Installation, Operation and Maintenance Manual IOMM AGZ-3 Group: Chiller Part Number: 074641003 Effective: June 2002 Supercedes: IOMM AGZ-2 Air-Cooled Scroll Compressor Chiller AGZ 035A through 065A 60 Hertz, R-22 Global Chiller Line
Table of Contents Introduction ....................................... 3 General Description..................................... 3 Inspection .................................................... 3 Nomenclature .............................................. 3 Installation ......................................... 4 Handling ...................................................... 4 Location....................................................... 5 Service Access .............................................
Introduction General Description McQuay Air-Cooled Global water chillers are complete, self-contained automatic refrigerating units. Every unit is completely assembled, factory wired, charged, and tested. Each unit consists of twin aircooled condensers with integral subcooler sections, two tandem scroll compressors, replaceable tube, dual circuit shell-and-tube evaporator, and complete refrigerant piping.
Installation Note: Installation is to be performed by qualified personnel who are familiar with local codes and regulations. WARNING Sharp edges on unit and coil surfaces are a potential hazard to personal safety. 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. Block the pushing vehicle away from the unit to prevent damage to the sheet metal cabinet and end frame (see Figure 1).
Location Unit Placement AGZ 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 Ibeam frame to support the unit above the roof. For ground level applications, install the unit on a substantial base that will not settle. A one-piece concrete slab with footings extended below the frost line is recommended.
Figure 3, Clearance Requirements 6 AGZ 035A through 065A IOMM AGZ-3
Vibration Isolators Vibration isolators are recommended for all roof mounted installations or wherever vibration transmission is a consideration. 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 kit number 350014821 provides the required four per unit.
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: 1. Vibration eliminators to reduce vibration and noise transmission to the building. 2. Shutoff valves to isolate the unit from the piping system during unit servicing. 3.
Figure 5, Typical Field Evaporator Water Piping 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 an equipment protection control and should never be used to cycle a unit. 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.
Water Connections Bring water piping to the evaporator through the side between the vertical supports. Provide taps for the connection of pressure gauges and thermometers in the inlet and outlet lines. 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 tables.
Table 4, Ethylene Glycol Correction Factors % E.G. 10 20 30 40 50 Freeze Point °F °C 26 -3 18 -8 7 -14 -7 -22 -28 -33 Capacity Power Flow Pressure Drop 0.991 0.982 0.972 0.961 0.946 0.996 0.992 0.986 0.976 0.966 1.013 1.040 1.074 1.121 1.178 1.070 1.129 1.181 1.263 1.308 Capacity Power Flow Pressure Drop 0.987 0.975 0.962 0.946 0.929 0.992 0.985 0.978 0.971 0.965 1.010 1.028 1.050 1.078 1.116 1.068 1.147 1.248 1.366 1.481 Table 5, Propylene Glycol Correction Factors % P.G.
Figure 7, Pressure Drop Curve 045 A-060A 035 A-040A 065A NOMINAL MAXIMUM MINIMUM Pressure Drop Flow Pressure Drop Flow Pressure Drop Flow (ft) of Water (gpm) (lps) (ft) of Water (gpm) (lps) (ft) of Water (gpm) (lps) 035AS 9.2 82 5.17 23.1 137 8.62 3.9 51 3.23 040AS 11.5 93 5.87 28.8 155 9.78 4.9 58 3.67 045AS 11.2 106 6.69 28.2 177 11.15 4.8 66 4.18 050AS 13.4 117 7.38 33.6 195 12.30 5.7 73 4.61 055AS 16.2 129 8.14 40.0 215 13.56 7.0 81 5.09 060AS 18.0 138 8.71 45.0 230 14.51 7.7 86 5.44 065AS 10.
Physical Data Table 7, AGZ 035AS through 045AS PHYSICAL DATA AGZ MODEL NUMBER STANDARD EFFICIENCY 035AS 040AS 045AS BASIC DATA Ckt.1 Ckt.2 Ckt.1 Ckt.2 Ckt.1 Ckt.2 Unit Capacity @ ARI Conditions (1), Tons (kW) 34.3 (120.5) 38.9 (136.7) 44.3 (156.0) Number Of Refrigerant Circuits 2 2 2 Unit Operating Charge, R-22, lb. 36 36 40 40 42 42 Unit Operating Charge, R-22, (kg) (16.3) (16.3) (18.1) (18.1) (19.0) (19.0) Cabinet Dimensions, LxWxH, In. 94.0 x 88.2 x 86.2 94.0 x 88.2 x 86.2 94.0 x 88.2 x 86.
Table 8, AGZ 050AS through 065AS PHYSICAL DATA STANDARD EFFICIENCY AGZ MODEL NUMBER 055AS 060AS Ckt.1 Ckt.2 Ckt.1 Ckt.2 54.1 (190.1) 58.9 (207.4) 2 2 54 54 56 56 (22.6) (22.6) (23.5) (23.5) 94.0 x 88.2 x 86.2 94.0 x 88.2 x 86.2 2388 x 2241 x 2190 2388 x 2241 x 2190 4055 (1840) 4115 (1865) 3950 (1790) 4010 (1820) 665 (300) 665 (300) 065AS BASIC DATA Ckt.1 Ckt.2 Unit Capacity @ ARI Conditions (1), Tons (kW) 61.6 (216.5) Number of Refrigerant Circuits 2 Unit Operating Charge, R-22, Lb.
Electrical Data Field Wiring CAUTION Internal power wiring to the compressors for single and multiple point option are different. Field wiring must be installed according to unit wiring diagram or serious electrical damage can occur. Wiring must comply with all applicable codes and ordinances. Warranty is void if wiring is not in accordance with specifications. Copper wire is required for all power lead terminations at the unit. Aluminum or copper can be used for all other wiring.
Table 10, AGZ 035A - 065A, 60 Hz, Compressor and Condenser Fan Motor Amp Draw AGZ Unit Size 035A 040A 045A 050A 055A 060A 065A Rated Load Amps Compressors Volts 208 230 380 460 575 208 230 380 460 575 208 230 380 460 575 208 230 380 460 575 208 230 380 460 575 208 230 380 460 575 208 230 380 460 575 No. 1&3 (Each) No. 2&4 (Each) 30.5 30.5 18.6 15.8 11.6 35.2 35.2 22.8 16.5 13.7 35.2 35.2 22.8 16.5 13.7 41.5 41.5 28.0 21.8 17.3 41.5 41.5 28.0 21.8 17.3 52.8 52.8 32.7 23.7 22.1 52.8 52.8 32.7 23.
Table 11, AGZ035A - 065A, 60 Hz Single Point Power, Field Wiring Data (continued) AGZ Unit Size 050E 055A 060A 065A Volts 208 230 380 460 575 208 230 380 460 575 208 230 380 460 575 208 230 380 460 575 Terminal Amps 335 335 335 175 175 335 335 335 175 175 335 335 335 175 175 335 335 335 175 175 Wiring to Standard Power Block Connector Wire Range (Copper Wire Only) # 4 - 400 MCM # 4 - 400 MCM # 4 - 400 MCM #12 - 2/0 #12 - 2/0 # 4 - 400 MCM # 4 - 400 MCM # 4 - 400 MCM #12 - 2/0 #12 - 2/0 # 4 - 400 MCM
Electrical Legend Figure 8, Electrical Legend 18 AGZ 035A through 065A IOMM AGZ-3
Figure 9, Typical Field Wiring with Global UNT Controller IOMM AGZ-3 AGZ 035A through 065A 19
Figure 10, Typical Field Wiring Diagram with MicroTech Controller 20 AGZ 035A through 065A IOMM AGZ-3
Figure 11, Single-point Connection with FanTrol IOMM AGZ-3 AGZ 035A through 065A 21
Figure 12, Single-point Connection with SpeedTrol 22 AGZ 035A through 065A IOMM AGZ-3
Figure 13, Unit Control Schematic (UNT) IOMM AGZ-3 AGZ 035A through 065A 23
Figure 14, Staging Schematic (UNT) 24 AGZ 035A through 065A IOMM AGZ-3
Figure 15, MicroTech Controller Schematic IOMM AGZ-3 AGZ 035A through 065A 25
Figure 16, Unit Control Schematic (MicroTech) 26 AGZ 035A through 065A IOMM AGZ-3
Figure 17, Staging Schematic (MicroTech) IOMM AGZ-3 AGZ 035A through 065A 27
Dimensional Data Figure 18, Dimensions AGZ 035A - 065A AGZ Model Number Center Of Gravity inches (mm) Unit Weights lb (kg) A B C D E F X Y Z 81.7 (2075) 81.7 (2075) 61.6 (1565) 61.6 (1565) 22.3 (566) 22.3 (566) 5.3 (134) 5.3 (134) 15.0 (381) 15.0 (381) 43.9 (1115) 43.9 (1115) 40.2 (1021) 40.2 (1021) 36.2 (920) 36.2 (920) 3480 (1580) 3535 (1605) 3405 (1545) 3460 (1570) 445 (200) 445 (200) 045AS 86.2 (2190) 81.7 (2075) 61.6 (1565) 22.3 (566) 4.3 (108) 16.0 (406) 44.2 (1123) 40.
Startup Pre Start-up The chiller must be inspected to ensure no components became loose or damaged during shipping or installation. Start-Up Refer to the Global UNT Controller section to become familiar with its operation before starting chiller. There should be adequate building load (at least 50 percent of the unit full load capacity) to properly check the operation of the chiller refrigerant circuits.
Extended 1. 2. Front seat both condenser liquid line service valves. 3. After the compressors have stopped, put System Switch (S1) in Emergency Stop position. 4. Front seat both refrigerant circuit discharge valves. 5. If chilled water system is not drained, maintain power to the evaporator heater to prevent freezing. Maintain heat tracing on the chilled water lines. 6. Drain evaporator and water piping to prevent freezing. 7.
Electrical Check Out CAUTION Electrical power must be applied to the compressor crankcase heaters 24 hours before starting unit to drive off refrigerant from the oil. 1. 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 operation and at least yearly thereafter. 2.
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. This applies power to the control circuit and a digital input to the Global UNT controller.
Software Description (Global UNT Interface Kit required to read or change variables) Variable Name LPSS SLPT MLPS LPSD LPFS LPHL LPLL FSTP PDTD Description Low Pressure Starting Setpoint Starting Low Pressure Time Minimum Low Pressure Setpoint Low Pressure Starting Differential Low Pressure Freezestat setpoint Low Pressure High Limit Low Pressure Low Limit Freezestat Time Period Pumpdown Delay Time Period Default Value 10 psi 260 sec 5 psi 5 psi 54 psi 57 psi 55 psi 60 sec 60 sec Range 5 to 15 psi 90 to
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 at full load. See Table 53 for pressure drop at other load points. Replace the filter drier if the pressure drop exceeds maximum.
NOTE: Before adjusting superheat, check that unit charge is correct and liquid line sightglass is full with no bubbles. 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 degrees F at 95°F outdoor ambient. Crankcase Heaters The scroll compressors are equipped with externally mounted band heaters located at the oil sump level.
Global UNT Controller Installation and Operation 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. The Global UNT’s operation is based on an adjustable setpoint and control band.
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 equipment protection set points must be checked by the installing contractor and adjusted as necessary before starting the unit. The “setpoint” control knob adjusts the leaving water setpoint. The “Control Band” knob adjusts the controller temperature control band.
Chilled Water Flow Switch The chilled water flow switch is connected to field wiring terminals #142 and #143 on TB-7. When the chilled water pump is enabled, the Global UNT controller checks for proof-of-flow through the flow switch digital input. Digital Outputs The digital outputs are controlled by the Global UNT controller. The outputs are double pole double throw plug-in type relays, with a 24Vac holding coil and 120Vac - 7.0 amp rated contacts. These relays are field replaceable.
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.
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). If the OAT sensor is missing or unreliable, no reset occurs and the Actual Leaving Water Setpoint equals the Leaving Water Setpoint.
Figure 21, Zone Temperature Reset LWRB LWSP ZTLL ZTHL ZTRB (ZTLL=ZTHL - ZTRB) As the Zone Temperature increases above the Zone Temperature Low Limit (ZTLL), the controller decreases the Actual Leaving Water Setpoint from its Leaving High Limit (Leaving Water Setpoint plus Leaving Reset Band) to the Leaving Water Setpoint. When the Zone Temperature reaches the ZTHL, the Actual Leaving Water Setpoint equals the Leaving Water Setpoint (AI-4).
Figure 23, DIP SWITCH CONFIGURATION REMOTE / DEMAND LIMIT Global UNT Dipswitch Settings Switch 1 On (10V) 2 3 4 5 6 X X X X X X X X X X SW2 Off (2V) X On X (T) SW1 Off (V) Additional Global UNT Features Remote Stop/Start When the remote stop/start switch is open, the controller will be in the unoccupied mode. The unit will be enabled when the remote start / stop switch is closed and will control at the leaving water temperature setpoint.
Pumpdown Control The AGZ units have a one time pump down. The pump down is activated when a circuit’s liquid line solenoid valve is de-energized. After the circuit’s liquid line solenoid valve is de-energized, the operating compressor(s) on that refrigerant circuit will operate until the low pressure switch opens and stops that compressor(s). The compressor will not cycle on if the evaporator pressure exceeds the low pressure cut-in value.
Head Pressure Control There are two condenser fans per refrigerant circuit. These fans are cycled on and off according to the circuit’s condenser pressure. Fan #1 of a refrigerant circuit will start when number one compressor of that refrigerant circuit has started. This fan will not cycle off until the circuit is stopped. The second fan on a refrigerant circuit will cycle on and off according to its head pressure controller (PC12 or PC22).
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.
OPERATING MODES Two operating modes are included: Monitor and Adjust. Monitor Mode As soon as the ZT is connected, it completes a self-check, and starts up in the Monitor Mode. 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.
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.
CONNECTING THE ZONE TERMINAL You can unit mount the ZT, or use it as a portable tool for convenient access to any chiller information. McQuay Global Scroll Controller Connection A standard telephone-style jack connects the ZT to a McQuay Chiller Controller directly.
Adjustable Points The following McQuay Global Scroll Chiller points are adjustable by the Zone Terminal.
OA Lockout - Indicates whether you are in OA lockout (see OA Lockout SP). No alarm. Cir#2Lead=On - Indicates which circuit is in the lead e.g., ½= On, 0 = Off indicates that circuit #2 is in the lead. Pmp/Stp #1=0 - |= Auto, circuit #1 allowed to run if cooling capacity is needed, 0 = Pump down circut #1 and stop. Pmp/Stp #2=0 - |= Auto, circuit #2 allowed to run if cooling capacity is needed, 0 = Pump down circut #2 and stop.
UNT Troubleshooting Chart PROBLEM POSSIBLE CAUSES 1. Main switch, circuit breakers open. 2. Fuse blown. 3. Thermal overloads tripped or fuses blown. Compressor will not run 4. Defective contactor or coil. 5. System shut down by protection devices. 6. No cooling required. 7. Liquid line solenoid will not open. 8. Motor electrical trouble. 9. Loose wiring. 1. Dirty condenser coils. 2. Fan not operating.
MicroTech Controller Installation and Operation All operational descriptions are based on the MicroTech controller software versions AGZ2E01A. Operating characteristics and menu selections can vary with other versions of software. Contact McQuay Technical Support for software update information. General Description The MicroTech control panel contains a model 250-06 microprocessor based controller that provides all control functions.
Interlock wiring The installing contractor provides all interlock wiring to field devices (such as flow switches and pump starters). See unit wiring diagrams and field wiring diagram. Unit set points and calibration The control software is installed and tested by the factory before shipping. Calibration of the controller is not necessary. All control and equipment protection set points must be checked by the installing contractor and adjusted as necessary before starting the unit.
Field Wiring Interconnecting wiring for the control panel can consist of the following: • 115 VAC power wiring • Chilled water pump relay • Analog input signals • Digital input signals • Digital output signals • Network communications • Communications to a personal computer • Telephone line for remote modem access Power Wiring The installing contractor provides the unit voltage power source, disconnect, fuses and necessary wiring for these circuits.
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. Be sure the relay coil is rated for a maximum load of 1.8 amps at 120Vac.
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 17 for details. Table 17, Analog Inputs Input LED Description Location Range 0 0 Leaving Chilled Water Temp Leaving Chw nozzle -40 to 263°F Resolution 0.
Relay Board Outputs All of the MicroTech panel outputs are controlled by solid-state relays which are driven by the model 250 controller. The controller activates a solid-state relay by sending a “trigger” signal to the output board via the attached ribbon cable. The relay responds to the trigger by lowering its resistance which allows current to flow through its “contacts”. When the controller removes the trigger signal, the relay’s resistance becomes very high, causing the current flow to stop.
Ice (for lower ice setpoint requirements, consult McQuay Marketing Support) 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.
Manual Operation Manual operating modes are available to simplify setup and troubleshooting of the unit. Any of the following manual modes can 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. The equipment should not be left unattended during manual operation as the automatic staging controls are disabled.
Pumpdown Control The AGZ units have a one-time pump down. If two compressors are operating on a refrigerant circuit and the chiller is commanded to stop, the lag compressor on that circuit will stop and the lead compressor will pump the circuit down. Pump down pressure depends on the chiller’s refrigerant type. Certain alarm conditions will not permit chiller pumpdown.
Circuit Alarm Conditions The “Circuit Alarm Conditions” are those alarms that 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 • Refrigerant Freeze Protection • Bad Pressure Transducer The chiller must have the manual reset system alarm conditions cleared before normal operation can resume.
If an alarm condition exists which prevents normal operation of both refrigerant circuits, the chiller will be disabled and the display will indicate OFF:Alarm. 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” conditions are true, the controller will initiate a start sequence.
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.
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. Temporary Shutdown Close both pumpdown switches. After pumpdown is completed, turn off the system switch. Open the remote start / stop input and the evaporator pump will stop. Perform the reverse to start up after a temporary shutdown.
Menu Structure (general description) The information stored in the MicroTech controller can be accessed through the keypad using a treelike structure. This tree structure is divided into Categories, Menus and Menu Items. There are three Categories that make up the tree structure: STATUS, CONTROL, and ALARM. Each category is divided into Menus and each Menu into Menu Items.
Keypad Key Functions The MicroTech keypad consists of twelve pressure sensitive membrane switches (refer to Figure 27). 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. Category Group The keys in this group provide quick access to strategic menus throughout the menu tree-structure.
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. EnterOnce a change has been made to a desired value, pressing “ENTER” locks in the new value. ClearPressing “ALARMS” followed by “CLEAR” clears the current alarm. Also, when a change is made to a menu item pressing “CLEAR” returns the display to the original value as long as “ENTER” has not been pressed.
Menu #6: Circuit 62 PressuresThe 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 TemperaturesThe circuit #I refrigerant temperatures are calculated from their corresponding pressure sensors and displayed here. If the optional Sensors are not present, the line item will flash “Open”.
to a value equaling the Leaving Evaporator Water Set Point ("Lvg Evap") plus the value stored in the "MaxChWRst". Any milliamp value between 4 and 20ma will cause a proportional value of the 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.
Figure 28, 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. If the softload timer is set to zero, no soft loading will take place.
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. Pressing the Next Menu key and the Next item key will advance the display to the Daily Time Schedule.
Menus for the AGZ MicroTech Controller Table 21, MENU 1 Chiller Status Table 24, MENU 4 Water Temp's Screen Screen 1 2 Display OFF: Manual Mode OFF: System Sw OFF: Remote Comm OFF: Remote Sw OFF: Time Clock OFF: Alarm OFF: PumpDnSw's Starting WaitForFlow WaitForLoad StageUp StageDn Stage Manual InterStg=xxx sec 1 2 3 Display Lvg Evap= xxx.x °F (°C) Short °F (°C) Open °F (°C) Ent Evap= xxx.
Table 27, MENU 7 Circ #1 Temp's Screen 1 2 3 4 5 6 7 Display Satur Evap=xxx°F (°C) N/A **°F (°C) SuctLine = xxx.x°F (°C) Open °F (°C) Short °F (°C) Super Ht =xxx.x°F (°C) N/A ** °F (°C) Satur Cond = xxx°F (°C) N/A **°F (°C) Liquid Ln = xxx.x°F (°C) N/A ** °F (°C) SubCoolg= xxx.
Table 33, MENU 13 Control Mode Screen 1 2 Display Manual Unit Off Automatic Manual Staging Factory Setpoint Manual Stage=xx 0 Range Manual Unit Off 1-8 Table 34, MENU 14 Lvg Evap Spts Values for R-22 refrigerant, ( ) indicates Centigrade values Screen Display Factory Setpoint 1 Actv Spt=xxx.x °F (°C) 2 Lvg Evap=xxx.x °F (°C) 44 (6.7) 3 CntrlBand x.x °F (°C) 3.0 (1.6) 4 StartUpD-T= x.x °F (°C) 3.0 (1.6) 5 ShutDn D-T= x.x °F (°C) 1.5 (0.8) 6 MaxPullDn= x.x °F (°C) 0.5 (0.
Table 36, MENU 15 SoftLoad Spts Screen 1 2 3 4 Display Time Left= xxmin SoftLoad= xx min SoftLdMaxStg= x LoadDelay= xxsec Factory Setpoint Range 20 4 15 0 - 254 1-4 0 - 254 Range 1234 1432 2143 2341 3214 3412 4123 4321 Table 37, MENU 16 CompressorSpt Screen Display Factory Setpoint 1 Sequence=Auto Auto 2 3 4 5 StageUp= xxx sec StageDn= xxx sec MinST-ST=xx min MinSP-ST xx min Comp #1 Comp #2 Comp #3 Comp #4 15 5 5 - 40 3 - 30 Disable / Enable Disable / Enable Disable / Enable Disable / Enable
Table 42, MENU 20 Schedule Screen 1 2 3 4 5 6 7 8 9 10 Display Override= xx.xx hr NMPSchedule= N/A Sun 00:00-23:59 Mon 00:00-23:59 Tue 00:00-23:59 Wed 00:00-23:59 Thu 00:00-23:59 Fri 00:00-23:59 Sat 00:00-23:59 Hol 00:00-23:59 Factory Setpoint 0.00 Hr N/A 00:00 - 23:59 00:00 - 23:59 00:00 - 23:59 00:00 - 23:59 00:00 - 23:59 00:00 - 23:59 00:00 - 23:59 00:00 - 23:59 Range 00:00 - 63.
Table 46, MENU 23 Misc Setup Screen 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 IOMM AGZ-3 Display Unit Type= Air Cooled Model AGZ 4 Stages # Compressors = 4 # Stages = 4 Fan Stg/Cir = 2 Begin PD = xx PSI End PD – xx PSI Full Pump DN - NO EndFullPD = xx PSI Low Ambi Opr = NO Low Ambi Temp = xx°F LvgEvapAdj = 0.0°F EntEvapAdj = 0.0°F #1 EvapAdj = 0.0 psi #2 EvapAdj = 0.0 psi #1 CondAdj= 0.0 psi #2 CondAdj= 0.
Trouble Analysis for the MicroTech Microprocessor Control Board The Microprocessor Control Board (MCB) is shown in Figure 29. It contains a microprocessor that is preprogrammed with the software required to monitor and control the chiller. The various MCB connections and components are described below.
Following is the normal start-up sequence that the three status LED’s should follow when power is applied to the MCB: 1. The red (“Reset”) LED turns on and remains on for approximately 5 seconds. During this period the MCB performs a self-test. 2. The red LED turns off and the green (“Running”) LED turns on. This indicates that the microprocessor has passed the self-test and is functioning properly. 3. The amber (“Active”) LED remains off continually if no alarm conditions exist in the network.
Figure 30, Hex Switches HI (left) hex switch LO (right) hex switch 3 4 5 3 4 5 BCDE 2 2 6 7 8 9A BCDE F 0 1 6 F 0 1 7 8 9A * Hex switch setting 01 shown Communication Ports The MCB has two communication ports: port A and port B. Each port has six terminals and is set up for both the RS-232C and RS-485 data transmission interface standards. The male and female connectors for these ports are manufactured by AMP.
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. However, this can also occur in some instances if there is a power supply problem. Refer to “Troubleshooting Power Problems” below.
6. 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. Any of these can be defective. Try repeating this step after removing or swapping the ADI board. 7. Reconnect the digital input ribbon cable. Cycle power to the controller and check the power fuses. If both fuses are intact, go to step 8.
Figure 31, MCB Power Supply Terminals POWER IN [18-24 VCT] AC AC GND GND POWER FUSES [BUSSMAN GDC-T2A] 4 3 Fuse F1 Fuse F2 2 1 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 back light. The MCB provides operating voltages, control signal outputs for the display, and input conditioning for the keypad inputs.
Troubleshooting Analog Inputs An analog input, such as a temperature sensor, is connected to the ADI board. The analog input is then conditioned by the ADI board. 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: 1. Try cycling power to the controller by opening and then closing circuit breaker CB1. 2.
Figure 32, Output Board Relay Socket 1 Fuse 2 *250V ~ 50/60 Hz *120V ~ 50/60 Hz 3 Test Resistor 330-680 Ohm 4 5 LED 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. Avoid them. One LED Out If one of the Output Board LEDs fails to illuminate when the MCB is commanding the associated output to energize, perform the following procedure: 1.
2. 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. 3. Check the discrete wiring and connections between the Output board and the Controller. Aux/Out terminal strip and the field wiring terminal strip.
3. 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. 4. 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. Troubleshooting Solid-State Relays As shown on the unit wiring diagrams, the Solid-State relays on the Output Boards all have normally open “contacts.
Unit Maintenance General On initial start-up and periodically during operation, it will be necessary to perform certain routine service checks. Among these are checking the liquid line sightglasses, taking condensing and suction pressure readings, and checking to see that the unit has normal superheat and subcooling readings. A recommended maintenance schedule is located at the end of this section. A Periodic Maintenance Log is located at the end of this manual.
the sightglass could also indicate an excessive pressure drop in the liquid line, possibly due to a clogged filter-drier or a restriction elsewhere in the liquid line. See Table 53 for maximum allowable pressure drops). If subcooling is low add charge to clear the sightglass. If subcooling is normal (10°15°F) and flashing is visible in the sightglass check the pressure drop across the filter-drier. Subcooling should be checked at full load with 70°F (21.1°C) outdoor air temperature and all fans running.
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 equipment protection controls must be investigated and corrected. 2. Disconnect all power before doing any service inside the unit. 3.
Evaporator The evaporator is 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. Normally no service work is required on the evaporator.
3. The charge can be added at any load condition between 25-100% load per circuit but at least two F 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. of reserve to fill the subcooler if the compressor is operating at 50-100% load. 5.
AGZ Troubleshooting Chart PROBLEM 1. 2. POSSIBLE CAUSES Main Switch. Fuse Blown. Circuit breakers open 1. 2. 3. Thermal overloads tripped 3. 4. 5. Defective contactor or coil. System Shutdown by equipment protection devices 4. 5. 6. 7. 8. 9. No cooling required Liquid line solenoid will not open Motor electrical trouble Loose wiring 6. 7. 8. 9. POSSIBLE CORRECTIVE STEPS Close Switch. Check electrical circuits and motor windings for shorts or grounds. Investigate for possible overloading.
Notes 94 AGZ 035A through 065A IOMM AGZ-3
This document contains the most current product information as of this printing. For the most up-todate product information, please go to www.mcquay.com. Post Office 2510, Staunton, Virginia 24402 USA • (800) 432-1342 • www.mcquay.
