Installation, Operation and Maintenance Manual IOMM ACR/AGR-1 Group: Chiller Part Number: 074644201 Effective: March 2000 Supersedes: IOMM ACR/AGR AIR-COOLED, RECIPROCATING, SPLIT SYSTEMS Chiller w/ Remote Evaporator, AGR 070AM-100AM Condensing Unit, ACR 060AS-120AS DX Evaporators, CDE 60 Hertz, R-22 Global Chiller Line © 1997 McQuay International
Table of Contents Introduction.........................................3 Inspection ...........................................................3 Installation...........................................4 Handling..............................................................4 Location...............................................................5 Service Access ...................................................5 Vibration Isolators..............................................7 Water Piping ................
Introduction IMPORTANT INFORMATION This Product Manual contains information on three different McQuay product lines. • Model AGR-AM This is the AGR packaged chiller but with the shell and tube evaporator shipped loose for remote mounting. Liquid line specialties are field supplied and mounted. Capacity control is included and is Johnson UNT as standard or optional McQuay MicroTech Control.
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. 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 AGR-AM and ACR 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. A one piece concrete slab with footings extended below the frost line is recommended.
Figure 3, Clearance Requirements Do not block the flow of air to and from the condenser coil. Restricting airflow or allowing air recirculation will result in a decrease in unit performance and efficiency because discharge pressures are increased. There must be no obstruction above the unit that would deflect discharge air downward where it could be recirculated back to the inlet of the condenser coil. The condenser fans are propeller type and will not operate with ductwork on the fan outlet.
Vibration Isolators Vibration isolators are recommended for all roof mounted installations or wherever vibration transmission is a consideration. Table 1 through Table 4 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.
Table 3, AGR-AM Isolator Loads At Each Mounting Location With Copper Fins AGR-AM Size 070 AM 075 AM 080 AM 085 AM 090 AM 095 AM 100 AM 1 lb 1171 1526 1587 1634 1669 1672 1673 2 kg 531 692 720 741 757 758 759 lb 1476 1863 1937 1995 2038 2041 2042 3 kg 670 845 879 905 924 926 926 lb 1009 1142 1187 1222 1249 1250 1251 4 kg 457 518 538 554 566 567 568 lb 1264 1384 1439 1482 1514 1516 1517 TOTAL UNIT lb kg 4920 2232 5915 2683 6150 2790 6334 2873 6469 2934 6479 2939 6483 2941 kg 574 628 653 672 687 688 6
. If the unit is used as a replacement chiller on a previously existing piping system, flush the system thoroughly before unit installation. Regular water analysis and chemical water treatment for the evaporator loop is recommended immediately at equipment start-up. 10. The total water volume in the system should be sufficient to prevent frequent “on-off” cycling. Turnover rate should not be less than 15 minutes for normal variable cooling loads.
Table 5, Flow Switch Minimum Flow Rates NOMINAL PIPE SIZE INCHES (mm) MINIMUM REQUIRED FLOW TO ACTIVATE SWITCH - gpm (L/s) 1 (25.4) 1 1/4 (31.8) 1 1/2 (38.1) 2 (50.8) 2 1/2 (63.50 3 (76.20 4 (101.6) 5 (127.0) 6 (152.4) 6.00 (0.38) 9.80 (0.62) 12.70 (0.80) 18.80 (1.20) 24.30 (1.50) 30.00 (1.90) 39.70 (2.50) 58.70 (3.70) 79.20 (5.
Table 6, Ethylene Glycol 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 7, Propylene Glycol Factors % P.G.
Figure 7, Pressure Drop Curve CDE Size AGR Unit Size 1204-1 1255-1 1455-1 - 070 AM 075 AM 080 AM 085 AM 090 AM 095 AM 100 AM PD ft of Water 11.2 8.9 10.3 11.8 10.5 12.0 13.4 NOMINAL Flow gpm lps 162 10.22 172 10.85 187 11.80 202 12.74 208 13.12 224 14.13 238 15.02 PD ft of Water 28.1 22.5 25.9 29.7 26.3 30.0 33.6 MAXIMUM Flow gpm 270 287 312 337 347 373 397 lps 17.03 18.09 19.66 21.24 21.87 23.55 25.02 PD ft of Water 4.8 3.8 4.4 5.0 4.5 5.2 5.7 MINIMUM Flow gpm 101 108 117 126 130 140 149 lps 6.
Refrigerant Piping Introduction Proper refrigerant piping can represent the difference between a reliable, trouble free system and months or years of inefficient, problematic performance. System concerns related to piping are: 1. Refrigerant pressure drop 2. Solid liquid feed to the expansion valve(s) 3. Continuous oil return The most important and least understood is number 3. “Continuous oil return”.
Add b and c above to obtain the total equivalent feet. Use ASHRAE Table 3 (for R22) or Table 4 (for R134a). Suction line selections are based upon the pressure equivalent of a 2ºF loss per 100 equivalent feet. Select a line size that displays an equal or slightly larger tons then that determined in 1a) above. To determine the actual line loss: 1. Modify the table tons by the value in Note 4 of Table 3 or 4 for the design condensing temperature. 2.
Underground Refrigerant Lines McQuay does not recommend the installation of suction lines underground. If job conditions require that they be located below ground, a suitable sized suction accumulator must be installed ahead of the compressor to interrupt liquid refrigerant slugs at start-up. 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.
totaling 10 x 3.05 psi (or 10 x 2.2) and still satisfy the objective of delivering solid liquid to the expansion valve. In calculating the pressure losses, or gains, note that each foot of rise in a liquid line results in approximately 0.5 psi loss. Thus a 10 foot rise represent 5 pounds per square inch loss in refrigerant pressure, or the equivalent of 1.6ºF subcooling with R-22.
Physical Data AGR-AM Table 10, AGR 070AM - 085AM PHYSICAL DATA STANDARD EFFICIENCY BASIC DATA Unit Capacity @ ARI Conditions (1), Tons (kW) Number Of Refrigerant Circuits Unit Operating Charge, R-22, lbs. (kg) Unit Operating Charge, R-134a, , lbs. (kg) Cabinet Dimensions, LxWxH, In. Cabinet Dimensions, LxWxH, (mm) Unit Operating Weight, Lbs. (kg) Unit Shipping Weight, Lbs. (kg) Add'l Weight If Copper Finned Coils, Lbs.
Table 11, AGR 090AM - 100AM PHYSICAL DATA STANDARD EFFICIENCY BASIC DATA Unit Capacity @ ARI Conditions (1), Tons (kW) Number Of Refrigerant Circuits Unit Operating Charge, R-22, lbs.(kg) Unit Operating Charge, R-134a, lbs.(kg) Cabinet Dimensions, LxWxH, In. Cabinet Dimensions, LxWxH, (mm) Unit Operating Weight, Lbs. (kg) Unit Shipping Weight, Lbs. (kg) Add'l Weight If Copper Finned Coils, Lbs. (kg) COMPRESSORS Type Nominal Horsepower Number Of Cylinders Per Compressor Oil Charge Per Compressor, oz.
Table 12, ACR 060AS - 070AS PHYSICAL DATA STANDARD EFFICIENCY BASIC DATA Unit Capacity @ ARI Conditions (1), mbh (kW) Number Of Refrigerant Circuits Unit Operating Charge, R-22, Lbs. Unit Operating Charge, R-22, (kg) Cabinet Dimensions, LxWxH, In. Cabinet Dimensions, LxWxH, (mm) Unit Operating Weight, Lbs. (kg) Unit Shipping Weight, Lbs. (kg) Add'l Weight If Copper Finned Coils, Lbs. (kg) Ckt.1 Ckt.2 703 (205.9) 2 46 46 (20.9) (20.9) 94.0 x 88.2 x 86.
Table 13, ACR 075A - 090A PHYSICAL DATA STANDARD EFFICIENCY BASIC DATA Unit Capacity @ ARI Conditions (1), mbh (kW) Number Of Refrigerant Circuits Unit Operating Charge, R-22, Lbs. Unit Operating Charge, R-22, (kg) Cabinet Dimensions, LxWxH, In. Cabinet Dimensions, LxWxH, (mm) Unit Operating Weight, Lbs. (kg) Unit Shipping Weight, Lbs. (kg) Add'l Weight If Copper Finned Coils, Lbs. (kg) Ckt.2 871 (255.0) 2 55 55 (24.9) (24.9) 94.0 x 88.2 x 96.
Table 14, ACR 100A - 120A PHYSICAL DATA STANDARD EFFICIENCY BASIC DATA Unit Capacity @ ARI Conditions (1), mbh (kW) Number Of Refrigerant Circuits Unit Operating Charge, R-22, Lbs. Unit Operating Charge, R-22, (kg) Cabinet Dimensions, LxWxH, In. Cabinet Dimensions, LxWxH, (mm) Unit Operating Weight, Lbs. (kg) Unit Shipping Weight, Lbs. (kg) Add'l Weight If Copper Finned Coils, Lbs. (kg) Ckt.1 Ckt.2 1178 (344.9) 2 82 82 (37.2) (37.2) 136.4 x 88.2 x 96.
Electrical Data Field Wiring Power 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. 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.
AGR-AM Data ACR Data Table 15, 60 Hz, Single Point Power Electrical Data ACR-AS Cond. Unit Model POWER SUPPLY Field Wire Conduit Hub Wire Nominal Quantity Quantity Gauge Size 3 250 1 2.00 3 250 1 2.00 3 1/0 1 1.5 3 #2 1 1.25 3 #3 1 1.00 Volts Minimum Circuit Ampacity (MCA) 060As 208 230 380 460 575 231 231 134 114 90 065AS 208 230 380 460 575 237 237 137 117 90 3 3 3 3 3 250 250 1/0 #1 #3 1 1 1 1 1 2.00 2.00 1.50 1.00 1.
Table 16, 60 Hz, Compressor & Condenser Fan Motor Amp Draw ACR-A Cond. Unit Size AGR-AM Chiller Unit Size Volts Rated Load Amps Compressors No. No. 1 2 Fan Motors (Each) No. Of Fan Fan Motors Motors (Each) Locked Rotor Amps Compressors Across-The-Line Reduced No. 1 No. 2 No. 1 470 565 292 470 565 292 285 342 N/A 235 260 141 200 230 130 Inrush No. 2 340 340 N/A 156 138 060AS 208 230 380 460 575 89 89 52 44 36 95 95 55 47 36 5.8 5.8 3.4 2.8 2.3 4 4 4 4 4 23.7 21.4 14.4 10.7 11.
Table 17, 60 Hz Single Point Power, Field Wiring Data ACR-AS Cond.
Electrical Notes Notes for “Electrical Data Single Point” Power: 1. Unit wire size ampacity (MCA) is equal to 125% of the largest compressor-motor RLA plus 100% of RLA of all other loads in the circuit including the control transformer. 2. If the control transformer option is furnished, no separate 115V power is required. 3. If a separate 115V power supply is used for the control circuit, then the wire sizing amps is 10 amps for all unit sizes. 4.
Electrical Legend Figure 8, Electrical Legend IOMM ACR/AGR-1 27
Wiring Diagrams Figure 9, AGR-AM, Typical Field Wiring with MicroTech Controller 28 IOMM ACR/AGR-1
Figure 10, AGR-AM, Typical Field Wiring Diagram with UNT Controller IOMM ACR/AGR-1 29
Figure 11, ACR-A, Field Wiring Diagram (No Capacity Control) 30 IOMM ACR/AGR-1
Figure 12, ACR-A, Field Wiring Diagram (Capacity Control Staging) IOMM ACR/AGR-1 31
Figure 13, AGR-AM, MicroTech Controller Schematic 32 IOMM ACR/AGR-1
Figure 14, AGR-AM, Unit Control Schematic (MicroTech) IOMM ACR/AGR-1 33
Figure 15, AGR-AM, Staging Schematic (MicroTech) 34 IOMM ACR/AGR-1
Dimensional Data Figure 16, Dimensions AGR 070AM and ACR 060AS -075AS ACR MODEL NUMBER 060A 065A 070A 075A - AGR MODEL NUMBER - ACR MODEL NUMBER 060A 065A 070A 075A - AGR MODEL NUMBER - 070AM 070AM IOMM ACR/AGR-1 OVERALL HEIGHT A 86.2 (2190) 86.2 (2190) 86.2 (2190) 96.2 (2444) 96.2 (2444) COMPRESSOR # 1 (SUCTION #1) inches (mm) C D E 50.84 (1391) 20.88 (597) 23.52 (597) 50.09 (1272) 20.88 (597) 23.52 (597) 50.09 (1272) 20.88 (597) 23.52 (597) 49.34 (1253) 20.88 (597) 23.52 (597) 49.34 (1253) 20.
Figure 17, AGR 075AM - 100AM and ACR 080AS - 120AS 36 ACR MODEL NUMBER AGR MODEL NUMBER 080A 090A 100A 110A 120A 075AM 080AM 085AM 090AM 095AM 100AM ACR MODEL NUMBER AGR MODEL NUMBER 080A 090A 100A 110A 120A 075AM 080AM 085AM 090AM 095AM 100AM COMPRESSOR # 1 (SUCTION #1) inches (mm) C D E 88.5 (2248) 20.9 (531) 25.5 (648) 88.5 (2248) 20.9 (531) 25.5 (648) 86.0 (2184) 23.9 (608) 27.8 (707) 86.0 (2184) 23.9 (608) 27.8 (707) 86.0 (2184) 23.9 (608) 27.8 (707) 86.0 (2184) 23.9 (608) 27.8 (707) 59.
CDE Evaporator Figure 18, CDE 1004-1 - 1204-1 CDE MODEL NUMBER CDE-1204-2 CDE-1204-1 CDE-1255-1 CDE-1455-1 C 39.3 (998) 36.0 (914) 54 (1372) 54 (1372) CDE MODEL NUMBER CDE-1204-2 CDE-1204-1 CDE-1255-1 CDE-1455-1 53.5 53.5 71.5 71.5 CDE MODEL NUMBER CDE-1204-2 CDE-1204-1 CDE-1255-1 CDE-1455-1 WATER CONNECTION inch (mm) L P 9.5 (241) 4.0 (102) 9.5 (241) 5.0 (127) 11.0 (278) 5.0 (127) 11.0 (278) 5.0 (127) 3.0 3.0 3.0 3.0 A (1359) (1359) (1816) (1816) K (76 (76 (76) (76) 17.5 17.5 17.5 19.1 50.0 50.
Startup Pre Start-up The system components must be inspected to ensure that nothing has become loose or damaged during shipping or installation. Start-Up For AGR-AM units refer to the Global UNT Controller or MicroTech Controller sections to become familiar with the operation before starting chiller. For ACR units, the field furnished and installed capacity control system should be thoroughly understood prior to starting the unit.
Extended 1. Front seat both condenser liquid line service valves. 2. Put both circuit switches in Pumpdown and Stop position. 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. 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 operations and at least yearly thereafter. 2.
Operation Hot Gas Bypass (Optional) This option allows the system to operate at low loads without the ON-OFF cycling of the compressor. When the hot gas bypass option is used it is required to be on both refrigerant circuits because of the lead / lag feature of the Global UNT controller. This option allows passage of discharge gas into the evaporator inlet (between the TX valve and the evaporator) which generates a false load to supplement the actual chilled water load.
System Adjustment To maintain peak performance at full load operation, the system superheat and liquid subcooling may require adjustment. Read the following subsections closely to determine if adjustment is required. Liquid Sightglass and Moisture Indicator The color of the moisture indicator is an indication of the dryness of the system and is extremely important when the system has been serviced. Immediately after the system has been opened for service, the element may indicate a wet condition.
DX Evaporator The evaporator is of the direct expansion type with removable internally finned tubes. The copper tubes are individually rolled into heavy duty steel tube sheets and sealed by a steel refrigerant head. The water connection nozzles that enter and leave the shell are on the same side of the unit. The water inlet is located on the end having the refrigerant connections. No special attention is required for the cooler except that clean, filtered water should be supplied.
Standard Controller Setpoints (optional Zone Terminal required to change values) TEMPLATE NAME VALUES FACTORY SETPOINT 80°F -40°F 0°F 70°F -10°F 20°F 50% 2 min OA/AI3 Lim SP OA/AI3 Reset SP LvgWtr Rband SP Unoccpd Lvg SP OA Lockout SP Lvg Low Lim SP SoftSta Capcty SoftStart Time RANGE 0 to 100°F -100 to 100°F 0 to 15°F 40 to 90°F -20 to 65°F 20 to 40°F 0 to 100% 0 to 20 minutes Software Description (Global UNT Interface Kit required to read or change variables) Variable Name LPSS SLPT MLPS LPSD LPFS LPH
UNT Controller, AGR-AM The ACR Condensing Unit does not come factory equipped with a staging control. The control is field supplied and installed. This section provides installation, setup and troubleshooting information for the Global UNT controller as furnished with the remote evaporator AGR-AM chiller. All operational descriptions are based on the Global UNT software SUZE4-2A. Operational characteristics may vary with other versions of software.
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” 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 Global UNT controller controls the digital outputs. 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 - Z TRB) 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).
Table 22, Dip Switch Configuration Remote Reset / 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 (T) X Off (V) SW1 UNT Controller 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 AGR 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.
Alarms 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 • Freezestat Protection The Alarm Light on the control panel will illuminate if either circuit has a high head pressure occurrence or a compressor motor protection occurrence. Freeze protection would be indicated on the optional Zone Terminal.
Figure 22, Zone Terminal Di spl ay Item L ist Di spl ay In dicator Do t Wa rning Si gna l McQuay AGZ/AGR Global Chiller INSERT 10 Disp lay Butto n 1 2 3 Mode Sel ector Butto n Mod e Se lecto r Pa nel ON On/Off Status OFF L vg W ater Tem p Ev ap P res #1 Ev ap P res #2 OA/A I3 I nput O A/A I3 H iLim SP O A/A I3 R eset SP Lvg Wate r S P Lv gWtr RBn d SP Co ntrl Ban d SP Act ual Lvg SP Uno ccpd Lvg SP OA L ocko ut S P Display Area 11 O ccup ied F low Fai lure O A L ocko ut C ir# 2Lea d=On P mp/ Stp
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 Reciprocating Controller Connection A standard telephone-style jack connects the ZT to a McQuay Chiller Controller directly.
Adjustable Points The following McQuay Global Reciprocating Chiller points are adjustable by the Zone Terminal.
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). Occupied - |= On, 0 = Off Flow Failure - |= Alarm, 0 = Normal OA Lockout - Indicates whether you're in OA lockout (see OA Lockout SP). No alarm.
Global UNT Controller 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 safety 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. High Discharge Pressure Low Discharge Pressure 3. 4. 5. 6. 7. High Ambient conditions.
Erratic Loading and Unloading 60 4. 5. 6. 7. Controller stage timing. Defective TXV. Hot gas bypass not set properly. Low ambient operation. 4. 5. 6. 7. Check timing and reset as necessary. Check and repair or replace. Set hot gas bypass. Install SpeedTrol, wind baffles. 1. 2. 3. 4. 5. Chilled water flow erratic. System load erratic. Bad water sensor. Reset function calibration. Defective UNT controller. 1. Check for reasons and correct. 2. Check water flow control valve operation. 3. Replace. 4.
MicroTech Controller All operational descriptions are based on the MicroTech controller software versions rcp2e02g.cod for English and rcp2s02g.cod for Metric. Operating characteristics and menu selections may 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 which 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 safety 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 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 • 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 25 for details.
Table 27, Relay Board Outputs Digital Output Number 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Output Description Alarm Circuit Chilled Water Pump Relay Liquid Line Solenoid Circuit #1 Liquid Line Solenoid Circuit #2 Compressor #1 Circuit #1 Compressor #2 Circuit #2 Hot Gas Bypass Circuit #1 Hot Gas Bypass Circuit #2 Compressor #3 Circuit #1 Compressor #4 Circuit #2 Condenser Fan (M11) Condenser Fan (M12) Spare Condenser Fan (M21) Condenser Fan (M22) Spare Reset Options User reset options are located in the “L
The remote 4-20mA input must be 4mA or less and the leaving water temperature will be controlled to the calculated setpoint. When the remote reset input is above 4mA, the value “MaxChwRst” is added to the leaving water setpoint. This will be the day operating setpoint. This value cannot be reset when in the day mode by any other reset options. The alarm setpoints must be adjusted to allow operation of the chiller at the lower temperatures.
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. The equipment should not be left unattended during manual operation as the automatic staging controls are disabled.
The MicroTech controller alarms can either be of the manual reset type or the auto reset type. Critical alarm conditions such as High Condenser Pressure, Refrigerant Freeze Protection, and Low Evaporator Pressure which protect against equipment damage are manual reset, which means they lockout compressor operation and must be cleared at the MicroTech keypad before operation can resume. Auto-clearing alarm conditions cause the compressors to shut off on the affected circuit until the condition is corrected.
Sequence of Operation Off Conditions With power supplied to the unit, 115Vac power is applied through the control fuse F1 to the compressor crankcase heaters (HTR1-4), the compressors motor protectors (MP1-4), the evaporator heater and the primary of the 24V control circuit transformer. The 24V transformer provides power to the MicroTech controller and related components. With 24V power applied, the controller will check the position of the front panel System Switch.
Low Ambient Start If the “LOW AMBIENT” option was selected and the out side air temperature is below 50°F, the low ambient start logic will replace the normal starting logic. The compressor with the lowest starts on the lead circuit will start when the liquid line solenoid valve is energized. The LPCutIn will be ignored and the refrigerant freeze protect set point will be ignored for 180 seconds to allow time for the refrigerant pressure to build.
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.
Move both pumpdown switches to the auto position. DH1-7 and DH2-15 will turn off. The controller will then activate one of the refrigerant circuit solenoids depending upon which is the lead circuit. (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.
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 25). 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”.
If the 4-20 milliamp reset option is enabled, the controller will reset the leaving chilled water temperature to a higher value based on a percentage of the Maximum Chilled Water Reset set point ("MaxChWRst"). At 4mA or less, no reset will occur. At 20mA, the chilled water set point will be reset to a value equaling the Leaving Evaporator Water Set Point ("Lvg Evap") plus the value stored in the "MaxChWRst".
Figure 26, 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 AGR MicroTech Controller Table 29, MENU 1 Chiller Status Table 32, MENU 4 Water Temp's Screen Screen 1 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 2 Capacity = % 3 InterStg=xxx sec 1 Display Lvg Evap= xxx.x °F (°C) Short °F (°C) Open °F (°C) 2 Ent Evap= xxx.
Table 35, MENU 7 Circ #1 Temp's Screen 1 Display Satur Evap=xxx°F (°C) N/A **°F (°C) 2 SuctLine = xxx.x°F (°C) Open °F (°C) Short °F (°C) 3 Super Ht =xxx.x°F (°C) N/A ** °F (°C) 4 Satur Cond = xxx°F (°C) N/A **°F (°C) 5 CondD-T °F (°C) 6 Liquid Ln = xxx.x°F (°C) N/A ** °F (°C) 7 SubCoolg= xxx.x°F (°C) N/A ** °F (°C) Table 36, MENU 8 Circ #2 Temp's Screen 1 Display Satur Evap=xxx°F (°C) N/A **°F (°C) 2 SuctLine = xxx.x°F (°C) Open °F (°C) Short 3 Super Ht =xxx.
Table 41, MENU 13 Control Mode Screen 1 2 Display Manual Unit Off Automatic Manual Staging Factory Setpoint Range Manual Stage=xx 0 1-8 Factory Setpoint 44 (6.7) Range 10 - 80 (-12.2 - 26.7) Manual Unit Off Table 42, MENU 14 Lvg Evap Spts Values for R-22 refrigerant, ( ) indicates Centigrade values Screen 1 Display Lvg Evap=xxx.x °F (°C) 2 Actv Spt=xxx.x °F (°C) 3 CntrlBand x.x °F (°C) 3.0 (1.6) 1.0 - 5.0 (0.5 - 2.7) 4 StartUpD-T= x.x °F (°C) 3.0 (1.6) 1.0 - 5.0 (0.5 - 2.
Table 44, MENU 15 SoftLoad Spts Screen 1 Display Time Left= xxmin Factory Setpoint Range 2 SoftLoad= xx min 20 0 - 254 3 SoftLdMaxStg= x 4 1-4 4 LoadDelay= xxsec 15 0 - 254 Range 1234 1432 2143 2341 3214 3412 4123 4321 Table 45, MENU 16 CompressorSpt Screen Display Factory Setpoint 1 Sequence=Auto Auto 2 StageUp= xxx sec 3 StageDn= xxx sec 4 MinST-ST=xx min 15 5 MinSP-ST xx min 5 5 - 40 3 - 30 Comp #1 Disable / Enable Comp #2 Disable / Enable Comp #3 Disable / Enable
Table 50, MENU 20 Schedule Screen 1 Display Override= xx.xx hr Factory Setpoint 0.00 Hr Range 00:00 - 63.
Table 54, 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 86 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.
MicroTech Controller Trouble Analysis Microprocessor Control Board The Microprocessor Control Board (MCB) is shown in Figure 27. 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 28, Hex Switches HI (left) hex switch LO (right) hex switch 3 4 56 7 8 9 A 2 3 4 56 B CDE A F 0 1 2 B CDE F 0 1 7 8 9 * 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. AMP manufactures the male and female connectors for these ports. Therefore, they are referred to as “AMP plugs” or “AMP connectors” throughout this manual.
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 may 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 29, MCB Power Supply Terminals POWER IN [18-24 VCT] AC AC GND GND POWER FUSES [BUSSMAN GDC-T2A] 4 3 2 Fuse F1 Fuse F2 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 backlight. 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 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: 1. Try cycling power to the controller by opening and then closing circuit breaker CB1. 2.
Figure 30, 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. Compressor Maintenance The reciprocating compressors are semi-hermetic and require no maintenance.
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. 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.
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. 2. Disconnect all power before doing any service inside the unit. 3.
Evaporator The remote evaporator on AGR-AM units and CDE evaporators are the direct expansion, shell-andtube 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.
2. Add the charge to the system through the suction shutoff valve or through the Schrader fitting on the tube entering the evaporator between the compressor and the evaporator head. 3. The charge can be added at any load condition between 25-100% load per circuit but at least two 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.
AGR 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 safety 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.
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