McQuay AGS 250B Installation Manual

Page 1
Installation and Maintenance Manual
IMM A GS - 1
Group: Chiller Part Number: 330262005 Date: November 2002 Supersedes: IMM AGS
GeneSys
AGS 230B through AGS 475B
60 Hertz, R-134a
Page 2
Table Of Contents
Introduction.......................................3
General Description...................................3
Nomenclature.............................................3
Inspection...................................................3
Installation and Start-up.................... 4
Handling ....................................................4
Location.....................................................5
Service Access...........................................5
Clearance Requirements............................6
Restricted Airflow......................................7
Vibration Isolators ...................................12
Lifting and Mounting Weights.................14
Chilled Water Pump .................................17
Water Piping ............................................17
System Water Volume..............................18
Variable Speed Pumping..........................18
Evaporator Freeze Protection...................18
Operating Limits:.....................................20
Flow Switch.............................................20
Water Connections...................................21
Refrigerant Charge...................................21
Glycol Solutions ......................................21
Water Flow and Pressure Drop........ 22
Physical Data...................................24
Dimensional Data............................27
Wind Baffles and Hail Guards.........29
Electrical Data................................. 31
Field Wiring.............................................31
Field Wiring Diagram......................37
Solid State Starters.......................... 38
Component Location....................... 45
Major Component Location.....................45
Power Panel.............................................47
Control Panel...........................................48
System Maintenance........................49
General ....................................................49
Compressor Maintenance........................ 49
Lubrication ..............................................49
Electrical Terminals.................................50
Condensers ..............................................50
Liquid Line Sight Glass........................... 50
Evaporator Sight Glass............................50
Lead-Lag..................................................51
Preventative Maintenance Schedule........51
Warranty Statement.........................52
Service.............................................52
Liquid Line Filter-Driers .........................52
Compressor Slide Valves.........................53
Electronic Expansion Valve.....................53
Evaporator...............................................53
Charging Refrigerant ...............................54
Charging Oil............................................55
Standard Controls....................................56
Optional Controls ....................................58
Controls, Settings and Functions .............59
Troubleshooting Chart.............................60
Periodic Maintenance Log.......................61
Our facility is ISO Certified
"McQuay" is a registered trademark of McQuay International
"Information covers the McQuay International products at the time of publication and we reserve the right to make changes in design
2 IMM AGS-1
2002 McQuay International
and construction at anytime without notice"
Page 3

Introduction

N

General Description

McQuay GeneSys refrigerating units that include the latest in engineered components arranged to provide a compact and efficient unit. Each unit is completely assembled, factory wired, evacuated, charged, tested and comes complete and ready for installation. Each unit consists of multiple air-cooled condenser sections with integral subcooler sections, multiple semi-hermetic single-screw compressors, solid­state starters, a multiple circuit shell-and-tube flooded evaporator, and complete refrigerant piping. Each compressor has an independent refrigeration circuit. Liquid line components included are manual liquid line shutoff valves, charging ports, filter-driers, sight-glass/moisture indicators, and electronic expansion valves. A discharge check valve is included and a compressor suction shutoff valve is optional. Other features include compressor heaters, evaporator head heaters, automatic one­time pumpdown of refrigerant circuit upon circuit shutdown, and an advanced fully integrated microprocessor control system.
Information on the operation of the unit and on the MicroTech II controller are in the OM AGS manual.

air-cooled water chillers are complete, self-contained automatic

Nomenclature

A G S - XXX B
Air-Cooled
Design Vintage
Global
Rotary Screw Compressor
ominal Tons

Inspection

When the equipment is received, all items should be carefully checked against the bill of lading to check for a complete shipment. All units should be carefully inspected for damage upon arrival. All shipping damage must be reported to the carrier and a claim must be filed with the carrier. The unit’s serial plate should be checked before unloading the unit to be sure that it agrees with the power supply available. Physical damage to unit after acceptance is not the responsibility of McQuay International.
Note: Unit shipping and operating weights are shown in the Physical Data Tables on page 24.
IMM AGS-1 3
Page 4

Installation and Start-up

Note: Installation and maintenance are to be performed only by qualified personnel who are familiar with local codes and regulations, and experienced with this type of equipment.
Sharp edges and coil surfaces are a potential injury hazard. Avoid contact with them.
Start-up by McQuayService is included on all units sold for installation within the USA and Canada and must be performed by them to initiate the standard limited product warranty. Two-week prior notification of start-up is required. The contractor should obtain a copy of the Start-up Scheduled Request Form from the sales representative or from the nearest office of McQuayService.

Handling

Care should be take n to avoid rough hand ling or shock due to impact or dropping the unit. Do not push or pull the unit.
Never allow any part of the unit to fall during unloading or moving as this can result in serious damage.
To lift the unit, lifting tabs with 2½" (64 mm) diameter holes are provided on the base of the unit. All lifting holes must be used when lifting the unit. Spreader bars and cables should be arranged to prevent damage to the condenser coils or unit cabinet (see Figure 1).
Improper lifting or moving unit can result in property damage, severe
personal injury or death. Follow rigging and moving instructions carefully.
WARNING
DANGER
Figure 1, Required Lifting Method
NOTES:
1. All rigging points on a unit must be used. See page 14 through page 15 for location, and weight at lifting points for a specific size unit.
2. Crosswise and lengthwise spreader bars must be used to avoid damage to unit. Lifting cables from the unit mounting holes up must be vertical.
3. The number of lifting points, condenser sections, and fans can vary from this diagram.
4 IMM AGS-1
Page 5

Location

Care should be taken in the location of the unit to provide proper airflow to the condenser. (See Figure 2 on page 6 for required clearances).
Due to the shape of the condenser coils on the AGS chillers, it is recommended that the unit be oriented so that prevailing winds blow parallel to the unit length, thus minimizing the wind effect on condensing pressure and performance. If low ambient temperature operation is expected, it is recommended that optional wind baffles be installed if the unit has no protection against prevailing winds.
Using less clearance than shown in Figure 2 can cause discharge air recirculation to the condenser and could have a significant detrimental effect on unit performance.
See Restricted Airflow beginning on page 7 for further informati on.

Service Access

Compressors, filter-driers, and manual liquid line shutoff valves are accessible on each side of the unit adjacent to the control box. The evaporator heaters are located in each head.
Each compressor (two or three depending on unit size) has its own duplex control panel located on the sides of the chiller between condenser coil sections. The outer control box contains the circuit microprocessor. The box for circuit #1 also contains the unit microprocessor controller. The solid state compressor starter, fan control and other power equipment are located in the inner panel.
The side clearance required for airflow provides sufficient service clearance. On all AGS units the condenser fans and motors can be removed from the top of the unit. The
complete fan/motor assembly can be removed for service. The fan blade must be removed for access to wiring terminals at the top of the motor.
WARNING
Disconnect all power to the unit while servicing condenser fan motors or compressors.
Failure to do so can cause bodily injury or death.
Do not block access to the sides or ends of the unit with piping or conduit. These areas must be open for service access. Do not block any access to the control panels with a field-mounted disconnect switches. In particular, be sure that the power conduit to each panel does not interfere with access to the filter-driers located on the unit base under the panels.
IMM AGS-1 5
Page 6

Clearance Requirements

Figure 2, Clearance Requirements, AGS 230B – 475B
5’-0” if open fence or 50% open wall 6’-0” if solid wall (see note 3 for pit)
5’-0” if open fence or 50% open wall 6’-0” if solid wall (see note 3 for pit)
No obstructions. Recommended area required for unit operation, air flow and maintenance access.
10’-0” min. for Evaporator Removal See Note 8
See notes 2 & 4 concerning wall height at unit sides.
Air Flow No obstructions allowed above unit at any height
See Note 5
Wall or Fence
Notes:
1. Minimum side clearance between two units is 12 feet (3.7 meters).
2. Unit must not be installed in a pit or enclosure that is deeper or taller than the height of the unit
unless extra clearance is provided per note 4.
3. Minimum clearance on each side is 8 feet (2.4 meters) when installed in a pit no deeper than the
unit height.
4. Minimum side clearance to a side wall or building taller than the unit height is 6 feet (1.8 meters)
provided no solid wall above 6 feet (1.8 meters) is closer than 12 feet (3.7 meters) to the opposite side of the unit.
5. Do not mount electrical conduits where they can block service access to compressor controls,
refrigerant driers or valves.
6. There must be no obstruction of the fan discharge.
7. Field installed switches must not interfere with service access or airflow.
8. The 10-ft. clearance required for removal of the evaporator is on the end that the evaporator
connections face. See dimension drawings on page 27 for details.
9. If the airflow clearances cannot be met, see the following page.
6 IMM AGS-1
Page 7

Restricted Airflow

General

The clearances required for design operation of AGS air-cooled condensers are described in the previous section. Occasionally, these clearances cannot be maintained due to site restrictions such as units being too close together or a fence or wall restricting airflow, or both.
The McQuay AGS chillers have several features that can mitigate the problems attributable to restricted airflow.
The “W” shape of the condenser section allows inlet air for these coils to come in from both sides
and the bottom. All the coils in one "W" section serve one compressor. Every compressor always has its own independent refrigerant circuit.
The MicroTech II control is proactive in response to off-design conditions. In the case of
single or compounded influences restricting airflow to the unit, the microprocessor will act to keep the compre ssor(s) running ( at reduced capacity) as l ong as possib le, rat her than all owing a shut-off on high discharge p ressure.
Figure 3, Coil and Fan Arrangement
The following sections discuss the most common situations of condenser air restriction and give capacity and power adjustment factors for each. Note that in unusually severe conditions, the MicroTech II controller would adjust the unit operation to remain online until a less severe condition is reached.
IMM AGS-1 7
Page 8

Case 1, Building or Wall on One Side of One Unit

The existence of a screening wall, or the wall of a building, in close proximity to an air-cooled chiller is common in both rooftop and ground level applications. Hot air recirculation on the coils adjoining the wall will increase compressor discharge pressure, decreasing capacity and increasing power consumption.
When close to a wall, it is desirable to place chillers on the north or east side of them. It is also desirable to have prevailing winds blowing parallel to the unit’s long axis. The worst case is to have wind blowing hot discharge air into the wall.
Figure 4, Unit Adjacent to Wall
D
H
Figure 5, Adjustment Factors
5 ft.
(1.5m)
6 ft.
(1.8m)
5 ft.
(1.5m)
6 ft.
(1.8m)
8 IMM AGS-1
Page 9

Case 2, Two Units Side By Side

Two or more units sited side by side are common. If spaced closer than 12 feet (3.7 meters) it is necessary to adjust the performance of each unit; circuits adjoining each other are affected. If one of the two units also has a wall adjoining it, see Case 1. Add the two adjustment factors together and apply to the unit located between the wall and the other unit.
Mounting units end to end will not necessitate adjusting performance. Depending on the actual arrangement, sufficient space must be left between the units for access to the control panel door opening and/or evaporator tube removal. See “Clearance” section of this guide for requirements for specific units.
Pit or solid wall surrounds should not be used where the ambient air temperature exceeds 105°F (40°C).
Figure 6, Two Units Side by Side
Figure 7, Adjustment Factor
IMM AGS-1 9
Page 10

Case 3, Open Screening Walls

Decorative screening walls are often used to help conceal a unit either on grade or on a rooftop. These walls should be designed such that the combination of their open area and distance from the unit do not require performance adjustment. It is assumed that the wall height is equal to, or less than the unit height when mounted on its base support. This is usually satisfactory for concealment. If the wall height is greater than the unit height, see Case 4, Pit Installation.
The distance from the sides of the unit to the side walls should be sufficient for service and opening control panel doors.
If each side wall is a different distance from the unit, the distances can be averaged, providing either wall is not less than 8 feet (2.4 meters) from the unit. For example, do not average 4 feet and 20 feet to equal 12 feet.
Figure 8, Open Screening Walls
Figure 9, Wall Free Area vs. Distance
6
(1.8)
to Unit - Ft. (M)
D - Distance from Wall
5
(1.5)
01020304050
% Open Wall Area
10 IMM AGS-1
Page 11

Case 4, Pit/Solid Wall Installation

Pit installations can cause operating problems and great care should be exercised if they are to be used on an installation. Recirculation and restriction can both occur. A solid wall surrounding a unit is substantially the same as a pit and the data presented in this case should be used.
Steel grating is sometimes used to cover a pit to prevent accidental falls or trips into the pit. The grating material and installation design must be strong enough to pr event such accidents, yet p rovide abundant open area or serious recirculation problems will occur. Have any pit installation reviewed by McQuay application engineers prior to installation to discuss whether it has sufficient airflow characteristics. The installation design engineer must approve the work and is responsible for design criteria.
Figure 10, Pit Installation
Figure 11, Adjustment Factor
IMM AGS-1 11
Page 12

Vibration Isolators

Vibration isolators are recommended for all roof-mounted installations or wherever vibration transmission is a consideration. The following section "Lifting and Mounting Weights" contains the location of unit lifting holes and the load at each location. Mounting holes dimensions and the bearing weight at each hole given.
The unit should be initially installed on shims or blocks at the illustrated "free height" of the isolator that is six inches for the McQuay isolators shown. When all piping, wiring, flushing, charging, etc. is complete, the springs should be adjusted upward to load them and to provide clearance to free the blocks, which are then removed.
Installation of spring isolators requires flexible pipe connections and at least three feet of conduit flex tie-ins. Piping and conduit should be supported independently from the unit so as not to stress connections.
Figure 12, Spring Flex Isolators
Table 1, Spring Vibration Isolators, AGS 230 – 320, Part Numbers and Spring Colors
Model
AGS230 AGS250 AGS270 AGS300 AGS320
Notes:
1. The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.
2. The -2- or -4- indicates that two or four springs are used in the isolator.
M1 M2 M3 M4 M5 M6 M7 M8 Kit Num ber
CP-2-28 CP-2-31 CP-2-28 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Green Gray Green Gray Gray Green Gray Green
CP-2-28 CP-2-31 CP-2-28 CP-2-31 CP-2-32 CP-2-31 CP-4-26 CP-2-28
Green Gray Green Gray White Gray Purple Green
CP-2-28 CP-4-26 CP-2-31 CP-2-32 CP-2-32 CP-2-31 CP-4-26 CP-2-28
Green Purple Gray White White Gray Purple Green
CP-2-28 CP-4-26 CP-2-31 CP-2-32 CP-2-32 CP-2-31 CP-4-26 CP-2-28
Green Purple Gray White White Gray Purple Green
CP-2-28 CP-4-26 CP-2-31 CP-2-32 CP-2-32 CP-2-31 CP-4-26 CP-2-28
Green Purple Gray White White Gray Purple Green
12 IMM AGS-1
Mounting Location (See Footprint Drawings Figure 13 or Figure 14)
350348101 350348102
350348103
Page 13
Table 2, Spring Vibration Isolators, AGS 340 – 475, Part Numbers and Spring Colors
Model
AGS340 AGS370 AGS400 AGS420 AGS440 AGS450 AGS475
Mounting Location (See Footprint Drawings Figure 15 or Figure 16)
M1 M2 M3 M4 M5 M6
CP-2-28 CP-4-26 CP-2-28 CP-4-26 CP-4-26 CP-2-28
Green Purple Green Purple Purple Green
CP-2-28 CP-4-26 CP-2-31 CP-4-26 CP-4-26 CP-2-31
Green Purple Gray Purple Purple Gray
CP-2-28 CP-4-26 CP-2-31 CP-4-26 CP-4-27 CP-2-31
Green Purple Gray Purple Orange Gray
CP-2-31 CP-4-26 CP-2-31 CP-4-27 CP-4-27 CP-2-31
Gray Purple Gray Orange Orange Gray
CP-2-31 CP-4-26 CP-4-26 CP-4-27 CP-4-27 CP-4-26
Gray Purple Purple Orange Orange Purple
CP-2-31 CP-4-26 CP-4-26 CP-4-27 CP-4-27 CP-4-26
Gray Purple Purple Orange Orange Purple
CP-2-31 CP-4-26 CP-4-26 CP-4-27 CP-4-27 CP-4-26
Gray Purple Purple Orange Orange Purple
Continued
Model
AGS340 AGS370 AGS400 AGS420 AGS440 AGS450 AGS475
Notes:
M7 M8 M9 M10 M11 M12 Kit Number
CP-4-26 CP-2-28 CP-2-31 CP-2-27 CP-2-27 CP-2-27
Purple Green Gray Orange Orange Orange
CP-4-26 CP-2-28 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Purple Green Gray Green Gray Green
CP-4-26 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Purple Gray Gray Green Gray Green
CP-4-26 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Purple Gray Gray Green Gray Green
CP-4-26 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Purple Gray Gray Green Gray Green
CP-4-26 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Purple Gray Gray Green Gray Green
CP-4-26 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Purple Gray Gray Green Gray Green
1. The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.
2. The -2- or -4- indicates that two or four springs are used in the isolator.
Mounting Location (Table Continued)
350348104 350348105 350348106 350348107
350348108
Table 3, Neoprene-in-Shear Isolators, AGS 230 – 320, Part Numbers
Model
AGS230 4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 350348201 AGS250 4-RED 4-RED 4-RED 4-RED 4-GREEN 4-RED 4-RED 4-RED 350348202 AGS270 4-RED 4-RED 4-RED 4-GREEN 4-GREEN 4-RED 4-RED 4-RED AGS300 4-RED 4-RED 4-RED 4-GREEN 4-GREEN 4-RED 4-RED 4-RED AGS320 4-RED 4-RED 4-RED 4-GREEN 4-GREEN 4-RED 4-RED 4-RED
Note:
M1 M2 M3 M4 M5 M6 M7 M8 Kit Number
1. The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.
Mounting Location (See Footprint Drawings Figure 13 or Figure 14)
350348203
Table 4, Neoprene-in-Shear Isolators, AGS 340 – 475, Part Numbers
Model
AGS340 4-RED 4-RED 4-RED 4-RED 4-RED 4-RED AGS370 4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED AGS400 4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED AGS420 4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED AGS440 4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED AGS450 4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED AGS475 4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED
Mounting Location (See Footprint Drawings Figure 15 or Figure 16)
M1 M2 M3 M4 M5 M6
Table continued on following page for M7 thr ough M12 plus kit numbers . 
IMM AGS-1 13
Page 14
Model
M7 M8 M9 M10 M11 M12 Kit Number
Mounting Location (Table Continued)
AGS340 4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 350348204 AGS370 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED AGS400 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED AGS420 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED AGS440 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED AGS450 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED AGS475 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED
Note:
1. The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.

Lifting and Mounting Weights

Figure 13, AGS 230B – AGS 250B Lifting and Mounting Locations
350348205
88.0
(2235.2)
NOTE: Evaporator connections point left.
Figure 14, AGS 270B - AGS 320B Lifting and Mounting Locations
2 (51)
Typical Spacing
for Isolator
Mounting (8)
2 (51)
Typical Spacing
for Isolator
Mounting (8)
88.0
(2235.2)
14 IMM AGS-1
Page 15
Table 5, AGS 230B - AGS 320B Lifting and Mounting Weights
AGS
Model
Lbs. 2183 3043 2563 2563 3043 2183 1683 2325 1681 2322 2322 1681 2325 1683
230B
250B
270B
300B
320B
(kg) 991 1382 1164 1164 1382 991 764 1055 763 1054 1054 763 1055 764
Lbs. 2183 3043 2700 2704 3374 2509 1683 2325 1681 2322 2693 2018 2421 1814
(kg) 991 1382 1226 1228 1532 1139 764 1055 763 1054 1223 916 1099 824
Lbs. 2509 3374 2841 2841 3374 2509 1814 2421 2018 2693 2693 2018 2421 1814
(kg) 1139 1532 1290 1290 1532 1139 824 1099 916 1223 1223 916 1099 824
Lbs. 2520 3383 2871 2871 3383 2520 1821 2425 2043 2721 2721 2043 2425 1821
(kg) 1144 1536 1304 1304 1536 1144 827 1101 928 1235 1235 928 1101 827
Lbs. 2550 3407 2956 2956 3407 2550 1838 2435 2111 2797 2797 2111 2435 1838
(kg) 1158 1547 1342 1342 1547 1158 834 1106 958 1270 1270 958 1106 834
NOTES:
1. Lifting tabs with 2 ½ in. (63.5 mm) holes at location "L" on side of base rail.
2. 1 in. (25.4 mm) mounting holes at location "M" on bottom of base rails.
Lifting Weight for Each Point lb (kg) Mounting Loads for Each Point lb. (kg)
L1 L2 L3 L4 L5 L6 M1 M2 M3 M4 M5 M6 M7 M8
Figure 15, AGS 340B – AGS 400B Lifting and Mounting Locations
NOTE: Evaporator connections point left.
Figure 16, AGS 420B - AGS 475B Lifting and Mounting Locations
2 (51)
Typical Spacing
for Isolator
Mounting (8)
88.0
(2235.2)
88.0
(2235.2)
2 (51)
Typical Spacing
for Isolator
Mounting (8)
IMM AGS-1 15
Page 16
Table 6, AGS 340B - AGS 475B Lifting Weights
Lifting Weight for Each Point lb (kg)
340B
370B
400B
420B
440B
450B
475B
AGS
Model
lbs 2312 3173 2681 2681 3352 2473 3192 2880
(kg) 1050 1441 1217 1217 1522 1123 1449 1307
lbs 2449 3296 2951 2951 3617 2742 3519 3216
(kg) 1112 1496 1340 1340 1642 1245 1597 1460
lbs 2449 3296 3119 3117 3917 3044 3519 3216
(kg) 1112 1496 1416 1415 1778 1382 1597 1460
lbs 2751 3596 3285 3285 3917 3044 3519 3216
(kg) 1249 1633 1491 1491 1778 1382 1597 1460
lbs 2783 3624 3361 3361 3945 3076 3519 3216
(kg) 1263 1645 1526 1526 1791 1396 1597 1460
lbs 2783 3624 3361 3361 3945 3076 3519 3216
(kg) 1263 1645 1526 1526 1791 1396 1597 1460
lbs 2783 3624 3361 3361 3945 3076 3519 3216
(kg) 1263 1645 1526 1526 1791 1396 1597 1460
L1 L2 L3 L4 L5 L6 L7 L8
Table 7, AGS 340B - AGS 475B Mounting Weights
Mounting Loads for Each Point lb. (kg)
340B
370B
400B
420B
440B
450B
475B
AGS
Model
lbs 1798 2442 1787 2426 2426 1787 2442 1798 1726 1557 1645 1484
lbs 1885 2511 1981 2638 2638 1981 2511 1885 1973 1803 1867 1706
lbs 1885 2511 1981 2638 3055 2357 2562 1977 1973 1803 1867 1706
lbs 1977 2562 2357 3055 3055 2357 2562 1977 1973 1803 1867 1706
lbs 1999 2579 2425 3128 3128 2425 2579 1999 1973 1803 1867 1706
lbs 1999 2579 2425 3128 3128 2425 2579 1999 1973 1803 1867 1706
lbs 1999 2579 2425 3128 3128 2425 2579 1999 1973 1803 1867 1706
M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12
kg 816 1109 811 1101 1101 811 1109 816 784 707 747 674
kg 856 1140 899 1198 1198 899 1140 856 896 819 847 775
kg 856 1140 899 1198 1387 1070 1163 897 896 819 847 775
kg 897 1163 1070 1387 1387 1070 1163 897 896 819 847 775
kg 908 1171 1101 1420 1420 1101 1171 908 896 819 847 775
kg 908 1171 1101 1420 1420 1101 1171 908 896 819 847 775
kg 908 1171 1101 1420 1420 1101 1171 908 896 819 847 775
16 IMM AGS-1
Page 17

Chilled Water Pump

It is required that the chilled water pumps' starter be wired to and controlled by the chiller's microprocessor. The controller will energize the pump whenever at least one circuit on the chiller is enabled to run, whether there is a call for cooling or not. The pump will also be energized when the controller senses a near-freezing temperature at the chiller outlet sensor to assist in cold weather freeze protection. Connection points are shown in Figure 24 on page 37.

Water Piping

Due to the variety of piping practices, it is advisable to follow the recommendations of local authorities. They can supply the installer with the proper building and safety codes required for a safe and proper installation.
NOTE: Chilled water piping must enter and exit the unit platform between the base rail and the
bottom of the condenser coil in the approximately 30-inch width shown on Figure 20 and Figure 21. The piping should be designed with a minimum number of bends and changes in elevation to keep
system cost down and performance up. It should contain:
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. Manual or automatic air vent valves at the high points of the system and drains at the low parts in
the system. The evaporator should not be the highest point in the piping system.
4. Some means of maintaining adequate system water pressure (i.e., expansion tank or regulating
valve).
5. Water temperature and pressure indicators located at the unit to aid in unit servicing.
6. A strainer to remove foreign matter from the water before it enters the pump. The strainer should
be placed far enough upstream to prevent cavitation at the p ump inlet (co nsult p ump manufacturer for recommendations). The use of a strainer will prolong pump life and help maintain high system performance levels.
NOTE: A strainer must also be placed in the supply water line just prior to the inlet of the
evaporator. This will aid in preventing foreign material from entering the evaporator and causing damage or decreasing its performance. Care must also be exercised if welding pipe or flanges to the evaporator connections to prevent any weld slag from entering the vessel.
7. Any water piping to the unit must be protected to prevent freeze-up if below freezing
temperatures are expected. See page 18 for further information on freeze protection.
CAUTION
If a separate disconnect is used for the 115V supply to the unit, it should power t he entire control circuit, not just the evaporator heaters. It should be clearly marked so that it is not accidentally shut off during cold seasons. Freeze damage to the evaporator could result. If the evaporator is drained for winter freeze protection, the heaters must be de-energized to prevent burnout.
8. If the unit is used as a replacement chiller on a previously existing piping system, the system
should be thoroughly flushed prior to unit installation and then regular chilled water ana l ysis and chemical water treatment is recommended immediately at equipment start-up.
9. The total water quantity in the system should be sufficient to prevent frequent "on-off" cycling.
For air conditioning systems, system gallons equal to 4 times the flow rate is recommended.
IMM AGS-1 17
Page 18
10. In the event glycol is added to the water system as a late addition for freeze protection, recognize
that the refrigerant suction pressure will be lower, cooling performance less, and water side pressure drop greater. If the percentage of glycol is large, or if propylene is employed in lieu of ethylene glycol, the added pressure drop and loss of performance could be substantial.
11. For ice making or glycol operation, a different freezestat pressure value can be desired. The
freezestat setting can be manually changed through the MicroTech II controller. A preliminary leak check should be made prior to insulating the water piping and filling the system. Piping insulation should include a vapor barrier to prevent moisture condensation and possible
damage to the building structure. It is important to have the vapor barrier on the outside of the insulation to prevent condensation within the insulation on the cold surface of the pipe.

System Water Volume

It is important to have adequate water volume in the system to provide an opportunity for the chiller to sense a load change, adjust to the change and stabilize. As the expected load change becomes more rapid, a greater water volume is needed. The system water volume is the total amount of water in the evaporator, air handling products and associated piping. If the water volume is too low, operational problems can occur including rapid compressor cycling, rapid loading and unloading of compressors, erratic refrigerant flow in the chiller, improper motor cooling, shortened equipment life and other undesirable consequences.
For normal comfort cooling applications where the cooling load changes relatively slowly, we recommend a minimum system volume of four minutes times the flow rate (gpm). For example, if the design chiller flow rate is 800 gpm, we recommend a minimum system volume of 3200 gallons (800 gpm x 4 minutes).
For process applications where the cooling load can change rapidly, additional system water volume is needed. A process example would be a quenching tank. The load would be very stable until the hot material is immersed in the water tank. Then, the load would increase drastically. For this type of application, system volume can need to be increased.
Since there are many other factors that can influence performance, systems can successfully operate below these suggestions. However, as the water volume decreases below these suggestions, the possibility of problems increases.

Variable Speed Pumping

Variable water flow involves changing the water flow through the evaporator as the load changes. McQuay chillers are designed for this duty, pro vided that the rate of change in water flow is slow and the minimum and maximum flow rates for the vessel are not exceeded.
The recommended maximum change in water flow is 10 percent of the change per minute. The water flow through the vessel must remain be tween the minimum and maximum values listed on
page 23. If flow drops below the minimum allowable, large reductions in heat transfer can occur. If the flow exceeds the maximum rate, excessive pressure drop and tube erosion can occur.

Evaporator Freeze Protection

Flooded evaporators are popular with chiller manufacturers because of their inherent high efficiency. Care must be exercised in the equipment design and in the operation of these evaporators to prevent freezing between 32°F and -20°F.
For protection down to 0°F (-18°C), the AGS chillers are equipped with thermostatically controlled evaporator heaters that help protect against freeze-up provided the chiller goes through its normal pumpdown cycle. Several occurrences can prevent this normal pumpdown from happening:
1. A power failure will prevent pumpdown and there is a potential for freezing outdoor equipment in
systems using 100 percent water as the chilled fluid.
18 IMM AGS-1
Page 19
2. Unit shutdown due to a fault will cause immediate compressor shutdown without the pumpdown
cycle. This situation can be remedied by correcting the fault, restarting the unit, and allowing it to go through its normal shutdown pumpdown.
NOTE: The heaters come from the factory connected to the control power circuit. The control power can be rewired to a separate 115V supply (do not wire directly to the heater). If this is done, the disconnect switch should be clearly marked to avoid accidental deactivation of the heater during freezing temperatures. Exposed chilled water piping also requires protection.
It is required that the chilled water pump’s starter be wired to, and controlled by, the chiller's microprocessor. The controller will energize the pump whenever at least one circuit on the chiller is enabled to run, whether there is a call for cooling or not. The pump will also be energized when the controller senses a near-freezing temperature at the chiller outlet sensor to assist in cold weather freeze protection. Connection points are shown in Figure 24 on page 37.
For additional protection to -20°F (-29°C) and to protect against the consequences described above, it is recommended that at least one of the following procedures be used during periods of sub-freezing temperatures:
1. Addition of a concentration of a glycol anti-freeze with a freeze point 15 degrees below the
lowest expected temperature. This will result in decreased capacity and increased pressure drop. Note: Do not use automotive grade antifreezes as they contain inhibitors harmful to chilled water
systems. Only use glycols specifically designated for use in building cooling systems.
2. Draining the water from outdoor equipment and piping and blowing the chiller tubes dry from the
chiller. Do not energize the chiller heater when water is drained from the vessel.
CAUTION
If fluid is absent from the evaporator, the evaporator heater must be de-energized to avoid
burning out the heater and causing damage from the high temperatures.
3. Providing opera tion o f the chilled water pump, circ ulating water thro ugh the chille d water system
and through the evaporator. The chiller micropr oce ssor will automatically start up the pump if so wired.
Table 8, Freeze Protection
Temperature
°F (°C)
20 (6.7)16181112
10 (-12.2) 25 29 17 20
0 (-17.8) 33 36 22 24
-10 (-23.3) 39 42 26 28
-20 (-28.9) 44 46 30 30
-30 (-34.4) 48 50 30 33
-40 (-40.0) 52 54 30 35
-50 (-45.6) 56 57 30 35
-60 (-51.1) 60 60 30 35
Notes:
1. These figures are examples only and cannot be appropriate to every situation. Generally, for an extended margin of protection, select a temperature at leas t 10 should be adjusted for solutions less t han 30% glycol.
2. Glycol of less than 20% concentration is not recommended bec aus e of t he pot ent ial for bacterial growth and loss of heat transfer efficiency.
Ethylene Glycol Propylene Glycol Ethylene Glycol Propylene Glycol
For Freeze Protection For Burst Protection
Percent Volume Glyc ol Concentration Required
°F lower than the expected lowest ambient temperature. Inhibitor levels
IMM AGS-1 19
Page 20

Operating Limits:

Maximum standby ambient temperature, 130°F (55°C) Maximum operating ambient temperature, 115°F (46°C), or 125°F (52°C) with optional high ambient
package
Minimum operating ambient temperature (standard), 35°F (2°C) Minimum operating ambient temperature (optional low-ambient control), 0°F (-18°C) Leaving chilled water range, 38°F to 50°F (3°C to 10°C) Leaving chilled fluid range (with anti-freeze), 20°F to 50°F (7°C to 10°C) Operating Delta-T range, 6 degrees F to 16 degrees F (10.8 C to 28.8 C) Maximum operating inlet fluid temperature, 66°F (19°C) Maximum startup inlet fluid temperature, 90°F (32°C) Maximum non-operat i ng inlet fluid temperature, 100°F (38°C) NOTE: Contact the local McQuay sales office for operation outside of these limits.

Flow Switch

A water flow switch must be mounted in the leaving chilled water line to prove that there is adequate water flow to the evaporator before the unit can start. It also serves to shut down the unit in the event that water flow is interrupted in order to guard against evaporator freeze-up.
A flow switch is available from McQuay under ordering number 017503300. It is a paddle-type switch and adaptable to any pipe size from 1" (25mm) to 8" (203mm) nominal.
Certain minimum flow rates are required to close the switch and are listed in Table 9. Installation should be as shown in Figure 17.
Electrical connections in the unit control center should be made at terminals 60 and 67. The normally open contacts of the flow switch should be wired between these two terminals. Flow switch contact quality must be suitable for 24 VAC, low current (16ma). Flow switch wire must be in separate conduit from any high voltage conduc tors (115 VAC and higher) and have an insul ation r ating of 6 00 volts.
Figure 17, Flow Switch
1 1/4" (32mm) pipe
dia. min. after switch
Flow direction marked
on switch
1" (25mm) NPT flow
switch connection
Tee
1 1/4" (32mm) pipe
dia. min. before switch
Table 9, Switch Minimum Flow Rates
NOMINAL PIPE
SIZE
INCHES (MM)
5 (127) 58.7 (3.7) 6 (152) 79.2 (5.0) 8 (203) 140 (8.8)
Note: Water pressure differential switches are not recommended for outdoor applications.
MINIMUM REQUIRED FLOW
TO ACTIVATE SWITCH
GPM (LPS)
20 IMM AGS-1
Page 21
Figure 18, Typical Field Water Piping
LEGEND
FS
Flow Switch
IN OUT
TW
TW
FS
Notes:
1. Connections for vent and drain fittings are located on t he t op and bottom of both evaporator water heads.
2. Piping must be supported to avoid putting strain on t he evaporator nozzles.
TW
Gate Valve
Pressure Gauge & Cock
Thermal Well
Flexible Co nnector
Strainer
Manual Vent

Water Connections

Water pipi ng to the evaporator must be bro ught out through the side o f the unit between the ver tical supports. The dimensional drawings on page 27 and 28 give the necessary dimensions and locations for all piping connections. Evaporator piping connections face toward the left side of the unit when looking at control panel #3.

Refrigerant Charge

All units are designed for use with R-134a and are shipped with a full operating charge. The operating charge for each unit is shown in the Physical Data Tables beginning on page 24.

Glycol Solutions

When using glycol anti-freeze solutions the chiller's capacity, glycol solution flow rate, and pressure drop through the evaporator can be calcul ated using the following formulas and tables.
Note: The procedure below does not specify the type of glycol. Use the derate factors found in Table 10 for corrections when using propylene glycol and those in Table 11 for ethylene glycol.
1. Capacity - Cooling capacity is reduced from that with plain water. To find the reduced value, multiply the chiller’s water system tonnage by the capacity correction factor to find the chiller’s capacity when using glycol.
2. Flow - To determine flow (or delta-T) knowing delta-T (or flow) and capacity:
()( )( )
GPM−=
Pressure drop - To determine pressure dr op through the evap orator when using glycol, enter
3.
24
the water pressure drop curve at the water flow rate. Multiply the water pressure drop found there by the "PD" factor to obtain corrected glycol pressure drop.
Power - To determine glycol system kW, multiply the water system kW by the factor designated
4. "Power".
Test coolant with a clean, accurate glycol solution hydrometer (similar to that found in service stations) to determine the freezing point. Obtain percent glycol from the freezing point table below. On glycol applications the supplier normally recommends that a minimum of 20% solution by weight be used for protection against corrosion.
factorflowtons
TDelta
IMM AGS-1 21
Page 22
CAUTION
Do not use automotive grade antifreeze. Industrial grade glycols must be used. Automotive antifreeze
contains inhibitors that will cause plating on the co pper tubes w ithin the chiller evapo rator. The
type and handling of glycol used must be consistent with local codes.
Table 10, Propylene Glycol Factors
Freeze
%
E.G
Point
oFo
10 26 -3.3 0.994 0.998 1.036 1.104 20 18 -7.8 0.979 0.990 1.060 1.256 30 7 -13.9 0.964 0.983 1.092 1.424 40 -7 -21.7 0.943 0.973 1.132 1.664 50 -28 -33.3 0.920 0.963 1.182 1.944
Cap. Power Flow PD
C

Water Flow and Pressure Drop

The chilled water flow through the evapor ator should be ad justed to meet specified co nditions. T he flow rates must fall between the minimum and maximum values shown in table on the following page. Flow rates below the minimum values shown will result in laminar flow that will reduce efficiency, cause erratic operation of the electronic expansion valve and could cause low temperature cutouts. On the other hand flow rates exceeding the maximum values shown can cause erosion on the evaporator water connections and tubes.
Table 11, Ethylene Glycol Factors
Freeze
%
P.G
Point
oFo
10 26 -3.3 0.985 0.993 1.017 1.120 20 19 -7.2 0.964 0.983 1.032 1.272 30 9 -12.8 0.932 0.969 1.056 1.496 40 -5 -20.6 0.889 0.948 1.092 1.792 50 -27 -32.8 0.846 0.929 1.139 2.128
Cap. Power Flow PD
C
Measure the chilled water pressure drop through the evap orator at field installe d pressure taps. It is important not to include valve or strainer pressure drop in these readings.
22 IMM AGS-1
Page 23
Figure 19, Evaporator Pressure Drops
AGS 230-270
AGS 300
AGS 340
AGS 440-475
AGS 370-420
AGS 320
Minimum/Nominal/Maximum Flow Rates
AGS
Unit
Size
230B 330 5.3 529 12.8 882 32.0 250B 365 6.5 585 15.3 975 37.5 270B 401 7.8 642 18.2 1070 44.0 300B 424 6.1 679 14.2 1132 35.2 320B 451 4.9 722 11.5 1203 39.0 340B 501 7.0 801 16.0 1336 42.0 370B 540 6.1 864 14.4 1440 36.0 400B 576 6.8 922 16.0 1537 40.0 420B 613 7.5 981 18.2 1635 44.0 440B 640 6.4 1025 15.2 1708 38.0 450B 660 6.7 1057 16.4 1762 41.0 475B 680 7.1 1089 17.0 1815 43.0
Minimum Flow Nominal Flow Maxim um Flow
Flow
gpm ft. gpm ft. gpm ft
PFlow∆∆∆∆PFlow∆∆∆∆P
∆∆
IMM AGS-1 23
Page 24

Physical Data

Table 12, Physical Data, AGS 230B – AGS 270B
AGS MODEL NUMBER
230B 250B 270BDATA
Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2
BASIC DATA
Cap. @ ARI Conditions, tons (kW) 220.5 (774) 243.9 (856) 267.5 (939) Unit Operating Charge lbs (kg) 298 (135) 298 (135) 298 (135) 321 (145) 321 (145) 321 (145) Cabinet Dimensions
L x W x H, in. (mm) Unit Operating Weight, lbs. (kg) 16285 (7394) 17301 (7855) 18319 (8317) Unit Shipping Wei ght, lbs (kg) 15862 (7201) 16877 (7662) 17895 (8124)
COMPRESSORS, SCREW, SEMI-HERMETIC
Nominal Capacity, tons (kW) 100 (350) 100 (350) 100 (350) 125 (437) 125 (437) 125 (437)
CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLER
Coil Face Area, ft2. (m2) 159 (14.8) 159 (14.8) 159 (14.8) 213 (19.8) 213 (19.8) 213 (19.8) Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3
CONDENSER FANS, DIRECT DRIVE PROPE L L ER TYPE
No. of Fans -- Fan Dia., in. (mm) 12 – 30 (762) 14 – 30 (762) 16 – 30 (762) No. of Motors -- hp (kW) 12 – 2 (1.5) 14 – 2 (1.5) 16 – 2 (1.5) Fan & Motor RPM, 60Hz 1140 1140 1140 60 Hz Fan Tip Speed, fpm 8954 8954 8954 60 Hz Total Unit Airflow, ft3/min 129,600 151,200 172,800
EVAPORATOR, FLOODED SHELL AND TUBE
Shell Dia.-Tube Length in.(mm) - in. (mm)
Evaporator R-134a Charge lbs (kg) 182 (37) 182 (37) 182 (37) 182 (37) 182 (37) 182 (37) Water Volume, gallons (liters) 48 (182) 48 (182) 48 (182) Max. Water Pressure, psi (kPa) 150 (1034) 150 (1034) 150 (1034) Max. Refrigerant Press., psi (kPa) 200 (1379) 200 (1379) 200 (1379)
278 x 88 x 100
(7087 x 2235 x 2550)
24 (610) – 96 (2438) 24 (610) – 96 (2438) 24 (610) – 96 (2438)
317 x 88 x 100
(8052 x 2235 x 2550)
355.x 88 x 100
(9017 x 2235 x 2550)
Table 13, Physical Data, AGS 300B – AGS 320B
AGS MODEL NUMBER
300B 320BDATA
Ckt 1 Ckt 2 Ckt 1 Ckt 2
BASIC DATA
Unit Cap. @ ARI, tons (k W) 283.1 (994) 300.9 (1056) Unit Operating Charge lbs (kg) 335 (152) 335 (152) 360 (163) 360 (163) Cabinet Dimensions
L x W x H, in. (mm) Unit Operating Weight, lbs. (kg) 18447 (8375) 18787 (8266) Unit Shipping Wei ght, lbs (kg) 17995 (8170) 18272 (8295)
COMPRESSORS, SCREW, SEMI-HERMETIC
Nominal Capacity, tons (kW) 125 (437) 150 (525) 150 (525) 150 (525)
CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLER
Coil Face Area, ft2. (m2) 213 (19.8) 213 (19.8) 213 (19.8) 213 (19.8) Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3
CONDENSER FANS, DIRECT DRIVE PROPE L L ER TYPE
No. of Fans -- Fan Dia., in. (mm) 16 – 30 (762) 16 – 30 (762) No. of Motors -- hp (kW) 16 – 2 (1.5) 16 – 2 (1.5) Fan & Motor RPM, 60Hz 1140 1140 60 Hz Fan Tip Speed, fpm 8954 8954 60 Hz Total Unit Airflow, ft3/min 172,800 172,800
EVAPORATOR, FLOODED SHELL AND TUBE
Shell Dia.-Tube Length in.(mm) - in. (mm)
Evaporator R-134a Charge lbs (kg) 196 (89) 196 (89) 221 (100) 221 (100) Water Volume, gallons (liters) 51 (195) 59 (221) Max. Water Pressure, psi (kPa) 150 (1034) 150 (1034) Max. Refrigerant Press., psi (kPa) 200 (1379) 200 (1379)
355 x 88 x 100
(9017 x 2235 x 2550)
24 (610) – 96 (2438) 26 (660) – 96 (2438)
355 x 88 x 100
(9017 x 2235 x 2550)
24 IMM AGS-1
Page 25
Table 14, Physical Data, AGS 340B – AGS 400B
AGS MODEL NUMBER
DATA 340B 370B 400B
Ckt. 1 Ckt. 2 Ckt. 3 Ckt. 1 Ckt. 2 Ckt. 3 Ckt. 1 Ckt. 2 Ckt. 3
BASIC DATA
Unit Cap. @ ARI, tons (k W) 334.1 (1173) 360.0 (1264) 384.3 (1349) Unit Operating Charge, lbs (kg) 285 (129) 285 (129) 285 (129) 312 (141) 312 (141) 312 (141) 312 (141) 335 (152) 335 (152)
Cabinet Dim., L x W x H, in. (mm) Unit Operating Weight, lbs. (kg) 23507 (10672) 25645 (11643) 26667 (11734)
Unit Shipping Wei ght, lbs (kg) 22958 (10101) 25034 (11015) 26056 (11829)
COMPRESSORS, SCREW, SEMI-HERMETIC
Nominal Capacity, tons (kW) 100 (350) 100 (350) 100 (350) 100 (350) 100 (350) 125 (437) 100 (350) 125 (437) 125 (437)
CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLER
Coil Face Area, ft2. (m2) 159 (14.8) 159 (14.8) 159 (14.8) 159 (14.8) 159 (14.8) 213 (19.9) 159 (14.8) 213 (19.9) 213 (19.9) Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3
CONDENSER FANS, DIRECT DRIVE PROPEL L ER TYPE
No. of Fans -- Fan Diameter, in. (mm) No. of Motors -- hp (kW) 18 – 2 (1.5) 20 – 2 (1.5) 22 – 2 (1.5) Fan & Motor RPM, 60Hz 1140 1140 1140 60 Hz Fan Tip Speed, fpm 8954 8954 8954 60 Hz Total Unit Airflow, ft3/min 194,400 216,000 237,600
EVAPORATOR, FLOODED SHELL AND TUBE
Shell Dia., Tube Length in.(mm) 26 (660) – 108 (2743) 30 (762) – 108 (2743) 30 (762) – 108 (2743) Evaporator R-134a Charge lbs (kg Water Volume, gallons (liters) 63 (237) 70 (263) 70 (263) Max. Water Pressure, psi (kPa) 150 (1034) 150 (1034) 150 (1034) Max. Refrigerant Press., psi (k Pa) 200 (1379) 200 (1379) 200 (1379)
164 (74) 164 974) 164 (74) 191 (86) 191 (86) 191 (86) 191 (86) 191 (86) 191 (86)
434 x 88 x 100
(11024 x 2235 x 2550)
18 – 30 (762) 20 – 30 (762) 22 – 30 (732)
472 x 88 x 100
(11989 x 2235 x 2550)
510 x 88 x 100
(12954 x 2235 x 2550)
Table 15, Physical Data, AGS 420B – AGS 440B
AGS MODEL NUMBER
DATA 420B 440B
Ckt. 1 Ckt. 2 Ckt. 3 Ckt. 1 Ckt. 2 Ckt. 3
BASIC DATA
Unit Cap. @ ARI, tons (k W) 408.8 (1435) 427.1 (1499) Unit Operating Charge, lbs (kg) 335 (152) 335 (152) 335 (152) 358 (162) 358 (162) 358 (162)
Cabinet Dim., L x W x H, in. (mm) Unit Operating Weight, lbs. (kg) 27684 (12568) 28042 (12731)
Unit Shipping Wei ght, lbs (kg) 27072 (12291) 27345 (12415)
COMPRESSORS, SCREW, SEMI-HERMETIC
Nominal Capacity, tons (kW) 125 (437) 125 (437) 125 (437) 125 (437) 125 (437) 150 (525)
CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLER
Coil Face Area, ft2. (m2) 213 (19.9) 213 (19.9) 213 (19.9) 213 (19.9) 213 (19.9) 213 (19. 9) Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3
CONDENSER FANS, DIRECT DRIVE PROPE L L ER TYPE
No. of Fans -- Fan Dia., in. (mm) 24 – 30 (762) 24 – 30 (762) No. of Motors -- hp (kW) 24 – 2 (1.5) 24 – 2 (1.5) Fan & Motor RPM, 60Hz 1140 1140 60 Hz Fan Tip Speed, fpm 8954 8954 60 Hz Total Unit Airflow, ft3/min 259,200 259,200
EVAPORATOR, FLOODED SHELL AND TUBE
Shell Dia. -- Tube Length in.(mm) - in. (mm) Evaporator R-134a Charge lbs (kg Water Volume, gallons (liters) 70 (263) 79 (300) Max. Water Pressure, psi (kPa) 150 (1034) 150 (1034) Max. Refrigerant Press., psi (kPa) 200 (1379) 200 (1379)
548 x 88 x 100
(13919 x 2235 x 2550)
30 (762) – 108 (2743) 30 (762) – 108 (2743)
191 (86) 191 (86) 191 (86) 214 (97) 214 (97) 214 (97)
548 x 88 x 100
(13919 x 2235 x 2550)
IMM AGS-1 25
Page 26
Table 16, Physical Data, AGS 450B – AGS 475B
AGS MODEL NUMBER
DATA 450B 475B
Ckt. 1 Ckt. 2 Ckt. 3 Ckt. 1 Ckt. 2 Ckt. 3
BASIC DATA
Unit Cap. @ ARI, tons (k W) 440.5 (1546) 453.9 (1593) Unit Operating Charge, lbs (kg) 358 (162) 358 (162) 358 (162) 358 (162) 358 (162) 358 (162)
Cabinet Dim., L x W x H, in. (mm) Unit Operating Weight, lbs. (kg) 28042 (12731) 28042 (12731)
Unit Shipping Wei ght, lbs (kg) 27345 (12415) 27345 (12415)
COMPRESSORS, SCREW, SEMI -HERMETIC
Nominal Capacity, tons (kW) 125 (437) 150 (525) 150 (525) 150 (525) 150 (525) 150 (525)
CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLER
Coil Face Area, ft2. (m2) 213 (19.9) 213 (19.9) 213 (19.9) 213 (19.9) 213 (19.9) 213 (19. 9) Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3
CONDENSER FANS, DIRECT DRIVE PROPELLER TYPE
No. of Fans -- Fan Dia., in. (mm) 24 – 30 (762) 24 – 30 (762) No. of Motors -- hp (kW) 24 – 2 (1.5) 24 – 2 (1.5) Fan & Motor RPM, 60Hz 1140 1140 60 Hz Fan Tip Speed, fpm 8954 8954 60 Hz Total Unit Airflow, ft3/sec 259,200 259,200
EVAPORATOR, FLOODED SHELL AND TUBE
Shell Dia. -- Tube Length in.(mm) - in. (mm) Evaporator R-134a Charge lbs (kg Water Volume, gallons (liters) 79 (300) 79 (300) Max. Water Pressure, psi (kPa) 150 (1034) 150 (1034) Max. Refrigerant Press. psi (kP a) 200 (1379) 200 (1379)
548 x 88 x 100
(13919 x 2235 x 2550)
30 (762) – 108 (2743) 30 (762) – 108 (2743)
214 (97) 214 (97) 214 (97) 214 (97) 214 (97) 214 (97)
548 x 88 x 100
(13919 x 2235 x 2550)
26 IMM AGS-1
Page 27

Dimensional Data

A
)
5.5
Figure 20, Dimensions, AGS 230B – AGS 320B
Note: See page 14 for lifting loc ations, m ounting locat ions, weights and m ounting loads.
51.1
(1297.9)
36.9
(937.3)
SINGLE POINT POWER ENTRY "D"
INLET
FE
C
FIELD CONTROL CONNECTION
CONTROL
CIRCUIT #1
CONTROL
CIRCUIT #2
OUTLET
OPENING FOR CHILLER WATER PIPING
POWER ENTRY POINT
0.875 (22.2) KNOCK-OUT
PANEL
PANEL
POWER ENTRY POINT
0.875 (22.2) KNOCK-OUT
(139.7)
SINGLE POINT POWER BOX OPTION
AGS 230-300
26.7 (678.2) AGS 320
25.7 (652.8)
B
POWER ENTRY
12.0 (304.8) POWER ENTRY LOCATION FAR SIDE
88.0
(2235.2)
DWG. 330556901
NOTE: Chilled water piping must enter and exit the unit platform between the base rail and the bottom of the
condenser coil in the “F” dimension on the side shown above.
AGS Unit
Size
AGS 230
AGS 250
AGS 270-320
Dimensions
Inches (mm)
ABCDEF
278.8
(7081.5)
316.9
(8049.3)
355.2
(9022.1))
133.4
(3388.4)
133.4
(3388.4)
171.6
(4358.6)
78.4
(1991.4)
78.4
(1991.4)
116.6
(2961.6)
192.6
(4892.0)
192.6
(4892.6)
230.8
(5862.3
Water Piping Inches (mm)
44.8
(1137.4)
44.8
(1137.4)
80.9
(2054.8)
30.0
(762.8)
30.0
(762.8)
31.4
(797.6)
Evaporator
Connection
Size
Inches (mm)
8
(203.2)
8
(203.2)
8
(203.2)
Fan Modules
Total
Module1Module
Fans
12 Fan 6 6
14 Fan 6 8
16 Fan 8 8
100.4
(2550.4
2
IMM AGS-1 27
Page 28
Figure 21, Dimensions, AGS 340B –475B
A
)
SING
Note: See page 14 for lifting loc ations, m ounting locat ions, weights and m ounting loads.
SINGLE POINT POWER ENTRY "D"
INLET
FIELD CONTROL CONNECTION
H
J
POWER ENTRY POINT
0.875 (22.2) KNOCK-OUT
CONTROL
PANE L
CIRCUIT #1
CONTROL
PANE L
CIRCUIT #2
5.5
(139.7)
LE POINT POWER
BOX OPTION
CONTROL PANEL CIRCUIT #3
F
K
G
C
B
OUTLET
OPENING FOR CHILLER WATER PIPING
POWER ENTRY
POWER ENTRY POINT
0.875 (22.2) KNOCK-OUT
12.0 (304.8) POWER ENTRY LOCATION FAR SIDE
E
POWER ENTRY POINT
0.875 (22.2) KNOCK-OUT
NOTE: Chilled water piping must enter and exit the unit platform between the base rail and the bottom of the
condenser coil in the “G” dimension on the side shown above.
AGS
Unit
Size AGS
340
AGS
370
AGS
400
AGS
420-475
Dimensions Inches (mm)
ABCDE F GHJK
434.2
(11027.9)
472.4
(11998.2)
510.6
(12968.5)
548. 8
(13939.0)
133.4
(3388.0)
133.4
(3388.1)
133.4
(3388.1)
171.6
(4358.4)
90.3
(2292.4)
90.3
(2292.4)
87.3
(2140.0)
125.5
(3186.4)
192.6
(4892.0)
192.6
(4892.0)
192.6
(4892.0)
230. 8
(5862.3)
288.8
(7335.5)
288.8
(7335.5)
327.0
(8305.8)
365.2
(9276.1)
Water Piping
Inches (mm)
44.7
(1137.4)
44.7
(1137.4)
44.7
(1137.4)
80.9
(2054.8)
30.0
(762.8)
30.0
(762.8)
30.0
(762.8)
31.4
(797.6)
Evaporator Connections
Inches (mm)
51.1
52.1
52.1
52.1
36.9
(937.3)
36.9
(937.3)
35.9
911.9)
35.9
911.9)
(652.8)8(203.2)
(911.9)10(254.0)
(911.9)10(254.0)
(911.9)10(254.0)
(1297.9)
(1323.3)
(1323.3)
(1323.3)
25.7
27.7
27.7
27.7
Evaporator
Connection
Size
Inches (mm)
Total Fans
18 Fan 6 6 6
20 Fan 6 6 8
22 Fan 6 8 8
24 Fans 8 8 8
88.00
(2235.2)
DWG. 330557001
Fan Modules
Module1Module2Module
3
100.41
(2550.4
28 IMM AGS-1
Page 29

Wind Baffles and Hail Guards

G
A
Wind Baffles/Hail Guards are a field installed option that are used to stabilize unit operation in high wind areas and to assist in operation at low ambient temperatures. Figure 22 shows a typical panel assembly on an AGS unit. The actual number of panels and parts will vary by model size. The parts are shown in the table below and referenced by balloon numbers. The baffles extend out 20 inches from each side.
Figure 22, Installation Sequence

Rib Attachment (First)

RIB FLANGES ON THE END
MUST POINT TO CENTER OF COIL TO HAVE A FINISHED LOOK. INTERIOR RIB FLANGES
CAN POINT IN ANY DIRECTION.
U
I
I
R
E
N
T
T
C
V
O
I
L
C
L
A

Front Panel Attachment (Second)

PLACE FRONT "A" AND FASTEN TO BOTH SIDES
C
O
L
I
C
I
A
L
V
E
R
U
2
T
N
T
I
C
B
A
ATTACH ALL RIBS TO COIL VERTICAL CHANNELS.
E
D
PLACE FRONT "B" BY LAPPIN OVER "A" AND REPEAT ATTACHMENT PROCEDURE.
1
3

Top Panel Attachment (Last)

E
ATTACH TOP "A" AT HORIZONTAL COIL CHANNEL FIRST.
IMM AGS-1 29
THIS WILL SQ UA RE THE PANEL .
OVERLAP THE FRONT PANEL FLANGE.
C
A
R
E
I
T
T
V
I
U
N
A
D
L
I
C
O
L
B
C
ATTACH LEFT SIDE SECOND.
LAP PANEL "B" OVER PANEL "A"
ND REPEAT ATTACHMENT PROCEDURE.
Page 30
Table 17, Packing List
L
O
t
Description Part Number Bubble Number
Vertical Support Rib 074758501 1
Top Cover 330409401 2
¼ - 20 x ½” Screw (Place in Poly Bag) 046093807
Front Panel 330409501 3
Figure 23, Components
Top Panel, Install Last
Overlap the Front panel
T
REAR (AGAINST UNIT)
VERTICAL SUPPORT RIB TOP COVER FRONT PANE
P
Front Panel, Install Second
Rib, Install Firs
30 IMM AGS-1
Page 31

Electrical Data

Field Wiring

General

Wiring must comply with all applicable codes and ordinances. Damage to the equipment caused by wiring not complying with specifications is not covered under warrant y.
An open fuse indicates a short, ground, or overload. Before replacing a fuse or restarting a compressor or fan motor, the trouble must be found and corrected.
Copper wire is required for all power lead terminations at the unit and copper must be used for all other wiring to the unit.
AGS units can be ordered with main power wiring for either multiple-point power (standard) or single­point connection (optional).
If the standard multiple-point power wiring is ordered, power connections are made to the individual circuit power panels located between the condenser sections. Two connections are required for models AGS 230 through 320 and three are required for models AGS 340 through 475. See the dimension drawings on pages 27 and 28 for detailed locations. Separate disconnects are required for each electrical circuit if McQuay factory-mounted disconnects are not ordered.
If the optional single-point power connection is ordered, a single large power connection point is provided and located in a box on the base of the unit. See the dimension drawings on pages 27 and 28 for the location. Factory wiring from the box to the individual compressor power panels on the unit is sized in accordance with the National Electrical Code. A disconnect is required and can be furnished as a factory option. The 115-volt control transformer is factory mounted and wired.
It can be desirable to have the unit evaporator heaters on a separate disconnect switch from the main unit power supply so that the unit power can be shut down without defeating the freeze protection provided by the cooler heaters. See page 18 for details.
Power blocks are standard on all size units. Multi-point power connections can have circuit breakers as an option. The single-point circuit breaker option has a main circuit breaker and individual breakers in each panel.
CAUTION
AGS unit compressors are single-direction rotation compressors and can be damaged if rotated in the wrong direction. For this reason proper phasing of electrical power is important. Electrical phasing must be A, B, C for electrical phases 1, 2 and 3 (A =L1, B=L2, C=L3) for sing le or multiple point wiring arrangements. The solid-state starters contain phase reversal protection. ALTER THE WIRING TO THE STARTERS.
DO NOT
IMM AGS-1 31
Page 32
Table 18, AGS 230B – AGS 475B, Electrical Data, Optional Single-Point
AGS
UNIT
VOLTS HZ
SIZE
230
250
270
300
320
340
370
400
420
440
450
475
Notes
1. Table based on 75°C field wire.
2. A “HACR” breaker is a circuit breaker designed for use on equipment with multiple motors. It stands for Heating, Air Conditioning, and Refrigeration.
3. Complete electrical notes are on page 36.
460 475 6 250 2 2.5 600 600 575 460 519 6 300 2 3.0 600 700 575 460 555 6 300 2 3.0 700 700 575 460 586 6 350 2 3.0 700 800 575 460 611 6 350 2 3.0 700 800 575 460 688 12 4/0 2 3.0 800 800 575 460 732 12 250 2 4.0 800 800 575 460 768 12 250 2 4.0 800 800 575 460 804 12 250 2 4.0 1000 1000 575 460 835 12 300 2 4.0 1000 1000 575 460 860 12 300 2 4.0 1000 1000 575 460 885 12 300 2 4.0 1000 1000 575
60
60
60
60
60
60
60
60
60
60
60
60
MINIMUM
CIRCUIT
FIELD WIRE
AMPACITY
(MCA)
QTY
418 6 4/0 2 2.0 500 500
447 6 4/0 2 2.0 500 600
471 6 250 2 2.5 600 600
496 6 250 2 2.5 600 700
516 6 300 2 3.0 600 700
605 12 3/0 2 3.0 700 700
634 12 3/0 2 3.0 700 800
658 12 4/0 2 3.0 800 800
683 12 4/0 2 3.0 800 800
708 12 4/0 2 3.0 800 800
728 12 4/0 2 3.0 800 800
748 12 250 2 4.0 800 800
POWER SUPPLY
(Conduit Connection)
WIRE
GAUGE
QTY
HUB
NOMINAL
SIZE (In.)
FIELD FUSE SIZE or
HACR BREAKER SIZE
RECOM-
MENDED
MAXIMUM
Table 19, AGS 230B – AGS 320B, Electrical Data, Standard Multiple-Point, Two-Circuit Units
ELECTRICAL CIRCUIT 1 (COMP 1) ELECTRICAL CIRCUIT 2 (COMP 2)
AGS UNIT SIZE
VOLTS HZ
MIN.
CIRCUIT
AMPS (MCA)
230
250
270
300
320
460 575 460 575 460 575 460 575 460 575
Notes:
1. Table based on 75°C field wire.
2. Complete electrical notes are on page 36.
3. 3/0 wire is required for the disconnect switch option, 2/0 can be used for power block connection.
262 6 3/0 (3) 1 3.0 350 450 262 6 3/0 (3) 1 3.0 350 450
60
230 3 250 1 2.5 300 400 230 3 250 1 2.5 300 400 262 6 3/0 (3) 1 3.0 350 450 306 6 3/0 1 3.0 400 500
60
230 3 250 1 2.5 300 400 260 6 3/0 (3) 1 3.0 350 400 306 6 3/0 1 3.0 400 500 306 6 3/0 1 3.0 400 500
60
260 6 3/0 (3) 1 3.0 350 400 260 6 3/0 (3) 1 3.0 350 400 306 6 3/0 1 3.0 400 500 337 6 4/0 1 3.0 450 500
60
260 6 3/0 (3) 1 3.0 350 400 285 6 3/0 1 3.0 350 450 337 6 4/0 1 3.0 450 500 337 6 4/0 1 3.0 450 500
60
285 6 3/0 1 3.0 350 450 285 6 3/0 1 3.0 350 450
POWER SUPPLY FIELD FUSING POWER SUPPLY FIELD FUSING
MIN.
CIRCUIT
AMPS (MCA)
FIELD WIRE
WIRE
QTY
GAUGE
HUB
(Conduit
Connection) QTY
FIELD WIRE
WIRE
QTY
GAUGE
HUB
(Conduit
Connection)
HUB
QTY
SIZE
REC
FUSE
SIZE
MAX
FUSE
SIZE
HUB SIZE
REC
FUSE
SIZE
MAX
FUSE
SIZE
32 IMM AGS-1
Page 33
Table 20, AGS 340B–AGS 475B, Electrical Data, Standard Multiple-Point, (Circuits # 1 & 2)
ELECTRI CAL CIRCUIT 1 (COMP 1) ELECTRI CAL CIRCUIT 2 (COMP 2)
AGS
UNIT
SIZE
VOLTS HZ
MIN.
CIRCUIT
AMPS (MCA)
340
370
400
420
440
450
475
Notes:
1. Table based on 75°C field wire
2. Complete electrical notes are on page 36.
3. 3/0 wire is required for the disconnect switch option, 2/0 can be used for power block connection.
460 575 460 575 460 575 460 575 460 575 460 575 460 575
262 6 3/0 (3) 1 3.0 350 450 262 6 3/0 (3) 1 3.0 350 450
60
230 3 250 1 2.5 300 400 230 3 250 1 2.5 300 400 262 6 3/0 (3) 1 3.0 350 450 262 6 3/0 (3) 1 3.0 350 450
60
230 3 250 1 2.5 300 400 230 3 250 1 2.5 300 400 262 6 3/0 (3) 1 3.0 350 450 306 6 3/0 1 3.0 400 500
60
230 3 250 1 2.5 300 400 260 6 3/0 (3) 1 3.0 350 400 306 6 3/0 1 3.0 400 500 306 6 3/0 1 3.0 400 500
60
260 6 3/0 (3) 1 3.0 350 400 260 6 3/0 (3) 1 3.0 350 400 306 6 3/0 1 3.0 400 500 306 6 3/0 1 3.0 400 500
60
260 6 3/0 (3) 1 3.0 350 400 260 6 3/0 (3) 1 3.0 350 400 306 6 3/0 1 3.0 400 500 337 6 4/0 1 3.0 450 500
60
260 6 3/0 (3) 1 3.0 350 400 285 6 3/0 1 3.0 350 450 337 6 4/0 1 3.0 450 500 337 6 4/0 1 3.0 450 500
60
285 6 3/0 1 3.0 350 450 285 6 3/0 1 3.0 350 450
POWER SUPPLY FIELD FUSING POWER SUPPLY FIELD FUSING
MIN.
CIRCUIT
AMPS (MCA)
FIELD WIRE
WIRE
QTY
GAUGE
HUB
(Conduit
Connection)
QTY
FIELD WIRE
WIRE
QTY
GAUGE
HUB
(Conduit
Connection)
HUB
QTY
SIZE
REC
FUSE
SIZE
MAX
FUSE
SIZE
HUB SIZE
REC.
FUSE
SIZE
MAX. FUSE
SIZE
Table 20, Electrical Data, AGS 340B – 475B, (Circuit #3)
ELECTRICAL CIRCUIT 3 (COMP 3)
AGS UNIT SIZE
VOLTS HZ
MINIMUM
CIRCUIT
AMPS (MCA)
340
370
400
420
440
450
475
Notes:
1. Table based on 75°C field wire.
2. Complete electrical notes are on page 36.
3. 3/0 wire is required for the disconnect switch option, 2/0 can be used for power block connection.
460 262 6 3/0 (3) 1 3.0 350 450 575 460 306 6 3/0 1 3.0 400 500 575 460 306 6 3/0 1 3.0 400 500 575 460 306 6 3/0 1 3.0 400 500 575 460 337 6 4/0 1 3.0 450 500 575 460 337 6 4/0 1 3.0 450 500 575 460 337 6 4/0 1 3.0 450 500 575
60
230 3 250 1 2.5 300 400
60
260 6 3/0 (3) 1 3.0 350 400
60
260 6 3/0 (3) 1 3.0 350 400
60
260 6 3/0 (3) 1 3.0 350 400
60
285 6 3/0 1 3.0 350 450
60
285 6 3/0 1 3.0 350 450
60
285 6 3/0 1 3.0 350 450
POWER SUPPLY FIELD FUSING
HUB
FIELD WIRE
WIRE
QTY
GAUGE
(Conduit
Connection)
HUB
QTY
SIZE
REC.
FUSE
SIZE
MAX.
FUSE
SIZE
IMM AGS-1 33
Page 34
Table 21, AGS230B–AGS 475B, Compressor and Condenser Fan Motor Amp Draw
AGS UNIT SIZE
230
250
270
300
320
340
370
400
420
440
450
475
RATED LOAD AMPS
VOLTS HZ
460 195 195 - 3.0 20 585 585 ­575 460 195 225 - 3.0 20 585 675 ­575 460 225 225 - 3.0 20 675 675 ­575 460 225 250 - 3.0 20 675 750 ­575 460 250 250 - 3.0 20 750 750 ­575 460 195 195 195 3.0 20 585 585 585 575 460 195 195 225 3.0 20 585 585 675 575 460 195 225 225 3.0 20 586 675 675 575 460 225 225 225 3.0 20 675 675 675 575 460 225 225 250 3.0 20 675 675 750 575 460 225 250 250 3.0 20 675 750 750 575 460 250 250 250 3.0 20 750 750 750 575
CIRCUIT#1CIRCUIT#2CIRCUIT
60
171 171 -
60
171 190
60
190 190 -
60
190 210 -
60
210 210 -
60
171 171 171
60
171 171 190
60
171 190 190
60
190 190 190
60
190 190 210
60
190 210 210
60
210 210 210
#3
NO OF
FAN
MOTORS
12
14
16
16
16
18
20
22
24
24
24
24
FAN
MOTORS
FLA
(EACH)
2.7 18 513 513 -
2.7 18 513 570 -
2.7 18 570 570 -
2.7 18 570 630 -
2.7 18 630 630 -
2.7 18 513 513 513
2.7 18 513 513 570
2.7 18 513 570 570
2.7 18 570 570 570
2.7 18 570 570 630
2.7 18 570 630 630
2.7 18 630 630 630
L R A
FAN
MOTORS
(EACH)
SOLID-STATE STARTING INRUSH
AMPS PER COMPRESSOR
CIRCUIT #1 CIRCUIT #2 CIRCUIT #3
Table 22, AGS 230B – AGS 475B, Customer Wiring Information With Single-Point Power
WIRING TO STANDARD UNIT POWER
AGS
VOLTS HZ
UNIT
SIZE
460
230
575 460
250
575 460
270
575 460
300
575 460
320
575 460
340
575 460
370
575 460
400
575 460
420
575 460
440
575 460
450
575 460
475
575
1. Terminal size amps are the maximum amps that the power block is rated for.
2. Complete electrical notes are on page 36.
60
60
60
60
60
60
60
60
60
60
60
60
MAXIMUM
TERMINAL
AMPS
1000 #6-350 800 #6-350 1000 #6-350 800 #6-350 1000 #6-350 800 #6-350 1000 #6-350 800 #6-350 1000 #6-350 800 #6-350 1000 #6-350 800 #6-350 1000 #6-350 800 #6-350 1000 #6-350 800 #6-350 1000 #6-350 800 #6-350 1000 #6-350 800 #6-350 1000 #6-350 1000 #6-350 1000 #6-350 800 #6-350 1000 #6-350 1000 #6-350 1000 #6-350 800 #6-350 1000 #6-350 1000 #6-350 1000 #6-350 800 #6-350 1000 #6-350 1000 #6-350 1000 #6-350 800 #6-350 1000 #6-350 1000 #6-350 1000 #6-350 800 #6-350 1000 #6-350 1000 #6-350 1000 #6-350 800 #6-350 1000 #6-350 1000 #6-350 1000 #6-350 800 #6-350
BLOCK
CONNECTOR LUG RANGE
PER PHASE
(COPPER WIRE ONLY)
WIRING TO OPTIONAL NONFUSED DISCONNECT
DISCONNECT
SIZE
SWITCH IN UNIT
CONNECTOR LUG RANGE
PER PHASE
(COPPER WIRE ONLY)
34 IMM AGS-1
Page 35
Table 23, AGS 230B–AGS 475B, Wiring Information with Multiple-Point
AGS
UNIT
VOLTS HZ
SIZE
230
250
270
300
320
340
370
400
420
440
450
475
Notes:
1. Terminal size amps are the maximum amps that the power block is rated for.
2. Complete electrical notes are on page 36.
460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575
TERMINAL SIZE (AMPS) CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY)
CKT 1 CKT 2 CKT 3 CKT 1 CKT 2 CKT 3
60 400 400 --
60 400 400 --
60 400 400 --
60 400 400 --
60 400 400 --
60 400 400 400
60 400 400 400
60 400 400 400
60 400 400 400
60 400 400 400
60 400 400 400
60 400 400 400
WIRING TO UNIT POWER BLOCK
#6-350 #6-350 --
#6-350 #6-350 --
#6-350 #6-350 --
#6-350 #6-350 --
#6-350 #6-350 --
#6-350 #6-350 #6-350
#6-350 #6-350 #6-350
#6-350 #6-350 #6-350
#6-350 #6-350 #6-350
#6-350 #6-350 #6-350
#6-350 #6-350 #6-350
#6-350 #6-350 #6-350
Table 24, AGS 230B–AGS 475B, Wiring Information with Multiple-Point
AGS UNIT SIZE
230
250
270
300
320
340
370
400
420
440
450
475
VOLTS HZ
460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575
60 400 400 - 3/0 - 500 3/0 - 500 -
60 400 400 - 3/0 - 500 3/0 - 500 -
60 400 400 - 3/0 - 500 3/0 - 500 -
60 400 400 - 3/0 - 500 3/0 - 500 -
60 400 400 - 3/0 - 500 3/0 - 500 -
60 400 400 400 3/0 - 500 3/0 - 500 3/0 - 500
60 400 400 400 3/0 - 500 3/0 - 500 3/0 - 500
60 400 400 400 3/0 - 500 3/0 - 500 3/0 - 500
60 400 400 400 3/0 - 500 3/0 - 500 3/0 - 500
60 400 400 400 3/0 - 500 3/0 - 500 3/0 - 500
60 400 400 400 3/0 - 500 3/0 - 500 3/0 - 500
60 400 400 400 3/0 - 500 3/0 - 500 3/0 - 500
TERMINAL SIZE (AMPS) CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONL Y)
CKT 1 CKT 2 CKT 3 CKT 1 CKT 2 CKT 3
WIRING TO UNIT DISCONNECT S WITCH
IMM AGS-1 35
Page 36

Electrical Data Notes

1. Allowable voltage limits
Unit nameplate 460V/60Hz/3Ph: 414V to 506V Unit nameplate 575V/60Hz/3Ph: 518V to 632V
Unit wire size ampacity (MCA) is equal to 125% of the largest compressor-motor RLA plus 100% of RLA of
2. all other loads in the circuit.
Single point power supply requires a single disconnect to supply electrical power to the unit. This power must
3. be fused.
All field wiring to unit power block or optional nonfused disconnect switch must be copper.
4.
5.
External disconnect switch(s) or HACR breakers must be field supplied.
Note: A non-fused disconnect switch in the cabinet is available as an option for single-point or multi-point
power connections.
6.
All wiring must installed as NEC Class 1 wiring system with conductor rated 600 volts and be done in
accordance with applicable local and national codes.
Recommended time delay fuse size or HACR circuit breakers is equal to 150% of the largest compressor
7. motor RLA plus 100% of remaining compressor RLAs and the sum of condenser fan FLAs.
Maximum time delay fuse size or HACR circuit breakers is equal to 225% of the largest compressor-motor
8. RLA plus 100% of remaining compressor RLAs and the sum of condenser fan FLAs.
If 1) the evaporator heater is to be powered during winter shutdown and 2) it is desired to disconnect 460/575
9. volt power to the unit, then the unit-mounted 3 KVA control transformer can be unwired and a field 115-volt, 30-amp power source wired to terminals TB1-1 and TB1-2. The MicroTech II control must be powered in order for the heaters to work.
36 IMM AGS-1
Page 37

Field Wiring Diagram

A
A
N
Figure 24, Typical Field Wiring Diagram, Circuit #1 Control Box
Note: Field-wired control connections are made in the control panel for circuit 1 only.
DISCONNECT
(BY OTHERS)
UNIT MAIN
TERMINAL BLOCK
3 PHASE
POWER SUPPLY
FUSED CONTROL
CIRCUIT TRANSFORMER
NOTE: ALL FIELD WIRING TO BE INSTALLED AS NEC CLASS 1 WIRING SYSTEM WITH CONDUCTOR RATED 600 VOLTS
CHW PUMP RELAY #1
120 VAC 1.0 AMP MAX
ALARM BELL OPTION
FACTORY SUPPLIED ALARM
FIELD WIRE D
ALARM BELL RELAY
CHW PUMP RELAY #2
120 VAC 1.0 AMP MAX
(BY OTHERS)
(BY OTHERS)
120 VAC
GND LUG
TB1
(115 VAC)
1
82 2
85 2
81
75
TB1-2
N
N
24 VAC
TO COMPRESSOR(S)
AND FAN MOTORS
120 VAC
120 VAC
REMOTE STOP
SWITCH
(BY OTHERS)
ICE MODE
SWITCH
(BY OTHERS)
CHW FLOW SWITCH
---MANDATORY–­(BY OTHERS)
TIME
CLOCK
NOR. OPEN PUMP AUX. CONTACTS (OPTIONAL)
4-20MA FOR CHW RESET
(BY OTHERS)
4-20MA FOR
DEMAND LIMIT
(BY OTHERS)
UTO
ON
UTO
ON
MANUAL
MANUAL
OFF
OFF
TB1
(24 VAC OR 30 VDC)
60
66
897
IF REMOTE STOP CONTROL IS USED, REMOVE LEAD 897 FROM TERM. 40 TO 53.
60
68
CONTROLLER
60
67
+
-
71 72
PE
+
-
GND
69
70
PE
GND
J11
Rx-/Tx-
Rx-/Tx-
GND
BLACK
WHITE
GREEN
DWG. 330803901 REV. 0B
*COMMUNICATIO
PORT
IMM AGS-1 37
Page 38

Solid State Starters

Solid state starters are standard on all AGS units. A solid state starter uses a silicon-controlled rectifier (SCR) power section to allow a motor to be brought to full speed with a reduced initial voltage that increases to full line voltage over a given time. The McQuay motor starter, custom designed for this specific application, is microprocessor controlled. Along with this starting technique, the motor starter also provides protection for the motor and monitors its load conditions.
The starter offers:
Solid state design.
Closed-loop motor current control.
Programmable motor protection.
Programmable operating parameters.
Programmable metering options.
The three-phase starter contains a six-SCR power section with two SCRs per phase connected in inverse paral lel. This power se ctio n is ca pab le o f pr ovid ing maximum torq ue pe r amp t hrougho ut the motor’s speed-torque curve with minimal motor and starter heating. At the same time, the starter continually monitors the amount of current being delivered to the motor, thus helping protecting the motor from overheating or drawing excessive current. The starter will automatically stop the motor if the line-to-line current is not within acceptable ranges, or if the current is lost in a line. The motor current scaling is set according to the motor size and the specific application. The starter circuitry is contained on a single printed circuit board, which contains all the logic and SCR gate drive circuitry.
Operating messages are displayed on a three-character LED display located in each compressor's control panel. The LED display on the control card displays:
Operating messages that indicate the status of the motor and/or starter.
Operating parameters that are programmed into the starter.
Fault codes that indicate a problem with the motor application or starter.
Operating Messages
Possible operating messages are as follows:
Message Meaning noL
Line voltage is not present.
rdy Line voltage is present and starter is ready. acc Motor is accelerating after a start command has been received. uts The motor has achieved full speed. run Motor is operating at full speed, and ramp time has expired. dCL A Stop command was received and the motor is decelerating with the set
deceleration profile.
OL OL will alternately blink with the normal display on the LED display when
motor thermal overload content has reached 90% to 99% of its capacity.
38 IMM AGS-1
Page 39
OLL The motor thermal overload content has reached 100%, and the motor has
stopped. The motor cannot be restarted until the overloaded motor has cooled and
OLt is displayed.
OLt The motor thermal overload content has been reduced to 60% or less, and
the motor can be restarted.
ena Passcode protection is enabled. dis Passcode is disabled. oxx xx = overload thermal content in percentage. Press the Down button to
toggle to this display.
cxx xx = pending fault. no Attempted to change a passcode protected parameter without proper
security.
Three decimal places blink when remote display is active.
Fxx xx Fault Code
Fault Codes
Fault codes will be displayed on the red, three-character LED display. Fault codes indicate a pro blem with the starter or motor application.
CODE CRITICAL
DESCRIPTION F1 YES Line phase sequence not ABC F3 YES System power is not three phase F5 Line fr equency less than 25hz. F6 Line frequency greater than 72hz. F23 Line current unbalance greater than set level. F24 Line currents are very unbalanced. F29 YES Operating parameter s have been lost F30 YES 3-phase default operating parameters have been loaded F31 1- phase default operating parameters have been loaded (N/A) F52 Current flow is present while starter is in stopped state. F54 Undercurrent trip F55 Overcurrent trip F70 Control power is low F71 YES CT burden switch changed while running. F73 YES B ypass fault F74 Motor stall time elapsed before motor reached full speed. F75 External Fault occurred. Thermistor/Motor Saver/Stack over
temperature/Bypass (Power removed from input). F77 YES Control card fault F78 YES Control card fault F90 YES Full-load amp(P1), CT ratio, or CT Burden Switch set incorrectly. F91 YES RLA not correct F92 YES Shorted SCR or excessivel y high current imbalance. F97 YES Control card fault F98 Lost main power F99 YES Excessively high load current.
IMM AGS-1 39
Page 40
Starter Preventative Maintenance
During commissioning:
Torque all power connections during commissioning. This includes factory wired components.
Check all of the control wiring in the package for loose connections.
During the first month after the starter has been put in operation:
Re-torque all power connections every two weeks. This includes factory-wired components.
Inspect cooling fans (if applicable) after two weeks for proper operation.
After the first month of operation:
Re-torque all power connections every year.
Clean any accumulated dust from the starter using a clean source of compressed air.
Inspect the cooling fans every three months for proper operation.
Clean or replace any air vent filters on the starter every three months.
NOTE: If mechanical vibrations are present at the installation site, inspect the connections more
frequently.
40 IMM AGS-1
Page 41
Figure 25, Trouble Shooting Guide
Start
Replace
Fuses
Replace
Circuit
Breaker
Correct
Inline
Fault
Line?
Fault
No
Order
NoYes
3
Swap
2
Leads
Any
Power
4
Yes
5
Yes
Yes
Low or Missing
1
No
Fuses
OK?
Phase
2
No
Circuit
Breaker
OK?
Thermal Trip?
Yes No
to
8
No
to
No
In-Line
OK?
Yes
Correct
Power
Source
Problem
Yes
No
Wiring
Interlock
Open?
No
OK?
6
7
High
Ambient?
Yes Yes
9
Replace
Control Card
Correct
Wait
Cool
and
Yes
Bad Air
Circulation?
Correct
Interlock
State
Correct
Wiring
No
No
Does Problem
Exist
Still
Yes
Return To
Service
No
Overloaded?
10
Motor
Yes
7
Goto
Page 39
No
Wiring
OK?
Lower
Load
Motor
Yes
Correct
Wiring
Return
Service
To
Correct
Wait
and
Cool
IMM AGS-1 41
Page 42
b
p
p
b
From Previous Page
11
Current
ImbalanceFault?
Yes
No
Correct Wiring
Replace
Defective
SCRs
No
No
7
Wiring Good?
Fuses Blown or
Breaker Tripped?
No
Yes Yes
12
Motor
Winding Short?
Yes
Replace Fuse
or Reset Breaker
No
SCRs OK?
13
Motor Pro
12
lem?
No
Yes Yes
14
All Gate
Pulses Present?
Yes
Repair or
Replace Motor
No Yes
Replace
Control Card
Contact
Benshaw
For Assistance
CT Burden
Switches Set
Correctly?
lace
Re
Control Card
15
No
Check Jum
ers
Parameters
and CTs
Return to
Normal
Operation
No
Does Pro
Still Exist?
lem
Yes
Contact
McQuay
For Assistance
42 IMM AGS-1
Page 43
FLOW CHART DETAILS:
1. Fuses Determine if power line fuses have been installed, and if they are
operating properly.
Circuit Breaker Determine if the circuit breaker is off, or has tripped and
2. disconnected the line from the starter.
Power Line Voltage Verify that line voltage is present, and is the correct voltage.
3.
4.
Phase Order Fault If Fault Codes F1 or F2 are displayed on the control card LED
display, exchange any two incoming power line cable connections.
5.
Heat Sink Switch Investigate whether heat sink thermal switch is open.
6.
Safety Device Determine if an equipment protection device attached to the
starter is disabling the start command.
7.
Wiring Connections Verify that the wiring connections are correct and that the
terminations are tightened.
8.
Air Temperature Investigate whether the air temperature surrounding the heat sink
is hot.
9.
Air Circulation Determine if the airflow around the heat sink fins is being
restricted, or if a fan has failed.
10.
Motor Overload Determine if the motor’s load is too large for the motor size.
11.
Current Imbalance Fault If Fault Codes F23 or F24 are displayed on the control card
LED display, diagnose and correct the cause of the current imbalance parameter
12.
Motor Winding Problem Conducting a megger test of the motor can identify an internal
P16.
motor winding problem. NOTE: To avoid damaging the starter isolate the motor before conducting the megger test.
WARNING
Hazardous voltages exist at the starter terminals. LOCK OUT ALL OF THE POWER
SOURCES before making resistance measurements to avoid personal injury or death.
13. SCRs This step can help determine if a problem exists with the SCRs. Using a multi-meter or similar device, measure the resistance between:
L1 terminal and T1 terminal
L2 terminal and T2 terminal
L3 terminal and T3 terminal
The resistance should be more than 50k ohms. Measure the gate resistance between the white and red of each twisted pair (6 total). The gate resistance should be between 8 and 50 ohms
.
14. Gate Pulses This step can help to determine if the control card is functioning properly. Check for gate firing voltage between 0.3 and 1.5 volts when the card is operating.
Motor Current Determine if motor current signal scaling is correct.
15.
IMM AGS-1 43
Page 44

Solid State Starter Settings

Operating Parameters Settings for Default Value and Settable Range:
No. Operating Parameter Default Range of Setting
P1 Motor Full Load Amps (FLA) 250A 1 to 350A P2 Motor Rated Load Amps (RLA) 1A 1 to 350A P3 Initial Motor Starting Current 225% 100 – 350% P4 Max. Motor Starting Current 300% 200 – 350% P5 Motor Ramp Time 7 sec 2 – 10 sec P6 Motor Stall Time 10 sec 5 – 10 sec P7 Deceleration Level 1 28% 40 – 100% P8 Deceleration Level 2 10% 0 – 20% P9 Deceleration Time 2 sec Off, 1 – 10 sec P10 Overcurrent Trip Level 140% 140% P11 Overcurrent Trip Time 2 sec Off, 1 – 15 sec P12 Undercurrent Trip Level 25% 25% - 100% P13 Undercurrent Trip Time Off Off, 1 – 15 sec P14 Motor Current Imbalance 15% 5, 10, 15, 20% P15 Current Transformer Ratio 460V/575V 2.64 RSD Standard P16 Meter Mode 10 RSD Standard P17 Meter Dwell Time 2 Off, 2 – 30 sec
P18 Passcode Off P19 Kick Start Off On, Off
P20 Auto Reset Capability Off On, Off
0 to 255 (enable), Off (disable)
44 IMM AGS-1
Page 45

Component Location

Major Component Location

Figure 26, Two-Compressor Unit Cutaway
Control/Power Panel
Circuit #1
Two-Circuit Flooded
Evaporator
Compressor #1
Condenser Section
Circuit #2
Oil Separator #1
Compressor #2
Control/Power Panel
Circuit #2
IMM AGS-1 45
Page 46
Figure 27, Piping Schematic
AIR
S05S02
FLOW
SIGHT GLASS
SOLENOID
VALVE
OIL
RETURN
NOTE: PIPING SHOWN FOR ONE CIRCUIT OF UNIT.
TO REAR OF COMPRESSOR
SUCTION
STRAINER
SIGHT GLASS
SCHRADER
OIL FILTER
S01 S04
BUTTERFLY VALVE
(OPTION)
BALL
VALVE
CHARGING
VALVE
DISCHARGE
TUBING
WATER OUT
S09
RELIEF VALVE (EVAP SHELL)
WATER IN
SENSOR
NUMBER
S01 S02 S03 S04
S05
S08
SCHRADER
DISCHARGE TEMPERATURE
VALVE
ANGLE VALVE
CHARGING
VALVE
DESCRIPTION
EVAP. PR ES S. TRAN S DUCER DISCH. PRESS. T RANSDUCER LIQUID PRESS. TRANSDUCER SUCTION TEMPERATURE
CHECK VALVE
DISCHARGE
OIL
SEPARATOR
AIR
FLOW
EXPANSION
VALVE
TUBING
CONDENSER
ASSEMBLY
SENSOR LOCATION CHART
SENSOR NUMBER
S06 S07 S08 S09
RELIEF
VALVE
CHARGING VALVE
LIQUID SHUT-OFF VALVE
FILTER DRIER
SCHRADER VALVE
SIGHT
GLASS
S03 S06
DESCRIPTION
LIQUID LINE TEMPERATURE OUTSIDE AIR TEMPERATURE EVAP. LEAVI NG WATER TEMP. EVAP. ENTERING WATER TEMP.
AIR
FLOW
S07
LIQUID TUBING
CONDENSER
ASSEMBLY
SCHRADER (EACH DISCH HEADER)
AIR
FLOW
NOTE: The above diagram illustrates one circuit of an AGS chiller. Models AGS 230 to 320 have two similar
circuits, Models AGS 340 to 475 have three such circuits. The evaporator is partitioned vertically into two or three refriger ant compartments with the water-filled tubes running from end to end.
46 IMM AGS-1
Page 47

Power Panel

Each compressor and its associated refrigerant circuit and controlled devices have a dedicated power and control system. They are contained in a duplex panel, the outer box containing the MicroTech II microprocessor with related accessories and the inner box containing the power components including the starter.
Starter Control Card
Silicon Controlled
Rectifier (SCR)
T1, Line to 115V
Transformer
Bypass Contactor
Phase/Voltage Monitor
Fan Motor Breakers
Fan Contactors
Main Circuit Breaker
Transformer T1 Fusing
Fan Contactors o r Optional Fan VFD
Term inal Block
Compressor
Motor Temp. Card
Microprocessor Control Pa nel
Panel Heater Thermostat
IMM AGS-1 47
Page 48

Control Panel

r
r
y
h
The control panel for Circuit #1 is shown below. The panel for circuit #2 is similar but does not contain the Unit Controller.
Distributed control architecture enhances unit reliability. Each compressor circuit has its own microprocessor controller so that if one controller is inoperative, the other compressor(s) will be allowed to run.
EWHR, Evaporator Heater Relay
T4, Load/
Unload Solenoid
Transforme
MHPR, Mech. High Pressure Relay
T3, Control
Transformer
T2, Control
Transformer
T5, Exp. Valve
Transforme
Expansion Valve Board
Circuit Breakers
Unit Switc
Circuit Switch
Solid State Starter Displa
Unit Controller, Located in Circuit #1 Panel Only
Circuit Controller
TB1, Field Control Connections, (Terminal Numbers on Top or Bottom)
48 IMM AGS-1
Page 49

System Maintenance

g

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 sight glasses, evaporator sight glasses, and oil separator sight glasses, plus taking condensing and suction pressure readings. Through the MicroTech II keypad, check 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. It is suggested that the log be copied and a report be completed on a regular basis. The log will serve as a useful tool for a service technician in the event service is required.
Initial start-up date, vibration readings, compressor megger readings and oil analysis information should be kept for reference base-line data.

Compressor Maintenance

Since the compressor is semi-hermetic, no yearly compressor maintenance is normally required, however, vibration is an excellent check for proper mechanical operation. Compressor vibration is an indicator of the requirement for maintenance and contributes to a decrease in unit performance and efficiency. It is recommended that the compressor be checked with a vibration analyzer at, or shortly after, start-up and again o n an annual basis. The lo ad shoul d be maintained as closely a s possib le to the load of the original test. The initial vibration analyzer test provides a benchmark of the compressor, and when performed routinely, can give a warning of impending problems.

Lubrication

No routine lubrication is required on AGS units. The fan motor bearings are permanently lubricated. No further lubrication is required. Excessive fan motor bearing noise is an indication o f a potential bearing failure.
Compressor oil must be Uniqema RL68HP, McQuay Part Number 735030442 in a 1 gallon container, or Uniqema RL68H, Part Number 735030444 in 1 gallon size. This is synthetic polyolester oil with anti-wear additives and is highly hygroscopic. Care must be taken to minimize exposure of the oil to air when charging oil into the system.
On early units, an oil filter is located in the oil return line from the oil separator to the compressor. This filter should be replaced after one month of operation or if the pressure drop exceeds 25 psi as measured at Schrader fittings up and down stream from the filter.
Figure 28, Compressor Oil Filter
On later units, the oil filter resides in the compressor housing as shown in Figure 28. Units without a suction service shutoff valve require pumping down the circuit in order to change the filter.
Oil Filter Housin
IMM AGS-1 49
Page 50

Electrical Terminals

DANGER
Electric shock hazard and risk of personal injury or death. Turn off all power before
continuing with following service.
Periodically check electrical terminals for tightness and tighten as required.

Condensers

The condensers are air-cooled and constructed of 3/8" (9.5mm) OD internally finned copper tubes bonded in a staggered pattern into louvered aluminum fins. 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.
WARNING
Use caution when applying such coil cleaners as they can contain potentially harmful chemicals. Breathing apparatus and protective clothing should be worn. Thoroughly rinse all surfaces to remove any cleaner residue. Care should be taken not to damage the fins during cleaning.
If the service technician has reason to believe that the refrigerant circuit contains noncondensables, recovery of the noncondensables can be required, strictly following Clean Air Act regulations governing refrigerant discharge to the atmosphere. The service Schrader valves are located on both vertical coil headers on both sides of the unit at the control box end of the coil. Access panels are located at the end of the condenser coil directly behind the control panel. Recover the noncondensables with the unit off, after shutdown of 15 minutes or longer, to allow air to collect at the top of the coil. Restart and run the unit for a brief period. If necessary, shut the unit off and repeat the procedure. Follow accepted environmentally sound practices when removing refrigerant from the unit.

Liquid Line Sight Glass

The refrigerant sight glasses should be observed periodically. (A weekly observation should be adequate.) A clear glass of liquid indicates that there is adequate refrigerant charge in the system to provide pr oper feed through the e xpansion valve. B ubbling refri gerant in the liq uid line sight glass, during stable run conditions, indicates that there can be an electronic expansion valve (EXV) problem since the EXV regulates liquid subcooling. Refrigerant gas flashing in the sight glass 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 25 for maximum allowable pressure drops).
NOTE: Exceeding normal charge can result in abnormally high discharge pressure and relief valve
discharge. An element inside the sight glass indicates the moisture condition corresponding to a given element
color. If the sight glass does not indicate a dry condition after about 12 hours of o peratio n, the circuit should be pumped down and the filter-drier changed. An oil acid test is also recommended.

Evaporator Sight Glass

Each circuit section of the evaporator has a sight glass located on the side, halfway up and adjacent to the internal tube sheet. There should be refrigerant level viewable in each circuit. A low level combined with low evaporator pressure indicated by a LowEvapPressHold alarm can indicate a low refrigerant charge for the circuit, a faulty TXV, a clogged filter-drier, or faulty head pressure control.
50 IMM AGS-1
Page 51

Lead-Lag

A feature on all McQuay AGS 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 II controller. When in the auto mode, the circuit with the fewest number of starts will be started first. If all circuits are operating and a stage down in the number of operating compressors is required, the circuit with the most operating hours will cycle off first. The operator can override the MicroTech II controller, and manually select the lead circuit as circuit #1, #2, or #3.

Preventative Maintenance Schedule

PREVENTATIVE MAINTENANCE SCHEDULE
OPERATION WEEKLY
General Complete unit log and review (Note 3) X Visually inspect unit for loose or damaged components and
visible leaks Inspect thermal insulation for integrity X Clean and paint as required X
Electrical Sequence test controls X Check contactors for pitting, replace as required X Check terminals for tightness, tighten as necessary X Clean control panel interior X Visually inspect components for signs of overheating X Verify compressor and oil heater operation X Megger compressor motor X
MONTHLY
(Note 1)
X
ANNUAL
(Note 2)
Refrigeration Leak test X Check sight glasses for clear flow X Check filter-drier pressure drop (see manual for spec) X Check oil filter pressure drop (Note 6) X Perform compressor vibration test X Perform acid test on compressor oil X
Condenser (air-cooled) Clean condenser coils (Note 4) X Check fan blades for tightness on shaft (Note 5) X Check fans for loose rivets and cracks, check motor brackets X Check coil fins for damage and straighten as necessary X
Notes:
1. Monthly operations include all weekly operations.
Annual (or spring start-up) operations include all weekly and monthly operations.
2.
Log readings can be taken daily for a higher level of unit observation.
3.
Coil cleaning can be required more frequently in areas with a high level of airborne particles.
4.
Be sure fan motors are electrically locked out.
5.
Replace the filter after first month of operation, thereafter replace the filter if pressure drop exceeds Table
6. 25 pressure levels.
IMM AGS-1 51
Page 52

Warranty Statement

)
Limited Warranty
Consult your local McQuay Representative for warranty details. Refer to Form 933- 43285Y. To find your local McQuay Representative, go to www.mcquay.com.

Service

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. Anyone servicing this equipment must comply with the requirements set forth by the EPA
in regards to refrigerant reclamation and venting.
Disconnect all power before doing any service inside the unit to avoid bodily injury or death. MULTIPLE POWER SOURCES CAN FEED THE UNIT.
CAUTION
DANGER

Liquid Line Filter-Driers

A replacement of the filter-drier cores is recommended any time excessive pressure drop is read across the filter-drier and/or when bubbles occur in the sight glass with normal subcooling. There are two two-core driers in each circuit. The maximum recommended pressure drop across the filter-drier is as follows:
Table 25, Liquid Line Filter-Drier Pressure Drop
PERCENT CIRCUIT MAXIMUM RECOMMENDED PRESS URE
100% 7 (48.3
75% 5 (34.5) 50% 3 (20.7) 25% 3 (20.7)
The filter-driers should also be changed if the moisture indicating liquid line sight glass indicates excess moisture in the system, or an oil test indicates the presence of acid.
During the first few months of operation the filter-drier replacement can be necessary if the pressure drop across the filter-drier exceeds the values listed in the table above. Any residual particles from the condenser tubing, compressor and miscellaneous components are swept by the refrigerant into the liquid line and are caught by the filter-drier.
The following is the procedure for changing the filter-drier core:
The standard unit pumpdown is set to stop pumpdown when 20 psig (138 kPa) suction pressure is reached. To fully pump down a circuit beyond 20 psig (138 kPa) for service purposes, a "Full Pumpdown" service mode can be activated using the keypad.
With Full Pumpdown = Yes, then the next time the circuit is pumped down, the pumpdown will continue until the evaporator pressure reaches 15 psig (103 kPa) or 120 seconds have elapsed, whichever occurs first. Upon completing the pumpdown, the "FullPumpDwn" setpoint is automatically changed back to "No".
52 IMM AGS-1
Page 53
The procedure to perform a full service pumpdown for changing the filter-drier core is as follows:
1.
Under the "Alarm Spts", change the "FullPumpDwn" setpoint from "No" to "Yes". Move the circuit switch to the OFF position. The compressor will unload to minimum slide
2. position and the unit will pump down.
Upon completing the full pumpdown per step 3, the "FullPumpDwn" setpoint is automatically
3. changed back to "No" which reverts back to standard 20 psig (138 kPa) pumpdown stop pressure.
If the pumpdown does not go to 15 psig (103 kPa) on the first attempt, one more attempt can be
4. made by repeating the above steps. Do not repeat "FullPumpDwn" more than once to avoid excessive screw temperature rise under this abnormal condition.
The circuit is now in the deepest pumpdown that can be achieved by the use of the compressor.
5. Close the two liquid line shutoff valves upstream of the filter-drier, on the circuit to be serviced plus the optional suction shutoff valve. Manually open the EXV, then pump the remaining refrigerant from the evaporator. Any remaining refrigerant must be removed from the circuit by the use of a refrigerant recovery unit.
Loosen the cover bolts, remove the cap and replace the filters.
6.
7.
Evacuate and open valves.
Evacuate the lines thro ugh the liqui d l ine manual shut off valve (s) t o r e move no nco nd ensa b le s that ca n have entered during filter replacement. A leak check is recommended before returning the unit to operation.

Compressor Slide Valves

The slide valves used for unloading the compressor are hydraulically actuated by pulses from the load/unload solenoid as controlled by the circuit controller. See OM AGS for details on the operation.

Electronic Expansion Valve

The electronic expansion valve is located in the liquid line entering the evaporator. The expansion valve meters the amount of refrigerant entering the evaporator to match the cooling
load. It does this by maintaining constant condenser subcooling. (Subcooling is the difference between the actual refrigerant temperature of the liquid as it leaves the condenser and the saturation temperature corresponding to the condenser pressure.) All AGS chillers are factory set at 20°F subcooling at 100% slide position and 10°F (12.2°C) subcooling at minimum slide position. These settings can be offset by discharge superheat.
When the control panel is first powered, the microprocessor will automatically step the valve to the fully closed (shut) position and the indicator light on the EXV will show closed position. The valve can also be heard closing as it goe s through the step s. The valve will take ap proximately 30 seco nds to go from a full open position to a full closed position.
The position of the valve can be viewed at any time by using the MicroTech II controller keypad through the View Refrigerant menus. T here are 6386 steps between closed and full open. There is also a sight glass on t he EXV to observe valve movement.

Evaporator

The evaporator is a flooded, shell-and-tube type with water flowing through the tubes and r efriger ant flowing up the shell over the tubes. The tubes are internally enhanced to provide extended surface and turbulent flow of water through the tubes. Normally no service work is required on the evaporator other than cleaning the water (tube) side in the event of improper water treatment or contamination.
IMM AGS-1 53
Page 54

Charging Refrigerant

The EXV controls liquid level in the condenser by controlling the circuit subcooling. Remaining refrigerant resides in the evaporator.

Indications of a low refrigerant R-134a charge:

Evaporator approach temperatures (leaving chilled fluid temperature minus the saturated
evaporating temperature) higher than normal
Suction superhe at higher than normal
Discharge superheat higher than normal
Microprocessor signaling Evaporator Low Pressure Inhibit
Microprocessor signaling Evaporator Low Pressure Unload
Microprocessor signaling Evaporator Low Pressure Trip
No refrigerant level in evaporator sight glass
Bubbles in the liquid line sight glass

Indications of a high refrigerant R-134a charge:

Discharge superheat less than normal
Evaporator approach temperatures (leaving chilled fluid temperature minus the saturated
evaporating temperature) lower than normal
Evaporator sight glass full
AGS air-cooled screw compressor chillers are shipped factory-charged with a full operating charge of refrigerant but there can be times that a unit must be recharged at the job site. Follow these recommendations when field charging. Refer to the unit operating charge found in the Physical Data Tables beginning on page 24. An initial charge of 80% to 90% of the nameplate is assumed. Unit charge adjustment should be done at 100% load and at normal cooling outdoor temperature (preferably higher than 70°F (21.1°C). Unit must be allowed to run 15 minutes or longer so that the condenser fan staging and load is stabilized at normal operating discharge pressure. For best results, charge with condenser pressure at design conditions.
Each circuit of the evaporator has a sight glass located on the side, halfway up and adjacent to the internal tube sheet. There should be refrigerant level viewable in each circuit. A low level combined with low evaporator pressure indicated by a LowEvapPressHold alarm indicates a low refrigerant charge for the circuit.
Procedure to charge an undercharged AGS unit:
1. If a unit is low on refrigerant, first determine the cause before attempting to recharge the unit.
Locate and repair any refrigerant leak. Evidence of oil is a good indicator of leakage. However, oil cannot be visible at all leaks. Liquid leak detector fluids work well to show bubbles at medium size leaks, but electronic leak detectors can be needed to locate small leaks.
Add the charge to the system only through the evaporator charging valve loc ated at the liquid line
2. connection at the bottom of the evaporator. Do not charge into the top of the evaporator.
The charge must be added at the 100% slide valve position.
3.
4.
Add sufficient charge to clear the conditions listed above under “Indications of a low refrigerant
R-134a charge”.
Check the unit subcooling value by reading the liquid line pressure and temperature at the liquid
5. line near the EXV. The subcooling values should be between 9 and 20 degrees F (5.0 and 11 degrees C) when the discharge superheat is above 20 degrees F (11 degrees C). When the discharge superheat is less than 20 degrees F, the subcooling will automatically be reset to a higher temperature.
Overcharging of refrigerant will raise the evaporator pressure and decrease discharge
6. temperature.
54 IMM AGS-1
Page 55

Charging Oil

Indications of a low oil charge:
Low Oil Level Alarms
Compressor excessively noisy
No oil level detected in either oil separator sight glass.
Upper Sight Glass
Indications of a high oil charge:
Lower Sight Glass
Evaporator approach temperatures (leaving chilled fluid
temperature minus the saturated evaporating temperature) higher than normal
Discharge superheat less than normal
Low Oil level Alarms (due to liquid refrigerant
entraining oil out of the oil separator and into the condenser and/or evaporator)
The oil separator is equipped with two sight glasses that are used to help determine the oil level. T he oil in the bottom of the separator forms a vortex (inverted cone). This can make the determination of the actual oil level difficult.
If no oil is visible in the bottom sight glass, examine the inside of the separator with a flashlight
1. to view the position of the vortex. If the top of the vortex is below the bottom sight glass, oil should be added. This condition can also cause NoOil NoRun alarms.
Pump oil into the system through the back-seat port on the angle valve at the oil separator outlet.
2. It is preferable to add oil at 100% circuit operation.
3.
Add oil during operation until the vortex covers the bottom sight glass.
Notes:
At part load operation oil will not be visible in the top sight glass,
Under any operating condition, the bottom glass should be full of oil.
The only acceptable oil is Emkarate RL68HP or Emkarate RL68H.
NOTE: Excessive oil charge can coat heat transfer surfaces and reduce unit performance.
IMM AGS-1 55
Page 56

Standard Controls

NOTE: A complete explanation of the MicroTech II controller and unit operation is contained
in the Operation Manual OM AGS. Thermistor sensors
Evaporator leaving water temperature
connection and is used for capacity control of the chiller and low water temperature freeze protection.
Evaporator entering water temperature - This sensor is located on the evaporator water inlet
connection and is used for monitoring purposes and return water temperature reset control.
Evaporator pressure transducer circuit #1, 2 (and 3) - This sensor is located on the suction side of
the compressor and is used to determine saturated suction refrigerant pressure and temperature. It also provides low pressure freeze protection.
Condenser pressure transducer circuit #1, 2 (and 3) - the sensor is located on the discharge of the
oil separator and is used to read pressure and saturated refrigerant temperature. The transducer will unload the compressor if a rise in head pressure occurs which is outside the MicroTech II controller setpoint limits. The signal is also used in the calculation of discharge superheat.
Liquid pressure transducer #1, 2 (and 3) – located on the liquid line ahead of the EXV. It is used to
determine liquid pressure and subcooling and is used to control the EXV.
Outside air - This sensor is located on the back of the control box on compressor #1 side. It
measures the outside air temperature, is used to determine if low ambient start logic is necessary and can be the reference for low ambient temperature lockout.
- This sensor is located on the evaporator water outlet
Suction temperature circuit #1, 2, (and 3) - The sensor is located in a well on the suction line. The
purpose of the sensor is to measure refrigerant temperature and superheat.
Discharge line temperature circuit #1, 2 (and 3) - The sensor is located in a well on the discharge
line. It measures the refrigerant temperature and is used to calculate discharge superheat.
Demand limit - This requires a field connection of a 4-20 milliamp DC signal from a building
automation system. It will determine the maximum number of cooling stages that can be energized.
Evaporator water temperature reset - This requires a 4-20 milliamp DC signal from a building
automation system or temperature transmitter to reset the leaving chilled water setpoint.
56 IMM AGS-1
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High condenser pressure control
MicroTech II control is equipped with high pressure transducers on each refrigerant circuit. The main purpose of the high pressure transducer is to maintain proper head pressure control. It also sends a signal to the MicroTech II control to unload the compressor in the event of an excessive rise in discharge pressure to 275 psig (1896 kPa). Also, MicroTech II control will inhibit additional circuit loading at 267 psig (1841 kPa). The high pressure switch trip setting is 282 psig (1944 kPa). The high pressure alarm is in response to the signal sent by the pressure transducer.
Mechanical high pressure equipment protection control
The high pressure equipment protection control is a single pole, pressure-activated switch that opens on a pressure rise. When the switch opens, the control circuit is de-energized, dropping power to the compressor and fan motor contactors. The switch is factory set (non-adjustable) to open at 310 psig (2137 kPa) ±7 psig and reclose at 200 psig (1379 kPa) ±7 psig. Although the high pr essure switch will close again at 200 psig (1379 kPa), the control circuit will remain locked out and it must be reset through the MicroTech II control.
The control is mounted in the control panel.
Compressor motor protection
The compressors are supplied with two types of motor protection. Solid state electronic overloads mounted in the control box sense motor current to within 2% of the operating amps. The MUST TRIP amps are equal to 140% of unit nameplate compressor RLA. The MUST HOLD amps are equal to 125% of unit nameplate RLA. A trip of these overloads can result from the unit operating outside of normal conditions. Repeat overload trips under normal operation can indicate wiring or compressor motor problems. The overloads are manual reset and must be reset at the overload as well as through the Mi croTech II controller.
The compressors also have a solid state Guardister protection. The Guardister
£ circuit has automatic reset and gives a Starter Fault (F75) that is cleared
£ circuit that provides motor over temperature
through the starter display and must also be reset through the MicroTech II control.
FanTrol head pressure control (standard)
FanTrol is a method of head pressure control that automatically cycles the condenser fans in response to condenser pressure. This maintains head pressure and allows the unit to run at ambient air temperatures down to 35°F (1.7°C).
The MicroTech II controller controls fans in response to the system discharge pressure. The use of this controller to stage on the fans as needed allows more precise control and avoids undesirable cycling of fans.
The control uses 6 or 8 stages of fan control with 4 or 6 outputs. The control logic sequences fan contactors to stage one fan at a time. On units with six or eight fans per circuit, a single fan is cut off when two fans are started to achieve adding one operating fan.
At any operating condition, the MicroTech II controller will determine the minimum lift pressure and a target discharge pressure, and will add or remove operating fans in sequence until the discharge pressure reaches the target value or falls within the control band of pressure set just above the target pressure value.
Each fan added has a decreasing percentage effect, so the control pressure band is smaller when more fans are on and largest with only one or two fans on.
Unit operation, with FanTrol, is satisfactory down to outdoor temperatures of 35°F (-1.7°C). Be low this temperature, the VFD option is required to regulate the speed of the first 2 fans on the system to adequately control the discharge pressure. The VFD option allows unit operation to 0°F (-17.8°C) outdoor temperature assuming no greater than 5-mph wind.
AGS FAN STAGING
Fan Stage 1 2 3 4 5 6 7 8 Digital Outputs ON #2 #2#3
Total Fans Operating 1 1, 2 1,2,3
IMM AGS-1 57
#2#3#4#2#3
#4#5
1,2,3,41,2,3,
#2#3
#4#6
5,6
#2#3#4
#5#6
1,2,3,4,
5,6
#2#3#5
#6#7
1,2,3,5,
6,7,8
#2#3#4
#5#6#7
1,2,3,4,
5,6,7,8
Page 58
NOTE: VFD and FanTrol will provide proper operating refrigerant discharge pressures at the
ambient temperatures listed for them, provided the coil is not affected by the existence of wind. Wind baffles must be utilized for low ambient operation if the unit is subjected to winds greater than 5 mph.
Low ambient start
Low ambient start is incorporated into the MicroTech II controller logic. The MicroTech II controller will measure the difference between freezestat and evaporator pressure and determine the length of time that the compressor will be allowed to run (to build up evaporator pressure) before taking the compressor off line. The danger of allowing the compressor to run for too long before building up evaporator pressure is that the evaporator could freeze.
Phase/voltage monitor
The phase/voltage monitor is a device that provides protection against three-phase electrical motor loss due to power failure conditions, phase loss, and phase reversal. Whenever any of these conditions occur, a NC contact opens in the external fault circuit of the starter generating a F75 fault code that then de-energizes all inputs. The F75 code is interrupted by the MicroTech II controller as an external fault and must be cleared through the MicroTech II co ntrol.
When prope r power is resto red, cont acts close and the fault must be cleared through b oth the st arter keypad and the MicroTech II control.
When three-phase power has been applied, the output relay should close and the "run light" should come on. If the output relay does not close, perform the following tests.
Check the voltages between L1-L2, L1-L3 and L2-L3. These voltages should be within 2% of
1. each other and within +10% of the rated three-phase line-to-line voltage.
If these voltages are extremely low or widely unbalanced, check the power system to determine
2. the cause of the problem.
If the voltages are within range, use a phase tester to verify that phases are in A, B, C sequence
3. for L1, L2 and L3. Correct rotation is required for compressor operation. If incorrect phase sequence is indicated, turn off the power and interchange any two of the supply power leads at the disconnect switch.
This can be necessary as the phase/voltage monitor is sensitive to phase reversal. Turn on the power. The output relay should now close after the appropriate delay.
Compressor short cycling protection
The MicroTech II controller contains logic to prevent rapid compressor restarting. Excessive compressor starts can be hard on starting components and create excessive motor winding temperatures. The anti-cycle timers are set for a five-minute stop-to-start cycle and a 20-minute start­to-start cycle. Both are adjust able through the MicroTech II control.

Optional Controls

VFD head pressure control (optional low ambient control)
NOTE: VFD head pressure control can be installed as standard equipment on certain units. The head pressure control operates in conjunction with the MicroTech II controller's standard head pressure control by modulating the motor speed of the first two fans in response to condensing temperature. It takes the place of fan stages #1 and #2. Start-up with low ambient temperature is improved because VFD controlled fans do not start until the condenser pressure builds up.
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Controls, Settings and Functions

Table 26, Controls
DESCRIPTION FUNCTION SYMBOL SETTING RESET LOCATION
Compressor Heaters Compressor
Solenoid - Load Compressor Solenoid - Unload Evaporator Heaters Help prevent evaporator freeze-up HTR-EVAP 38oF (3.3oC) N/A Water Heads Electronic Expansion Valve Board Electronic Expansion Valve Solid State Starter Thermistor Card Mechanical High High Pressure Switch MicroTech II Unit Controller MicroTech II Circuit Controller
Phase Voltage Monitor
Oil Return Solenoid Oil Level Sensor Senses oil level i n the oil separator OLS NC with oil pres ent N/A Oil Separator
Differential Press ure Switch Fan VFD (Optional) Controls discharge pressure FAN VFD In controller code N/A Power Panel
Control Panel Heater Maintain control l er operat i on
Lightning Arrestor
Oil Separator Heaters
Low Pressure Switch
To provide heat to drive off liquid refrigerant when compressor is off.
Loads compressor LOAD N/A N/A
Unloads the compress or UNLOAD N/A N/A
To provide power and step control to the EXV stepper motors commanded by the MT II. To provide efficient unit refri gerant flow and control subcooling. To provide motor temperature prot ection at about 220 For UL, ETL, etc.,…safety code to prevent high pressure above the relief valve.
To control unit functions . Refer to OM AGS. To control individual circui t functions. One
per circuit. Refer to OM AGS. To prevent reverse rotation of the motor and protect it from under/over voltage. Controls oil flow from evaporator to compressor
Pressure difference from compressor discharge to oil entering compressor.
To protect from high voltage spikes and surges.
Provide heat to maintai n vi scosity at low temperatures
Protects com pressor from running with insufficient oil pressure
o
F (104oC).
HTR1-COMPR
EXV-DRIVER N/A N/A Control Panel
EXV In Controller Code N/A
K2 Fault MHPR Refer to
UNIT CONTROLLER CIRCUIT CONTROLLER
PVM N/A Auto Power Panel OIL RETURN
SOLENOID
DPS 25 psig
HTR- CONTROL BOX
LA N/A N/A Power Panel
HTR 6-13
LPS Refer to OM AGS Auto
On, when compressor is off.
None, Inherent in design
OM AGS N/A
N/A
Closed when compressor is off
On at 40°F N/A Control Panel
On when compressor is off and oil level is present
N/A
Auto Power Panel
Auto Control Panel Refer to
OM AGS Refer to OM AGS
N/A
N/A Oil Separator
On the Compressor On the Compressor On the Compressor
In Main Liquid Line
Control Panel
Control Panel
Oil line from evap to compressor
Condenser Coil Support
IMM AGS-1 59
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Troubleshooting Chart

Table 27, Troubleshooting
PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS
Compressor will not run.
Compressor Noisy or Vibrating
Compressor Overload K2 Tripped or Circuit Breaker Trip or Fuses Blown
Compressor Will Not Load or Unload
High Discharge Pressure
Low Discharge Pressure
Low Suction Pressure
Differential Pressure Switch Trips
Low Oil Level Trip 1. Insufficient oil.
High Suction Pressure
1. Main power switch open.
2. Unit S1 system switch open.
3. Circuit switch, CS in pumpdown position.
4. Chilled water flow switch not closed.
5. Circuit breakers open.
6. Fuse blown or circuit breakers tripped.
7. Unit phase voltage monitor not satisfied.
8. Compressor overload tripped.
9. Defective compressor contactor or contactor coil.
10. System shut down by protection devices.
11. No cooling required.
12. Motor electrical trouble.
13. Loose wiring.
1. Compressor Internal problem.
2. Oil injection not adequate.
1. Low voltage during high load condition.
2. Loose power wiring.
3. Power line fault causing unbalanced voltage.
4. Defective or grounded wiring in the motor.
5. High discharge pressure.
1. Defective capacity control solenoids.
2. Unloader mechanism defective.
1. Noncondensables in the system.
2. Fans not running.
3. Fan control out of adjustment.
4. System overcharged with refrigerant.
5. Dirty condenser coil.
6. Air recirculation from fan outlet into unit coils.
7. Air restriction into unit.
8. Oil separator plugged
1. Wind effect or a low ambient temperature.
2. Condenser fan control not correct.
3. Low suction pressure.
4. Compressor operating unloaded.
1. Inadequate refrigerant charge quantity.
2. Clogged liquid line filter-drier.
3. Expansion valve malfunctioning.
4. Insufficient water flow to evaporator.
5. Water temperature leaving evaporator is too low.
6. Evaporator tubes fouled.
7. Suction valve (partially) closed.
8. Glycol in chilled water system
1. Clogged filter-drier.
2. Clogged oil separator.
3. Separator outlet valve (partially) closed.
2. Low discharge pressure.
1. Excessive load - high water temperature.
2. Compressor unloaders not loading compressor.
3. Superheat is too low.
1. Close switch.
2. Check unit status on MicroTech II display. Close switch.
3. Check circuit status on MicroTech II display. Close switch.
4. Check unit status on MicroTech display. Close switch.
5. Close circuit breakers.
6. Check electrical circuits and motor windings for shorts or grounds. Investigate for possible overloading. Check for loose or corroded connections. Reset breakers or replace fuses after fault is corrected.
7. Check unit power wiring to unit for correct phasing. Check voltage.
8. Overloads are manual reset. Reset overload at button on overload. Clear alarm on MicroTech II display.
9. Check wiring. Repair or replace contactor.
10. Determine type and cause of shutdown and correct problem before attempting to restart.
11. Check control settings. Wait until unit calls for cooling.
12. See 6,7,8 above.
13. Check circuits for voltage at required points. Tighten all power wiring terminals.
1. Contact McQuayService.
2. Check that oil line sight glass is full during steady operation Check pressure drop across oil filter and oil separator sight glasses
1. Check supply voltage for excessive voltage drop.
2. Check and tighten all connections.
3. Check supply voltage.
4. Check motor and replace if defective.
5. See corrective steps for high discharge pressure.
1. Check solenoids for proper operation. See capacity control section.
2. Replace.
1. Purge the noncondensables from the condenser coil after shutdown.
2. Check fan fuses and electrical circuits.
3. Check that fan setup in the controller matches unit fan number. Check MicroTech II condenser pressure sensor for proper operation.
4. Check for discharge superheat less than 15°F. Remove the excess charge.
5. Clean the condenser coil.
6. Remove the cause of recirculation.
7. Remove obstructions near unit.
8. Check oil separator pressure drop
1. Protect unit against excessive wind into vertical coils.
2. Check that fan setup in the MicroTech II controller matches unit fan number. Check SpeedTrol fan on units with SpeedTrol option.
3. See corrective steps for low suction pressure.
4. See corrective steps for failure to load.
1. Check liquid line sightglass and evaporator sightglass. Check unit for leaks. Repair and recharge to clear sightglass.
2. Check pressure drop across the filter-drier. Replace filter-driers.
3. Check expansion valve superheat and valve opening position. Replace valve only if certain valve is not working.
4. Check water pressure drop across the evaporator and adjust gpm.
5. Adjust water temperature to higher value.
6. Inspect by removing water piping. Clean chemically.
7. Open valve.
8. Check glycol concentration
1. Check pressure drop, replace.
2. Clean or replace.
3. Open valve.
1. Check oil line and separator sight glasses.
2. Possible overcharge or faulty EXV.
1. Reduce load or add additional equipment.
2. See corrective steps below for failure of compressor to load.
3. Check superheat on MicroTech II display. Check suction line sensor installation and sensor.
60 IMM AGS-1
Page 61

Periodic Maintenance Log

Date of inspection: Address: Facility/job name: City/State: Unit model number: Physical location of unit: Unit serial number: Service technical (name): Software identification: Operating hours: Compressor #1 Compressor #2 Compressor #3 Number of starts Compressor #1 Compressor #2 Compressor #3 Follow up service required: Yes No
General Actions to be Taken
Upper part of report completed: Yes No Fill in above Compressor operation: Yes No Explain all “No” checks
1. Mechanical operation acceptable (noise, vibration, etc.)?
2. Look at cycling and cooling, is unit controlling at set points?
3. No refri gerant leaks (full liquid sight glass ) ?
4. Liquid line moisture indicator shows dry system?
5. Proper condensing fan operation?
6. Condenser coil clean?
7. No corrosion or paint problems?
Compressor elec trical operat ion:
8. Satisfactory electrical operation?
9. MicroTech II hardware operation satisfactory?
10. MicroTech II software operation satisfactory?
11. Unit status %
12. Circuit status 1 % Capacity Circuit status 2 % Capacity Circuit status 3 % Capacity
13. Water temperature – Evaporator: Entering/Leaving /
14. No. of fan states active:
15. Evaporator pressure:
16. Condenser pressure:
17. EXV position – Steps open or percent open:
18. Superheat:
19. Subcooling:
20. Liquid line temperature:
21. Chiller % rated load amps – Unit:
22. Outside air temperature:
23. Leaving evaporator setpoint temperature:
24. Reset option programmed ? Yes No Ice stora g e unit? Yes No
25. Is VFD included? Yes No VFD operation OK? Yes No
26. Current alarm: ___ ___ ___ Circuit #1 ______ Circuit #2 ______ Circuit #3 ______
27. Previous alarm – Show all: Alarm Type Date
Circuit #1
Circuit #2
Circuit #3
Circuit #1 Circuit #2 Circuit #3
Data at Job Site:
28. Volts: L1_____ L2_____ L3_____
29. Amps:Comp #1 Ph 1____ PH 2____ PH 3____
30. Amps:Comp #2 PH 1____ PH 2____ PH 3____
31. Amps:Comp #3 PH 1____ PH 2____ PH 3____
Data from MicroTech II Controller:
32. Vibration – Read every six months using IRD (or equal) unfiltered at flat on top of motor end: ______ In/Sec Comp #1
______ In/Sec Comp #2 ______ In/Sec Comp #3
IMM AGS-1 61
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This document contains the most current product inf ormation as of this printing. For the m ost up-to-date produc t information, please go to www.mcquay.com
2002 McQuay International www.mcquay .com • (800) 432-1342
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