McQuay AGS 140DH Installation Manual

Installation and Maintenance Manual

IMM AGSD3

Air-Cooled Screw Compressor Chiller

AGS 140DS/H - AGS 210DS/H, Packaged AGS 140DM/F – AGS 210DM/F, Remote Evaporator

60 Hertz, R-134a

Group: Chiller Part Number:: 331376001 Date: FEB 2008 Supersedes: DEC 2007

Table of Contents

Introduction..............................................3

General Description.............................3

Nomenclature ......................................3

Inspection ............................................3

Field Wiring Diagram.............................38

Remote Evaporator ...............................44

Piping Layout.....................................44

Field Wiring (Remote Evaporator).....45

Installation and Start-up ..........................4

Handling...............................................4

Location ...............................................5

Service Access ....................................5

Clearance Requirements.....................6

Restricted Airflow.................................7

Vibration Isolator Location.................13

Chilled Water Pump...........................16

Kit Components .................................45

Refrigerant Line Sizing ......................46

Remote Evaporator Dimensions & Weights

...............................................................

Physical Data, Standard Efficiency....53

Vibration Isolators..............................55

Solid State Starters................................57

Water Piping......................................16

System Water Volume.......................17

Variable Speed Pumping...................17

Evaporator Freeze Protection............18

Operating Limits:................................19

Component Location .............................64

Major Component Location................64

Power Panel.......................................66

Control Panel.....................................67

Flow Switch........................................19

Refrigerant Charge............................20

Glycol Solutions.................................20

Water Flow and Pressure Drop.............21

Physical Data ........................................23

Dimensions & Weights..........................25

Lifting, Mounting, and Total Weights..28

Electrical Data.......................................30

Field Wiring........................................30

Standard Efficiency............................31

High Efficiency...................................35

BAS Interface.....................................37

System Maintenance.............................68

Preventative Maintenance Schedule.70

Warranty Statement...............................71

Service...................................................71

Liquid Line Filter-Driers......................71

Compressor Slide Valves...................72

Electronic Expansion Valve (EXV).....72

Evaporator .........................................72

Charging Refrigerant .........................72

St andard Controls..............................73

Controls, Settings and Functions.......76

Troubleshooting Chart.......................77

Periodic Maintenance Log.................78

Unit controllers are LONMARK certified

with an optional

communications module

LONWORKS

Manufactured in an ISO Certified Facility

in design and construction at anytime without notice. ™® The following are trademarks or registered trademarks of their respective companies: BACnet from ASHRAE;

LONMARK, LonTalk, LONWORKS, and the LONMARK logo are managed, granted and used by LONMARK International under a license gr anted by

Echelon Corporation; Compliant Scroll from Copeland Corporation; E l ectroFin from AST ElectroFin Inc.; Modbus from Schneider Electric; FanTrol, MicroTech II, Open Choices, and SpeedTrol from McQuay International

2 IMM AGSD3

Introduction

General Description

McQuay AGS air-cooled water chillers are complete, self-contained automatic refrigerating units that include the latest in engineered components arranged to provide a compact and efficient unit. Each unit is completely assembled, (except remote evaporator applications) factory wired, evacuated, charged, tested and comes complete and ready for installation. Each unit consists of two air-cooled condenser sections with integral subcooler sections, two semi-hermetic, singlescrew compressors with solid-state starters, a two-circuit shell-and-tube direct expansion 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, solenoid valves and electronic expansion valves. A discharge shutoff valve is included and a compressor suction shutoff valve is optional. Other features include compressor heaters, evaporator heaters for freeze protection, automatic one-time pumpdown of each refrigerant circuit upon circuit shutdown, and an advanced fully integrated microprocessor control system.

AGS units are available as standard efficiency (model DS) and high efficiency units (DE). The high efficiency units have certain larger components to improve efficiency.

The units are optionally available with the evaporator shipped separately for remote mounting indoors.

Information on the operation of the unit MicroTech II controller is in the OM AGSD3 manual.

Nomenclature

A G S - XXX D S

Rotary Screw Compressor

Air-Cooled

Global

Nominal Tons

S=Standard Efficiency, Packaged Unit M=Standard Efficiency, Remote Evaporator E= High Efficiency, Packaged Unit F= High Efficiency, Remote Evaporator.

Design Vi ntage

Inspection

When the equipment is received, carefully check all items against the bill of lading to check for a complete shipment. Check all units for damage upon arrival. All shipping damage must be reported to the carrier and a claim must be filed 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 on page

23.

IMM AGSD3 3

Installation and Start-up

Sharp edges and coil surfaces are a potential injury hazard. Avoid contact with them.

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.

Start-up by McQuayService is included on all units sold for installation within the USA and Canada and must be performed by them to initiate the standard limited product warranty. Two-week prior notification of start-up is required. The contractor should obtain a copy of the Start-up Scheduled Request Form from the sales representative or from the nearest office of McQuayService.

Escaping refrigerant can displace air and cause suffocation. Immediately evacuate and ventilate the equipment area. If the unit is damaged, follow Environmental Protection Agency (EPA) requirements. Do not expose sparks, arcing equipment, open flame or other ignition source to the refrigerant.

Handling

Avoid rough handling shock due to impact or dropping the unit. Do not push or pull the unit.

WARNING

Never allow any part of the unit to fall during unloading or moving, as this can result in serious damage.

To lift the unit, lifting tabs with 2½" (64 mm) diameter holes are provided on the base of the unit. All lifting holes must be used when lifting the unit. Spreader bars and cables should be arranged to prevent damage to the condenser coils or unit cabinet (see

DANGER

Improper lifting or moving unit can result in property damage, severe personal injury or death. Follow rigging and moving instructions carefully

Figure 1).

Figure 1, Required Lifting Method

NOTES:

1. All rigging points on a unit must be used. See location and weights at lifting points beginning on page 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 condenser sections, and fans can vary from this diagram.

23 for a specific size

4 IMM AGSD3

Location

Locate the unit carefully to provide proper airflow to the condenser. (See Figure 2on page 6 for required clearances).

Due to the shape of the condenser coils on the AGS chillers, it is recommended that the unit be oriented so that prevailing winds blow parallel to the unit length, thus minimizing the wind effect on condensing pressure and performance. If low ambient temperature operation is expected, optional louvers should be installed if the unit has no protection against prevailing winds.

Using less clearance than shown in condenser and could have a significant detrimental effect on unit performance.

See Restricted Airflow beginning on page 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

Figure 2 can cause discharge air recirculation to the

7 for further information.

Service Access

Compressors, filter-driers, and manual liquid line shutoff valves are accessible on each side or end of the unit. The evaporator heater is located on the barrel.

The control panels are located on the end of the chiller. The left-hand control box contains the unit and circuit microprocessors as well as transformers, fuses and terminal. The right-hand panel contains a circuit breaker and solid state starter for each compressor plus fuses, fan VFD (optional) and fan contactors. A minimum of four feet of clearance is required in front of the panels.

The side clearance required for airflow provides sufficient service clearance. On all AGS units, the condenser fans and motors can be removed from the top of the unit. The

complete fan/motor assembly can be removed for service. The fan blade must be removed for access to wiring terminals at the top of the motor.

WARNING

Disconnect, lockout and tag all power to the unit before 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.

IMM AGSD3 5

Clearance Requirements

Figure 2, Clearance Requirements

5ft (1.5m)if open fence or 50% open wall 6ft (1.8m)

4ft (1.2m) For electric panel access

if solid wall (see note 3 for pit)

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

5ft (1.5m)if open fence or 50% open wall 6ft (1.8m)

if solid wall (see note 3 for pit)

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

No obstructions allowed above unit at any height

Air Flow

3ft (1m) for service

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 evaporator can be removed from the side of the unit and may require the temporary removal of a

coil section support post. See dimension drawings beginning on page

9. If the airflow clearances cannot be met, see the following pages on Restricted Airflow.

25 for details.

6 IMM AGSD3

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 shape of the condenser section allows inlet air for these coils to come in from both sides

and the bottom. All the coils on one side 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 will adjust the unit operation to remain online until a less severe condition is reached.

IMM AGSD3 7

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

The existence of a screening wall, or the wall of a building, in close proximity to an air-cooled chiller is common in both rooftop and ground level applications. Hot air recirculation on the coils adjoining the wall will increase compressor discharge pressure, decreasing capacity and increasing power consumption.

When close to a wall, it is desirable to place chillers on the north or east side of them. It is also desirable to have prevailing winds blowing parallel to the unit’s long axis. The worst case is to have wind blowing hot discharge air into the wall.

Figure 4, Unit Adjacent to Wall

Figure 5, Adjustment Factors

5 ft.

(1.5m)

6 ft.

(1.8m)

5 ft.

(1.5m)

6 ft.

(1.8m)

8 IMM AGSD3

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), or 8 feet (2.5 meters), depending on size, it is necessary to adjust the performance of each unit. Circuits adjoining each other are affected. NOTE: This case applies only to two units side by side. See Case 3 for three or more parallel units. 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.

Figure 6, Two Units Side by Side

Figure 7, Adjustment Factor

3.0

2.0

1.0

(2.7)

(3.0)

(3.3)

(3.6)

6.0

4.0

2.0

(2.7)

(3.0)

(3.3)

(3.6)

IMM AGSD3 9

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 AGSD3

Case 4, 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 5, Pit Installation.

The distance from the ends of the unit to the end walls must be sufficient for service, opening control panel doors, and pulling evaporator tubes, as applicable.

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 AGSD3 11

Case 5, Pit/Solid Wall Installation

Pit installations can cause operating problems and great care must 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 the McQuay sales office 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 AGSD3

Vibration Isolator Location

Spring-Flex Locations

NOTE: See dimension drawings for mounting point location.

Table 1, Standard Efficiency with Aluminum Fin Condensers

Unit

Size

140DS to

170DS

190DS to

210DS

M1 M2 M3 M4 M5 M6

CP-2 CP-2 CP-2 CP-2 CP-2 CP-2

White White White White Gray Gray

CP-2 CP-2 CP-2 CP-2 CP-2 CP-2

White White White White White White

Table 2, High Efficiency with Aluminum Fin Condensers

Unit Size

149DE to

190DE

M1 M2 M3 M4 M5 M6

CP-2 CP-2 CP-2 CP-2 CP-2 CP-2

White White White White Gray Gray

Table 3, Standard Efficiency with Copper Fin Condensers

Unit Size

140DS to

210DS

CP-4 CP-4 CP-4 CP-4 CP-4 CP-4

Orange Orange Orange Orange Orange Orange

Mounting Location

Mounting Locations

M3 M4 M5 M6

Spring Kit

Number

330904106

330904126

Spring Kit

Number

330904126

Spring Kit

Number

330904127

Table 4, High Efficiency with Copper Fin Condensers

Unit Size

140DE to

210DE

M1 M2 M3 M4 M5 M6

CP-4 CP-4 CP-4 CP-4 CP-4 CP-4

Orange Orange Orange Orange Orange Orange

Mounting Locations

Spring Kit

Number

330904127

IMM AGSD3 13

R-I-S Locations

NOTE: See dimension drawings for mounting point location.

Table 5, Standard Efficiency with Aluminum Fin Condensers

Unit Size

140DS to

210DS

1 2 3 4 5

RP-4 330904133 RP-4 RP-4 RP-4

Green Green Green Green Red

Table 6, High Efficiency with Aluminum Fin Condensers

Unit Size

140DE to

190DE

RP-4 RP-4 RP-4 RP-4 RP-4 RP-4

Green Green Green Green Red Red

Table 7, Standard Efficiency with Copper Fin Condensers

Unit Size

170DS to

210DS

1 2 3 4 5 6

RP-4 RP-4 RP-4 RP-4 RP-4 RP-4

Green Green Green Green Green Green

R-I-S Mountings

3 4 5 6

R-I-S Mountings

RP-4

Red

R-I-S Kit Number

330904133

R-I-S Kit Number

330904133

R-I-S Kit Number

330904125

Table 8, High Efficiency with Copper Fin Condensers

Unit Size

170DE to

190DE

1 2 3 4 5 6

RP-4 RP-4 RP-4 RP-4 RP-4 RP-4

Green Green Green Green Green Green

R-I-S Mountings

R-I-S Kit

Number

330904125

14 IMM AGSD3

Figure 14,CP-4 Spring Flex Mounting Figure 15, RP-4 Rubber-in-Shear

Mounting

IMM AGSD3 15

Chilled Water Pump

It is recommended that the chilled water pumps' starters 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. Wiring connection points are shown in Figure 22 on page 38.

Water Piping

Due to the variety of piping practices, follow the recommendations of local authorities. They can supply the installer with the proper building and safety codes required for a proper installation.

Design the piping with a minimum number of bends and changes in elevation to keep system cost down and performance up. It should contain:

1. Vibration eliminators to reduce vibration and noise transmission to the building.

2. Shutoff valves to isolate the unit from the piping system during unit servicing.

3. Manual or automatic air vent valves at the high points of the system and drains at the low parts

in the system. The evaporator should not be the highest point in the piping system.

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

valve).

5. Water temperature and pressure indicators located at the evaporator inlet and outlet to aid in

unit servicing. Any connections should be made prior to filling the system with water.

6. A strainer to remove foreign matter from the water before it enters the pump. Place the strainer

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. Any water piping to the unit must be protected to prevent freeze-up if below freezing

temperatures are expected.

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 burnout.

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

system thoroughly prior to unit installation. Perform regular chilled water analysis and chemical water treatment immediately at equipment start-up.

16 IMM AGSD3

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, a different freezestat pressure value is

usually required. 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 with the 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

All chilled water systems need adequate time to recognize a load change, respond to that load change and stabilize, without undesirable short cycling of the compressors or loss of control. In air conditioning systems, the potential for short cycling usually exists when the building load falls below the minimum chiller plant capacity or on close-coupled systems with very small water volumes.

Some of the things the designer should consider when looking at water volume are the minimum cooling load, the minimum chiller plant capacity during the low load period and the desired cycle time for the compressors.

Assuming that there are no sudden load changes and that the chiller plant has reasonable turndown, a rule of thumb of “gallons of water volume equal to two to three times the chilled water gpm flow rate” is often used.

A properly designed storage tank should be added if the system components do not provide sufficient water volume.

Variable Speed Pumping

Variable water flow involves reducing the water flow through the evaporator as the load decreases. 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 occur. If the flow exceeds the maximum rate, excessive pressure drop and tube erosion can occur.

22. If flow drops below the minimum allowable, large reductions in heat transfer can

IMM AGSD3 17

Evaporator Freeze Protection

AGS chillers are equipped with thermostatically controlled evaporator heaters that help protect against freeze-up down to -20°F (-28°C).

NOTE: The heaters come from the factory connected to the control power circuit. The control power can be rewired in the field to a separate 115V supply (do not wire directly to the heater). See the field wiring diagram on page accidental deactivation of the heater during freezing temperatures. Exposed chilled water piping also requires protection.

For additional protection, at least one of the following procedures should be used during periods of sub-freezing temperatures:

1. Adding of a concentration of a glycol anti-freeze with a freeze point 10 degrees F 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. Use only glycols specifically designated for use in building cooling systems.

2. Draining the water from outdoor equipment and piping and blowing the chiller tubes dry

from the chiller. Do not

38. If this is done, mark the disconnect switch clearly to avoid

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.

Table 9, 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:

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 15°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 loss of heat transfer efficiency.

Ethylene Glycol Propylene Glycol Ethylene Glycol Propylene Glycol

For Freeze Protection For Burst Protection

Percent Volume Glycol Concentration Required

18 IMM AGSD3

Operating Limits:

Maximum standby ambient temperature, 130°F (55°C) Maximum operating ambient temperature, 125°F (51.7°C) 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 60°F (4°C to 16°C) Leaving chilled fluid range (with anti-freeze), 20°F to 60°F (-7°C to 16°C). Unloading is not

permitted with fluid leaving temperatures below 30°F (-1°C). Operating Delta-T range, 6 degrees F to 16 degrees F (10.8 C to 28.8 C) Maximum operating inlet fluid temperature, 76°F (24°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 any of these limits.

Two series of units are available with the AGS-D chillers.

Standard Efficiency,

model number following the “D” vintage designation (i.e. AGS 200DS

designated by a "S" (or “M” with remote evaporator) as the last digit in the

or AGS 200DM) are

designed to meet ASHRAE 90.1 efficiency standard. They provide the lowest dollar per ton price.

High Efficiency,

model number (i.e. AGS 200DE

designated by an "E" (or “F” with remote evaporator) as the last digit in the

or AGS 200DF) are designed for high efficiency operation. The high efficiency models have larger components, and/or more fans than the comparable standard efficiency models. This results in improved efficiency and the ability to operate at higher ambient air temperatures.

Flow Switch

A flow switch must be included in the chilled water system to prove that there is

Figure 16, Flow Switch

Flow direction

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

1" (25mm) NPT flow

switch connection

Tee

evaporator freeze-up. A solid state flow switch that is factory-

mounted and wired in the chiller leaving water nozzle is available as an option.

A flow switch for field mounting and

1 1/4" (32mm) pipe

dia. min. before

switch

1 1/4" (32mm)

pipe dia. min.

wiring in the leaving chilled water is also available as an option 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 should be as shown in

Figure 17.

Table 10. Installation

Electrical connections in the unit control center should be made at terminals 60 and 67 from switch terminals Y and R. The normally open contacts of the flow switch should be wired between these

IMM AGSD3 19

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 10, Flow Switch Flow Rates

(NOTE)

Min.

Adjst.

Max.

Adjst.

Flow

Flow Lpm 11.4 22.9 35.9 38.6 Flow

Flow Lpm 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 3-inch paddle

3. Flow rates for a 6-inch paddle.

inch 4 5 6 8 Pipe Size

mm 102 (4) 127 (4) 153 (4) 204 (5)

gpm 65.0 125.0 190.0 205.0 Lpm 14.8 28.4 43.2 46.6 gpm 50.0 101.0 158.0 170.0

gpm 128.0 245.0 375.0 415.0 Lpm 29.1 55.6 85.2 94.3 gpm 122.0 235.0 360.0 400.0

Figure 17, Typical Field Water Piping

Suction

Vent

Out

Liquid

Drain

Notes:

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

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

Vibration

Eliminator

Valved

Pressure

Gauge

Flow

Switch

Vibration

Eliminator

Balancing

Valve

Water

Strainer

Gate

Valve

Flow

Gate

Valve

Protect All Field Piping

Flow

gainst Freezing

Refrigerant Charge

All packaged 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 packaged units, and page

53 for remote evaporator models. Model AGS-CM/CB with remote

23 for

evaporators are shipped with a full unit charge. Refrigerant must be added in the field for the evaporator and for the refrigerant lines.

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 procedure below does not specify the type of glycol. Use the derate factors found in Table 11 for corrections when using propylene glycol and those in Table 12 for ethylene glycol.

1. Capacity - Cooling capacity is reduced from that with plain water. To find the reduced value,

multiply the chiller’s water system tonnage by the capacity correction factor to find the chiller’s capacity when using glycol.

2. Flow - To determine flow (or Delta-T) knowing Delta-T (or flow) and capacity:

20 IMM AGSD3

(

GPM

()( )

factorflowtons

)

−

TDelta

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 sy stem 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 25% solution by weight be used for protection against corrosion or that additional inhibitors should be employed.

NOTE: Do not use automotive antifreeze. Industrial 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 11, Ethylene Glycol Factors

Freeze

E.G.

Point

oF o

26 -3.3 0.996 0.998 1.036 1.097

18 -7.8 0.988 0.994 1.061 1.219

7 -13.9 0.979 0.991 1.092 1.352

-7 -21.7 0.969 0.986 1.132 1.532

-28 -33.3 0.958 0.981 1.182 1.748

Capacity Power Flow PD

Water Flow and Pressure Drop

Adjust the chilled water flow through the evaporator to meet specified conditions. The flow rates must fall between the minimum and maximum values shown in the table on the following page. Flow rates below the minimum values shown will result in laminar flow that will reduce efficiency, cause erratic operation of the electronic expansion valve and could cause low temperature cutouts. On the other hand, flow rates exceeding the maximum values shown can cause erosion on the evaporator water connections and tubes.

Table 12, Propylene Glycol Factors

% P.G.

10 20 30 40 50

Freeze

Point

oF o

26 -3.3 0.991 0.996 1.016 1.092 19 -7.2 0.981 0.991 1.032 1.195

9 -12.8 0.966 0.985 1.056 1.345

-5 -20.6 0.947 0.977 1.092 1.544

-27 -32.8 0.932 0.969 1.140 1.906

Capacit

Power Flow PD

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

IMM AGSD3 21

Figure 18, Evaporator Pressure Drops

Minimum/Nominal/Maximum Flow Rates

AGS

MODEL

Standard Efficiency

140DS/DM A 201 3.72 12.7 11.1 321 8.51 20.2 25.4 535 21.18 33.7 63.2 160DS/DM A 233 4.83 14.7 14.4 372 11.16 23.5 33.3 621 27.74 39.2 82.8 170DS/DM A 246 15.5 2.8 8.4 393 24.8 6.8 20.3 655 41.3 20.5 61.2 190DS/DM B 200DS/DM B 283 4.49 17.9 13.4 453 10.42 28.6 31.1 756 26.24 47.7 78.3 210DS/DM B 302 4.99 19.0 14.9 483 11.63 30.4 34.7 804 29.29 50.7 87.4

High Efficiency

140DE/DF A 217 4.26 13.7 12.7 347 9.82 21.9 29.3 578 24.43 36.5 72.9 170DE/DF B 250 5.50 15.8 16.4 401 12.70 25.3 37.9 668 31.50 42.1 94.0 190DE/DF B 279 4.36 17.6 13.0 447 10.15 28.2 30.3 744 25.53 47.0 76.2

CURVE

22 IMM AGSD3

MINIMUM FLOW NOMINAL FLOW MAXIMUM FLOW

gpm ft l/s kpa gpm ft l/s kpa gpm ft l/s kpa

265 3.95 16.7 11.8 424 9.21 26.7 27.5 706 23.15 44.5 69.1

Physical Data

Standard Efficiency

Table 13, Standard Efficiency, AGS 140DS – AGS 210DS

DATA

BASIC DATA

Unit Cap. @ ARI tons (kW) 137.0 (481.9) 155.2 (545.9) 163.7 (575.8) Unit Operating Charge lbs (kg) 170 (77) 170 (77) 170 (77) 170 (77) 170 (77) 170 (77) Cabinet Dimensions 229.2x88x100.1 229.2x88x100.1 229.2x88x100.1 L x W x H, in. (mm) (5821x2235x2542) (5821x2235x2542) (5821x2235x2542) Unit Operating Weight, lbs. (kg) 10990 (4985) 10990 (4985) 10990 (4985) Unit Shipping Weight, lbs (kg) 10415 (4724) 10415 (4724) 10415 (4724)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Capacity, tons (kW) 70 (246) 70 (246) 70 (246) 85 (299) 85 (299) 85 (299) Minimum Capacity (% of Full Load) 12.5 12.5 12.5

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLER

Pumpdown Capacity, lbs (kg) 399 (181) 399 (181) 399 (181) 399 (181) 399 (181) 399 (181) Coil Inlet Face Area, sq. ft. (sq m.) 131.8 (12.2) 131.8 (12.2) 131.8 (12.2) 131.8 (12.2) 131.8 (12.2) 131.8 (12.2)

CONDENSER FANS, DIRECT DRIVE PROPELLER TYPE

No. of Fans/Circuit – 30 in. Fan Dia. 5 5 5 5 5 5 Fan Motor hp (kW) 2.0 (1.5) 2.0 (1.5) 2.0 (1.5) Fan & Motor RPM, 60Hz 1140 1140 1140 60 Hz Fan Tip Speed, fpm (m/s) 8950 (45.5) 8950 (45.5) 8950 (45.5) 60 Hz Total Unit Airflow, cfm (l/s) 108630 (51280) 108630 (51280) 108630 (51280)

EVAPORATOR, DIRECT EXPANSION SHELL AND TUBE

Shell Dia.-Tube Length, in.(mm) 16x108 (406x2750) 16x108 (406x2750) 16x108 (406x2750) Water Volume, gallons (liters) 65.8 (249.4) 65.8 (249.4) 65.8 (249.4) Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048) 152 (1048) Max. Refrigerant Press., psi (kPa) 350 (2413) 350 (2413) 350 (2413)

DATA

BASIC DATA

Unit Cap. @ ARI, tons (kW) 176.5 (620.8) 188.9 (664.4) 201.1 (707.4) Unit Operating Charge lbs (kg) 190 (86) 190 (86) 200 (91) 200 (91) 200 (91) 200 (91) Cabinet Dimensions 267.4x88x100.1 267.4x88x100.1 267.4x88x100.1 L x W x H, in. (mm) (6792x2235x2542) (6792x2235x2542) (6792x2235x2542) Unit Operating Weight (1), lbs. (kg) 11730 (5321) 11730 (5321) 11730 (5321) Unit Shipping Weight(1), lbs (kg) 11170 (5067) 11170 (5067) 11170 (5067)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Capacity, tons (kW) 85 (299) 85 (299) 95 (335) 95 (335) 100 (352) 100 (352) Minimum Capacity (% of Full Load) 12.5 12.5 12.5

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE

Pumpdown Capacity, lbs (kg) 438 (199) 438 (199) 438 (199) 438 (199) 438 (199) 438 (199) Coil Inlet Face Area, sq. ft. (sq m.) 158.3 (14.7) 158.3 (14.7) 158.3 (14.7) 158.3 (14.7) 158.3 (14.7) 158.3 (14.7)

CONDENSER FANS, DIRECT DRIVE PROPELLER TYPE

No. of Fans/Circuit – 30 in. Fan Dia 6 6 6 6 6 6 Fan Motor -- hp (kW) 2.0 (1.5) 2.0 (1.5) 2.5 (1.9) Fan & Motor RPM, 60Hz 1140 1140 1140 60 Hz Fan Tip Speed, fpm (m/s) 8950 (45.5) 8950 (45.5) 8950 (45.5) 60 Hz Total Unit Airflow, cfm (l/s) 130360 (61530) 130360 (61530) 137328 (64819)

EVAPORATOR, DIRECT EXPANSION SHELL AND TUBE

Shell Dia.-Tube Length, in.(mm) 16x108 (406x2750) 16x108 (406x2750) 16x108 (406x2750) Water Volume, gallons (liters) 63.6 (241) 63.6 (241) 63.6 (241) Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048) 152 (1048) Max. Refrigerant Press., psi (kPa) 350 (2413) 350 (2413) 350 (2413)

140DS 160DS 170DS

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

190DS 200DS 210DS

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

IMM AGSD3 23

High Efficiency

Table 14, High Efficiency, AGS 140DE – AGS 190DE

DATA

BASIC DATA

Unit Cap. @ ARI tons (kW) 145.6 (512) 166.9 (586) 186.1 (654) Unit Operating Charge lbs (kg) 180 (82) 180 (82) 180 (82) 200 (91) 200 (91) 205 (93) Cabinet Dimensions 267.4x88x100.1 267.4x88x100.1 267.4x88x100.1 L x W x H, in. (mm) (6792x2235x2542) (6792x2235x2542) (6792x2235x2542) Unit Operating Weight, lbs. (kg) 11730 (5321) 11730 (5321) 11730 (5321) Unit Shipping Weight, lbs (kg) 11170 (5067) 11170 (5067) 11170 (5067)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Capacity, tons (kW) 70 (246) 70 (246) 70 (246) 85 (299) 85 (299) 95 (335) Minimum Capacity (% of Full Load) 12.5 12.5 12.5

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLER

Pumpdown Capacity, lbs (kg)

Coil Inlet Face Area, sq. ft. (sq m.)

CONDENSER FANS, DIRECT DRIVE PROPELLER TYPE

No. of Fans/Circuit – 30 in. Fan Dia. 6 6 6 6 6 6 Fan Motor hp (kW) 2.0 (1.5) 2.0 (1.5) 2.0 (1.5)

Fan & Motor RPM, 60Hz 1140 1140 1140 60 Hz Fan Tip Speed, fpm (m/s) 8950 (45.5) 8950 (45.5) 8950 (45.5) 60 Hz Total Unit Airflow, cfm (l/s) 130360 (61530) 130360 (61530) 130360 (61530)

EVAPORATOR, DIRECT EXPANSION SHELL AND TUBE

Shell Dia.-Tube Length, in.(mm) 16x108 (406x2750) 16x108 (406x2750) 16x108 (406x2750) Water Volume, gallons (liters) 65.8 (249.4) 65.8 (249.4) 63.6 (241) Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048) 152 (1048) Max. Refrigerant Press., psi (kPa) 350 (2413) 350 (2413) 350 (2413)

140DE 170DE 190DE

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

438

(199)

158.3 (14.7)

438 (199) 438 (199) 438 (199) 438 (199) 438 (199)

158.3

(14.7)

158.3

(14.7)

158.3 (14.7)

24 IMM AGSD3

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