McQuay GZ 035AM Installation, Operation And Maintenance Manual
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McQuay GZ 035AM Installation, Operation And Maintenance Manual

Air-cooled, scroll compressor, split systems
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Installation, Operation and Maintenance
AIR-COOLED, SCROLL COMPRESSOR, SPLIT SYSTEMS
Chiller w/ Remote Evaporator, AGZ 035AM-050AM
Condensing Units, ACZ 045A-055A
DX Evaporators, CDE
60 Hertz, R-22
Global Chiller Line
© 1997 McQuay International
IOMM ACZ/AGZ-1
Manual
Group: Chiller
Part Number: 074644101
Effective: February 2000
Supersedes: IOMM ACZ/AGZ

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  • Page 1 Manual Group: Chiller Part Number: 074644101 Effective: February 2000 Supersedes: IOMM ACZ/AGZ AIR-COOLED, SCROLL COMPRESSOR, SPLIT SYSTEMS Chiller w/ Remote Evaporator, AGZ 035AM-050AM Condensing Units, ACZ 045A-055A DX Evaporators, CDE 60 Hertz, R-22 Global Chiller Line © 1997 McQuay International...

  • Page 2: Table Of Contents

    "McQuay" is a registered trademark of McQuay International © 1997 McQuay International "Information represents McQuay International products at the time of publication and we reserve the right to make changes in design and construction at anytime without notice" IOMM ACZ/AGZ-1...

  • Page 3: Introduction

    Check all items carefully against the bill of lading. Inspect all units for damage upon arrival. Report shipping damage and file a claim with the carrier. Check the unit name plate before unloading, making certain it agrees with the power supply available. McQuay is not responsible for physical damage after unit leaves the factory.

  • Page 4: Installation

    Installation Note: Installation is to be performed by qualified personnel who are familiar with local codes and regulations. WARNING Sharp edges and coil surfaces are a potential hazard. Avoid contact with them. Handling Be careful to avoid rough handling of the unit. Do not push or pull the unit from anything other than the base.

  • Page 5: Location

    Location Unit Placement AGZ-AM and ACZ units are for outdoor applications and can be mounted on a roof or ground level. Set units on a solid and level foundation. For roof mounted applications, install the unit on a steel channel or I-beam frame to support the unit above the roof. For ground level applications, install the unit on a substantial base that will not settle.
  • Page 6 Figure 3, Clearance Requirements IOMM ACZ/AGZ-1...

  • Page 7: Vibration Isolators

    Table 1 and Table 2 list isolator point loads for all unit sizes, Figure 4 shows isolator locations. See Dimensional Data for detailed dimensions required to secure each isolator to the mounting surface. The spring flex isolators are white type CP2-32, McQuay part number 047792932. A total of four per unit is required.

  • Page 8: Water Piping

    Water Piping Local authorities can supply the installer with the proper building and safety codes required for safe and proper installation. Install piping with minimum bends and changes in elevation to minimize pressure drop. Consider the following when installing water piping: Vibration eliminators to reduce vibration and noise transmission to the building.

  • Page 9: Flow Switch

    Mount a water flow switch in either the entering or leaving water line to shut down the unit when water flow is interrupted. A flow switch is available from McQuay (part number 017503300). It is a “paddle” type switch and adaptable to any pipe size from 3” (76mm) to 8” (203mm) nominal. Certain minimum flow rates are required to close the switch and are listed in Table 3.

  • Page 10: Glycol Solutions

    Glycol Solutions The use of a glycol/water mixture in the CDE evaporator to prevent freezing will reduce system capacity and efficiency and increase pressure drop. The system capacity, required glycol solution flow rate, and pressure drop with glycol may be calculated using the following formulas and Table 4 and Table 5.
  • Page 11 Table 6, Capacity and Power Derates Chilled Water Fouling Factor Delta-T ALTITUDE 0.00025 (0.044) 0.00075 (0.132) 0.00175 (0.308) °F °C Cap. Cap. Cap. 0.992 0.995 0.996 0.982 0.911 0.935 0.995 0.997 0.969 0.984 0.914 0.937 1.000 1.000 0.975 0.986 0.919 0.939 LEVEL 1.005...

  • Page 12: Evaporator Flow And Pressure Drop

    Figure 7, Pressure Drop Curve AGZ 035AM - 040AM CDE 1004-1 AGZ 045AM - 050AM CDE 1204-3 AGZ-AM NOMINAL MAXIMUM MINIMUM Unit Unit Pressure Drop Flow Pressure Drop Flow Pressure Drop Flow Size Size (ft) of Water (gpm) (lps) (ft) of Water (gpm) (lps) (ft) of Water...

  • Page 13: Refrigerant Piping

    Suction Lines McQuay recommends the use of ASHRAE for guidelines in sizing and routing piping with one exception. See the 1998 ASHRAE Handbook Refrigeration Edition, Chapter 2 for tables and guidelines.
  • Page 14 d. If a vertical riser exists including the trap at the coil, determine the minimum tons for the circuit. Add b and c above to obtain the total equivalent feet. Use ASHRAE Table 3 (for R22) or Table 4 (for R134a).
  • Page 15 Long Vertical Riser Installation Where job conditions require refrigerant gas lifts of more than 25 feet, McQuay recommends the installation of a short trap half-way up the riser or at not more than 20 feet intervals. These traps are required to capture and hold small quantities of oil during off cycles.

  • Page 16: Liquid Lines

    Liquid Lines Liquid lines are generally sized for 1 to 2 degree F line losses or their equivalent in pressure drop. Actual selection can vary based upon the pressure drop expected from refrigerant specialties such as solenoids, refrigerant driers, valves, etc. piping lifts or risers and the amount of condenser sub-cooling expected.
  • Page 17 Where rises in liquid lines result in a 0.5 psi loss per foot of lift, a drop in the liquid line results in a rise in the refrigerant pressure. A substantial drop in the liquid line can assure the existence of pure liquid at the valve.

  • Page 18: Physical Data

    Physical Data AGZ-AM Table 8, AGZ 035AM - 050AM PHYSICAL DATA AGZ-AM MODEL NUMBER STANDARD EFFICIENCY 035AM 040AM 045AM 050AM CAPACITY @ ARI Conditions (1), Tons (kW) 34.3 (120.5) 38.9 (136.7) 44.3 (156.0) 48.9 OUTDOOR UNIT BASIC DATA Ckt.1 Ckt.2 Ckt.1 Ckt.2 Ckt.1...
  • Page 19 ACZ Condensing Units Table 9, ACZ 030A - 040A PHYSICAL DATA ACZ MODEL NUMBER STANDARD EFFICIENCY 030A 035A 040A UNIT CAPACITY @ ARI Conditions (1), Tons (kW) 31.8 (111.7) 35.0 (123.0) 38.4 (134.9) BASIC DATA Ckt.1 Ckt.2 Ckt.1 Ckt.2 Ckt.1 Ckt.2 Number Of Refrigerant Circuits Unit Operating Charge, R-22, Lbs.
  • Page 20 Table 10, ACZ 045A - 055A PHYSICAL DATA ACZ MODEL NUMBER STANDARD EFFICIENCY 045AS 050AS 055AS BASIC DATA Ckt.1 Ckt.2 Ckt.1 Ckt.2 Ckt.1 Ckt.2 Unit Capacity @ ARI Conditions (1), Tons (kW) 43.6 (153.2) 48.8 (171.4) 53.5 (188.0) Number Of Refrigerant Circuits Unit Operating Charge, R-22, Lbs.

  • Page 21: Electrical Data

    Control Wiring AGZ-AM chillers are equipped with either a Johnson Controls UNT control or a McQuay MicroTech microprocessor control mounted in the outdoor unit. The control sensor for capacity control must be mounted in the leaving chilled water line in a thermowell provided in the water chiller nozzle.

  • Page 22: Electrical Data Agz-Am

    Electrical Data AGZ-AM Electrical Data ACZ Table 11, AGZ-030AM - 050AM, ACZ 030A - 055A, 60 Hz, Single Point Power Electrical Data POWER SUPPLY Max. Fuse Minimum Field Wire AGZ-AM Circuit Volts HACR Unit Size Unit Size Ampacity Wire Nominal Breaker Quantity Quantity...

  • Page 23: Electrical Notes

    Table 13, AGZ-AM, ACZ A, 60 Hz Single Point Power, Field Wiring Data Wiring to Standard Wiring to Optional AGZ-AM Power Block Non-Fused Disconnect Switch Unit Size Unit Volts Terminal Connector Wire Range Terminal Connector Wire Range Size Amps (Copper Wire Only) Amps (Copper Wire Only) # 4 - 400 MCM...
  • Page 24 Notes for “Compressor and Condenser Fan Amp Draw”: Compressor RLA values are for wiring sizing purposes only but do not reflect normal operating current draw at rated capacity. If unit is equipped with SpeedTrol condenser fan motors, the first motor on each refrigerant circuit is a single phase, 1hp motor, with a FLA of 2.8 amps at 460 volts, 5.6 amps at 208, 230, and 575 volts.

  • Page 25: Wiring Diagrams

    Wiring Diagrams Figure 10, AGZ-AM, Typical Field Wiring with Global UNT Controller IOMM ACZ/AGZ-1...
  • Page 26 Figure 11, AGZ-AM, Typical Field Wiring Diagram with MicroTech Controller IOMM ACZ/AGZ-1...
  • Page 27 Figure 12, AGZ-AM, Single-point Connection with FanTrol IOMM ACZ/AGZ-1...
  • Page 28 Figure 13, AGZ-AM, Single-point Connection with SpeedTrol IOMM ACZ/AGZ-1...
  • Page 29 Figure 14, AGZ-AM, Unit Control Schematic (UNT) IOMM ACZ/AGZ-1...
  • Page 30 Figure 15, AGZ-AM, Staging Schematic (UNT) IOMM ACZ/AGZ-1...
  • Page 31 Figure 16, AGZ-AM, MicroTech Controller Schematic IOMM ACZ/AGZ-1...
  • Page 32 Figure 17, AGZ-AM, Unit Control Schematic (MicroTech) IOMM ACZ/AGZ-1...
  • Page 33 Figure 18, AGZ-AM, Staging Schematic (MicroTech) IOMM ACZ/AGZ-1...
  • Page 34 Figure 19, ACZ Field Connection Diagram (No Capacity Control) IOMM ACZ/AGZ-1...
  • Page 35 Figure 20, ACZ Field Wiring Diagram (Capacity Control Staging) IOMM ACZ/AGZ-1...

  • Page 36: Dimensional Data

    Dimensional Data AGZ-AM Figure 21, Dimensions AGZ 035AM - 050AM and ACZ 045A - 055A DIMENSIONS CENTER OF GRAVITY UNIT WEIGHTS ADD’L. WEIGHT MODEL MODEL inches (mm) inches (mm) lbs (kgs) FOR COPPER NUMBE NUMBE FINS lbs (kgs) OPERATING SHIPPING 035AM 86.2 (2190) 81.7 (2075)
  • Page 37 Figure 22, CDE 1004-1 - 1204-3 WATER CONNECTION REFRIGERANT CONNECTION MODEL INCHES (mm) INCHES (mm) NUMBER CDE-1004-1 39.3 (998) 8.5 (216) 4.0 (102) 5.4 (137) 1 5/8 (41) 1 3/8 (35) CDE-1204-3 39.3 (998) 9.5 (241) 4.0 (102) 5.4 (137) 1 5/8 (41) 1 3/8 (35) CDE-1204-2...

  • Page 38: Startup

    Record all operating parameters required by the “Compressorized Equipment Warranty Form”. Return this information within 10 working days to McQuay International as instructed on the form to obtain full warranty benefits. Verify chilled water pressure drop across the evaporator or air flow for DX coil.

  • Page 39: Water Piping Checkout

    Extended Front seat both condenser liquid line service valves. Put both circuit switches in Pumpdown and Stop position. After the compressors have stopped, put System Switch (S1) in Emergency Stop position. Front seat both refrigerant circuit discharge valves. If chilled water system is not drained, maintain power to the evaporator heater to prevent freezing. Maintain heat tracing on the chilled water lines.

  • Page 40: Refrigerant Charging

    Refrigerant Charging Liquid line subcooling at the liquid shut-off valve should be between 15 and 20 degrees F at full load. If the unit is at steady full load operation and bubbles are visible in the sightglass, then check liquid subcooling.

  • Page 41: Electrical Check Out

    Electrical Check Out CAUTION Electrical power must be applied to the compressor crankcase heaters 24 hours before starting unit. Open all electrical disconnects and check all power wiring connections. Start at the power block and check all connections through all components to and including the compressor terminals. These should be checked again after 3 months of operations and at least yearly thereafter.

  • Page 42: Operation

    Operation Sequence of Operation Starting With control power on, 115Vac power is applied through F1 to the compressor crankcase heaters and control transformer T2. T2 supplies 24Vac to the Global UNT controller. The green light on the Global UNT controller will begin to flash. The panel Alarm Light will illuminate. Put the System Switch S1 into the AUTO position.

  • Page 43: Hot Gas Bypass (Optional)

    Software Description (Global UNT Interface Kit required to read or change variables) Variable Default Description Range Name Value LPSS Low Pressure Starting Setpoint 10 psi 5 to 15 psi SLPT Starting Low Pressure Time 260 sec 90 to 300 seconds MLPS Minimum Low Pressure Setpoint 5 psi...

  • Page 44: Filter Driers

    Filter Driers Each refrigerant circuit is furnished with a full flow filter drier or an optional replaceable core type filter-drier. The core assembly of the replaceable core drier consists of a filter core held tightly in the shell in a manner that allows full flow without bypass. Pressure drop across the filter drier at full load conditions must not exceed 10 psig.

  • Page 45: Crankcase Heaters

    The suction superheat for the suction leaving the evaporator is set at the factory for 8° to 12°F at full load. To have full rated unit performance the superheat must be about 8°F at 95°F outdoor ambient. Crankcase Heaters The scroll compressors are equipped with externally mounted band heaters located at the oil sump level.

  • Page 46: Global Unt Controller, Agz-Am

    Global UNT Controller, AGZ-AM This section provides installation, setup and troubleshooting information for the Global UNT controller. All operational descriptions are based on the Global UNT software SUZE4-2A. Operational characteristics may vary with other versions of software. General Description The Global UNT is a microprocessor based leaving water controller designed for multiple stage operation.
  • Page 47 Unit Set Points and Calibration The control software is installed and tested by the factory before shipping. No periodic calibration of the controller is necessary. All control and safety set points must be checked by the installing contractor and adjusted as necessary before starting the unit. The “setpoint”...

  • Page 48: Controller Inputs /Outputs

    The Global UNT controller can be connected to an IBM or IBM compatible computer for setpoint changes and downloading of different software’s. A Global UNT Interface Kit is available from your local McQuay Sales Representative. Software Identification Control software is factory installed and tested in each panel prior to shipment. The software is identified by a program code which is printed on the a small label attached to the controller.
  • Page 49 Digital Inputs Note: All Digital Inputs are 24Vac supplied by transformer T2 in the control panel. Do not use inputs from another power supply external to the unit. This can cause failure of the Global UNT controller. Table 18, Digital Inputs Input Description Location...
  • Page 50 As the OAT increases above the Outdoor Air Low Limit (OALL), the Actual Leaving Water Setpoint is decreased from its Leaving High Limit (Leaving Water Setpoint plus Leaving Reset Band) to the Leaving Water Setpoint. When OAT reaches the OAHL, the Actual Leaving Water Setpoint equals the Leaving Water Setpoint (AI4).

  • Page 51: Additional Unt Features

    Zone Temperature (optional Zone Temperature Sensor) When selected, a Zone Temperature Sensor is connected to TB-7 terminals #134 and #135. Four variables are used to setup the reset ramp that calculates the Actual Leaving Water Setpoint. These are: Leaving Water Dial Setpoint (AI-4), Reset Band SP selected with the Zone Terminal, Zone Temperature High Limit (ZTHL), and Zone Temperature Reset Band (ZTRB).

  • Page 52: Soft Start

    Unoccupied Mode When the remote start / stop input is opened, the unoccupied mode is initiated. The chiller will maintain a higher leaving water temperature setpoint (default 70°F) if the chilled water circulation is maintained. The unoccupied leaving water setpoint can be changed from the Zone Terminal. Soft Start Soft loading limits the number of available stages when the unit is started to prevent excessive power consumption and possible overshoot of the leaving water temperature set point.

  • Page 53: Alarms

    Freezestat Control On startup the Global UNT controller will check the evaporator pressure after the SLPT (starting low pressure time) timer times out. If the evaporator pressure is greater than the low pressure high limit (LPHL) value, the Global UNT controller will continue to stage up as additional cooling is required. If the evaporator pressure is less than the LPHL, the Global UNT controller will de-energize BO7 or BO8 (depends on circuit starting) which will stop the compressor.

  • Page 54: Zone Terminal (Optional)

    ZONE TERMINAL (optional) The Zone Terminal (ZT) is a hand-held or unit mounted device that monitors and adjusts your McQuay Global Scroll Chiller information. A standard telephone-style jack directly connects the ZT to the McQuay Global UNT controller. Features •...

  • Page 55: Operating Modes

    Monitor Mode lets you view up to three of chiller settings/sensed values at a time. To allow you to monitor your system, a clear plastic Insert (factory made and installed) relates the ZT’s output to your McQuay Global UNT controller. You can simultaneously monitor the chiller in three ways: •...
  • Page 56 DISPLAYS, SYMBOLS, KEYS, AND BUTTONS The Zone Terminal simultaneously displays three set points or sensed values. In addition, flashing symbols indicate when items are in a state of alarm. The keys, buttons, displays, and symbols are explained below. Table 20, Displays, Symbols, Keys, Buttons DISPLAYS, SYMBOLS, DESCRIPTION KEYS, BUTTONS...
  • Page 57 McQuay Global Scroll Controller Connection A standard telephone-style jack connects the ZT to a McQuay Chiller Controller directly. Figure 28, Connecting ZT to a Global UNT Controller Using 6 to 8 Pin Cable 1 2 3 4 5 6 7 8...

  • Page 58: Zone Terminal Glossary

    Adjustable Points The following McQuay Global Scroll Chiller points are adjustable by the Zone Terminal. Table 21, Adjustable Points TEMPLATE VALUES NAME FACTORY SETPOINT RANGE OA/AI3 HiLim SP 80°F 0 to 100°F OA/AI3 Reset SP -40°F -100 to 100°F LvgWtr Rband SP 0°F...
  • Page 59 Cir #2 Starts - Counts the number of starts for circuit #2. Note: If power is lost to the controller, this data is lost and will start counting over. When power is applied and kept on, the controller will allow 10 starts for circuit #1 as the lead circuit, then will switch to circuit #2 for the next 10 starts, etc (Automatic Lead/Lag).

  • Page 60: Global Unt Controller Troubleshooting Chart

    Global UNT Controller Troubleshooting Chart PROBLEM POSSIBLE CAUSES CORRECTIVE ACTIONS 1. Main switch, circuit breakers open. 1. Close switch. 2. Fuse blown. 2. Check electrical circuits and motor winding for shorts or grounds. Possible overloading. Replace fuse or reset breakers after fault is 3.
  • Page 61 6. Hot gas bypass not set properly. 5. Check and repair or replace. 7. Low ambient operation. 6. Set hot gas bypass. 7. Install SpeedTrol, wind baffles. 1. Chilled water flow erratic. 1. Check for reasons and correct. 2. System load erratic. 2.

  • Page 62: Microtech Controller, Agz-Am

    Important operating conditions at the time of the alarm are retained in the controller’s memory to aid in troubleshooting and unit diagnostics. McQuay MicroTech Monitor software is available for remote adjustment and monitoring of the chiller.

  • Page 63: Interlock Wiring

    Lead-Lag A feature on all McQuay AGZ air-cooled chillers is a system for alternating the sequence in which the compressors start to balance the number of starts and run hours. Lead-Lag of the refrigerant circuits is accomplished automatically through the MicroTech Controller. When in the auto mode the circuit with the fewest number of starts will be started first.

  • Page 64: Chilled Water Flow Switch

    Field Wiring Interconnecting wiring for the control panel may consist of the following: • 115Vac power wiring • Chilled water pump relay • Analog input signals • Digital input signals • Digital output signals • Network communications • Communications to a personal computer •...
  • Page 65 Digital Outputs The digital output board has normally open solid-state relays with an on-board replaceable 5 amp fuse. The status of all outputs are shown by the individual output red LEDs. Chilled Water Pump Relay The optional chilled water pump relay is connected to terminal #10 and #9 on TB-2. When the unit is enabled, the chilled water pump relay is energized.
  • Page 66 Controller Inputs /Outputs Analog Inputs Analog inputs are used to read the various temperatures and pressures on the chiller as well as any customer supplied 4-20mA reset signals. The controller’s internal regulated 5Vdc and 12Vdc supplies provide correct operating voltage for the sensors. See Table 22 for details. Table 22, Analog Inputs Input Description...
  • Page 67 When in “Ice” reset mode, and adequate amount of glycol must be added to the system to protect the evaporator from freezing. McQuay recommends a minimum of 30% solution of ethylene glycol to protect to 7°F with the minimum leaving water temperature at unit shut down of 21°F. At 21°F shut down, the saturated refrigerant temperature can approach 10°F.
  • Page 68 (21°F + 2°F = 23°F; 23°F = 46psig) Network A network refers to a McQuay MicroTech control panel (CSC or RMS) that can provide controlling functions to several McQuay chillers. One function is to control the chiller leaving water temperature according to some control logic in the network control panel.

  • Page 69: Manual Operation

    Manual Operation Manual operating modes are available to simplify setup and troubleshooting of the unit. Any of the following manual modes may be selected from the Control Mode Menu. Note: These manual settings are intended to aid in troubleshooting and should not be considered to be normal operating modes.
  • Page 70 Thus, the alarm must be manually cleared. When a McQuay Chiller with a MicroTech controller is used with the McQuay RMS (Remote Monitoring and Sequencing) Panel, the user must note that alarm nomenclature varies. The RMS has three possible categories of alarms: faults, problems, and warnings.

  • Page 71: Sequence Of Operation

    Circuit Alarm Conditions The “Circuit Alarm Conditions” are those alarms which only affect one circuit and can stop the compressors of that circuit. These alarms are: • Compressor Motor Protection • High Condenser Pressure • Mechanical High Pressure Switch • Low Evaporator Pressure •...
  • Page 72 Assuming none of the above “OFF” conditions are true, the controller will examine the internal time clock schedule to determine if the chiller should start. The operating mode will be OFF:TimeClock if the time schedule indicates an “OFF” time period. Start - Up If none of the “OFF”...

  • Page 73: Start-Up And Shutdown

    Start-Up and Shutdown Pre-Start Checkout Configuration default set points are entered at the factory and all values must be checked and reset for each installation. Make sure the field wiring for all flow switches, interlocks or jumpers matches the connections detailed on the field wiring drawing. Setting of the HEX Address Switches The controller HEX address switches for each unit determine its logical address in a MicroTech network or in an Open Protocol network.

  • Page 74: Keypad / Display

    (output relay #4 circuit #1or output relay #5 circuit #2) When the evaporator pressure rises above the LPCutIn value, a compressor on the lead circuit will start. Refer to the unit staging schematic to determine which LED is associate to a compressor. The controller will stage up and down to maintain the desired leaving water temperature.
  • Page 75 Menu Structure (general description) The information stored in the MicroTech controller can be accessed through the keypad using a tree- like structure. This tree structure is divided into Categories, Menus and Menu Items. There are three Categories which make up the tree structure: STATUS, CONTROL, and ALARM. Each category is divided into Menus and each Menu into Menu Items.
  • Page 76 Keypad Key Functions The MicroTech keypad consists of twelve pressure sensitive membrane switches (refer to Figure 29). These keys are used to step through, access, and manipulate the information in the MicroTech controller tree structure. The keypad keys are divided into four groups with two or four keys in each. These groups of keys and their functions are described below.

  • Page 77: Menu Descriptions

    Decr.When changing the value of a menu item entry, pressing “DECR. -” shifts the menu item display line to the next lower value or previous available selection. EnterOnce a change has been made to a desired value, pressing “ENTER” locks in the new value. ClearPressing “ALARMS”...
  • Page 78 Menu #6: Circuit 62 PressuresThe circuit #2 evaporator and condenser refrigerant pressure readings are displayed under this menu. The calculated minimum and maximum condenser pressure values are also shown. Menu #7: Circuit #l TemperaturesThe circuit #I refrigerant temperatures are calculated from their corresponding pressure sensors and displayed here.
  • Page 79 Maximum Chilled Water Reset to be added to the Leaving Chilled Water Set Point. The external 4-20 milliamp control signal and current reset set point will be displayed under "Reset Sig" and "Active Spt", respectively, on Menu 14. By selecting Return as the reset mode, the leaving chilled water temperature will be reset by the controller as required to maintain a constant return water temperature.
  • Page 80 Figure 30, Delta-T Setpoints for Chillers Menu #15: Softload Set Points—The controller can limit the number of available stages when the unit is initially started to prevent excessive power consumption and help control overshoot of the water temperature set point. The maximum number of stages will equal the Soft Load Maximum Stages for the time period defined in the softload timer set point.
  • Page 81 Press the Next Item key. The display will show the current Day, Hour, Minute and Second. If this information needs to be changed, follow the same procedure used to set the Date in the previous section. Menu #20: Daily Schedule—This section will help you to set the Daily Start/Stop time for automatic operation of the chiller.
  • Page 82 Menus for the AGZ MicroTech Controller Table 26, MENU 1 Chiller Status Table 29, MENU 4 Water Temp's Screen Display Screen Display Lvg Evap= xxx.x °F (°C) OFF: Manual Mode Short °F (°C) OFF: System Sw Open °F (°C) OFF: Remote Comm Ent Evap= xxx.x °F (°C) OFF: Remote Sw Short °F (°C)
  • Page 83 Table 32, MENU 7 Circ #1 Temp's Table 35, MENU 10 Comp RunHours Screen Display Satur Evap=xxx°F (°C) Screen Display N/A **°F (°C) Comp #1 =xxxxxx SuctLine = xxx.x°F (°C) Comp #2=xxxxxx Open °F (°C) Comp #3=xxxxxx Short °F (°C) Comp #4=xxxxxx Super Ht =xxx.x°F (°C) N/A ** °F (°C)
  • Page 84 Table 38, MENU 13 Control Mode Screen Display Factory Setpoint Range Manual Unit Off Automatic Manual Unit Off Manual Staging Manual Stage=xx 1 - 8 Table 39, MENU 14 Lvg Evap Spts Values for R-22 refrigerant, ( ) indicates Centigrade values Screen Display Factory Setpoint...
  • Page 85 Table 41, MENU 15 SoftLoad Spts Screen Display Factory Setpoint Range Time Left= xxmin SoftLoad= xx min 0 - 254 SoftLdMaxStg= x 1 - 4 LoadDelay= xxsec 0 - 254 Table 42, MENU 16 CompressorSpt Screen Display Factory Setpoint Range 1234 1432 2143...
  • Page 86 Table 47, MENU 20 Schedule Screen Display Factory Setpoint Range Override= xx.xx hr 0.00 Hr 00:00 - 63.50 NMPSchedule= N/A Sun 00:00-23:59 00:00 - 23:59 00:00 - 23:59 Mon 00:00-23:59 00:00 - 23:59 00:00 - 23:59 Tue 00:00-23:59 00:00 - 23:59 00:00 - 23:59 Wed 00:00-23:59 00:00 - 23:59...

  • Page 87: Trouble Analysis For The Agz Microtech Controller

    Table 51, MENU 23 Misc Setup Screen Display Factory Setpoint Range Unit Type= Air Cooled Model AGZ 4 Stages # Compressors = 4 # Stages = 4 Fan Stg/Cir = 2 Begin PD = xx PSI 42 – 70 psi End PD –...
  • Page 88 Figure 31, Microprocessor Control Board (MCB) EXPANSION BUS ADDRESS FUSE 1 Hex switches PORT A PORT B COMMUNICATIONS [FUSE: BUSSMAN MCR-1/4] RUNNING RESET STATUS ACTIVE OUTPUT 0 Microprocessor status LED's POWER FUSES [BUSSMAN GDC-T2A] DIGITAL OUTPUTS AUX /OUT Digital Inputs Connection The MCB receives digital inputs from the Analog Digital Input (ADI) board through the Digital Inputs connector via a plug-in ribbon cable.
  • Page 89 If the above sequence does not occur after power is applied to the controller, there is a problem with the MCB or its power supply. Table 56 and Table 57 summarize the green, red, and amber status LED indications. Table 56, Green and Red Status LED Indication Green Indication LED State...
  • Page 90 communications drivers from voltage in excess of ±12Vdc. Following are brief descriptions of each port’s function. Port A: Port A is for communications with an IBM compatible PC using the RS-232C interface standard. The PC can be directly connected, over a limited distance, with a twisted, shielded pair cable, or it can be remotely connected via phone lines with a modem.

  • Page 91: Test Procedures

    Test Procedures Status LED Diagnostics The MCB status LED indications can aid in controller diagnostics. If the status LEDs do not operate normally there is a problem with the MCB. Following are troubleshooting procedures for the various symptoms. Red LED Remains On If the red LED remains on after the 5-second self-test period, it is likely that the MCB is defective.
  • Page 92 Reconnect the analog input ribbon cable. Cycle power to the controller and check the power fuses. If both fuses are intact, go to step 7. If either fuse blows check the ADI board, the connecting ribbon cable, and the field wiring for shorts.
  • Page 93 Figure 33, MCB Power Supply Terminals POWER FUSES [BUSSMAN GDC-T2A] Fuse F1 Fuse F2 9 8 7 6 5 4 3 2 1 AUX/OUT Troubleshooting the Keypad/Display Interface The Keypad/Display Interface is connected to the MCB via a ribbon cable and discrete wiring for the backlight.
  • Page 94 Troubleshooting Analog Inputs An analog input, such as a temperature sensor, is connected to the ADI board. The ADI board then conditions the analog input. The conditioned input is transferred to the MCB via a ribbon cable. Analog Input not Read by the MCB If the MCB appears to be functioning properly and the analog input is not being read by the MCB, perform the following procedure: Try cycling power to the controller by opening and then closing circuit breaker CB1.
  • Page 95 Figure 34, Output Board Relay Socket Fuse *250V ~ 50/60 Hz *120V ~ 50/60 Hz Test Resistor 330-680 Ohm WARNING Electric shock hazard. Can cause severe injury or death. Even when power to the panel is off, solid-state relay socket terminals 1 and 2 on the output board could be connected to high voltage.
  • Page 96 Remove power from the controller by placing CB1 to the OFF position. Disconnect at least one wire from the power input terminals of the Output Board. The resistance should not be less than 3000 ohms. If the resistance is greater than the acceptable value, go to step 3. If the resistance is less than the acceptable value, the Output Board is defective.
  • Page 97 Remove power from the controller by opening CB1. Try to improve the connections in the Aux/Out plug insulation displacement terminals by pressing down on the wires with a small screwdriver. Check all other wiring and connectors for bent pins or mis-wires. If the chatter does not stop, the electromechanical relay or contactor is probably defective.

  • Page 98: Unit Maintenance

    No maintenance is ordinarily required except the routine removal of dirt and debris from the outside surface of the fins. McQuay recommends the use of foaming coil cleaners available at most air conditioning supply outlets. Use caution when applying such cleaners as they may contain potentially harmful chemicals.

  • Page 99: Preventative Maintenance Schedule

    Subcooling should be checked at full load with 70°F (21.1°C) outdoor air temperature and all fans running. An element inside the sightglass indicates the moisture condition corresponding to a given element color. If the sightglass does not indicate a dry condition after about 12 hours of operation, the circuit should be pumped down and the filter-drier changed.

  • Page 100: Service

    Service CAUTION 1. Service on this equipment is to be performed by qualified refrigeration personnel familiar with equipment operation, maintenance, correct servicing procedures, and the safety hazards inherent in this work. Causes for repeated tripping of safety controls must be investigated and corrected.

  • Page 101: Evaporator

    Evaporator The remote evaporator on AGZ-AM units and CDE evaporators are the direct expansion, shell-and- tube type with refrigerant flowing through the tubes and water flowing through the shell over the tubes. The tubes are internally finned to provide extended surface as well as turbulent flow of refrigeration through the tubes.
  • Page 102 3. The charge can be added at any load condition between 25-100% load per circuit but at least twoF fans should be operating per refrigerant circuit if possible. The suction superheat should be in the 6°F-12°F (3.3°C-6.6°C) range. 4. Add sufficient charge to clear the liquid line sightglass and until all flashing stops in the sightglass. Add an extra 15-20 lbs.

  • Page 103: Troubleshooting Chart

    Troubleshooting Chart PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS Compressor will not Main Switch. Close Switch. Fuse Blown. Circuit breakers open Check electrical circuits and motor windings for shorts or grounds. Investigate for possible overloading. Replace fuse or reset breakers after fault is corrected. Check for loose or corroded connections. Thermal overloads tripped Overloads are auto-reset Check unit closely when unit comes back on line.
  • Page 104 Post Office Box 2510, Staunton, Virginia 24402-2510 USA • (800) 432-1342 • www.mcquay.com...

This manual is also suitable for:

Gz 050amAgz-050amAgz 035amAgz 040amAgz 045amAcz 050a

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