compressor controllers has the same menu screens as shown in the fol
72. ments The Cold Weather scheme provides better startup under cold ambient air temperature conditions The check valve may be required to prevent entraining air at the pump inlet Figure 5 Bypass Mild Weather Operation Bypass Cold Weather Operation TOWER TOWER Z SUMP t SUMP OM WMC 3 Operating the Control System Interface Panel On Off The Operator Interface Panel is turned on and off with a switch located at the lower front of the panel Screen control buttons are located to either side of it and elicit on screen prompts when pressed The screen is equipped with a screen saver that blackens the screen Touching the screen anywhere reactivates the screen If the screen is black touch it first to be sure it is on before using the ON OFF botton Start Stop Unit There are four ways to start or stop the chiller Three are shown below and selected in SETPOINT MODE SP3 the fourth way is through panel mounted switches 1 Operator Interface Panel LOCAL Home Screen 1 has AUTO and STOP buttons that are only active when the unit is in LOCAL CONTROL This prevents the unit from being accidentally started or stopped when it is normally under control from a remote switch or BAS When these buttons are pressed the unit will cycle through its normal starting or stopping sequence 2 Remote SWITCH Selecting SWITCH in SP3 will put the unit under the control of a remote switch that must be wir
73. minus the Shutdown Delta T Multi Chiller Setup Component Description Communication Setup The communication wiring and setup required for dual compressor operation is setup in the factory and should be reviewed when the chiller is initially started after installation or if there is any change made in the chiller control hardware RS485 communication wiring between chillers should be field wired before start up and installed as a NEC Class 1 wiring system Table 1 Address DIP Switch Settings for Controllers Using Multi chiller communication Chiller Comp 1 1 Unit Controller 5 Reserved 6 Operator Interface 7 Reserved 8 100000 010000 101000 011000 111000 000100 9 10 13 14 15 16 100100 010100 101100 011100 111100 000010 NOTES 1 Two WMC units can be interconnected 2 The interface setting is not a DIP switch setting The Operator Interface Touch Screen OITS address is selected by selecting the service set screen Then with the Technician level password active select the PLAN Comm button Buttons A 7 B 15 C 23 D 31 will appear in the middle of the screen then select the letter for the OITS address for the chiller that it is on Then close the screen Note that A is the default setting from the factory 3 There are six Binary DIP Switches Up is On indicated by 1 Down is Off indicated by
74. n Lift 45 psi 10 to 130 psi Stage 3 On Lift 55 psi 10 to 130 psi Stage 4 On Lift 65 psi 10 to 130 psi Cooling Tower Valve VFD Z Z Z Z Z Z z 2 2 2 2 2 Z 2 gj g g g zZ g g z g zZ gz z z z None Valve Setpoint Valve Stage Valve VFD Control VFD Stage Valve SP VFD Stage Valve Setpoint Temp 40 to 120 F Valve Setpoint Lift 10 to 130 psi Valve Deadband Temp 1 0 to 10 0 F Valve Deadband Lift Continued on next page 20 1 0 to 20 0 psi OM WMC 3 Manual Stage Down 20 0 to 100 Stage Up 80 0 to 100 Valve Control Range Min 10 0 to 100 Valve Control Range Max 90 0 to 100 NC To Tower NG ENG Minimum Start Position 0 0 to 100 Minimum Position 60 F 0 to 100 F Maximum Start Position 100 0 to 100 Maximum Position 90 F 0 to 100 F Error Gain 25 10 to 99 Slope Gain 25 10 to 99 Z Valve Type Z Z Z Z Z Z Zz z z z g g g Z zZ zZ Z Z z Z These setpoints are normally viewed or changed on the OITS Faults Problems Warnings Faults Equipment Protection Shutdowns There are no Unit protection shutdown alarms all such alarms are handled through the compressor controllers Problems Limit Alarms The following alarms limit operation of the chiller in some way as described in the Action Taken column Table 7 Unit Controller Limit Alarms Occurs When Act
75. n the operator interface panel on the Setpoint Timer screen Configure the transfer switch provided with the generator to automatically shut down the chiller before transfer is made The automatic shut off function can be accomplished through a BAS interface or with the remote on off wiring connection shown in Figure 10 on page 31 A start signal can be given anytime after the stop signal since the three minute start to start timer will be in effect Chiller Control Power For proper operation on standby power the chiller control power must remain as factory wired from a unit mounted transformer Do not supply chiller control power from an external power source because the chiller may not sense a loss of power and do a normal shutdown sequence OM WMC 3 11 Sequence of Operation Start up of WMC Compressors Next On Status If none of the OFF conditions are true then all the MicroTech II compressor controls in a network of up to 2 units four compressors will pole the status of each to determine the one having Next On status which is usually the compressor with the least starts This takes about one minute Evap Evaporator Pump Start Once this is determined the unit controller of the chiller with the Next On compressor when there are two chillers will start the evaporator pump and determine if there is load based on the water temperature This is determined if the leaving evaporator water is above the
76. ns in the direction indicated by the arrows default mode e Select a specific data screen in the menu matrix using dynamic labels on the right side of the display such as ALARM VIEW etc this mode is entered by pressing the MENU key For ease of use a pathway connects the appropriate button to its respective label on the screen e Change field values in setpoint programming mode according to the following table LEFT key Default RIGHT key Cancel UP key Increase DOWN key Decrease These four programming functions are indicated by one character abbreviation on the right side of the display This programming mode is entered by pressing the ENTER key Getting Started There are two basic procedures to learn in order to utilize the MicroTech II controller 1 Navigating through the menu matrix to reach a desired menu screen and knowing where a particular screen is located 2 Knowing what is contained in a menu screen and how to read that information or how to change a setpoint contained in the menu screen Navigating The menus are arranged in a matrix of screens across a top horizontal row Some of these top level screens have sub screens located under them The location of each controller s screens can be found in the following table Controller Screen Details Unit Page 58 Page 60 Compressor Page 75 Not Applicable There are two ways to navigate through the menu matrix to reach a desired menu screen 1
77. nt only if Valve VFD Control setpoint VFD Stage OR Valve SP VFD Stage Down staging occus when the the following conditions are met e The stage down timer completes e The ECWT is lt Stage X ON Temp setpoint Stage Differential Temp setpoint point only if the Tower Control setpoint Temperature e The Lift pressure is lt Stage X ON Lift setpoint Stage Differential Lift setpoint point only if the Tower Control setpoint Lift e Bypass valve position is lt the Stage Down setpoint only if Valve VFD Control setpoint Valve Stage e VFD Speed is lt the Stage Down setpoint only if Valve VFD Control setpoint VFD Stage OR Valve SP VFD Stage Each stage up or stage down event restarts both the stage up and stage down timers Only one fan output is switched at a time except that all outputs switch OFF when the condenser pump state equals OFF Analog Output Control Each analog output is controlled according to the following rules algorithms and in accordance with whether the Compressor Mode setpoint is set to AUTO or MANUAL normal operation or TEST test mode All outputs are initialized to 0 at power on Cooling Tower Bypass Valve When the Valve VFD Control setpoint is set to None OR VFD Stage this output is set to 0 Otherwise it is controlled as described below Initial Valve Position When the condenser pump is not in the RUN state the valve output is set as a function of entering condenser water temperatu
78. oaded The flag is set full load when one or more of the following conditions are met The compressor is at its physical limit of capacity which means For VFD Set Point NO The load output has been pulsed ON for a cummulative time equal to or greater than the Full Load set point menu 4 Any unload pulse will reset the cumulative time to zero For VFD Set Point YES Load pulsing has exceeded the Full Load set point as described above AND the VFD speed 100 OR The Vanes Open digital input is On AND the VFD speed 100 The RLA is above or equals the Maximum Amp limit set point The RLA is above or equals the Demand Limit analog input value The RLA is above or equals the Network Limit value e The evaporator pressure is below the Low Evap Pressure Inhibit set point When none of the above conditions are met the Full Load flag is cleared Absolute Capacity Each compressor estimates its absolute capacity from the present value of RLA and the Absolute Capacity set point from the equation Absolute Capacity RLA Factor Absolute Capacity set point Where the RLA Factor is interpolated from the following table RLA 0 50 75 100 150 RLA Factor 0 0 35 0 75 1 00 1 50 SET COMP N 9 Protocol M BUS MSTR Ident Number 001 Baud Rate 19200 SET COMP N 10 68 OM WMC 3 Refrg Sat Pressure Evp Offset 00 0psi Cnd Offset 00 O0psi SET COMP N 11 ELWT Offset 00 0 F S
79. off control of unit can be accomplished by installing a set of dry contacts between terminals 70 and 54 If field supplied pressure differential or flow switches are used they must be installed across the vessel and not the pump They must be suitable for 24vac and low current application The unit is shipped with factory mounted and wired thermal dispersion flow switches Customer supplied 115 vac 20 amp power for optional evaporator and condenser water pump control power and tower fans is supplied to unit control terminals UTB1 85 power 86 neutral PE equipment ground Optional customer supplied 115 vac 25 VA maximum coil rated chilled water pump relay ep1 amp 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 amp 2 is to be wired as shown Units with free cooling must have condenser water above 60 F before starting Optional customer supplied 115 vac 25 VA maximum coil rated cooling tower fan relays C1 C2 standard C3 C4 optional may be wired as shown This option will cycle the cooling tower fans in order to maintain unit head pressure Auxiliary 24 vac rated contacts in both the chilled water and condenser water pump starters should be wired as shown Voltage unbalance not to exceed 2 with a resultant current unbalance of 6 to 10 times the vol
80. olenoids and pressure temperature sensors Figure 9 Compressor Electric Electronic Components 30 1 Rectifiers 2 Main Power Block 3 Soft Start Controller 4 Insulated gate High Voltage DC DC Compressor Bearing Motor interstage pressure Suction Pressure Bipolar Transistor 1 G B T Inverter Converter Controllers temperature sensor temperature sensor OM WMC 3 Figure 10 Field Wiring Diagram MICROTECH CONTROL BOX TERMINALS asv eav UTB1 PE 54 il GND J e 85 REMOTE POWER ON OFF NOTE6 NOTE 4 86 NEUTRAL e o a o NOTE 9 so 70 EN K MODE SWITCH cooune q ale NOTE TOWER ie e o t FOURTH 86 0 T STAGE Pa STARTER 86 EP2 e T NOTE 10 a a peA CHILLED NOTE 9 6 EWI 2 WATER a A s PUMP COOLING q 6 79 NOTE7 STARTERS a f AN gt A mu an LT TOWER THIRD STAGE on STARTER 7 EPA J 77 NOTE 10 PJ NOTE 9 EWM N A 6 scooune J DS 7 g s TOWER fG A SECOND NOTE 5 NOTE 5 STAGE SWITCH SWITCH STARTER Py DELTAP DELTA P NOTES FLOW OR FLOW OR 1 COOLING i cs cs ly H CF1 EVAP COND Ile NOTE 9 o Lit
81. ontrol panel as well as on board the compressors providing monitoring and control functions required for the controlled efficient operation of the chiller The system consists of the following components e Operator Interface Touch Screen OITS one per unit provides unit information and is the primary setpoint input instrument It has no control function e Unit Controller one per chiller controls unit functions and communicates with all other controllers It is the secondary location for setpoint input if the OITS is inoperative It is located in the control panel that is adjacent to the OITS Panel e Compressor Controller for each compressor controls compressor functions They are located in the control panel e On board compressor controller mounted on each compressor that monitors compressor operation and controls bearing operation The operator can monitor all operating conditions by using the unit mounted OITS In addition to providing all normal operating controls the MicroTech II control system monitors equipment protection devices on the unit and will take corrective action if the chiller is operating outside of its normal design conditions If a fault condition develops the controller will shut a compressor or the entire unit down and activate an alarm output Important operating conditions at the time an alarm condition occurs are retained in the controller s memory to aid in troubleshooting and fault analysis 8 OM WMC 3
82. or shorted Annunciation Automatic Sensor is open or shorted Annunciation Automatic Unit Controller Functions Leaving Water Temperature LWT Reset The Active Leaving Water variable shall be set to the current Leaving Water Temperature LWT setpoint unless modified by one of the reset methods below The current LWT setpoint is Cool LWT as determined by the chiller mode The type of reset in effect is determined by the LWT Reset Type setpoint Reset Type NONE The Active Leaving Water variable is set equal to the current LWT setpoint Reset Type RETURN The Active Leaving Water variable is adjusted by the return water temperature When the chiller mode COOL the Active Leaving Water variable is reset using the following parameters 1 Cool LWT setpoint 2 Max Reset Delta T setpoint 3 Start Reset Delta T setpoint Reset is accomplished by changing the Active Leaving Water variable from the Cool LWT setpoint to the Cool LWT setpoint Max Reset Delta T setpoint when the evaporator return leaving water temperature delta varies from the Start Reset Delta T setpoint to 0 The Active Leaving Water variable is set equal to the Cool LWT setpoint if the reset signal is less than or equal to 4 mA It is set equal to Cool LWT setpoint Max Reset Delta T setpoint if the reset signal equals or exceeds 20 mA The Active Leaving Water variable will vary linearly between these extremes if the reset signal is between
83. or under it The arrow keys then operate as follows CANCEL gt Key Reset the current field to the value it had when editing began DEFAULT lt Key Set value to original factory setting INCREMENT th Key Increase the value or select the next item in a list DECREMENT J Key Decrease the value or select the previous item in a list During edit mode the display shows a two character wide menu pane on the right as shown below OM WMC 3 73 SET UNIT SPs X data data data Additional fields can be edited by pressing the ENTER key until the desired field is selected When the last field is selected pressing the ENTER key switches the display out of edit mode and returns the arrow keys to scroll mode Alarms When an alarm occurs the alarm type date and time are stored in the active alarm buffer corresponding to that alarm viewed on the Alarm Active screens and also in the alarm log buffer viewed on the Alarm Log screens The active alarm buffers hold a record of the last occurrence of each alarm and whether or not it has been cleared The alarm can be cleared by pressing the Edit key A separate buffer is available for each alarm High Cond Pressure Evaporator Freeze Protect etc The alarm history buffer holds a chronological account of the last 25 alarms of any type Display Languages Languages currently available are e English Units of Measure It is possible to select units of measure direct
84. ord The Alarm ON OFF button is usually only found on demonstration software The red ALARM light appears on this and many other screens when an alarm becomes active There is no alarm active on this demonstration screen so the Alarm shows as dark blue OPERATING MANUAL displays the manual in Adobe It can be downloaded via the USB port PARTS LIST displays the list It may not be active on some units 52 OM WMC 3 HISTORY Screens Figure 29 History Trend Graph vap OUT Evap IN Cond OUT Cond IN 0 10 00 14 00 TIME of DAY Pressure COMP p foo ooo ee The Trend History Overview allows the user to view the various parameters listed on the right side of the screen The temperature scale in F is on the left Pressure in psi and RLA are represented by the right hand scale The screen can display history for 8 hour 2 hour or 20 minute periods by pressing 8 2 or 1 3 respectively Pressing NOW for any time period will start the display for the current time beginning on the right of the screen with history flowing to the left The arrow buttons scroll the time period forward or backward Obviously if NOW is selected the forward button gt will not go into the future The COMP button toggles between compressors one and two OM WMC 3 53 Figure 30 Alarm History Floppy Download Alarm Color Code Jj FAU LT C omp Corrective Action Limits Operation In Some Way Op f S
85. other setpoint can be selected Additional setpoints can be changed by selecting another setpoint on the screen or by selecting an entirely new group of setpoints Explanation of Setpoints Each of the seven setpoint group of screens are detailed in the following section 1 Ph ee E TIMERS for setting timers such as start to start etc ALARMS for setting the limit and shutdown alarms VALVE sets the parameters for operation of an optional field installed tower bypass valve TOWER selects the method of controlling the cooling tower and sets the parameters for fan staging VFD MOTOR selects motor related setpoints such as amp limits Also has maximum and minimum rate of change of chilled water temperature MODES selects various modes of operation such as control source multiple compressor staging pump staging BAS protocol etc WATER leaving water temperature setpoint start and stop delta T resets etc OM WMC 3 41 TIMERS Setpoint Figure 20 TIMERS Setpoint Screen Unit Status Chiller A coor AUTO Remote Switch S ET P N TS Compressor Status 1 RUN Hold O F PSI 2 OFF Awaiting Load J wn Evap Recirculate Timer Sets the amount of time the evaporator pump must run before a compressor can start TIMERS 0 2 to 5 0 Minutes Full Load Time Interlock Timer CANCE Prelube Timer Stop To Start Timer Start To Start Timer DOWN H Evap Recirculate Timer m ENTER HISTORY
86. p Press rises above Inhibit Loading setpoint SP 3psi Low Evaporator Pressure Pressure lt Low Evap Pressure Unload Evap Press rises above Unload setpoint SP 3psi Inhibit loading Unload Evaporator Freeze Evap Sat Refr Temp lt Evaporator Freeze Start evaporator Temp gt Evaporator Freeze Protect setpoint pump SP 2 F Condenser Freeze Cond Sat Refr Temp lt Condenser Freeze Start condenser Temp gt Condenser Freeze Protect Setpoint pump SP 2 F Temperature gt High Discharge Temp lt High Dsch Temp Temperature Load SP AND Load Load SP 3 F OR Suction superheat lt 15 F Superheat gt 18 F High Discharge Temperature Warnings Warnings advise that a non catastrophic problem exists such as failed temperature sensor that provides a signal for information not control purposes There are no Warnings associated with the compressor controllers Compressor Controller Functions Each compressor determines if it has reached its maximum capacity or maximum allowed capacity and if so set its Full Load flag The flag is based on a number of conditions Absolute Capacity Each compressor estimates its absolute capacity from the present value of RLA and the Absolute Capacity setpoint from the equation Absolute Capacity RLA Factor Absolute Capacity setpoint where the RLA Factor is interpolated from the following table YRLA 0 50 75 100 150 RLA Factor 0 0 35
87. p limit imposed by an outside signal such as the load limit function Condenser Recirc Recirculation Timer A timing function with a 30 second default that holds off any reading of condenser water for the duration of the timing setting This delay allows the sensors to take a more accurate reading of the condenser water temperature Dead Band The dead band is a set of values associated with a setpoint such that a change in the variable occurring within the dead band causes no action from the controller For example if a temperature setpoint is 44 F and it has a dead band of 2 0 degrees F nothing will happen until the measured temperature is less than 42 F or more than 46 F DIN Digital input usually followed by a number designating the number of the input Discharge Superheat Discharge superheat is calculated using the following equation Discharge Superheat Discharge Temperature Condenser Saturated Temperature Error In the context of this manual Error is the difference between the actual value of a variable and the target setting or setpoint Evaporator Approach The evaporator approach is calculated for each circuit The equation is as follows Evaporator Approach LWT Evaporator Saturated Temperature Evap Hold loading This is a setpoint that establishes the minimum evaporator pressure to which the chiller is allowed to go It signals that the unit is at full load so the no further loading will occur
88. p to the total number of compressors Sequence number has priority over other considerations If four compressors in a system are given the sequence numbers 1 through 4 they will always start in that order With the same number they will auto sequence e In HI EFF or PUMP Mode all compressors must have the same sequence number e Max Comprs ON limits the number of compressors allowed to run in multi compressor systems It provides a floating standby compressor All compressor controllers must have the same setting for this setpoint SET COMP N SPs 3 StageDeltaT 1 0 F Stop Start 03min Start Start 40min SET COMP N SPs 4 Full Load 300sec Name Plate RLA 085 Full Load timing is one of several full load flags parameters that indicate a compressor is at full load SET COMP N SPs 5 Nom Capacity 0100T Hotgasbypass Ignore hot gas bypass setting WMC chillers are not so equipped SET COMP N SPs 6 IntrLokTmr 010sec UnloadTimer 030sec Max Str LWT XXX F Ignore Max Str LWT setting OM WMC 3 67 SET COMP N 7 WMC Automatic Vane Control blank menu Ignore this menu on WMC chillers SET COMP N 8 MAX KW 076 0 Lag Start 000Sec Step Down 060Sec Staging Parameters Full Load Determination Each compressor determines if it is at its maximum capacity or maximum allowed capacity and if so set its Full Load flag The flag advises other components that the compressor is fully l
89. r for 2 compressor if 1 it is always first to start if 2 is always second Note 1 Normal uses standard sequencing Efficiency starts one compressor on each unit Pump starts all compressors on one chiller first Standby uses this compressor only if another fails Sets sequence number for 1 compressor if 1 it is always first to start if 2 is always second Note 1 Ditto No 9 Total number of compressors minus standby Sets BAS Standard Protocol to be used or LOCAL if none Pump 1 Only Pump 2 Only use only these pumps AUTO balance hours between 1 and 2 1 Primary 2 Primary if primary fails use other Pump 1 Only Pump 2 Only use only these pumps AUTO balance hours between 1 and 2 1 Primary 2 Primary if primary fails use other Control Source LOCAL BAS SWITCH Sets control source Pump 1 Only Pump 2 3 2 1 OFF everything is off AUTO Evap pump on Unit Enable OFF AUTO comp cond pump and tower on as required to meet LWT 1 If both compressors have the same sequence number they will automatically balance starts and run hours 2 See page 68 for further details on pump operation 50 OM WMC 3 WATER Setpoints Figure 27 WATER Setpoint Screen Unit Status Chiller A SETPOINTS Compressor Status 1 RUN Hold o F PSI 2 OFF Awaiting Load gt m D Leaving Water Temp Cool ets control target for evaporator leaving water temperature in COOL mod
90. re ECWT per the following graph Figure 34 Bypass Valve Position Initial Valve Position values are examples only Max Position Set Point 90 F Min Position Set Point 60 F Min Start Position Max Start Position Set Point 10 Set Point 90 Normal Operation 72 OM WMC 3 When the condenser pump is in the RUN state the valve output is controlled in one of two modes as specified by the Valve VFD Control setpoint The controlled parameter CP is either ECWT or Lift as specified by the Tower Control setpoint When the desired output signal varies from 0 to 100 the output voltage will vary as follows e Oto 10 VDC Valve Type NC to tower e 10to0 VDC Valve Type NO to tower Valve Setpoint Mode This mode is operational when the Valve VFD Control setpoint is set to Valve Setpoint OR Valve SP VFD Stage In this mode the valve output is varied with a proportional derivative PD algorithm with deadband in order to maintain the controlled parameter CP at the desired value The output is always limited between the Valve Control Range Min setpoint and the Valve Control Range Max setpoint A valve increment is computed once every 5 seconds according to the following equation e Increment Error Error Gain setpoint Slope Slope Gain setpoint Where Error ECWT Valve Setpoint Temp only if Tower Control setpoint Temperature e Error Lift Valve Setpoint Lift only if
91. ressure Rapid Stop High Motor Temperature Digital Input High Temperature Rapid Stop Temp gt Surge High Suct SH Start SP during first 5 minutes of Compressor ON Temp gt Surge High Suct SH Run SP after first 5 minutes of Compressor ON RLA gt Motor Current Threshold SP with Compressor OFF for 30 sec Starter Fault Digital Input Fault AND Compressor State START INTLOK RUN or UNLOAD Sensor shorted or open Rapid Stop Surge High Suct SH Starting Rapid Stop Surge High Suct SH Running Rapid Stop Annunciation No Compressor Stop Starter Fault Rapid Stop Leaving Evaporator Water Temperature Sensor Fault Evaporator Pressure Sensor Fault Sensor shorted or open Rapid Stop Condenser Pressure Sensor Fault Sensor shorted or open Rapid Stop Suction Temperature Sensor Fault Sensor shorted or open Rapid Stop Discharge Temperature Sensor Fault Evaporator Water Flow Loss Evaporator Flow DI No Flow for gt 10 sec Rapid Stop Condenser Water Flow Loss Condenser Flow DI No Flow for gt 10 sec Rapid Stop Sensor shorted or open Rapid Stop Compressor Controller Events Limit Alarms The following alarms do not cause compressor shutdown but limit operation of the chiller as described in the Action Taken column OM WMC 3 25 Table 15 Compressor Controller Events Occurs When Action Taken Automatic Reset Low Evaporator Pressure Pressure lt Low Evap Pressure Inhibit Eva
92. scriminately as to whether they are unit or compressor Table 6 Unit Controller Setpoints Unit Unit Enable OFF KEYPAD Manual Reference OFF ON KEYPAD BAS DIGITAL INPUT F psi C kPa ENGLISH TBD NONE BACnet LonWorks MODBUS N2 Control Source Display Units F psi Language ENGLISH BAS Protocol NONE z ziz Z s s Leaving Water Cool LWT 44 0 F Startup Delta T 3 0 F Shutdown Delta T 3 0 F LWT Reset Type NONE Max Reset Delta T 0 0 F Start Reset Delta T 10 0 F Timers Evap Recirculate 30 sec Pumps 40 0 to 80 0 F 0 0 to 10 0 F 0 0 to 3 0 F NONE RETURN 4 20mA 0 0 to 20 0 F 0 0 to 20 0 F Z Z Z S S E Zz 15 sec to 5 min Pump 1 Pump 1 Only Pump 2 Only Auto Only Lead 1 Primary 2 Primary Pump 1 Pump 1 Only Pump 2 Only Auto Only Lead 1 Primary 2 Primary Evap Pump Cond Pump Cooling Tower Tower Control None Tower Stages 2 1to4 None Temperature Lift 1 to 60 min 1 to 60 min 1 0 to 10 0 F 1 0 to 20 0 psi Stage Up Time 2 min Stage Down Time 5 min Stage Differential Temp 3 0 F Stage Differential Lift 6 0 psi Stage 1 On Temp 70 F 40 to 120 F Stage 2 On Temp 75 F 40 to 120 F Stage 3 On Temp 80 F 40 to 120 F Stage 4 On Temp 85 F 40 to 120 F Stage 1 On Lift 35 psi 10 to 130 psi Stage 2 O
93. tage unbalance per NEMA MG 1 1998 Standard OM WMC 3 31 Interface Touch Screen Navigation The home view screen shown on page 34 is usually left on there is a screen saver built in that is reactivated by touching the screen anywhere This VIEW screen contains the STOP and AUTO buttons used to start and stop the unit when in Local control Other groups of screens can be accessed from the Home screen by pressing one of three buttons on the bottom of the screen HISTORY VIEW SET HISTORY will go to the last history screens viewed and can toggle between the two history screens Trend History Alarm History VIEW will go to the home View screen Pressing again will go to the detail View screen used to look in detail at settings and the operation of the chiller Pressing VIEW from any other screen will return to the last displayed View screen A new button called MENU will appear when in the View mode See page 37 for details SET will go to the last Set screen used Figure 11 on the following page illustrates the arrangement of the various screens available on the OITS A few minutes practice on an actual OITS should provide an acceptable level of confidence in navigating through the screens 32 OM WMC 3 Figure 11 OITS Screen Layout ET REEN HOME SCREEN SET PRESS VIEW i PRESS SET Y EACH GROUP OF SETPOINTS HAVE SETTING AND RANGE EXPLAINED ON SCREEN SETROINTS Co SEE FI
94. tate OFF OR SHUTDOWN TEST Manual OFF DI OFF OR OR Safety Alarm Vanes Closed OR Unit State OFF OR Unload Timer Expired OR Safety Alarm START TASK Start STOP Timer Start Stop Start Timer amp Update Run Hours TASK Start Interlok Timer 10sec TEST Manual OFF DI OFF OR Unit State OFF TEST Unit State AUTO amp Next Off No InterLock UNLOAD TEST Unit State AUTO amp Evap State RUN amp TEST Unit State SHUTDOWN OR Next Off Yes amp Stage Down Now Yes TASK Start Unload Timer Compressor Capacity Control Cond State RUN amp Vanes Closed amp InterLok Timer Expired TASK Increment of starts Leaving Water Control Mode Compressor capacity is determined by the status of the leaving chilled water temperature LWT which is a direct indicator of whether the chiller is producing enough cooling to satisfy the cooling load The LWT is compared to the active chilled water setpoint and compressor loading or unloading ensues considering any capacity overrides that may be in effect Capacity Overrides The conditions described in the following subparagraphs override normal capacity control when the chiller is in the COOL mode These overrides are not in effect for loading and unloading when the Vane Mode is set to MANUAL Of the following limits the one creating the lowest amp limit is in effect The resulting present limit value for compressor current is stored in the
95. temperature ST slope value above Surge Slope Limit 8 9 A which alarm occurs Active only if ST gt SP7 F min deg F min at start 7 5 ae 5 2 At start Surge Temp ST is compared to Surge Temperature Limit 2 to 45 F this SP Alarm at STs2x SP a l 3 5 Max discharge temp to shut down High Discharge Temp Stop 6 190 F 120 to 240 F compressor Sets discharge temp above which a forced capacity increase occurs High Condenser Pressure 120 to 240 psi Max discharge pressure stop compressor Low Evap Pressure Stop 10 to 45 psi Min evap pressure stop compressor Low Evap Pressure Unload 20 to 45 psi Min evap pressure unload compressor Low Evap Pressure Inhibit 20 to 45 psi Min evap pressure inhibit loading High Discharge Temp Load 120 to 240 F OM WMC 3 43 Cooling Tower Bypass VALVE Settings Figure 22 Tower Bypass VALVE Setpoint Screen Unit Status SETPOINTS Compressor Status oO 1 RUN F iz PSI 2 OFF alve Control Slope Sain Control Slope Gain alye Contro Eror Gan Control Error Gain lt gt lt m Tower Valve Type NC Valve is normally closed to tower Valve Control Range Max Control Range Max NO Valve is normally ee Minimum Start Position Stage Down CANCEL t p E Valve Deadband Lift f Valve Deadband Temp Valve Target Lift Valve Target Temp Tower Valve T a oe r E Table 20 Tower Bypass VALVE Setpoints See page 46 for complete explanation
96. ter Temp FullLoad 300sec FullLoad 300sec Surge Slp Str 20 F Valve VFD Control StartDelta 3 0 F Name Plate RLA 085 Surge Tmp Run 06 F None StopDelta 3 0 F MtrCurThrshld 10 Valve Type NC A SET UNIT SPs 5 SET COMP SPs 5 SETCOMP 2 SPs 5 SET ALARM LMTs 5 SET TOWER SPs 5 Rest Type NONE Evap Freeze 34 0 F Valve Sp type MaxResetDT 00 0 F Nom Capacity 0100T Nom Capacity 0100T Cond Freeze 34 0 F Valve DB type StrtResetDT 10 0 F A SET UNIT SPs 6 SET COMP SPs 6 SET COMP 2 SPs 6 SET TOWER SPs 6 Soft Load OFF InterLokTmr 010sec UnloadTimer 060 sec ValveStartPosition BeginAmpLimit 040 UnloadTimer 030 sec PostlubeTmr 030 sec Min 010 060 F SoftLoadRamp 05min Max 090 090 F Alarm Log 25 SET UNIT SPs 7 SET COMP SPs 7 SET COMP SPs 7 SET TOWER SPs 7 description Max Min LWT Rates WMC Automatic WMC Automatic Valve Control Range HH MM SS Max 0 5 F min Vane Control Vane Control Min 010 MM DD YY Min _ 0 1 F min blank mask page blank mask page Max 090 SET UNIT SPs 8 SET COMP SPs 8 SET COMP SPs 8 SET TOWER SPs 8 EvapRecTmr 0 5min MAX KW 76 0 MAX KW 76 0 PD Control Loop EvapPump 1 ONLY Lag Start 000Sec Lag Start 000Sec Error Gain 25 CondPump 1 ONLY Step Down 060Sec Step Down 060Sec Slope Gain 25 SET UNIT SPs 9 SET COMP SPs 9 SET COMP SPs 9 Templifier Src Water Protocol M BUS Protocol M BUS No Start 070 F MSTR MSTR
97. ter Temperature NTC Thermistor 10k 25 C 58 to 212 F Liquid Line Refrigerant Temperature NTC Thermistor 10k 25 C 58 to 212 F Demand Limit 4 20 mA Current 0 100 RLA Evaporator Water Flow 4 to 20 mA Current 0 to 10 000 gpm Condenser Water Flow 4 to 20 mA Current 0 to 10 000 gpm Refrigerant Leak Sensor 4 to 20 mA Current 0 to 100 ppm Spare 1 2 3 4 5 6 7 8 9 a oO Table 3 Unit Controller Digital Inputs Description Unit OFF Switch 0 VAC Stop 24 VAC Auto Remote Start Stop 0 VAC Stop 24 VAC Start Not Used Evaporator Water Flow Switch 0 VAC No Flow 24 VAC Flow Condenser Water Flow Switch 0 VAC No Flow 24 VAC Flow Table 4 Unit Controller Digital Outputs Description Load Output OFF Output ON Evaporator Water Pump 1 Pump Contactor Pump OFF Pump ON Evaporator Water Pump 2 Pump Contactor Pump OFF Pump ON Condenser Water Pump 1 Pump Contactor Pump OFF Pump ON Condenser Water Pump 2 Pump Contactor Pump OFF Pump ON Tower Fan 1 Fan Contactor Fan OFF Fan ON Tower Fan 2 Fan Contactor Fan OFF Fan ON Spare Alarm Alarm Indicator Alarm OFF Alarm ON Tower Fan 3 Fan Contactor Fan OFF Fan ON Tower Fan 4 Fan Contactor Fan OFF Fan ON OlCIN OD oO AJW N oO Table 5 Unit Controller Analog Outputs Description Output Signal Range Cooling Tower Bypass Valve Position 0 to 10 VDC 0 to 100 Open Cool
98. that would lower the pressure even further Evap Recirc Evaporation Recirculation Timer A timing function with a 30 second default that holds off any reading of chilled water for the duration of the timing setting This delay allows the chilled water sensors to take a more accurate reading of the chilled water temperature EXV Electronic expansion valve used to control the flow of refrigerant to the evaporator controlled by the circuit microprocessor OM WMC 3 5 Load Limit An external signal from the keypad the BAS or a 4 20 ma signal that limits the compressor loading to a designated percent of full load Used to limit unit power input Load Balance Load balance is a technique that equally distributes the total unit load between two or more running compressors Low Pressure Hold Inhibit Setpoint The psi evaporator pressure setting at which the controller will not allow further compressor loading Hold and Inhibit are used interchangeably Low Pressure Unload Setpoint The psi evaporator pressure setting at which the controller will unload the compressor in an effort to maintain the minimum setting LWT Evaporator leaving water temperature The water is any fluid used in the chiller circuit LWT Error Error in the controller context is the difference between the value of a variable and the setpoint For example if the LWT setpoint is 44 F and the actual temperature of the water at a given moment is 4
99. the right to make changes in design and construction at anytime without notice 1 The following are trademarks or registered trademarks of their respective companies BACnet from ASHRAE LONMAaRKk LonTalk LONWoRKS and the LONMARK logo are managed granted and used by LONMARK International under a license granted by Echelon Corporation Compliant Scroll from Copeland Corporation ElectroFin from AST ElectroFin Inc Modbus from Schneider Electric FanTrol MicroTech Il Open Choices and SpeedTrol from McQuay International References to ARI and ETL apply to the WMC only OM WMC 3 Introduction This manual provides setup operating and troubleshooting information for McQuay WMC centrifugal chillers with the MicroTech II controller Please refer to the current version of IMM WMC for information relating to the unit itself A WARNING Electric shock hazard Improper handling of this equipment can cause personal injury or equipment damage This equipment must be properly grounded Connections to and service of the MicroTech II control panel must be performed only by personnel that are knowledgeable in the operation of the equipment being controlled A CAUTION Static sensitive components A static discharge while handling electronic circuit boards can cause damage to the components Discharge any static electrical charge by touching the bare metal inside the control panel before performing any service work Never unplug any cables circu
100. to be viewed for either compressor Pressing the UNIT I O button displays the unit inputs and outputs as described in Figure 17 on page 38 Pressing the EVAP or COND button will give detailed information on the evaporator or condenser pressures and temperatures Pressing the ACTIVE LWT SETPOINT button will show a window from which the leaving water setpoints can be changed However it is recommended that the SETPOINT screens described later be used for this purpose Pressing the MENU button on the bottom of the screen will go to a menu see Figure 14 from which the above listed screens can also be accessed This screen will be superimposed on the right side of the VIEW screen This screen will remain visible until another display button such as STATE I O etc is pressed 36 OM WMC 3 Figure 14 View Menu Chiller A COOL AUTO Remote Switch VIEW Caillte emiir Aa 1 RUN Hold S PS 2 OFF Awaiting Load Compressor Compressor Compressor LABELED BAR GRAPHS Unit Evaporator Exit Menu This View Menu is accessed by pressing the MENU button from the Detail View Screen The menu screen accesses several informational screens as shown in the above figure Figure 15 View Compressor State Screen For example pressing the Compressor State button on the Menu screen in Figure 14 will display the screen shown in Figure 15 on the right side of both the Menu screen and the Detail View screen The Compressor State
101. um Number of compressors ON setpoint MAX_ON_SP Possible settings 1 4 This setpoint is the same for all compressors 4 Number of starts for all compressors 5 Number of run hours for all compressors 6 Status of all compressors On line Available Unavailable Starting Running etc Configuration Rules 1 Each standby compressor must have a sequence number greater than or equal to all non standby compressors for which it is in standby 2 All compressors in an efficiency priority or pump priority group must be set to the same sequence number OM WMC 3 27 Compressor State Control Comp State Operation of the compressor is controlled by the state transition diagram shown below A state variable Comp State shall be used to maintain the current state OFF START INTLOK RUN UNLOAD or STOP Transitions from one state to another are controlled by the condition statements in the TEST boxes TASK boxes indicate actions that must be performed Figure 8 Compressor State TEST Unit State AUTO amp Evap State RUN amp Next On Yes amp Power ON s eee tage Up Now YES amp Unit Mode NOT HEAT OR OFF EvLWT Temperature gt Source No Start SP amp Start Start Timer Expired amp Stop Start Timer Expired amp NNo Safety Alarms TASK Restart Start Start Timer TEST Motor Current lt Motor Current Threshold SP amp STOP Timer Expired VaneCloseDelay TEST Manual OFF DI OFF OR Unit S
102. ure command RUN Manual Vanes amp Speed RUN Load Vanes Manual Speed RUN Hold Vanes Manual Speed RUN Unload Vanes Manual Speed RUN Load Speed Manual Vanes RUN Hold Speed Manual Vanes RUN Unload Speed Manual Vanes Used for service purposes T password required Operated from compressor controller RUN Unload Vanes Lag Start RUN Hold Vanes Evap Press RUN Unload Vanes Evap Press RUN Unload Vanes Soft Load RUN Hold Vanes Soft Load RUN Load Vanes Disch Temp RUN Hold Vanes Pull down Rate RUN Unload Vanes Demand Limit RUN Hold Vanes Min Amps Overrides water temperature command RUN Load Vanes RUN Hold Vanes RUN Unload Vanes Normal operation SHUTDOWN Unload Unloading during the shutdown sequence NOTES 1 Timer countdown values will be shown where xxx is shown below 2 Vanes or Speed is shown in the RUN state to indicate if the capacity is controlled by speed from the VFD or by vane control Action Buttons for e Chiller Control normal start AUTO button and STOP button The STOP button activates the normal shutdown sequence These buttons are only active when the when control is in the Local Control mode This eliminates the possibility of inadvertently shutting off the unit locally when it is under control of a remote signal such as a BAS e HISTO

Centrifugal chiller McQuay WMC User manual

Contents

Download Pdf Manuals

Related Search

Related Contents