McQuay MicroTech Unit Controller Installation And Maintenance Data
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McQuay MicroTech Unit Controller Installation And Maintenance Data

McQuay MicroTech Unit Controller Installation And Maintenance Data

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Summary of Contents for McQuay MicroTech Unit Controller

  • Page 1 Installation and Maintenance Data Unit Controller...

  • Page 2: Table Of Contents

    CONTENTS I N T R O D U C T I O N F a u l t H i s t o r y - C l e a r F a u l t . G e n e r a l D e s c r i p t i o n P a n e l H a r d w a r e .
  • Page 3 Some discrepancy may exist between display statements, Figure 1. MicroTech Control Panel GENERAL DESCRIPTION The MicroTech Unit Controller is a microprocessor based con- using MIcroTech software. trol panel designed to initiate the step-by-step start functions In the event the compressors’ operation is interrupted by...
  • Page 4 Power Cartridge (Input/Output) Oil Pump Contactor \ I Mother Board Guardistor Field Relays Connection Terminal Strip High Press. (Left) and Low Press. EnGinn TR-3 (Top) - TR-2 Transformers to DC volts Signal Converter Output Relays and Mounting Board The control panel contains the following components: display EnGinn.
  • Page 5 VACUUM FLUORESCENT DISPLAY The other four (4) reset options require an external 4 to 20 The display type used was carefully selected for its clarity and mA signal, input to the field connection terminals 69, 70, and long life. The system is equipped however to automatically 71.

  • Page 6: Factory Mounted & Wired

    100 feet will be required, an extended range if a remote starter is used), and to chilled water and con- kit is recommended (McQuay part number 654870B-01). denser water flow switches and interlocks, alarm relay and Miscellaneous chilled water pump, condenser water pump, external cycling or reset control.

  • Page 7: Starter Type

    AC is 12 GA. for a maximum length of 50 feet. If greater than on some models. If not factory installed, refer to the installa- 50 feet refer to McQuay for recommended wire size. Wire size tion manual and wire as shown.

  • Page 8: Starter Overload Relay Contacts

    McQuay IQ-1000. Install a normally open contact from the time clock or If an IQ-1000 or similar solid-state overload is used, the nor-...

  • Page 9: Alarm Relay

    If this action is not desirable because the controlled pump RELAY ALARM is the principal system pump, the alarm relay circuit may be (See Table for Relay Coil Characteristics) used with a normally closed contact to provide a parallel con- Provision exists on the MicroTech control panel to activate an tact in the pump’s control circuit.

  • Page 10: Wiring

    LEAD-LAG/LOAD BALANCE (LLLB) date at “0", “ 0” . For more information see the keypad sec- The lead-lag/load balance (LLLB) control is a special purpose tion covering the “Clock Schedule”. computer. It is designed to interact with two separate MicroTech unit panels for maximum control efficiency. Through Dual compressor units shipped from the factory have the a simple twisted pair wiring connection between the wall, or clock schedule S1 First Day=Sun.
  • Page 11 Table 3. Control Devices On the oil line leaving the oil cooler & entering the compressor. Analog Strapped to, or in a well in the oil pump below the oil level. From a pressure to electric signal transducer located on the back of the Table 4.
  • Page 12 Figure 12. Typical Schematic Wiring (Dwg. No. 706306D-01, Rev. OP) Page 12 I IM...
  • Page 13 Figure 13. Legend-Symbols and Wiring Schematic Notes (Dwg. No. 706105C-01) LEGEND ALARM, RELAY COIL TRANSFORMER (24 VAC CT) TR-1. TR-2. TR.3 CAP........CAPACITOR DAUGHTERBOARD CONN.
  • Page 14 Table 6. Field Connection Terminal Strip 24 VAC Lube Box (O.D. Corn-Term OP Aux. Contact 24 VAC Term 78 Lube Box (O.D. & VC S 24 VAC MHP & MLP & Lube Box (O.D. S Fault Relay Coil Suraeauard Relav Coil Alarm Bell Relay Co11 24 VAC Starter Fault Safety Trip...
  • Page 15 ALL FIELD CO TO BE MADE THIS AREA OF TROL BOX TO Table 7. Outrmt Relav Switches 4 - 3 SB Solenoid & Light HGBP Solenoid 6 - 5 12-11 Liquid Injection Solenoid 14-13 Cycles #l Tower Fan completed to control panel terminal No.
  • Page 16 Figure 15. Daughter Board NOTE: The daughter board colle& and condltlons dIgItal signals and delivers lh,: neww plug-in ribbon cable FUSE STRIP Table 8. LED Description L3, etc. These lights will glow when the contact in the ap- SURGEGUARD propriate protective circuit is closed. Contacts are +24 volt MOTOR TEMPERATURE AC and must be closed, lighting the LED for the starting se- HIGH DISCt’ARGE PRESSURE...
  • Page 17 NOTE: No field connecttons required to this terminal block. Figure 16. Typical Starter Connection Diagram [Control Only). C O N T R O L T R A N S F O R M E R (CPT) C U R R E N T T R A N S F O R M E R A N D A D J U S T A B L E R E S I S T O R T O P R O V I D E AVAILABLE SUBSTITUTE ;M.

  • Page 18: C H E C K S

    STARTING THE UNIT INITIAL START-UP CHECKS munications address by which one microprocessor provides The following checks of the control system are recommend- and/or retrieves information to or from another. ed before power is applied to the compressor. There are two hex switches on the Control EnGinn and two on the door-mounted Display EnGinn.
  • Page 19 MECHANICAL PROTECTIVE SWITCH SETTINGS gure 19. Solid-state Relay Position See Table 12 for the recommended settings for the Mechanical High Pressure (MHP), Mechanical Low Pressure (MLP), and Oil Differential Pressure (OD) protective controls. OUTPUTS Table 12. Setpoint Settings. DRY RUNNING THE CONTROL PANEL On initial start-up of a new system, it’s desirable to dry run the starter and control panel to check operation of both operating and protective controls.
  • Page 20 The technician should followed. For detailed recommendations, see McQuay SM001 then immediately release the “bump” switch, opening the cir- and IM 392 covering general start-up and the IQ-1000 solid- cuit to the MCR relays and stopping the compressor.
  • Page 21 Figure 21. IQ-1000. Figure 22 IQ-Data Pius. F igure 23. Typical Variable Resistor & Typical Current Transformers. NOTE: If the unit has 2 resistors in parallel providing the AC L o a d Amps, (nameplate RLA). voltage signal, see Catalog SM001 for calculation of the prin- Stop loading the compressor at the design RLA.

  • Page 22: Setpoint

    OPERATION OPERATING SEQUENCE pletion of this starting step. The following describes the unit’s normal operating sequence 7. Within 5 seconds of energizing the condenser water pump, provided the time delay requirements are met and no safety if the compressors’ vane closed switch shows the vanes control has tripped or holiday schedule set to keep the unit off.
  • Page 23 (where us- ed) all contain the software information required to control and mable components replaced, the Version number must be furnished to McQuay. protect the chiller. Version number codes for the three (3) basic components, For varied reasons, there are different software versions.
  • Page 24 OIL TEMPERATURE produce the display “Now=Low Sump Temp”. To maintain a separation of refrigerant and oil in the refrigerant The two sensors that produce the actual calculated atmosphere, the oil must be heated to a temperature approx- temperature difference are the oil sump sensor (Number 10) imately 40°F to 50°F above saturated refrigerant (Evap.) and the Evap.

  • Page 25: I N F O R M A T I O N

    THE KEYPAD The second different keypad under the Display section is the “Data Scroll” key. Following a single press of this key, The keypad consists of 24 touch sensitive membrane key swit- a complete list of all of the functional values available in the ches that provide a total of over 160 separate statements regar- ding the operation, setpoints, and service history of the con- Display section and other data will be displayed, each for an...

  • Page 26: K E Y P A D

    “WATER TEMPS” KEYPAD (Setpoints) of step one. This value can also range between 30% and Actual water temperature is displayed by pressing the “Water 100%; but must be a lower setting than the setting displayed Temps” keypad under the Display section. in the first keypress, (above).

  • Page 27: C O N T R O L

    CLOCK SCHEDULE KEYPAD Similarily, if unloading is desired, pressing the “-/No” keypad This keypad requires a total of 49 keystrokes to sequence en- will display a reduction in amps confirming that the com- tirely through the loop. See the keystrokes sequence table pressor has unloaded.

  • Page 28: Time Control Functions (Not Clock Schedule)

    Setpoints section keys,--"Water Temps” operation. The time periods alloted are satisfactory for all sizes and/or “Max Amp Limit”, of McQuay Centrifugal compressors. For a detailed explanation of the available “Reset” feature, see the subsection “Reset Options”. Condenser Pump Timer-This timer determines the length Tower Staging will control cooling tower fan operation;...

  • Page 29: Delay Timer

    Ent Evap. Timer-This timer is an integral part of the “Enter- MCR Is On (or Stop, Unloading)-The time interval associ- ing” chilled water temperature reset feature. As the building ated with the MCR operation is intended to establish load changes, entering, or return, chilled water temperature reasonable delay for closure of the starter transition contacts.
  • Page 30 Table 14. KEY: DISPLAY SECTION Key Press Sequence Display Key Press Sequence Display LEAVING EVAP=XX M O T O R R L A = X X ENTERING EVAP=XX Motor AMPS=XXX Amps LEAVING COND=XX EVAPORATOR = XX SUCTION LINE =XX OIL SUMP TEMP=XXX Temp’s SUPERHEAT=XX Pres’s...
  • Page 31 27) CLEARING THIS FAULT Change Pass- word (Starts unit (McQuay Service phone number) “Local” start mode switch) Set-up KEY: Options Table 17. RESET OPTIONS = 222 NONE, ENT. CHW. AMP, AMPENT, AMPCHW MAX. CHW RESET = Xx.X N/A, 0°F mmimum to 15°F maximum ENT EVAP.
  • Page 32 Clock KEY: Sched- Current Time = XX:XX Override (Hrs.) =X.X Hour Now, O-23 = XX Seconds, O-59 = XX Day Of Week = ZZZ Month, l-12 = XX Date, l-31 = XX Year, O-99 = XX O F F Sunday. Monday, Tuesday, etc O-23 Hours O-59 Mrnutes O-23 Hours...
  • Page 33 KEY: Table 20. HIGH SUCT OFF = XXX 125°F 100 PSI to t60 PSI 140 PSI HI COND PRES = XX2 NOTES: SP means Service Password LP means Low Pressure SPT means Setpoint Default Setting the factory input setting. Default pressure values are R12: for MOO. use pressures equal to the saturated temperatures of the 1312 pressures. Press 5-“Low Oil Delta”...
  • Page 34 Figure 26. Typical Communications Interconnections. PC DOS/MS DOS COMPATIBLE COMPUTER WITH McQUAY SOFTWARE OPTIONAL 4-20mAdc EMS SIGNAL FOR RESET OF CHILLED WATER OPTIONAL 4-20mAdc EMS SIGNAL FOR DEMAND “.’ LIMITING MICROTECH SYSTEM CONTROLLER (LLLB PANEL) ADDRESS 00 MICROTECH UNIT MICROTECH UNIT...

  • Page 35: Service

    SIGNAL CONVERTER display are programmed for “Local” control, we recom- The McQuay furnished signal converter accepts a zero to mend that the unit be programmed for “Remote” and a 5, 6, or 7 volt AC signal and converts it to a zero to 4 volt DC jumper or toggle switch wired across Field Connection ter- signal.

  • Page 36: Oil Gauge Transducer

    OIL GAUGE TRANSDUCER (OGT) SENSORS The oil gauge transducer is a zero to 300 PSI input, 1 to 5 With the exception of sensors numbered 11, 12, and 13 the volt DC output LVDT type transducer. The device is powered omission or the failure of analog sensors connected to the by a 17 VDC unregulated power supply from the daughter daughter board terminals TS3 and TS4 will be discerned by...
  • Page 37 Table 22. MicroTech Thermistors Resistance vs. Saecified Temaerature 16.104 3,477 15,627 14.720 7.228 14.288 13,871 3.074 13,467 13,076 2.927 I 14 12,698 12.333 1 k> 11,979 2.72 3 11.636 1 10 11,304 10,983 2,474 10,672 10,371 2.4 16 10,079 2.360 9.797 9.523 9,258...
  • Page 38 Recommended Testing Procedure Solid-state relay switches may be depicted as shown in the FUSE SOLID-STATE McQuay schematic wiring diagram; de-energized, with con- (TYPICAL) RELAYS tacts open. The contacts are not ‘open’, however, in the sense that conventional electrical-mechanical relays open their contacts.
  • Page 39 Table 23. Trouble SvmDtom Ch BLINKING UNIT OFF LOGIC CARTRIDGE MOTHERBOARD (1 & 2) DAUGHTER BOARD FUSE BLOWN TRANS 3 FUSIBLE LINK BLOWN BLINKING BLANK SOME ON TRANS 2 FUSIBLE SOME OFF LINK BLOWN DISPLAY ENGINN BAD BLINKING BLINKING NORMAL MICROPROCESSOR LED BAD ON CONSTANT...

  • Page 40: Test Procedure-Trouble Analysis

    TEST PROCEDURE - TROUBLE ANALYSIS iated with each. Numbers below coincide with numbers shown in the right If a daughter board LED is lit, yet the display statement hand column of the Trouble Symptom Chart. shows that contact to be open, it’s possible that the System or chiller operating problems are not described.
  • Page 41 above, the fuse is probably bad. Remove the fuse and Check the signal converter-to-analog terminal strip wir- test with an ohmmeter. ing and circuitry. NOTE: The solid-state relay number 3 is in series with If the signal converter fails in such a manner as to pass the relay number 14.
  • Page 44 PRODUCT WARRANTY SnyderGeneral Corporation, hereinafter referred to as the pose. In no event and under no circumstances shall the “Company,” warrants that it will provide, at the Company’s Company be liable for incidental or consequential option, either free replacement parts or free repair of com- damages, whether the theory be breach of this or any ponent parts in the event any product manufactured by the other warranty, negligence or strict tort.

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