McQuay AGS 251DP Installation Manual

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Page 1

Installation and Maintenance Manual

IMM AGSDP

Air-Cooled Screw Compressor Chillers

AGS 226DP through AGS 501DP

60 Hertz

R-134a

Group: Chiller

Part Number: 331375801

Date: November 2006

Supersedes: July 2006

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................................... 13

Lifting and Mounting Weights................. 16

Chilled Water Pump ................................ 19

Water Piping............................................ 19

System Water Volume.............................. 20

Variable Speed Pumping ......................... 20

Evaporator Freeze Protection .................. 20

Operating Limits:..................................... 22

Flow Switch............................................. 22

Water Connections................................... 23

Refrigerant Charge .................................. 23

Glycol Solutions ...................................... 23

Water Flow and Pressure Drop........ 24

Solid State Starters...........................40

Component Location .......................48

Major Component Location..................... 48

Power Panel ............................................. 50

Control Panel ........................................... 51

Optional Features.............................52

Controls ................................................... 52

Electrical.................................................. 52

Unit.......................................................... 53

Start-up and Shutdown ....................54

Extended (Seasonal) Shutdown ............... 55

System Maintenance........................57

General .................................................... 57

Compressor Maintenance ........................ 57

Lubrication .............................................. 57

Electrical Terminals................................. 58

Condensers .............................................. 58

Liquid Line Sight Glass ........................... 58

Evaporator Sight Glass ............................ 59

Lead-Lag.................................................. 59

Preventative Maintenance Schedule ........ 60

Physical Data................................... 26

Dimensional Data ............................ 28

Wind Baffles and Hail Guards......... 30

BAS/Remote Panel Interface........... 32

BAS Interface.......................................... 32

Electrical Data ................................. 33

Field Wiring ............................................ 33

Field Wiring Diagram...................... 39

Warranty Statement.......................... 60

Service .............................................61

Liquid Line Filter-Driers.......................... 61

Compressor Slide Valves ......................... 62

Electronic Expansion Valve..................... 62

Evaporator ............................................... 63

Charging Refrigerant ............................... 63

Charging Oil ............................................ 66

Standard Controls .................................... 66

Controls, Settings and Functions ............. 71

Troubleshooting Chart ............................. 72

Periodic Maintenance Log ....................... 73

Unit controllers are LONMARK certified

with the optional LONWORKS

communications module.

Manufactured in an ISO Certified facility

Information covers the McQuay International products at the time of publication and we reserve the right

to make changes in design and construction at anytime without notice.

 The following are trademarks or registered trademarks of their respective companies: BACnet from ASHRAE; LonTalk from Echelon Corporation;

Modbus from Schneider Electric Ltd.; Open Choices from McQuay International.

2 IMM AGS-DP

Page 3

Introduction

General Description

McQuay AGS-DP air-cooled water chillers are complete, self-contained, automatic refrigerating units that include the latest in engineered components, arranged to provide a compact and highly 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 an integral subcooler section. Each condenser circuit has a semi-hermetic single-screw compressor, solid-state starter, a multiple-circuit shelland-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 one-time 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-DP manual. Installation and operating instructions will be shipped with the unit if a LONT



ALK

, Modbus or BACnet BAS interface is ordered.

Nomenclature

A G S - XXX D P

Rotary Screw Compressor

Air-Cooled

Global

Premium Efficiency

Design Vintage

Model Number (Nominal Tons)

Inspection

When the equipment is received, check all items carefully against the bill of lading to check for a complete shipment. Carefully inspect for damage upon arrival. Report shipping damage to the carrier and file a claim with the carrier. Check the unit’s serial plate 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 26.

IMM AGS-DP 3

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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.

Start-up by McQuay Factory Service 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 McQuay sales representative or from the nearest office of McQuay Factory Service.

Handling

Avoid rough handling 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. Arrange spreader bars and cables to prevent damage to the condenser coils or unit cabinet (see Figure 1).

WARNING

Avoid contact with them.

Improper lifting or moving unit can result in property damage, severe

personal injury or death. Follow rigging and moving instructions carefully.

NOTES:

1. All rigging points on a unit must be used. See page 16 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.

DANGER

Figure 1, Required Lifting Method

4 IMM AGS-DP

Page 5

Location

Locate 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-DP chillers, it is desirable to orient the unit 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 or louvers be factory or field 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 information.

For pad-mounted units, it is recommended that the unit be raised a few inches with suitable supports, located at least under the mounting locations, to allow water to drain from under the unit and to facilitate cleaning under it.

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. A control panel is to the left of the condenser and compressor it controls. 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 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-DP 5

Page 6

Clearance Requirements

5’-0” if open fence or 50% open wall

6’-0” if solid wall (see note 3 for pit)

10’-0” min. for

Evaporator Removal

Air Flow

No obstructions allowed

above unit at any height

Figure 2, Clearance Requirements, AGS 226DP – 501DP

No obstructions. Recommended area required for unit operation, air flow and maintenance access.

5’-0” if open fence or 50% open wall

See notes 2 & 4 concerning wall height at unit sides.

See Note 8

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 28 for details.

9. See the following pages if the airflow clearances cannot be met.

6 IMM AGS-DP

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 compressor(s) running (at reduced capacity) as long as possible, rather than allowing a shut-off on high discharge pressure.

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-DP 7

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

5 ft.

(1.5m)

(1.8m)

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

Figure 5, Adjustment Factors

(1.5m)

6 ft.

(1.8m)

5 ft.

6 ft.

8 IMM AGS-DP

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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

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Case 3, Three or More Units Side By Side

When three or more units are side by side, the outside units (chillers 1 and 3 in this case) are influenced by the middle unit only on their inside circuits. Their adjustment factors will be the same as Case 2. All inside units (only chiller 2 in this case) are influenced on both sides and must be adjusted by the factors shown below.

Figure 8, Three or More Units

Chiller 1 Chiller 2 Chiller 3

Figure 9, Adjustment Factor

4.0

3.0

2.0

1.0

(4.6)

(4.9)

(5.2)

(5.5)

8.0

6.0

4.0

2.0

(4.6)

(4.9)

(5.2)

(5.5)

10 IMM AGS-DP

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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 10, Open Screening Walls

Figure 11, Wall Free Area vs. Distance

IMM AGS-DP 11

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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 prevent such accidents, yet provide 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 12, Pit Installation

Figure 13, Adjustment Factor

12 IMM AGS-DP

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Vibration Isolators

Max. L oad

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 are also given.

Table 1, Spring Flex Isolator Data

9.0

(228. 6)

9.0

(228. 6)

9.0

(228. 6)

9.0

(228. 6)

5.0

(127. 0)

5.0

(127. 0)

5.0

(127. 0)

Dimensions

In. (m m)

7.7

(195. 6)

7.7

(195. 6)

7.7

(195. 6)

7.7

(195. 6)

Dimensions

In. (m m)

0.56

(14.2)

0.56

(14.2)

0.56

(14.2)

2.7

(68.6)

2.7

(68.6)

2.7

(68.6)

2.7

(68.6)

0.25 (6.4)

5.75

(146. 0)

5.75

(146. 0)

5.75

(146. 0)

5.75

(146. 0)

1.6

(41.1)

1.6

(41.1)

1.6

(41.1)

Housing

Part

Number

226103B -00 (2) 226117A-00

226103B -00 (2) 226118A-00

226103B -00 (2) 226119A-00

226103B -00 (2) 226120A-00

6.5

(165. 1)

6.5

(165. 1)

6.5

(165. 1)

4.6

(116. 8)

4.6

(116. 8)

4.6

(116. 8)

Housing

CP-2-27 Orange

CP-2-28 Green

CP-2-31 Gray

CP-2-32 White

Spring

Color

Max. L oad

Each

Lbs. (kg)

1500

(681)

1800

(815)

2200

(998)

2600

(1180 )

Def l.

In. (m m)

0.5

(12.7)

0.5

(12.7)

0.5

(12.7)

0.5

(12.7)

A B C D E

10.2

(259. 1)

10.2

(259. 1)

10.2

(259. 1)

10.2

(259. 1)

Table 2, Neoprene-in-Shear Isolator Data

Type

RP-4 B lack

RP-4 Red

RP-4 Green

Note (1) "D" is the m ounting hole diam eter.

Each

Lbs. (kg)

1500

(681)

2250

(1019 )

3300

(1497 )

Def l.

In. (m m)

0.25

(6.4)

0.25

(6.4)

0.25

(6.4)

A B C D (1) E H L W

3.75

(95.3)

3.75

(95.3)

3.75

(95.3)

0.5

(12.7)

0.5

(12.7)

0.5

(12.7)

Spring

Part Number

McQuay

Part

Number

216398A -04

216398A -01

216398A -03

Figure 14, Spring Flex Mountings, CP-2 Figure 15, Neoprene-in-Shear

Mounting, RP-4

IMM AGS-DP 13

Page 14

Table 3, Spring Vibration Isolators, AGS 226DP–301DP, Part Numbers and Spring Colors

Model

AGS 226DP

AGS 251DP

AGS 276DP

AGS 301DP

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 Number

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

Mounti ng Location , See Foo tp ri nt Drawin gs Figure 16 or Figu re 17

Table 4, Spring Vibration Isolators, AGS 351DP–501DP, Part Numbers and Spring Colors

Model

AGS 351DP

AGS 391DP

AGS 401DP

AGS 451DP

AGS 501DP

Model

AGS 351DP

AGS 391DP

AGS 401DP

AGS 451DP

AGS 501DP

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.

Mounti ng Location , See Foo tp ri nt Drawin gs Figure 18, Figure 19

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-4-27 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

Mounting Location (Table Continued)

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-2-31 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

350348101

350348102

350348103

Continued

350348104

350348106

350348107

350348108

14 IMM AGS-DP

Page 15

Table 5, Neoprene-in-Shear Isolators, AGS 226 – 301, RP Part Numbers

Model

AGS 226DP AGS 251DP AGS 276DP AGS 301DP

Note: The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.

M1 M2 M3 M4 M5 M6 M7 M8 Kit Number

4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 350348201 4-RED 4-RED 4-RED 4-RED 4-GREEN 4-RED 4-RED 4-RED 350348202 4-RED 4-RED 4-RED 4-GREEN 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 4-GREEN 4-GREEN 4-RED 4-RED 4-RED

Mounti ng Location , See Foo tp ri nt Drawin gs Figure 16 or Figu re 17

Table 6, Neoprene-in-Shear Isolators, AGS 351 – 501, RP Part Numbers

Model

AGS 351DP AGS 391DP AGS 401DP AGS 451DP AGS 501DP

Model

AGS 351DP AGS 391DP AGS 401DP AGS 451DP AGS 501DP

Note: The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.

Mounti ng Location , See Foo tp ri nt Drawin gs Figure 18, Figure 19

M1 M2 M3 M4 M5 M6

4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED 4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED 4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED 4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED

4-RED

Mounting Location (Table Continued)

M7 M8 M9 M10 M11 M12 Kit Number

4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 350348204 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED 4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED

350348205

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.

350348203

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.

IMM AGS-DP 15

Page 16

Lifting and Mounting Weights

AGS226

AGS251

2 (51)

Typical Spacing

Figure 16, AGS 226DP – AGS 251DP Lifting and Mounting Locations

AGS226 AGS251

AGS226

AGS226 AGS251

AGS251

Figure 17, AGS 276DP - AGS 301DP Lifting and Mounting Locations

Table 7, AGS 226DP - AGS 301DP Lifting and Mounting Weights (Aluminum Fin)

AGS

Model

226DP

251DP

276DP

301DP

NOTES:

1. Lifting tabs with 2½ 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 Weigh t fo r Each Po int lb (k g) Mounting Loads for Each Point lb. (kg )

L1 L 2 L3 L4 L5 L6 M1 M2 M3 M4 M 5 M6 M7 M 8

Lbs. 2183 3043 2563 2563 3043 2183 1683 2325 1681 2322 2322 1681 2325 1683

(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. 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

for Isolator

Mounting (8)

88.0

(2235.2)

16 IMM AGS-DP

Page 17

Table 8, AGS 226DP - AGS 301DP Lifting and Mounting Weights (Copper Fin)

2 (51)

Typical Spacing

391

2 (51)

Typical Spacing

AGS

Model

226DP

251DP

276DP

301DP

Lbs. 2499 3359 2879 2879 3359 2499 1920 2562 1918 2559 2559 1918 2562 1920

(kg) 1135 1525 1307 1307 1525 1135 872 1163 871 1162 1162 871 1163 872

Lbs. 2552 3412 3069 3073 3743 2878 1960 2602 1958 2599 2970 2295 2698 2091

(kg) 1158 1549 1393 1395 1699 1306 890 1181 889 1180 1348 1042 1225 949

Lbs. 2930 3795 3262 3262 3795 2930 2130 2737 2334 3009 3009 2334 2737 2130

(kg) 1330 1723 1481 1481 1723 1330 967 1243 1060 1366 1366 1060 1243 967

Lbs. 2971 3828 3377 3377 3828 2971 2154 2751 2427 3113 3113 2427 2751 2154

(kg) 1349 1738 1533 1533 1738 1349 978 1249 1102 1413 1413 1102 1249 978

NOTES:

1. Lifting tabs with 2½ 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 18, AGS 351Dp – AGS 391DP Lifting and Mounting Locations

AGS351

AGS391

AGS351

391

88.0

(2235.2)

AGS351

391

Figure 19, AGS 401DP - AGS 501DP Lifting and Mounting Locations

for Isolator

Mounting (8)

for Isolator

Mounting (8)

88.0

(2235.2)

IMM AGS-DP 17

Page 18

Table 9, AGS 351DP- AGS 501DP Lifting Weights (Aluminum Fin)

Model

351DP

391DP

401DP

451Dp

501DP

AGS

L1 L2 L3 L4 L5 L6 L7 L8

lbs 2312 3173 2681 2681 3352 2473 3192 2880

(kg) 1050 1441 1217 1217 1522 1123 1449 1307

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

Lifting Weight for Each Point lb. (kg)

Table 10, AGS 351DP- AGS 501DP Lifting Weights (Copper Fin)

Model

351DP

391DP

401DP

451Dp

501DP

AGS

L1 L2 L3 L4 L5 L6 L7 L8

lbs 2668 3529 3037 3037 3708 2829 3548 3236

(kg) 1211 1602 1379 1379 1683 1284 1611 1469

lbs 2884 3731 3554 3552 4352 3479 3954 3651

(kg) 1309 1694 1613 1612 1976 1579 1795 1657

lbs 3225 4070 3759 3759 4391 3518 3993 3690

(kg) 1464 1848 1707 1707 1994 1597 1813 1675

lbs 3257 4098 3835 3835 4419 3550 3993 3690

(kg) 1479 1860 1741 1741 2006 1612 1813 1675

lbs 3257 4098 3835 3835 4419 3550 3993 3690

(kg) 1479 1860 1741 1741 2006 1612 1813 1675

Lifting Weight for Each Point lb. (kg)

Table 11, AGS 351DP- AGS 501DP Mounting Weights (Aluminum Fin)

Mounting Loads for Each Point lb. (kg)

351DP

391DP

401DP

451Dp

501DP

AGS

Model

lbs 1798 2442 1787 2426 2426 1787 2442 1798 1726 1557 1645 1484

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

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 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

Table 12, AGS 351DP- AGS 501DP Mounting Weights (Copper Fin)

AGS

Model

351DP

391DP

401DP

451Dp

501DP

M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12

lbs 2035 2679 2024 2663 2663 2024 2679 2035 1963 1794 1882 1721

kg 924 1216 919 1209 1209 919 1216 924 891 814 854 781

lbs 2175 2801 2271 2928 3345 2647 2852 2267 2263 2093 2157 1996

kg 987 1272 1031 1329 1518 1202 1295 1029 1027 950 979 906

lbs 2293 2878 2673 3371 3371 2673 2878 2293 2289 2119 2183 2022

kg 1041 1307 1214 1530 1530 1214 1307 1041 1039 962 991 918

lbs 2315 2895 2741 3444 3444 2741 2895 2315 2289 2119 2183 2022

kg 1051 1314 1244 1564 1564 1244 1314 1051 1039 962 991 918

lbs 2315 2895 2741 3444 3444 2741 2895 2315 2289 2119 2183 2022

kg 1051 1314 1244 1564 1564 1244 1314 1051 1039 962 991 918

Mounting Loads for Each Point lb. (kg)

18 IMM AGS-DP

Page 19

Chilled Water Pump

It is required that the starter(s) for the chilled water pump 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 freeze protection. Connection points are shown in Figure 27 on page 39.

Drain Valves at Initial Start-up

The evaporator water side is pressurized and drained in the factory and shipped with open drain valves in each head. Be sure to close these valves before filling the vessel with fluid.

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

rail and the bottom of the condenser coil in the approximately 30-inch width shown on Figure 23 and Figure 24.

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

4. Some means of maintaining adequate system water pressure (i.e., expansion tank or

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

: Chilled water piping must enter and exit the unit platform between the base

parts in the system. If the evaporator is the highest point in the piping system, it must be equipped with an air vent.

regulating valve).

should be placed far enough upstream to prevent cavitation at the pump inlet (consult pump manufacturer for recommendations). The use of a strainer will prolong pump life and help maintain high system performance levels.

NOTE: A 20-mesh 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. Protected water piping to the unit to prevent freeze-up if below freezing temperatures are

expected. See page 20 for further information on freeze protection.

CAUTION

If a separate disconnect is used for the 115V supply to the unit, it should power the 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 heater burnout.

IMM AGS-DP 19

Page 20

8. If the unit is used as a replacement chiller on a previously existing piping system, flush the

system thoroughly prior to unit installation. Then regular chilled water analysis and chemical water treatment is recommended at equipment start-up.

9. 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.

10. For ice making or low temperature glycol operation, the freezestat pressure value will need

to be checked and probably lowered. The freezestat setting can be manually changed through the MicroTech II controller.

Make a preliminary leak check prior to insulating the water piping and filling the system.

Include a vapor barrier on piping insulation 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 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 occurrences.

For normal comfort cooling applications where the cooling load changes relatively slowly, we recommend a minimum system volume of two to three minutes times the flow rate (gpm). For example, if the design chiller flow rate is 600 gpm, we recommend a minimum system volume of 1200 to 1800 gallons (600 gpm x 2 to 3 minutes).

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, provided 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 between the minimum and maximum values listed on page 25. 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:

20 IMM AGS-DP

Page 21

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.

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. If desired, the 3 KVA control transformer can be unwired and a field 115-volt power source wired to terminals TB1-1 and TB1-2 in the control panel for circuit #1 (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.

CAUTION

It is required that the chilled water pump’s starter be wired to, and controlled by, the chiller's microprocessor year around to avoid severe or terminal damage to the evaporator.

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 27 on page 39.

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:

Addition of a concentration of a glycol anti-freeze with a freeze point 10 degrees F (5.5 degrees C) 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.

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 operation of the chilled water pump, circulating water through the chilled water

system and through the evaporator. The chiller microprocessor will automatically start up the pump if so wired.

Table 13, Freeze Protection

Temperature

°°°°F (°°°°C)

20 (6.7) 16 18 11 12

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 are on following page.

Ethylene Glycol Propylene Glycol Ethylene Glycol Propylene Glycol

For Freeze Protection For Burst Protection

Percent Volume Glycol Concentration Required

IMM AGS-DP 21

Page 22

1. These figures are examples only and cannot be appropriate to every situation. Generally, for an extended margin of protection, select a temperature at least 10°F lower than the expected lowest ambient temperature. Inhibitor levels should be adjusted for solutions less than 25% glycol.

2. Glycol of less than 25% concentration is not recommended because of the potential for bacterial growth and subsequent loss of heat transfer efficiency, or add inhibitors.

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 temperature, 40°F to 50°F (4.4°C to 10°C)

Leaving chilled fluid temperature (with anti-freeze), 20°F to 50°F (7°C to 10°C)

Operating Delta-T range, 6 degrees F to 16 degrees F (3.3 C to 8.8 C)

Maximum operating inlet fluid temperature, 66°F (19°C)

Maximum startup inlet fluid temperature, 90°F (32°C)

Maximum non-operating 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 paddletype 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 14. Installation should be as shown in Figure 20.

Electrical connections in the unit control center should be made at terminals 60 and 67. Terminals Y and R 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 conductors (115 VAC and higher) and have an insulation rating of 600 volts.

Table 14, Flow Switch Flow Rates

(NOTE !)

Min.

Adjst.

Max.

Adjst.

Flow

Flow Lpm 0.8 1.1 2.2 2.8 4.3 11.4 22.9 35.9 38.6

Flow

Flow Lpm 2.8 4.1 6.1 7.3 11.4 27.7 53.4 81.8 90.8

NOTES:

1. A segmented 3-inch paddle (1, 2, and 3 inches) is furnished mounted, plus a 6-inch paddle loose.

2. Flow rates for a 2-inch paddle trimmed to fit the pipe.

3. Flow rates for a 3-inch paddle trimmed to fit the pipe.

4. Flow rates for a 3-inch paddle.

5. Flow rates for a 6-inch paddle

inch 1 1/4 1 1/2 2 2 1/2 3 4 5 6 8 Pipe Size

mm 32 (2) 38 (2) 51 63 (3) 76 102 (4) 127 (4) 153 (4) 204 (5)

gpm 5.8 7.5 13.7 18.0 27.5 65.0 125.0 190.0 205.0 Lpm 1.3 1.7 3.1 4.1 6.2 14.8 28.4 43.2 46.6 gpm 3.7 5.0 9.5 12.5 19.0 50.0 101.0 158.0 170.0

gpm 13.3 19.2 29.0 34.5 53.0 128.0 245.0 375.0 415.0 Lpm 3.0 4.4 6.6 7.8 12.0 29.1 55.6 85.2 94.3 gpm 12.5 18.0 27.0 32.0 50.0 122.0 235.0 360.0 400.0

22 IMM AGS-DP

Page 23

Figure 20, Flow Switch

Valve

Protect All Field Piping

Flow direction marked

on switch

1" (25mm) NPT flow

switch connection

Tee

1 1/4" (32mm) pipe

dia. min. after switch

1 1/4" (32mm) pipe

dia. min. before switch

Figure 21, Typical Field Water Piping

Vent

Out

Drain

Valved

Pressure

Gauge

Water

Strainer

Vibration

Eliminator

Notes:

1. Connections for vent and drain fittings are located on the top and bottom of both evaporator water heads.

2. Piping must be supported to avoid putting strain on the evaporator nozzles.

Vibration

Eliminator

Gate

Flow

Switch

Balancing

Valve

Against Freezing

Gate

Valve

Water Connections

Water piping to the evaporator must be brought out through the side of the unit between the vertical supports. The dimensional drawings on page 28 and following 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 26.

IMM AGS-DP 23

Glycol Solutions

When using glycol anti-freeze solutions the chiller's capacity, glycol solution flow rate, and pressure drop through the evaporator can be calculated using the following formulas and tables.

Note: The following procedure does not specify the type of glycol. Use the derate factors found in Table 15 for corrections when using ethylene glycol and those in Table 16 for propylene glycol.

Page 24

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 (Cap) 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−=

factorflowtons

TDelta

(Water only, use Flow correction for glycols)

3. Pressure drop - To determine pressure drop through the evaporator when using glycol, enter 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.

4. Power - To determine glycol system kW, multiply the water system kW by the factor designated "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.

CAUTION

Do not use automotive grade antifreeze. Industrial grade glycols must be used.

Automotive antifreeze contains inhibitors that will cause plating on the copper

tubes within the chiller evaporator. The type and handling of glycol used must be

consistent with local codes.

Table 15, Ethylene Glycol Factors

Freeze

E.G

Point

oF o

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

Water Flow and Pressure Drop

The chilled water flow through the evaporator should be adjusted to meet specified conditions. The 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.

Measure the chilled water pressure drop through the evaporator at field installed pressure taps. It is important not to include valve or strainer pressure drop in these readings.

Table 16, Propylene Glycol Factors

Freeze

P.G

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

Point

oF o

Cap. Power Flow PD

24 IMM AGS-DP

Page 25

Figure 22, Evaporator Pressure Drop, AGS 226DP - AGS 501DP

Minimum/Nominal/Maximum Flow Rates

AGS Unit Size

226DP

251DP

276DP

301DP

351DP

391DP

401DP

451DP

501DP

IMM AGS-DP 25

Minimum Flow Nominal Flow Maximum

Flow

gpm ft. gpm ft. gpm ft

331 6.0 529 14.3 882 37.0

366 7.1 585 17.0 976 43.0

406 4.0 649 9.5 1082 26.5

454 4.8 727 12.2 1211 33.3

510 4.6 816 11.4 1360 30.0

576 5.0 922 12.6 1537 34.0

613 6.2 981 15.4 1635 40.0

661 7.0 1057 17.3 1762 45.0

688 4.8 1100 12.2 1834 32.0

∆∆∆∆P

Flow

∆∆∆∆P

Flow

∆∆∆∆P

Page 26

Physical Data

Table 17, Physical Data, AGS 226DP – AGS 27DP

DATA

BASIC DATA

Unit Cap. @ ARI Conditions, tons (kW) 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 (1), lbs. (kg) 16285 (7394) 17301 (7855) 18319 (8317) Unit Shipping Weight (1), 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) 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) 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, cfm (l/s) 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)

NOTE: 1. Add 158 lbs (72 kg) per fan for copper fin coils.

159 (14.8) 159 (14.8) 159 (14.8) 213 (19.8) 213 (19.8) 213 (19.8)

226DP 251DP 276DP

Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2

220.5 (774) 243.9 (856) 270.5 (951)

278 x 88 x 100

(7087 x 2235 x 2550)

24 (610) – 96 (2438) 24 (610) – 96 (2438) 24 (610) – 96 (2438)

Table 18, Physical Data, AGS 301DP

DATA

BASIC DATA

Unit Cap. @ ARI, tons (kW) 302.8 (1065) Unit Operating Charge lbs (kg) 360 (163) 360 (163) Cabinet Dimensions L x W x H, in. (mm) Unit Operating Weight (1), lbs. (kg) 18787 (8266) Unit Shipping Weight(1), lbs (kg) 18272 (8295)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Capacity, tons (kW) 150 (525) 150 (525)

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE

Coil Face Area, ft2. (m2) Fins Per Inch x Rows Deep 16 x 3 16 x 3

CONDENSER FANS, DIRECT DRIVE PROPELLER TYPE

No. of Fans -- Fan Dia., in. (mm) 16 – 30 (762) No. of Motors -- hp (kW) 16 – 2 (1.5) Fan & Motor RPM, 60Hz 1140 60 Hz Fan Tip Speed, fpm 8954 60 Hz Total Unit Airflow, cfm (l/s) 172,800

EVAPORATOR, FLOODED SHELL AND TUBE

Shell Dia.-Tube Length in.(mm) - in. (mm) Evaporator R-134a Charge lbs (kg) 221 (100) 221 (100) Water Volume, gallons (liters) 59 (221) Max. Water Pressure, psi (kPa) 150 (1034) Max. Refrigerant Press., psi (kPa) 200 (1379)

NOTE: 1. Add 158 lbs (72 kg) per fan for copper fin coils.

AGS MODEL NUMBER

301DP

Ckt 1 Ckt 2

355 x 88 x 100

(9017 x 2235 x 2550)

213 (19.8) 213 (19.8)

26 (660) – 96 (2438)

AGS MODEL NUMBER

317 x 88 x 100

(8052 x 2235 x 2550)

355 x 88 x 100

(9017 x 2235 x 2550)

26 IMM AGS-DP

Page 27

Table 19, Physical Data, AGS 351Dp – AGS 401DP

DATA 351DP 391DP 401DP

Ckt. 1 Ckt. 2 Ckt. 3 Ckt. 1 Ckt. 2 Ckt. 3 Ckt. 1 Ckt. 2 Ckt. 3

BASIC DATA

Unit Cap. @ ARI, tons (kW) 340.1 (1196) 384.3 (1349) 408.8 (1435) Unit Operating Charge, lbs (kg) 285 (129) 312 (141) 312 (141) 312 (141) 312 (141) 312 (141) 335 (152) 335 (152) 335 (152)

Cabinet Dim., L x W x H, in. (mm)

Operating Weight(1), lbs. (kg) 23507 (10672) 26667 (11734) 27684 (12568) Shipping Weight(1), lbs (kg) 22958 (10101) 26056 (11829) 27072 (12291)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Capacity, tons (kW) 100 (350) 100 (350) 100 (350) 100 (350) 125 (437) 125 (437) 125 (437) 125 (437) 125 (437)

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLER

Coil Face Area, ft2. (m2) 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 PROPELLER TYPE

No. of Fans - Fan Dia., in. (mm) 18 – 30 (762) 22 – 30 (732) 24 – 30 (762) No. of Motors -- hp (kW) 18 – 2 (1.5) 22 – 2 (1.5) 24 – 2 (1.5) Fan & Motor RPM, 60Hz 1140 1140 1140 60 Hz Fan Tip Speed, fpm 8954 8954 8954 60 Hz Total Unit Airflow, cfm (l/s)

EVAPORATOR, FLOODED SHELL AND TUBE

Shell Dia.,Tube Length in.(mm) 26 (660) – 108 (2743) 30 (762) – 108 (2743) 30 (762) – 108 (2743) Evap. R-134a Charge lbs (kg 164 (74) 164 974) 164 (74) 191 (86) 191 (86) 191 (86) 191 (86) 191 (86) 191 (86) 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 (kPa)

NOTE: 1. Add 158 lbs (72 kg) per fan for copper fin coils.

159 (14.8) 159 (14.8) 159 (14.8) 159 (14.8) 213 (19.9) 213 (19.9) 213 (19.9) 213 (19.9) 213 (19.9)

434 x 88 x 100

(11024 x 2235 x 2550)

194,400 237,600 259,200

200 (1379) 200 (1379) 200 (1379)

AGS MODEL NUMBER

510 x 88 x 100

(12954 x 2235 x 2550)

548 x 88 x 100

(13919 x 2235 x 2550)

Table 20, Physical Data, AGS 451DP – AGS 501DP

DATA 451DP 501DP

Ckt. 1 Ckt. 2 Ckt. 3 Ckt. 1 Ckt. 2 Ckt. 3

BASIC DATA

Unit Cap. @ ARI, tons (kW) 440.5 (1546) 458.4 (1612) 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)

Operating Weight (1), lbs. (kg) 28042 (12731) 28042 (12731) Shipping Weight(1), 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) 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, cfm (l/s)

EVAPORATOR, FLOODED SHELL AND TUBE

Shell Dia. -- Tube Length in.(mm) - in. (mm) Evap. R-134a Charge lbs (kg 214 (97) 214 (97) 214 (97) 214 (97) 214 (97) 214 (97) Water Volume, gallons (liters) 79 (300) 79 (300) Max. Water Pressure, psi (kPa) 150 (1034) 150 (1034) Max. Refrigerant Press. psi (kPa)

NOTE: 1. Add 158 lbs (72 kg) per fan for copper fin coils.

213 (19.9) 213 (19.9) 213 (19.9) 213 (19.9) 213 (19.9) 213 (19.9)

548 x 88 x 100

(13919 x 2235 x 2550)

259,200 259,200

30 (762) – 108 (2743) 30 (762) – 108 (2743)

200 (1379) 200 (1379)

AGS MODEL NUMBER

548 x 88 x 100

(13919 x 2235 x 2550)

IMM AGS-DP 27

Page 28

Dimensional Data

100.4

(2550.4)

SINGLE POINT POWER ENTRY "D"

5.5

88.0

(2235.2)

44.0

(1117.6)

36.0

(914.4)

Figure 23, Dimensions, AGS 226DP – AGS 301DP

Note:

1. See page 16 for lifting locations, mounti ng locations, wei gh ts and mounting loads.

2. Allow one-inch m anufacturin g tolerance.

51.1

(1297.9)

36.9

(937.3)

INLET

FIELD CONTROL CONNECTION

OUTLET

OPENING FOR CHILLER WATER PIPING

POWER ENTRY POINT

0.875 (22.2) KNOCK-OUT

CONTROL

PANEL

CIRCUIT #1

CONTROL

PANEL

CIRCUIT #2

POWER ENTRY POINT

0.875 (22.2) KNOCK-OUT

(139.7)

SINGLE POINT POWER

BOX OPTION

AGS 230-300

27.5 (698.5) AGS 320

26.5 (673.1)

AGS DP

AGS 226

AGS 251

AGS 276-

NOTES:

Unit Size

301

POWER ENTRY

12.0 (304.8) POWER ENTRY LOCATION FAR SIDE

1. Chilled water piping must enter and exit the unit platform in the opening between the base rail and the bottom

of the condenser coil as shown in the plan view above.

2. Victaulic connections are standard. Flanged connection available as an option. Mating flange is field-

supplied.

Dimensions

inches (mm)

A B C D E F

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)

Connection

Sizes

inches (mm)

30.0

(762.8) 8 (203.2)

30.0

(762.8) 8 (203.2)

31.4

(797.6) 8 (203.2)

Center of

Gravity

in. (mm)

139

(3531)

146

(3708)

177

(4496)

Fan Modules

No. of

Fans 1 2

12 Fan 6 6

14 Fan 6 8

16 Fan 8 8

28 IMM AGS-DP

Page 29

DWG. 330557001-R3

LOCATION FAR SIDE

100.41

(2550.4)

88.00

(2235.2)

51.1

SINGLE POINT POWER

36.0

(914.4)

44.0

(1117.6)

(1297.9)

(937.2)

Figure 24, Dimensions, AGS 351DP –501DP

Note:

1. See page 17 for lifting locations, mounti ng locations, wei gh ts and mounting loads.

2. Allow one-inch m anufacturin g tolerance.

5.5

(139.7)

36.9

SINGLE POINT POWER ENTRY "D"

INLET

FIELD CONTROL CONNECTION

OUTLET

OPENING FOR CHILLER WATER PIPING

POWER ENTRY POINT

0.875 (22.2) KNOCK-OUT

CONTROL

PANEL

CIRCUIT #1

CONTROL

PANEL

CIRCUIT #2

POWER ENTRY POINT

0.875 (22.2) KNOCK-OUT

BOX OPTION

CONTROL PANEL CIRCUIT #3

POWER ENTRY POINT

0.875 (22.2) KNOCK-OUT

26.5

(673.1)

AGS-DP

Unit Size

351

391

401-501

POWER ENTRY

12.0 (304.8) POWER ENTRY

NOTES:

1. Chilled water piping must enter and exit the unit platform in the opening between the base rail and the bottom

of the condenser coil as shown in the plan view above.

2. Victaulic connections are standard. Flanged connection available as an option. Mating flange is field-supplied.

Dimensions Inches (mm)

Water Piping inches (mm)

A B C D E F G

434.2

(11027.9)

510.6

(12968.5)

548. 8

(13939.0)

133.4

(3388.0)

133.4

(3388.1)

171.6

(4358.4)

90.3

(2292.4)

87.3

(2140.0)

125.5

(3186.4)

192.6

(4892.0)

192.6

(4892.0)

230. 8

(5862.3)

288.8

(7335.5)

327.0

(8305.8)

365.2

(9276.1)

44.7

(1137.4)

44.7

(1137.4)

80.9

(2054.8)

Connection

Sizes

inches

(mm)

30.0

(762.8) 8 (203.2)

30.0

(762.8)

31.4

(797.6)

(254.0)

Center of

Gravity

in. (mm)

210

(5334)

228

(5791)

260

(6604)

Fan Modules

No. of

Fans

1 2 3

18 6 6 6

22 6 8 8

24 8 8 8

IMM AGS-DP 29

Page 30

Wind Baffles and Hail Guards

COIL VERTICAL CHANNELS.

NIT VER

AL COIL

PLACE FRONT "B" BY LAPPING

AND REPEAT ATTACHMENT PROCEDURE.

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 25 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 25, 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.

Front Panel Attachment (Second)

PLACE FRONT "A" AND FASTEN TO BOTH SIDES

UNI

ATTACH ALL RIBS TO

OVER "A" AND REPEAT ATTACHMENT PROCEDURE.

ATTACH TOP "A" AT HORIZONTAL COIL CHANNEL FIRST.

30 IMM AGS-DP

Top Panel Attachment (Last)

THIS WILL SQUARE THE PANEL.

OVERLAP THE FRONT PANEL FLANGE.

ICAL CO

NIT VER

ATTACH LEFT SIDE SECOND.

LAP PANEL "B" OVER PANEL "A"

Page 31

Table 21, Packing List

FRONT PANEL

TOP

Rib, Install First

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 26, Components

REAR (AGAINST UNIT)

VERTICAL SUPPORT RIB TOP COVER

Top Panel, Install Last

Overlap the Front panel

Front Panel, Install Second

IMM AGS-DP 31

Page 32

BAS/McQuay Remote Panel Interface

BAS Interface

Connection to the chiller for all building automation systems (BAS) protocols is at the unit controller. An optional interface module, depending on the protocol being used, may have been factory-installed in the unit controller (or it can be field installed).

Protocols Supported

Table 23, Standard Protocol Data

Protocol Physical Layer Data Rate Controller Other

BACnet/IP or

BACnet/Ethernet

BACnet MSTP RS-485

LONWORKS

Modbus RTU RS-485 or RS-232

Ethernet 10 Base-T

FTT-10A 78kbits/sec

The interface kits on the MicroTech II controller are as follows:

• BACnet Kit P/N 350147404: BACnet MS/TP

BACnet Kit P/N

350147406:

BACnet

• LONWORKS Kit P/N 350147401: LonTalk (FTT-10A)

• Modbus: Modbus RTU

Optional Protocol Selectability BAS interfaces. The locations and interconnection requirements for the various standard protocols are found in their respective installation manuals.

Megabits/sec

9600, 19200 or

38400 bits/sec

9600 or 19200

bits/sec

IP or BACnet Ethernet

MicroTech II

Reference ED

15100

Reference ED

15062

15063

Modbus: IM 743 LONWORKS: IM 735 BACnet -MS/TP: IM 736

BACnet -IP/Ethernet IM 837

Referenced documents may be obtained from the local McQuay sales office, from the local McQuayService office, or from the McQuay Technical Response Center, located in Staunton, Virginia (540-248-0711).

These documents can also be found on www.mcquay.com under Product Information > (chiller type) > Control Integration.

 The following are trademarks or registered trademarks of their respective companies: BACnet from

the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., LonTalk, LONMARK and LONWORKS from Echelon Corporation, and Modbus and Modbus RTU from Schneider Electric.

Remote Operator Interface Panel

The box containing the optional remote interface panel will have installation instructions, IOM MT II Remote, in it. The manual is also available for downloading from www.mcquay.com.

32 IMM AGS-DP

Page 33

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 warranty.

An open fuse or circuit breaker 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 single-point connection (optional).

If the standard multiple-point power wiring is ordered, power connections are made to the individual circuit power blocks in power panels located between the condenser sections. Two connections are required for models AGS 226 through 301 and three are required for models AGS 351 through 501. See the dimension drawings on pages 28 and 29 for detailed locations. Separate disconnects are required for each electrical circuit if McQuay factory-mounted disconnects with through-the-door handles 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 page 28 and following 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. Each circuit has a factory wired compressor isolation circuit breaker. 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 19 for details.

CAUTION

The heaters come from the factory connected to the control power circuit. If desired, the 3 KVA control transformer can be unwired and a field 115-volt power source wired to terminals TB1-1 and TB1-2 in the control panel for circuit #1 (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.

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 single or multiple point wiring arrangements. The solid-state starters contain phase reversal protection.

DO NOT ALTER THE WIRING TO THE STARTERS.

IMM AGS-DP 33

Page 34

Table 22, AGS 226DP – AGS 501DP, Electrical Data, Optional Single-Point

AGS UNIT SIZE

226DP

251DP

276DP

301DP

351DP

391DP

401DP

451DP

501DP

NOTES

1. Table based on 75°C field wire.

2. Complete notes are on page 38.

VOLTS HZ

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 3.0 700 700 575 460 611 6 350 2 3.0 700 800 575 460 688 12 4/0 2 3.0 800 800 575 460 768 12 250 2 4.0 800 800 575 460 804 12 250 2 4.0 1000 1000 575 460 860 12 300 2 4.0 1000 1000 575 460 885 12 300 2 4.0 1000 1000 575

MINIMUM

CIRCUIT

AMPACITY

(MCA)

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

516 6 300 2 3.0 600 700

605 12 3/0 2 3.0 700 700

658 12 4/0 2 3.0 800 800

683 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

FIELD WIRE

QTY

POWER SUPPLY

(Conduit Connection)

WIRE

GAUGE

QTY

HUB

NOMINAL

SIZE (In.)

FIELD FUSE

BREAKER SIZE

RECOM-

MENDED

MAXIMUM

Table 23, AGS 226DP – AGS 320B, Electrical Data, Standard Multiple-Point, Two-Circuit Units

ELECTRICAL CIRCUIT 1 (COMP 1) ELECTRICAL CIRCUIT 2 (COMP 2)

POWER SUPPLY

AGS

UNIT

VOLTS HZ

SIZE

226DP

251DP

276DP

301DP

NOTES:

1. Table based on 75°C field wire.

2. Complete notes are on page 38.

3. 3/0 wire is required for the disconnect switch option, 2/0 may be used for power block connection.

460

575

460

575

460

575

460

575

MINIMUM

CIRCUIT

AMPS (MCA)

262 6 3/0 (3) 1 3.0 350 450 262 6 3/0 (3) 1 3.0 350 450

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

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

260 6 3/0 (3) 1 3.0 350 400 260 6 3/0 (3) 1 3.0 350 400

337 6 4/0 1 3.0 450 500 337 6 4/0 1 3.0 450 500

285 6 3/0 1 3.0 350 450 285 6 3/0 1 3.0 350 450

FIELD WIRE

WIRE

QTY

GAUGE

HUB

(Conduit

Connectio

HUB

QTY

SIZE

FIELD

FUSING

REC

FUSE

SIZE

MAX

FUSE

SIZE

MINIMUM

CIRCUIT

AMPS (MCA)

POWER SUPPLY FIELD FUSING

HUB

FIELD WIRE

WIRE

QTY

GAUGE

(Conduit

Connection

)

HUB

QTY

SIZE

REC

FUSE

SIZE

MAX

FUSE

SIZE

34 IMM AGS-DP

Page 35

Table 24, AGS 340B–AGS 475B, Electrical Data, Standard Multiple-Point, Circuits # 1 & 2

ELECTRICAL CIRCUIT 1 (COMP 1) ELECTRICAL CIRCUIT 2 (COMP 2)

POWER SUPPLY

AGS

UNIT

VOLTS HZ

SIZE

351DP

391DP

401DP

451DP

501DP

NOTES:

1. Table based on 75°C field wire.

2. Complete notes are on page 38.

3. 3/0 wire is required for the disconnect switch option, 2/0 may be used for power block connection.

460

575

460

575

460

575

460

575

460

575

MINIMUM

CIRCUIT

AMPS (MCA)

262 6 3/0 (3) 1 3.0 350 450 262 6 3/0 (3) 1 3.0 350 450

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

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

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

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

285 6 3/0 1 3.0 350 450 285 6 3/0 1 3.0 350 450

FIELD WIRE

WIRE

QTY

GAUGE

HUB

(Conduit

Connection

)

HUB

QTY

SIZE

FIELD

FUSING

REC

FUSE

SIZE

MAX

FUSE

SIZE

MIN.

CIRCUIT

AMPS (MCA)

POWER SUPPLY

FIELD WIRE

WIRE

QTY

GAUGE

HUB

(Conduit

Connection

)

HUB

QTY

SIZE

FIELD

FUSING

REC

FUSE

SIZE

MAX

FUSE

SIZE

Circuit #3

ELECTRICAL CIRCUIT 3 (COMP 3)

POWER SUPPLY FIELD FUSING

AGS

UNIT

351DP

391DP

401DP

451DP

501DP

NOTES:

1. Table based on 75°C field wire.

2. Complete notes are on page 38.

3. 3/0 wire is required for the disconnect switch option, 2/0 may be used for power block connection.

VOLTS HZ

SIZE

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

460 337 6 4/0 1 3.0 450 500

575

460 337 6 4/0 1 3.0 450 500

575

MINIMUM

CIRCUIT

AMPS (MCA)

230 3 250 1 2.5 300 400

260 6 3/0 (3) 1 3.0 350 400

285 6 3/0 1 3.0 350 450

FIELD WIRE

WIRE

QTY

GAUGE

HUB

(Conduit

Connection

)

HUB

QTY

SIZE

REC

FUSE

SIZE

MAX

FUSE

SIZE

IMM AGS-DP 35

Page 36

Table 25, AGS 226DP–AGS 475B, Compressor and Condenser

CIRCUIT

Fan Motor Amp Draw

AGS UNIT SIZE

226DP

251DP

276DP

301DP

351DP

391DP

401DP

451DP

501DP

RATED LOAD AMPS

VOLTS HZ

460 195 195 - 3.0 20 575 460 195 225 - 3.0 20 575 460 225 225 - 3.0 20 575 460 250 250 - 3.0 20 575 460 195 195 195 3.0 20 575 460 195 225 225 3.0 20 575 460 225 225 225 3.0 20 575 460 225 250 250 3.0 20 575 460 250 250 250 3.0 20 575

CIRCUIT

171 171 -

171 190

190 190 -

210 210 -

171 171 171

171 190 190

190 190 190

190 210 210

210 210 210

NO OF

FAN

MOTORS

FAN

MOTORS

FLA

(EACH)

2.7 18

L R A

FAN

MOTORS

(EACH)

Table 26, AGS 226DP – AGS 475B, Customer Wiring Information With Single-Point Power

AGS

UNIT

SIZE

226DP

251DP

276DP

301DP

351DP

391DP

401DP

451DP

501DP

NOTES:

1. Terminal size amps are the maximum amps that the power block is rated for.

2. Complete notes are on page 38.

VOLTS HZ

460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575 460 575

WIRING TO STANDARD UNIT POWER BLOCK

TERMINAL SIZE

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 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

CONNECTOR LUG RANGE

PER PHASE

(COPPER WIRE ONLY)

WIRING TO OPTIONAL NONFUSED

DISCONNECT SWITCH IN UNIT

SIZE

CONNECTOR LUG RANGE

PER PHASE

(COPPER WIRE ONLY)

36 IMM AGS-DP

Page 37

Table 27, AGS 226DP–AGS 475B, Wiring Information with Multiple-Point

AGS UNIT

VOLTS HZ

SIZE

226DP

251DP

276DP

301DP

351DP

391DP

401DP

451DP

501DP

NOTES:

1. Terminal size amps are the maximum amps that the power block is rated for.

2. Complete notes are on page 38.

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 --

60 400 400 400

WIRING TO UNIT POWER BLOCK

#6-350 #6-350 --

#6-350 #6-350 #6-350

Table 28, AGS 226DP–AGS 475B, Wiring Information with Multiple-Point

AGS

UNIT

VOLTS HZ

SIZE

226DP

251DP

276DP

301DP

351DP

391DP

401DP

451DP

501DP

NOTES:

1. Complete notes are on page 38.

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 - 3/0 - 500 3/0 - 500 -

60 400 400 400 3/0 - 500 3/0 - 500 3/0 - 500

WIRING TO UNIT DISCONNECT SWITCH

IMM AGS-DP 37

Page 38

Electrical Data Notes

1. Allowable voltage limits Unit nameplate 460V/60Hz/3Ph: 414V to 506V Unit nameplate 575V/60Hz/3Ph: 518V to 632V

2. Unit wire size ampacity (MCA) is equal to 125% of the largest compressor-motor RLA plus 100% of RLA of all other loads in the circuit.

3. Single point power supply requires a single disconnect to supply electrical power to the unit. This power must be fused.

4. All field wiring to unit power block or optional nonfused disconnect switch must be copper.

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 multipoint 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.

7. Recommended time delay fuse size or HACR circuit breakers is equal to 150% of the largest compressor motor RLA plus 100% of remaining compressor RLAs and the sum of condenser fan FLAs.

8. Maximum time delay fuse size or HACR circuit breakers is equal to 225% of the largest compressormotor RLA plus 100% of remaining compressor RLAs and the sum of condenser fan FLAs.

9. If 1) the evaporator heater is to be powered during winter shutdown and 2) it is desired to disconnect 460/575 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.

Power Limitations:

1. Voltage within ± 10 percent of nameplate rating.

2. Voltage unbalance not to exceed 2% with a resultant current unbalance of 6 to 10 times the voltage unbalance per NEMA MG-1, 1998 Standard.

Optional Protocol Selectability Connection

Optional Protocol Selectability BAS interfaces. The locations and interconnection requirements for the various standard protocols are found in their respective installation manuals, obtainable from the local McQuay sales office and also shipped with each unit:

Modbus IM 743 LONW

ORKS

IM 735 BACnet IM 736

38 IMM AGS-DP

Page 39

Field Wiring Diagram

DISCONNECT

UNIT MAIN

120 VAC

24 VAC

TB1

IF REMOTE STOP CONTROL

IS USED, REMOVE LEAD 897

897

AUTO

MANUAL

AUTO

MANUAL

4-20MA FOR

DEMAND LIMIT

GND

*COMMUNICATION

J11

Rx-/Tx-

CONTROLLER

24 VAC

Figure 27, Typical Field Wiring Diagram, Circuit #1 Control Box

Note: Field-wired control connections are made in the control panel for circuit 1 only.

(BY OTHERS)

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

ALARM BELL OPTION

FACTORY SUPPLIED ALARM

FIELD WIRED

ALARM BELL RELAY

TERMINAL BLOCK

CHW PUMP RELAY #1

(BY OTHERS)

120 VAC 1.0 AMP MAX

CHW PUMP RELAY #2

(BY OTHERS)

120 VAC 1.0 AMP MAX

GND LUG

TB1

(115 VAC)

TO COMPRESSOR(S)

TB1-2

AND FAN MOTORS

REMOTE STOP

SWITCH

(BY OTHERS)

ICE MODE

SWITCH

(BY OTHERS)

CHW FLOW SWITCH

---MANDATORY–(BY OTHERS)

TIME

CLOCK

NOR. OPEN PUMP AUX. CONTACTS (OPTIONAL)

CHW RESET

(BY OTHERS)

OFF

(24 VAC OR 30 VDC)

FROM TERM. 40 TO 53.

BLACK

WHITE

GND

GREEN

LABEL DWG. 330803901 REV. 0D

PORT

IMM AGS-DP 39

Page 40

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 parallel. This power section is capable of providing maximum torque per amp throughout 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.

40 IMM AGS-DP

Page 41

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.

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 problem with the starter or motor application.

Table 29, Fault Codes

Number Des cr iption

00 No F ault -- --

01 UTS Tim e Lim it Expired Y Y

02 Motor Therm al Overlo ad Trip Y N

10 Phas e Rot at ion E rror, Not A-B-C N Y

12 Low Line Frequenc y N Y

13 High L ine Frequ ency N Y

15 Input Power N ot Thre e phase N Y

21 Low Line L1-L2 Voltage Y Y

22 Low Line L2-L3 Voltage Y Y

23 Low Line L3-L1 Voltage Y Y

24 High L ine L1-L2 Volt age Y Y

25 High L ine L2-L3 Volt age Y Y

26 High L ine L3-L1 Volt age Y Y

27 Phas e los s N Y

28 No Lin e Vol tage N Y

30 I.O. C. (I nstan taneous Overcu rr ent) N N

31 Overcu rrent Y N

Continued next page

Controlled

Stop

Auto

Res et

IMM AGS-DP 41

Page 42

Number Des cr iption

37 Current Imbalanc e Y Y

38 Ground Fault Y N

39 No Cur re nt At Run N Y

40 Shorte d/Open SCR N N

41 Current W hile Stopp ed N N

47 St ac k P rotec tion Fa ult N Y

48 Bypass Co nt act or Fault (on S TOP i nput) Y N

50 Contro l Power L ow N Y

51 Current Sensor Off set E rror -- N

52 Burden Switch Error N N

60 Thermis tor Trip N N

61 St ac k O T Switc h T ri p N N

71 Anal og Inpu t Trip Y Y

82 Modbus Time-out Y Y

94 CPU Error – Soft ware Fault N N

95 CPU Error – Parameter S torage Fault N N

96 CPU Error – Illega l Ins truct ion Trap N N

97 CPU Error – Soft ware Watchdog F au lt N N

98 CPU Error – Spurious Interrupt N N N

99 CPU Error – Program S torage Fa ult N N

Controlled

Stop

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.

Auto

Res et

NOTE: If mechanical vibrations are present at the installation site, inspect the

connections more frequently.

42 IMM AGS-DP

Page 43

Figure 28, Trouble Shooting Guide

Start

Replace

Fuses

Replace

Circuit

Breaker

Correct

Inline Fault

Yes

Fuses OK?

Circuit

Breaker OK?

Yes No

In-Line OK?

Yes

Correct Power

Source

Problem

Yes

Low or Missing

Line?

Phase Order

Fault

Thermal Trip?

Interlock

Open?

Wiring OK?

Yes

NoYes

Yes

Yes Yes

Swap Any

2 Power

Leads

High

Ambient?

Correct

Interlock

State

Correct

Wiring

Replace

Control Card

Does Problem

Still Exist

Yes

Goto Pag

Correct Wiring

Return To

Service

Correct and

Wait to Cool

Return To

Service

Wiring OK?

Yes

Correct and

Wait to Cool

Yes

Bad Air

Circulation?

Motor

Overloaded?

Yes

Lower Motor

Load

IMM AGS-DP 43

Page 44

Yes

blem?

ror

Motor

act

stanc

Replace

ControlCard

CheckJumper

Parameter

andCT

DoesProblem

StillExist?

Contact

From Previous Page

Current

Imbalance Fault?

Yes

Correct Wiring

Replace

Defective SCRs

Wiring Good?

Yes Y

Motor

Winding Short?

SCRs OK?

Yes Y

All Gate

Pulses Present?

Replace

Control Card

Yes

Fuses Blown or

Breaker Tripped?

Replace Fuse

or Reset Breaker

Motor Pro

Repai

Replace

Cont

Bensh

For Assi

CT Burden

Switches Set

Correctly?

Return to

Normal

Operation

McQuay

For Assistance

44 IMM AGS-DP

Page 45

FLOW CHART DETAILS:

1. Fuses Determine if power line fuses have been installed, and if they

are operating properly.

2. Circuit Breaker Determine if the circuit breaker is off, or has tripped and

disconnected the line from the starter.

3. Power Line Voltage Verify that line voltage is present, and is the correct voltage.

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 P16.

12. Motor Winding Problem Conducting a megger test of the motor can identify an

internal 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.

15. Motor Current

Determine if motor current signal scaling is correct.

IMM AGS-DP 45

Page 46

Table 30, Solid State Starter Settings

No. Operating Parameter Default Range of Setting P1 Motor Full Load Amps (FLA) Note 1 1A 1 to 9999A P2 Motor Rated Load Amps (RLA) Note 2 1A 1 to 9999A P3 Motor Service Factor 1.08 1.00 to 1.99 P4 Motor Overload cless 10 Off, 1 to 40 P5 Initial Motor Current 100 50 to 400 % FLA P6 Maximum Motor Current 600 100 to 800 % FLA P7 Ramp Time 15 0 to 300 seconds P8 UTS Time 30 1 to 900 seconds

P9 Stop Mode CoS

P10 Decel Begin Level 40 100 to 0 % Volts P11 Decel End Level 20 50 to 0 % Volts P12 Decel Time 15 1 to 180 Seconds P13 Default Meter Display0 0 to 19 P14 Overcurrent Trip level Off Off, 50 to 800 % RLA P15 Overcurrent Trip Delay Time 2.0 0.1 to 90.0 Seconds

P16 Rated RMS Voltage 480

P17 Over Voltage Trip Level 10 Off, 1 to 40 5 Rated Volts P18 Under Voltage Trip Level 15 Off, 1 to 40 5 Rated Volts P19 Over/Under Voltage Delay Time 1.0 0.1 to 90.0 Seconds P20 Current Imbalance Trip Level 20 5 to 40 % P21 Controlled Fault Stop Off On, Off P22 Auto Fault Reset Time 60 Off, 1 to 120 Seconds

P23 CT Ratio 2640

P24 Control Source TEr TEr: Terminal, NEt: Network P25 Modbus Address 2 1 to 247 P26 Modbus Baud Rate 19.2 1.2, 2.4, 4.8, 9.6, 19,2 Kbps P27 Modbus Timeout 3 Off, 1 to 120 Seconds P28 Analog Output Function, Note 3 1 0 to 11 P29 Analog Output Span 100 1 to 125 % P30 Analog Output offset 0 0 to 99 % P31 Passcode - 0 to 9999 P32 Fault Log - xFyy

NOTES

1. FLA set according to voltage.

2. RLA set per table below:

Compressor Size 380V 460V 575V

205 Future 195 171 220 Future 225 190235 Future 250 210

3. The analog output functions available are shown below:

0: OFF (no output) 4: Thermal Overload % 8: kW (0-10MW) 1: Ave Current (0-200%RLA) 5: KW (0-10 kW) 9: Analog Input 2: Ave Current (0-800%RLA) 6: kW (0-100kW) 10: Output Voltage (5of FV) 3: Ave Voltage (0-750VAC) 7: kW (0-1MW) 11: Calibrate (Full 100% output)

CoS: Coast Dcl: Voltage Decel

100, 110, 120, 200, 208, 220, 230, 240, 350, 380, 400, 415, 440, 460, 480, 575, 600, 660, 1000 Volts

72, 96, 144, 288, 864, 2640, 2880, 5760, 8000

46 IMM AGS-DP

Page 47

Operation

LED Display

• View parameters, messages and faults

• Shows software version on power-up

Programming

• Press PARAM to enter the menu and then UP or DOWN to reach the desired parameter.

• Press ENTER to show the present value of the parameter.

• Press UP or Down to change the value of the parameter.

• Press ENTER to store the new value or PARAM to abandon the change.

Quick Meters

• Press DOWN to display the motor thermal overload content.

• Press UP to display the incoming line phase order.

• Press ENTER to display the status meter.

Fault Log

• Select P32 and press ENTER. The most recent fault will be displayed as xFyy where x

will be a 1 to indicate the most recent fault being displayed and yy is the fault code.

• Press DOWN to view older faults. Up to 9 previous faults can be stored in the log.

Resetting a Fault

• Press RESET to reset from a fault.

Resetting Parameters

• Press and hold PARAM and ENTER on power-up to reset parameters to default values.

Emergency Thermal Reset

• Press RESET and DOWN to perform an emergency thermal reset.

CT Burden Switch Settings (P1 and P23)

FLA in Amps Setting

864:1 CTs 2640:1 CTs 5760:1 CTs 8000:1 CTs SW1 SW2

24 to 42 73 to 128 160 to 280 223 to 390 Off Off 42 to 50 128 to 151 280 to 330 390 to 465 Off On

50 to 108 151 to 330 330 to 720 465 to 1000 On Off

108 to 190 330 to 590 720 to 1280 1000 to 1800 On On

IMM AGS-DP 47

Page 48

Component Location

Major Component Location

Figure 29, Two-Compressor Unit Cutaway

Control/Power Panel

Two-Circuit Flooded

Compressor #1

Circuit #1

Evaporator

Condenser Section

Circuit #2

Compressor #2

Control/Power Panel

Circuit #2

Oil Separator #1

48 IMM AGS-DP

Page 49

Figure 30, Piping Schematic

CHECK

VALVE

S0 5

S02

SENSOR LOC ATION CHART

S06

S07

S08

S09

EVAP. LEAVING WATER TEMP.

S07

S03

S0 6

DESCRIPTION

CHARGING

VALVE

DISC HARGE

TUBING

SCHRADER

VALVE

OIL

SEPARATOR

DISC HARGE

TUBING

RELIEF

VALVE

AIR

FLOW

SCHRADER (EACH DISCH HEADER)

SIGHT GLASS

SO LENOID

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

RELIEF VALVE

(EVAP SHELL)

WATER OUT

S09

WATER IN

SENSOR NUMBER

S08

S01

EVAP. PRESS. TRANSDUCER

S02

DISC H. PRESS. TRANSDUCER

S03

LIQUID PRESS. TRANSDUCER

S04

SUCTION TEMPERATURE

S05

DISC HARGE TEMPERATURE

ANGLE VALVE

CHARGING

VALVE

DESCRIPTION

AIR

FLOW

EXPANSION

VALVE

CONDENSER

ASSEMBLY

SENSOR NUMBER

LIQUID LINE TEMPERATURE OUTSIDE AIR TEMPERATURE

EVAP. ENTERING WATER TEMP.

AIR

FLOW

CHARGING VALVE

LIQUID SHUT-OFF VALVE

FILTER DRIER

SCHRADER VALVE

SIGHT

GLASS

LIQUID TUBING

CONDENSER

ASSEMBLY

AIR

FLOW

IMM AGS-DP 49

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 refrigerant compartments with the water-filled tubes running from end to end.

Page 50

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 or Optional Fan VFD

Terminal Block

Compressor

Motor Temp. Card

Microprocessor Control Panel

Panel Heater Thermostat

50 IMM AGS-DP

Page 51

Control Panel

Transformer

Display

Unit Switch

The control panel for Circuit #1 is shown below. The panel for circuit #2 and #3 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.

T4, Load/

Unload Solenoid

Transformer

T5, Exp. Valve

T3, Control

T2, Control

Transformer

EWHR, Evaporator Heater Relay

MHPR, Mech. High Pressure Relay

Expansion Valve Board

Circuit Breakers

Circuit Switch

Solid State Starter

Unit Controller, Located in Circuit #1 Panel Only

Circuit Controller

TB1, Field Control Connections, (Terminal Numbers on Top or Bottom)

IMM AGS-DP 51

Page 52

Optional Features

There are a number of options that may or may not be present on any specific unit. These options can affect unit control operation and how a unit is installed and wired.

Controls

Ice Storage

The unit is equipped with control logic to handle the low temperatures associated with thermal storage applications. Additional evaporator insulation is recommended.

Water Flow Switch

(Part Number 01750330) A water flow switch is available for field installation in the chilled water piping to protect against evaporator freeze-up under low or no flow conditions. Terminals are provided in the control center for circuit #1 for field wiring of the water flow switch to the unit. NOTE: Installation of a flow detection device is required.

High Ambient Operation

Option required for operation at ambient temperatures above 115°F (46°C) or when the unit is equipped with the VFD low ambient fan control option. The kit includes a thermostat controlled, panel ventilation fan and inlet grille with filter. The option can be ordered with any unit. Ordering a “High Efficiency” unit does not automatically include this kit, it must be ordered separately. Compressor loading and unloading is adaptively determined by system load, ambient air temperature and other inputs to the MicroTech II control algorithms.

Building Automation System (BAS) Interface

This is the Protocol Selectability option to the MicroTech II controller. The addition of this optional communications module to the standard unit controller enables the controller to communicate using standard protocols such as LONT any of the following data link layer options: BACnet MS/TP, BACnet/IP, BACnet Ethernet or LONT

ALK

entering an order. The communications module can also be added later in the field to an existing controller.

Alarm Bell

Field installed and wired to the control panel to provide remote.

Electrical

Single-Point Power Block

A single power supply to a power block mounted in a box located on the unit's frame. Each circuit is factory-wired from the box to a power block in each circuit's power panel. See dimension drawings for the box location. Includes factory wiring to a circuit breaker located in each circuit's power panel. Multiple-point power block (one circuit per compressor) is standard.

Multi-Point w/Disconnect Switch

Separate power supply to each circuit's power panel which is equipped with a disconnect switch with a through-the-door handle. Each disconnect switch can isolate its circuit for service purposes.

ALK

, Modbus and BACnet using

(FTT-10A). It is necessary to identify the data link layer that will be used when

Single-Point w/ Disconnect Switch

Single power supply to a factory-mounted disconnect switch. Includes factory wiring to a circuit breaker located in each circuit's power panel.

52 IMM AGS-DP

Page 53

High- Short Circuit Current Protection

The control panels and single point connection box (if ordered) will have the high short circuit current rating as shown below. A high interrupt circuit breaker is included.

115 Volt Convenience Outlet

A 10.0 amp, 115-volt convenience outlet mounted inside the control panel is available as an option on all units. The outlet is located in the #2 circuit control box.

Lightning Arrestor per Compressor

Unit

Protective Base Guards

Optional factory installed wire mesh lower base guards provide protection for ground level installations. Coil guards are standard.

Wind Baffles/Hail Guard

The presence of wind will have an adverse affect on any air-cooled chiller. Wind across a condenser coil will not allow a chiller to operate as efficiently, or possibly not even start, at low ambient temperatures. Wind in effect raises the minimum ambient temperature in which the chiller can operate. The AGS air-cooled chillers are available with field installed wind baffles which allow the chiller to operate effectively down to the ambient temperature for which it was designed.

Hail can have a damaging effect on the performance of an air-cooled condenser. As the finned area is flattened against the coil, restricting airflow, the efficiency of the coil is reduced.

If desired, the wind/hail guards can be purchased for only one side of a unit in cases where an adjacent wall provides protection.

Louvers

Stamped metal louvers for the coil section (upper part of unit) or combined with lower louvers to cover the full height of the side of the unit, for field installation. They provide protection from hail and vandalism and add a decorative appearance to the unit.

Vibration Isolators

Spring vibration isolators are available for field installation under the unit base frame on sound sensitive applications. Consult the local McQuay sales office for seismic isolation.

Evaporator Insulation

Double evaporator thermal insulation is available and recommended for low fluid temperature applications.

Suction Butterfly Valve

An optional factory-mounted suction butterfly shutoff valve is available to assist in isolating the compressor for service.

IMM AGS-DP 53

Page 54

Start-up and Shutdown

McQuayService personnel or factory authorized service agency

must perform initial start-up in order to activate warranty.

Most relays and terminals in the unit control center are powered when S1

is closed and the control circuit disconnect is on. Therefore, do not close S1

until ready for start-up or the unit may start unintentionally.

Switches

There is a single unit on-off switch, S1, located in the control box for circuit #1. S1 will cause a rapid shutdown, without pumpdown, when opened. The circuit #1 box and all other control boxes also have a circuit switch, CS, which will put the circuit into pumpdown when put in the open position. The (1) on the switch is on and the (0) is off.

Seasonal Start-up

1. Double check that the optional compressor suction butterfly valve is open.

2. Check that the manual liquid-line shutoff valves at the outlet of the subcooler coils are

open.

3. Check the leaving chilled water temperature setpoint on the MicroTech II controller to be

sure it is set at the desired chilled water temperature.

4. Start the auxiliary equipment for the installation by turning on the time clock, and/or

remote on/off switch, and chilled water pump.

5. Check to see that circuit switches, CS, are in the off position. Put the unit switch, S1, in

the on position.

6. Under the "Control Mode" menu of the keypad, place the unit into the automatic cool

mode.

7. Start the system by placing the circuit #1 pumpdown switch CS in the on position.

8. Repeat step 7 for the balance of the circuits.

NOTICE

CAUTION

Temporary Shutdown

Move pumpdown switches CS to the off position. After the compressors have pumped down, turn off the chilled water pump.

CAUTION

Do not turn the unit off using the "S1" switch, without first moving PS1 and PS2

to the off position, unless it is an emergency, as this will prevent the unit from

going through a proper shutdown/pumpdown sequence.

54 IMM AGS-DP

Page 55

CAUTION

The unit has a one-time pumpdown operation. When the CS switches are in the Off position the unit will pump down once and not run again until the switches are moved to the On position. If the CS switches are in the On position and the load has been satisfied, the unit will go into one-time pumpdown and will remain off until the MicroTech II control senses a call for cooling and starts the circuit. Under no circumstance use the compressors for pumping down of the system with the liquid line valves closed.

CAUTION

It is important that the water flow to the unit is not interrupted before the compressors pump down to avoid freeze-up in the evaporator.

CAUTION

If all power is turned off to the unit, the compressor heaters will become inoperable. Once power is resumed to the unit, it is important that the compressor and oil separator heaters are energized a minimum of 12 hours before attempting to start the unit. Failure to do so could damage the compressors due to excessive accumulation of liquid in the compressor.

Start-up After Temporary Shutdown

1. Insure that the compressor heaters have been energized for at least 12 hours prior to

starting the unit.

2. Start the chilled water pump.

3. With system switch S1 in the "on" position, move the circuit pumpdown switches CS to

the on position.

4. Observe the unit operation until the system has stabilized.

Extended (Seasonal) Shutdown

1. Move the CS switches to the off position.

2. After the compressors have pumped down, turn off the chilled water pump.

3. Turn off all power to the unit and to the chilled water pump.

4. If fluid is left in the evaporator, confirm that the evaporator heaters are operational.

5. Move the emergency stop switch S1 to the off position.

6. Close the optional compressor suction valve (if so equipped) as well as the liquid line

shutoff valves.

7. Tag all opened compressor disconnect switches to warn against start-up before opening the

compressor suction valve and liquid line shutoff valves.

8. If glycol is not used in the system, drain all water from the unit evaporator and chilled

water piping if the unit is to be shutdown during winter and temperatures below -20°F can be expected. The evaporator is equipped with heaters to help protect it down to

-20°F. Chilled water piping must be protected with field-installed protection. Do not leave the vessels or piping open to the atmosphere over the shutdown period.

9. Do not apply power to the evaporator heaters if the system is drained of fluids as this can

cause the heaters to burn out.

IMM AGS-DP 55

Page 56

Start-up After Extended (Seasonal) Shutdown

1. With all electrical disconnects locked and tagged open, check all screw or lug-type

electrical connections to be sure they are tight for good electrical contact.

2. Check the voltage of the unit power supply and see that it is within the ±10% tolerance

that is allowed. Voltage unbalance between phases must be within ±2%.

3. See that all auxiliary control equipment is operative and that an adequate cooling load is

available for start-up.

4. Check all compressor flange connections for tightness to avoid refrigerant loss. Always

replace valve seal caps.

5. Make sure system switch S1 is in the off position and circuit pumpdown switches, CS, are

set to the off position. Place the main power and control disconnect switches to on. This will energize the crankcase heaters. Wait a minimum of 12 hours before starting up unit. Turn compressor circuit breakers to "off" position until ready to start unit.

6. Open the optional compressor suction butterfly as well as the liquid line shutoff valves.

7. Vent the air from the evaporator water side as well as from the system piping. Open all

water flow valves and start the chilled water pump. Check all piping for leaks and recheck for air in the system. Verify the correct flow rate by taking the pressure drop across the evaporator and checking the pressure drop curves in the installation manual, IMM AGS

8. The following table gives glycol concentrations required for freeze protection.

Table 31, Freeze Protection

Temperature

°°°°F (°°°°C)

20 (6.7)

10 (-12.2)

0 (-17.8)

-10 (-23.3)

-20 (-28.9)

-30 (-34.4)

-40 (-40.0)

-50 (-45.6)

-60 (-51.1)

Notes

2. Glycol of less than 25% concentration is not recommended because of the potential for bacterial growth and loss of heat transfer efficiency.

Ethylene Glycol Propylene Glycol Ethylene Glycol Propylene Glycol

For Freeze Protection For Burst Protection

16 18 11 12

25 29 17 20

33 36 22 24

39 42 26 28

44 46 30 30

48 50 30 33

52 54 30 35

56 57 30 35

60 60 30 35

Percent Volume Glycol Concentration Required

56 IMM AGS-DP

Page 57

System Maintenance

Oil Filter Housing

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 a full set of refrigerant pressure and temperature 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 data including evaporator pressure drop, 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 on an annual basis. The load should be maintained as closely as possible 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 of a potential bearing failure.

Compressor oil must be ICI RL68HB, McQuay Part Number 735030446 in a 1-gallon container or ICI RL68H, Part Number 735030444. This is synthetic polyolester oil with antiwear 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.

Figure 31, Compressor Oil Filter

On later units, the oil filter resides in the compressor housing as shown in Figure 31. Units without a suction service shutoff valve require pumping down the circuit in order to change the filter.

Replace this filter if the pressure drop exceeds 7 psi (48 kPa) as measured at Schrader fittings up and down stream from the filter.

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Electrical Terminals

DANGER

Electric shock hazard and risk of personal injury or death exists. 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 (standard material) 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

Under normal operation, the AGS-DP chiller electronic expansion valve is controlled by maintaining a calculated liquid line subcooling value. If the circuit is in subcooling control, the EXV control will vary the subcooling from 2 to 20 degrees F (1 to 11 degrees C) or greater, depending upon operating conditions. If the circuit is operating in subcool control, the liquid line sight glasses will not be an indication of charge amount. This is due to the chiller controlling the liquid subcooling at that location. Calibration of the liquid line pressure transducer and thermistor is required for proper control. An improper calibration may cause the liquid line sight glass to flash due to false subcooling calculation.

On startup and during other operating conditions such as high LWT and ICE mode, the expansion valve control will be in pressure control. If the circuit is in pressure control, a flashing liquid line sight glass may be an indication of low refrigerant. The chiller will not go to subcooling control if the subcooling is not equal to the calculated subcooling target for the operating conditions while in pressure control. A flashing sight glass, while in pressure control, may indicate excessive pressure drop in the liquid line, possibly due to a clogged filter-drier or a restriction elsewhere in the liquid line (see Table 32 on page 61 for maximum allowable pressure drops).

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NOTE

valve discharge, or cause low discharge superheat resulting in oil loss into the system.

An element inside the sight glass indicates the moisture condition corresponding to a given element color. The color code is printed on the edge of the sight glass. If the sight glass does not indicate a dry condition after about 12 hours of operation, the circuit should be pumped down and the filter-drier changed. An oil acid test is also recommended.

: Exceeding normal charge can result in abnormally high discharge pressure and relief

Evaporator Sight Glass

There are evaporator sight glasses on the side of the evaporator barrel, 1 for each circuit, located approximately half way up the vessel. The evaporator sight glasses are for reference use only. The electronic expansion valve control algorithms vary with operating conditions and will cause a higher or lower liquid level in the evaporator. You can use the sight glasses to give you some relative decision making information. If there is a considerable amount of oil out in the system, you may see oil floating on the evaporator liquid level, the refrigerant may have a yellowish tint or you may see an oil film on the sight glass as the liquid level rises and falls. Oil in the evaporator is often an indication of too much oil in the circuit, or the circuit is running low discharge superheat. Oil will also increase the evaporator approach value above normal. For refrigerant charge while in subcooling control, typically half of a sight glass full is normal. A full sight glass with low discharge superheat. is a good indication of too much refrigerant charge. An empty sight glass, with low pressure unload and trip events, is a good indication of insufficient refrigerant charge.

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 off 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.

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Preventative Maintenance Schedule

Visually inspect unit for loose or damaged components and

PREVENTATIVE MAINTENANCE SCHEDULE

OPERATION WEEKLY

General Complete unit log and review (Note 3) X

MONTHLY

(Note 1)

ANNUAL

(Note 2)

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

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.

2. Annual (or spring start-up) operations include all weekly and monthly operations.

3. Log readings can be taken daily for a higher level of unit observation.

4. Coil cleaning can be required more frequently in areas with a high level of airborne particles.

5. Be sure fan motors are electrically locked out.

6. Replace the filter if pressure drop exceeds Table 32 pressure levels.

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.

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Service

100%

7 (48.3)

CAUTION

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

2. Anyone servicing this equipment must comply with the requirements set forth by the EPA regarding refrigerant reclamation and venting.

DANGER

Disconnect all power before doing any service inside the unit to avoid bodily

injury or death. Multiple power sources can feed the unit.

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 32, Liquid Line Filter-Drier Pressure Drop

Percent Circuit

Loading (%)

75% 5 (34.5)

50% 3 (20.7)

25% 3 (20.7)

Maximum Recommended Pressure

Drop Across Filter Drier psig (kPa)

Change the filter-driers when the moisture indicating liquid line sight glass indicates excess moisture in the system, or an oil test indicates the presence of acid.

The following is the procedure for changing the filter-drier core:

The standard unit pumpdown is set to stop pumping down when 25 psig (172 kPa) suction pressure is reached. To fully pump down a circuit beyond 25 psig (172 kPa) for service purposes, a "Full Pumpdown" service mode can be activated on the circuit controller 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 pump down, the "FullPumpDwn" setpoint is automatically changed back to "No".

The procedure to perform a full service pumpdown for changing the filter-drier core is as follows:

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1. On the circuit controller, under the "SET EXV SPs (2)", change the "Service Pumpdown"

set point from "No" to "Yes".

2. If the circuit status is "Off:PumpDwnSw", move the circuit pumpdown switch from

"Pumpdown and Stop" to "Auto". Also clear the anticycle timers through the MicroTech keypad.

3. Move the circuit switch to the OFF position. The compressor will unload to minimum

slide position and the unit will pump down.

4. Upon completing the full pumpdown per step 3, the "Service Pumpdown" setpoint is

automatically changed back to "No" which reverts back to standard 25 psig (172 kPa) pumpdown stop pressure.

5. If the pumpdown does not go to 15 psig (103 kPa) on the first attempt, one more attempt

can be made by repeating the above steps. Do not repeat "Service Pumpdown" more than once to avoid excessive screw temperature rise under this abnormal condition.

6. The circuit is now in the deepest pumpdown that can be achieved by the use of the

compressor. 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.

7. Loosen the cover bolts, remove the cap and replace the filters.

8. Evacuate and open valves.

Evacuate the lines through the liquid line manual shutoff valve(s) to remove noncondensables that can 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 liquid line pressure.) All AGS chillers are factory set at 20 degrees F subcooling at 100% slide position and approximately 5 degrees F subcooling at minimum slide position. The controller will offset these settings based on discharge superheat.

When the control panel is first powered, the microprocessor will automatically step the valve to the fully closed (shut) position. The valve will take approximately 30 seconds 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. There are 6386 steps between closed and full open. There is also a sight glass on the EXV to observe valve movement.

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Evaporator

The evaporator is a flooded, shell-and-tube type with water flowing through the tubes and refrigerant 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.

Charging Refrigerant

Why does the AGS flooded evaporator use subcooling control?

Subcool control maintains proper evaporator level for efficiency and is the most stable value with which to control a flooded evaporator chiller. Discharge superheat control is affected by many variables such as motor heat, refrigerant flow, number of fans operating, amount of refrigerant in the oil, etc. Additionally, the chiller cannot be controlled by the traditional suction superheat control due to the saturated refrigerant entering the suction cooled motor. Often this is a heavily saturated vapor that helps cool the motor and is not suitable for flow control purposes.

Do not use the evaporator sight glasses to charge the unit.

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.

Use these sight glasses for reference only. The expansion valve control varies with operating conditions and may cause a higher or lower level based on control decisions. The sight glasses can give you some relative information for decision making. If there is a considerable amount of oil in the system, you may see oil floating on the evaporator liquid level and/or oil smearing on the sight glass as the liquid level rises and falls.

Discharge superheat

The most important value to monitor while setting the charge on an AGS flooded evaporator chiller is the discharge superheat (DSH), and especially at full load. Between 20 and 22 degrees F (11 and 12 degrees C) DSH, the compressor will hold its slide target and will not load up. If the DSH drops below 20 degrees F (11 degrees C), it will unload. Excessive refrigerant charge, excessive oil, a large amount of oil in circulation and a leaking or over feeding evaporator solenoid valve will all cause low discharge superheat.

Approach temperatures:

Oil in the system will affect the condenser and evaporator approach temperatures. The design approach (saturated discharge temperature minus ambient air temperature) on the condenser at full load is 30 to 35 degrees F (16 to 19 degrees C). The evaporator approach should be 3 to 10 degrees F (1.6 to 5.5 degrees C), depending on conditions and percent of glycol, if used.

Oil in evaporator:

Oil in the evaporator will float on the liquid refrigerant and get pulled out with suction gas, carrying liquid refrigerant with it and reducing the discharge superheat. The goal is to keep the discharge superheat above 22 degrees F (12 degrees C), and ideally at 35 degrees F (19 degrees C), while trying to get the compressor loaded up. The higher the refrigerant flow, the quicker the oil will be recovered.

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Evaporator Oil Return Line:

In some applications, the evaporator oil return line can cause low discharge superheat and some oil loss into the system. It may be necessary to reduce the flow through the evaporator oil return line by incrementally closing down the ball valve. This can help maintain oil in the oil separator and higher DSH, if it is overfeeding and dropping the DSH too much. The minimum superheat the control will allow is 35 degrees F (19 degrees C) to help ensure that the DSH does not cause issues with limiting the compressor with low discharge superheat or cause oil loss. Most of the oil recovery is done through carry-over through the suction line. The evaporator oil return line is used more effectively for discharge temperature control, and a by-product is that a small percentage of oil will be recovered.

Basic Charging Information:

Determine the following:

1. What control mode is the EXV in?

2. What is the circuit status?

3. What is the compressor slide position?

4. What is the DSH at 100% load?

5. What is the suction pressure at 100% load?

6. Is the evaporator oil return line (EORL) solenoid on?

7. What is the outdoor air temperature (OAT) and how many fans are on?

8. How does the discharge superheat compare to Figure 32 on page 65.

Details to Consider:

1. The unit must be in Subcool control before being able to fine-tune the charge. If the unit

has insufficient subcooling, it will not convert to Subcool control. At 100% load there must be a minimum of 20 degrees F (11 degrees C) of liquid line subcooling before the circuit will allow subcooling control, therefore you may need to add charge to get to this point in the case of severely undercharged units.

2. Verify that the circuit is not limited on a capacity limit or inhibit event. Limitation of the

chiller on low DSH, high lift, or low evaporator pressure may be clues to help determine a refrigerant or oil charging issue.

3. It is hard to determine proper charge amounts while at part loads. For best charging results

the slide target should be at 100%. If there is a significant over or under charge you may have to make adjustments to get the compressor to full load. It may be necessary to revisit a unit when it would be at full load, to check and fine tune the charge. Sequentially shutting off all but one circuit may provide a full load on the remaining circuit.

4. In order to maintain oil integrity, the discharge superheat needs to be greater than

20 degrees F (11 degrees C). The compressor will unload below this value. Between 20 and 22 degrees F (11 and 12 degrees C) DSH, the compressor will not load up and will be in a low discharge superheat inhibit event. At high refrigerant flows, more liquid carryover will occur and the DSH will be lower. This means the compressor will have to be at l00% to set up the refrigerant charge correctly.

5. Typically the suction pressure will be near the Low PressureHold setpoint while at full

load. You may need to sacrifice some suction pressure by removing some refrigerant to get the discharge superheat up.

6. See above note on evaporator oil return line.

7. The lower the OAT, and the lower the saturated condensing temperature is, the more

refrigerant flow there will be, increasing the possibility of more liquid carry over from the evaporator.

8. Use Figure 32, Discharge Superheat vs. Pressure Lift chart to verify charge. For a given

lift, superheat above the curve indicates low charge, below indicates high charge.

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Summary:

At 100% slide position, in Subcool control, the DSH should be as high as possible with suction pressure at a operable value based on water/glycol mixture. At 100% load, in Subcool control, the DSH and suction pressure need to be balanced.

Example: Running circuit 1 at 100% slide target, with water only in the loop, set the low evaporator pressure unload to 28psi (32°sat.) and the low evaporator pressure hold to 30psi. Run the suction pressure at approximately 32psi at full load. This should allow room for 2530° DSH. As a rule of thumb, as outdoor air temperature drops, it becomes more difficult to maintain minimum DSH with a given charge amount, due to higher refrigerant flows.

Figure 32, Discharge Superheat vs. Pressure Lift at Full Circuit Load For Various Chilled Water Temperatures

Discharge Superheat vs. Pressure Lift

Discharge Superheat, (F = C/0.55))

50.0 70.0 90.0 110.0 130.0 150.0 170.0 190.0 210.0 230.0 250.0

Pressure Lift, PSI (Discharge Pressure - Suction Pressure) (PSI = kPa/6.9)

34/44 44/54

54/64 64/74

Discharge superheat is directly related to the amount of liquid carried from the evaporator and amount of motor heat rejected into the refrigerant.

Higher pressure lifts will result in higher discharge superheats.

More liquid carry over will result in lower discharge superheats, less liquid carry over will result in higher discharge superheats.

More liquid carry over will occur when:

1. The refrigerant circuit is overcharged.

2. Excessive oil is in the evaporator.

3. Mass flow rate of compressor is increased.

4. Oil return solenoid is energized or leaking (more liquid injection than oil return).

5. Evaporator tubes fouled or are plugged.

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Charging Oil

Upper

Sight

The oil separator is equipped with two sight glasses that are used to indicate oil quantity. Oil charge determination must be done at, or near, full load. It may be normal to see the oil below the bottom sight glass while running at part load conditions due to oil laying in the compressor casting at low refrigerant flows. However, oil trips at part load indicate low oil level. While operating at full load with a proper oil charge in a circuit, the bottom sight glass should show full with some movement of bubbles, the top sight glass should appear full but there should be a violent show of bubbles.

If the separator has too much oil while at full load, both sight glasses will be clear (level above the upper sight glass) and may exhibit some bubbling in the top sight glass. If the circuit has too much oil, the circuit may be limited on low discharge superheat, low suction pressure, high evaporator approach, and/or high condenser approach due to an excessive amount of oil out in the system. If the oil separator is low on oil there will be visible levels in one or both sight glasses (this tends to be a collection of oil in sight glasses as the oil travels down the sides of the vessel during the separation process). Low oil trips in the Event (1 time trip) and Alarm buffers (2 trips in 60 minutes) may indicate low oil charge, or operation with low discharge superheat due to over charging oil or over charging refrigerant.

Glass

Lower

Glass

If it is determined that oil should be added to a circuit, the oil should be pumped in at the backseat port on the service valve either on the top of the oil separator barrel or at the service valve on the oil line exiting the oil separator. It may be necessary to shut the circuit off to reduce the pressure in the oil separator to make it easier to pump oil in to the separator.

Compressor oil must be ICI RL68HP, McQuay Part Number 735030442 in a 1 gallon container, or ICI RL68H, Part Number 735030444 in a 1 gallon container.

NOTE

Unit operation with low discharge superheat due to excessive oil or excessive refrigerant charge can cause poor oil separation in the oil separator and the subsequent coating of heat transfer surfaces, which will reduce unit performance and limit unit operating range.

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 - This sensor is located on the evaporator water outlet connection and is used for capacity control of the chiller and low water temperature freeze protection.

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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.

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.

High condenser pressure control

The MicroTech II is equipped with a transducer in the high pressure side of each refrigerant circuit. This pressure value is converted to saturated condenser temperature for condenser fan staging and for limiting compressor capacity to keep the circuit within safe operating conditions. For a detailed description of condenser fan logic, see the unit operating manual, AGS OM-4 or later revision.

The high condenser pressure control operates according to a maximum allowable operating condenser pressure curve which is based on the saturated evaporator temperature(see the AGS OM for details). The circuit controller will display the calculated max saturated condenser temperature “MaxCondSatT” on the View Refrigerant (6) screen. At 5 degrees F (2.7 degrees C) saturated condenser temperature below the MaxCondSatT value, the chiller will be in a hold condition and will not allow the compressor to load up. At 3 degrees F (1.6 degrees C) below the MaxCondSatT the compressor will begin to unload to reduce the condenser pressure.

If the saturated condenser temperature exceeds the MaxCondSatT, it will shut down the compressor with no pumpdown and go into an OFF: Alarm state. At the time of the alarm the circuit data will be recorded in the Alarm buffer.

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.

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Although the high pressure 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 MicroTech II controller.

The compressors also have a solid state Guardistor circuit that provides motor over temperature protection. The Guardistor circuit has automatic reset and gives a Starter Fault (F75) that is cleared through the starter display and must also be reset through the MicroTech II control.

Head pressure control

The compressor must be running in order to stage its fans on.

Condenser pressure trim control is accomplished using a variable frequency drive (VFD) on the first two fans that turn on. This VFD control uses a proportional integral function to drive the saturated condenser temperature to a target value by changing the fan speed. The target value is normally the same as the saturated condenser temperature target setpoint.

The VFD will start the fans when the saturated condenser temperature goes above the temperature target. Once the VFD fans are on, they will not shut off until the saturated condenser temperature is less than the minimum saturated temperature plus 5 degrees F (2.7 degrees C).

Stage up Compensation

In order to create a smoother transition when another fan is staged on, the VFD compensates by slowing down initially. This is accomplished by adding the new fan stage up deadband to the VFD target. The higher target causes the VFD logic to decrease fan speed. Then, every 10 seconds, 0.5 degrees F (0.25 degrees C) is subtracted from the VFD target until it is equal to the saturated condenser temperature target setpoint. This will allow the VFD to slowly bring the saturated condenser temperature back down.

Condenser Target

This logic is only used with VFD = Yes in the controller set point screen. Most applications will benefit from using the factory default values. The AGSU30101F software version has two setpoints used to set a minimum(Min) and a maximum(Max) range for the saturated condenser target. This can be found on the circuit controller at Set Fan Sps(5). This allows for a floating condenser target based on saturated evaporator temperature. The default values of the minimum and maximum are both set to 110°F (43.3°C) saturated condensing temperature. This will normally provide the most stable unit operation. Adjusting the Min or Max setpoint at each circuit controller will vary the condenser target along a line determined by two points which are; 1) 85°F (29.4C) saturated condenser and 20°F (6.7°C) saturated suction, and 2) 110°F (43.3°C) saturated condenser and 50°F (10.0°C) saturated suction. Note that the chiller system is designed for specific refrigerant flow capacities, which may be exceeded by decreasing the condenser target. The result will be at lower ambient temperatures, the chiller may attain the maximum unit tonnage capacities while compressor loading will be limited on low discharge superheat.

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Fan Stages with VFD Option

The VFD option must always be enabled. The first two fans are controlled by the fan VFD. This leaves 6 stages of fan control available with 8 fan circuits, and 4 stages available on 6 fan circuits. Although fans 5/6 and 7/8 are controlled by one contactor each, more stages are created by using virtual stages. See the table below:

Table 33, Staging with VFD

Stage Fans On

1 1,2,3 2 1,2,3,4 3 1,2,4,5,6 4 1,2,3,4,5,6 5 1,2,3,5,6,7,8 6 1,2,3,4,5,6,7,8

Staging Up

There are four stage-up deadbands that apply to the fan control stages. Stages one through three use their respective deadbands. Stage four to eight share the fourth stage-up deadband.

When the saturated condenser temperature is above the Target + the active deadband, a Stage Up error is accumulated.

The saturated condenser temperature must not be falling for a Stage Up accumulation to occur.

Stage Up Error Step = Saturated Condenser Refrigerant temperature – (Target + Stage

Up deadband)

The Stage Up Error Step is added to Stage Up Accumulator once every Stage Up Error Delay seconds. When Stage Up Error Accumulator is greater than the Stage Up Error Setpoint, another stage is added.

When a stage up occurs, or the saturated condenser temperature falls back within the Stage Up deadband, the Stage Up Accumulator is reset to zero.

Forced Fan Stage At Start

Fans may be started simultaneously with the compressor based on outdoor ambient temperature. When the compressor starts, a fan stage is forced, based on the following table.

Table 34, Forced Staging

Outside Air

Temperature

> 75 oF Forced FanTrol 1 Set Point > 90 oF Forced FanTrol 2 Set Point

> 105 oF Forced FanTrol 3 Set Point

Fan Stage At Start

Staging Down

There are four Stage Down deadbands. Stages one through three use their respective deadbands. Stages four to eight share the fourth Stage Down deadband.

When the condenser saturated refrigerant temperature is below the Target – the active deadband, a Stage Down error is accumulated.

Stage Down Error Step = (Target – Stage Down deadband) − Saturated Condenser Refrigerant temperature

The Stage Down Error Step is added to Stage Down Accumulator once every Stage Down Error Delay seconds. When the Stage Down Error Accumulator is greater than the Stage Down Error Setpoint, another stage of condenser fans turned off.

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When a stage down occurs, or the saturated temperature rises back within the Stage Down deadband, the Stage Down Error Accumulator is reset to zero. The accumulator is also held at zero after startup until either the outside ambient temperature is less than, or equal to 75°F (23.9°C), or the saturated condenser temperature is greater than the condenser target, less the active stage down deadband.

The head pressure control will provide proper operating refrigerant discharge pressures at the ambient temperatures listed for it, 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 motor loss due to power failure conditions, phase loss, and phase reversal. Whenever any of these conditions occur, a Normally Closed 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 control.

When proper power is restored, contacts close and the fault must be cleared through both the starter 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.

1. Check the voltages between L1-L2, L1-L3 and L2-L3. These voltages should be within

2% of each other and within +10% of the rated three-phase line-to-line voltage.

2. If these voltages are extremely low or widely unbalanced, check the power system to

determine the cause of the problem.

3. If the voltages are within range, use a phase tester to verify that phases are in A, B, C

sequence 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 20minute start-to-start cycle. Both are adjustable through the MicroTech II control.

There is also a timer with a 5 minute default for minimum time between any two circuit starts.

70 IMM AGS-DP

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Controls, Settings and Functions

Table 35, 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 in the oil separator OLS NC with oil present N/A Oil Separator

Differential Pressure

Switch

Fan VFD Controls discharge pressure FAN VFD In controller code N/A Power Panel

Control Panel Heater Maintain controller operation

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 compressor 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 refrigerant flow and

control subcooling.

To provide motor temperature protection at

about 220oF (104oC).

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 circuit 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 and controls discharge superheat

Pressure difference from compressor

discharge to oil entering compressor.

To protect from high voltage spikes and

surges.

Provide heat to maintain viscosity at low

temperatures

Protects compressor from running with

insufficient oil pressure

HTR1-COMPR

EXV-DRIVER N/A N/A Control Panel

EXV In Controller Code N/A

K2 Fault

MHPR

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

Refer to

OM AGS

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

Oil line from evap

to compressor

Condenser Coil

Support

IMM AGS-DP 71

Page 72

Troubleshooting Chart

Table 36, 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.

72 IMM AGS-DP

Page 73

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 refrigerant 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 electrical operation:

8. Satisfactory electrical operation?

9. MicroTech II hardware operation satisfactory?

10.

MicroTech II software operation satisfactory?

11. Unit status %

Data from MicroTech II Controller:

12. Circuit status 1 % Capacity Circuit status 2 % Capacity Circuit status 3 % Capacity

13. Water temperature – Evaporator: Entering/Leaving /

Circuit #1 Circuit #2 Circuit #3

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 storage 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

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____

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-DP 73

Page 74

This document contains the most current product information as of this printing. For the most up-todate product information, please go to www.mcquay.com.

 2006 McQuay International • www.mcquay.com • (800) 432-1342 IMM AGS DP (11/06)

McQuay AGS 251DP Installation Manual

Specifications and Main Features

Frequently Asked Questions

User Manual