McQuay AGZ025DH Installation Manual

Installation and Maintenance Manual IM 1100

Air-Cooled Scroll Compressor Chiller

AGZ025DH - AGZ190DH R-410A 50/60 Hz

Group: Chillers

Part Number: IM 1100

Date: October 18, 2010

Installation and Application Information . . . . . . . . 3

Modbus

*AHRI Certification and ETL Listing apply to 60Hz models only

©2010 McQuay International. Illustrations and data cover the McQuay International product 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: LEED is a registered trademark of the U.S. Green Building Council; BACnet from ASHRAE; LONMARK, LonTalk, LONWORKS, and the LONMARK logo are managed, granted and used by LONMARK International under a license granted by Echelon Corporation; ElectroFin from AST ElectroFin Inc.; Modbus from Schneider Electric; FanTrol, MicroTech III, Open Choice from McQuay International

Handling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Unit Placement. . . . . . . . . . . . . . . . . . . . . . . . . 4

Chilled Water Piping. . . . . . . . . . . . . . . . . . . . . 9

Water Piping. . . . . . . . . . . . . . . . . . . . . . . . . . 10

Flow Switch . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Glycol Solutions . . . . . . . . . . . . . . . . . . . . . . . 13

Operating and Standby Limits . . . . . . . . . . . . 13

Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Lifting and Mounting Weights. . . . . . . . . . . . . . . . 22

Physical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Pressure Drop Data . . . . . . . . . . . . . . . . . . . . . . . . 34

Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Electrical Data Notes . . . . . . . . . . . . . . . . . . 35

Field Wiring Diagram . . . . . . . . . . . . . . . . . . 36

Start-up and Shut-down Procedures. . . . . . . . . . 53

Pre Start-up. . . . . . . . . . . . . . . . . . . . . . . . . . 53

Start-Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Component Operation . . . . . . . . . . . . . . . . . . . . . 55

Component Operation . . . . . . . . . . . . . . . . . . . . 55

Wind Baffles and Hail Guards . . . . . . . . . . . . . . . 57

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Hazard Identification

DANGER

Dangers indicate a hazardous situation which will result in death or serious injury if not avoided.

WARNING

Warnings indicate potentially hazardous situations, which can result in property damage, severe personal injury, or death if not avoided.

CAUTION

Cautions indicate potentially hazardous situations, which can result in personal injury or equipment damage if not avoided.

Note: Cover photograph is an AGZ190D with standard protective coil grilles.

This manual covers AGZ-D vintage air cooled scroll chillers. For AGZ-C vintage models, see IM 1078, available at www.mcquay.com.

Document: IM 1100 Issue Date: October 18, 2010 Revision Date: -Replaces: NEW

2 IM 1100

Installation and Application Information

G Z XXX D H

Air-Cooled

Global Design Scroll Compressor

Nominal Tons

Application

Design Vintage

H = Standard Packaged

Blocking is required

across full width

All rigging loc ation s

mu st be used.

Spreader ba rs

required

(use cautio n)

Number of fans may vary

from this diagram. The lifting

method will remain the same.

Spreader ba rs

required

(use cautio n)

Installation and Application Information

Chiller Nomenclature

WARNING

Installation is to be performed by qualified personnel who are familiar with local codes and regulations.

CAUTION

Sharp edges on unit and coil surfaces are a potential hazard to personal safety. Avoid contact with them.

General Description

McQuay Air-Cooled Water Chillers are complete, selfcontained automatic chiller units designed for outdoor installation. Every unit is completely assembled, factory wired, charged, and tested.

The electrical control center includes all equipment protection and operating controls necessary for dependable automatic operation.

Additional Manuals

This manual covers the installation, of dual circuit, AGZ-DH packaged, scroll compressor chillers using R-410A.

Operating and maintenance information is contained in the operating manual OMM 1087, available at www.mcquay.com.

Inspection

Check all items carefully against the bill of lading. Inspect all units for damage upon arrival. Report shipping damage and file a claim with the carrier. Check the unit nameplate before unloading, making certain it agrees with the power supply available. McQuay is not responsible for physical damage after the unit leaves the factory.

Figure 1: Suggested Pushing Arrangment

Figure 2: Required Lifting Arrangement

Handling

Be careful to avoid rough handling of the unit. Do not push or pull the unit from anything other than the base. Block the pushing vehicle away from the unit to prevent damage to the sheet metal cabinet and end frame (see Figure 1).

To lift the unit, 2-1/2" (64mm) diameter lifting eyes are provided on the base of the unit. Arrange spreader bars and cables to prevent damage to the condenser coils or cabinet (see

Figure 2).

IM 1100 3

CAUTION

All lifting locations must be used to prevent damage to unit.

Installation and Application Information

Unit Placement

AGZ units are for outdoor applications and can be mounted either on a roof or at ground level. For roof mounted applications, install the unit on a steel channel or I-beam frame to support the unit above the roof. For ground level applications, install the unit on a substantial base that will not settle. Use a one-piece concrete slab with footings extended below the frost line. Be sure the foundation is level within the lesser of 0.25” per foot (6mm per 254mm) or 0.5"(13mm) over its length and width. The foundation must be strong enough to support the weights listed in the Physical Data Tables beginning on page 28.

Install the unit on vibration pads, springs or some other devise to keep the steel rais off the concrete pad if the unit is so mounted.

Service Clearance

Sides: Minimum of 4 feet (1.22 m) Control panel end: Minimum of 4 feet Opposite control panel:

• Minimum 4 feet on models 025 to 130;

• 12 feet on models 140-190 (allows clearance to remove the evaporator ).

Air Clearance

Sufficient clearance must be maintained between the unit and adjacent walls or other units to allow the required unit air flow to reach the coils. Failure to do so will result in a capacity reduction and an increase in power consumption. No obstructions are allowed above the unit at any height.

Spacing Requirements

In general, with a small performance penalty in some cases, AGZ-D units can be spaced at four feet from other units or a wall. Curves on the following pages give the minimum clearance for different types of installations and also capacity reduction and power increase if closer spacing is used.

For convenience, the table below gives the minimum unit spacing with no performance penalty. Closer spacing will incur capacity penalties, however, these penalties are quite small and a unit may still meet the building load requirements.

Wind diretion and velocity can affect recirculation.

Table 1: Minimum Full Capacity Unit Spacing

AGZ-D Unit Size 025-070 075-100 110-130 140-180 190

Case

Side Wall (Note 2)

(1.2)4 (1.2)6(1.8)6 (1.8)7 (2.1)

Case

2 Units, Side-by-Side

Case33 or More Units,

Side-by-Side (Note 3)

Case5Pit, No Deeper than

Unit Height (Note 4)

Note 1: Units of Measure: ft (m) Note 2: For a wall higher than the unit, wall openings or greater distance is

required for full capacity.

Note 3: Use Case 3 table value for inside unit. Use Case 2 value for either

outside unit.

(1.2)4 (1.2)6(1.8)6(1.8)14(4.3)

(1.2)4 (1.2)8 (2.4)10(3.0)12(3.7)

(1.8)8(2.4)8 (2.4)10(3.0)10(3.0)

4 IM 1100

Installation and Application Information

Full Load Capacity Reduction (AGZ110-130)

0.0

1.0

2.0

0 8 12 16 20 24

Wall Height (ft)

Distance = 4ft Distance = 5ft

Power Increase (AGZ110-130)

0.0

1.0

2.0

0 8 12 16 20 24

Wall Height (ft)

% Power Increase

Distance = 4ft Dista nce = 5f t

Full Load Capa city Reduction (AGZ140-180)

0.0

1.0

2.0

0 8 12 16 20 24

Wa ll Height (ft)

Distance = 4ft Distance = 6f t

Power Increase (AGZ140-180)

0.0

1.0

2.0

0 8 12 16 20 24

Wall Height (ft)

% Power Increase

Distance = 4ft Distance = 6ft

Full Load Capacity Reduction (AGZ190)

0.0

1.0

2.0

0 8 12 16 20 24

Wall Height (ft)

Dist ance = 4ft Distance = 5ft Distance = 7ft

Power Increase (AGZ190)

0.0

1.0

2.0

3.0

0 8 12 16 20 24

Wall Height (ft)

% Power Increase

Distance = 4ft Distance = 5ft Distance = 7ft

Case 1: Wall on One Side

In this case a solid wall up to 24-feet is considered. (For walls higher than 24 ft, use the 24-foot values.) Also use these charts for an adjacent building. For perforated screening walls, use Case 4. Spacing is differentiated by unit size families.

Figure 3: Wall on One Side of Unit

Note: Maintain a minimum of 4-feet on all sides; except models

140-190, which require 12-feet opposite the control panel to remove the evaporator.

For models AGZ 025-100: use 4 feet from any height wall. For models 110-190, use Performance Adjustment curves below.

Figure 5: Case 1 Adjustment Factors (AGZ140D-180D)

% Capacity Reduction

Figure 4: Case 1 Adjustment Factors (AGZ110D-130D)

Figure 6: Case 1 Adjustment Factors (AGZ190D)

% Ca pacity Reduction

% Capacity Reduction

IM 1100 5

Installation and Application Information

Full Load Capacity Reduction

0.0

0.5

1.0

1.5

2.0

2.5

3.0

4568

Distance Betwe en Units (ft)

% Capacity Reduction

AGZ075-100D AGZ110-130D AGZ140-180D AGZ190D

Power Increase

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

4568

Distance Between Units (ft)

% Power Increase

AGZ075-100D AGZ110-130D AGZ140-180D

Full Load Capacity Reduction

4568

Distance Between Units

% Capacity Reduction

AGZ075-100D AGZ110-130D AGZ 14 0-1 8 0D AGZ190D

Power Incre ase

4568

Distance Between Units (ft)

% Power Increase

AGZ075-100D AGZ110-130D AGZ140-180D AGZ190D

Case 2: Two Units, Side-by-Side

Maintain a minimum of 6-feet on all sides; except models 140190, which require 12-feet opposite the control panel to remove the evaporator.

Figure 7: Case 2 - Two units side by side

For models AGZ 025-100: use 4 feet between units. For models 110-190, use Performance Adjustment chart in

Figure 8.

Figure 8: Case 2 Adjustment Factors

Case 3: Three or More Units, Side-by-Side

Maintain a minimum of 6-feet on all sides; except models 140190, which require 12-feet opposite the control panel to remove the evaporator. For more than three units, allow an additional 2-feet clearance between units.

Figure 9: Case 3 - 3 units side by side

Data is for the middle unit - with a unit on each side. See Case 2, page 6 for Adjustment Factors for the two outside units.

Figure 10: Case 3 Adjustment Factors

6 IM 1100

AGZ190

Installation and Application Information

Wall Free Area vs. Distance

0 1020304050

% Open Wall Area

Distance from Wall to Unit (ft)

AGZ025-070 AGZ075-130 AGZ140-190

Full Load Capacity Reduction (AGZ025-0 70)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 8 10 12 13 14

Depth of Pit (ft)

% Capacity Red uction

Distance = 4 ft Distance = 5 ft Distance = 6 ft

Power Increase (AGZ025-070)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0 8 10 12 13 14

Depth of Pit (ft)

% Power Increase

Distance = 4 ft Distance = 5 ft Distance = 6 ft

Case 4: Open Screening Walls

Decorative screening walls are often used to help conceal a unit either on grade or on a rooftop. Design these walls 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. If the wall height is greater than the unit height, see Case 5, Pit Installation, page 7. The distance from the sides of the unit to the side walls must be sufficient for service, such as opening control panel doors. For uneven wall spacing, the distance from the unit to each wall can be averaged providing no distance is less than 4 feet. Values are based on walls on all four-sides.

Figure 11: Case 4 Adjustment Factor

Case 5: Pit Installation

Pit installations can cause operating problems resulting from recirculation and restriction, and require care that sufficient air clearance is provided, safety requirements are met and service access is provided. Pit covers must have abundant open area at least equal to the chiller footprint.A solid wall surrounding a unit is substantially a pit and this data 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 to avoid recirculation problems. Have any pit installation reviewed by McQuay prior to installation to ensure it has sufficient air-flow characteristics, and approved by the installation design engineer avoid risk of accident.

Figure 12: Case 5 - Pit Installation

IM 1100 7

Figure 13: Case 5 Adjustment Factors (AGZ025D-070D)

Installation and Application Information

Full Load Capacity Reduction (AGZ075-130)

0 8 10 12 13 14

Depth of Pit (ft)

% Capacity Reduction

Distance = 5 ft Distance = 6 ft Distance = 8 ft

Power Increase (AGZ075-130)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0 8 10 12 13 14

Depth of Pit / Wall Heig ht (ft )

% Power In crease

Distance = 5 ft Distance = 6 f t Distance = 8 f t

Full Load Capacity Reduction (AGZ140-190)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 8 10 12 13 14

Depth of Pit (ft)

% Capacity Reduction

Distance = 6 ft Di sta nc e = 8 f t Dis tanc e = 10 ft

Power Increase (AGZ140-190)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0 8 10 12 13 14

Depth of Pit / Wall Height (ft)

% Power Increase

Distance = 6 ft Distance = 8 ft Distance = 10 ft

Figure 14: Case 5 Adjustment Factors (AGZ075D-130D) Figure 15: Case 5 Adjustment Factors (AGZ140D-190D)

8 IM 1100

Installation and Application Information

Chilled Water Piping

Flush the system water piping thoroughly before making connections to the unit evaporator. Install a 40-mesh strainer in the inlet pipe to the chiller. Design the water piping so the chilled water circulating pump discharges into the evaporator inlet.

Connect the return water line to the evaporator inlet connection. Connect the supply water line to the evaporator outlet connection.

Install a flow switch in the horizontal piping of the supply (evaporator outlet) water line.

Provide drain connections at low points in the system to permit complete drainage of the system. Locate air vents at the high points in the system to purge air out of the system. A vent connection on top of the evaporator vessel allows air to be purged out of the evaporator. Purge air from the water system before unit start-up to provide adequate flow through the evaporator.

Install pressure gauges in the inlet and outlet water lines to the evaporator. Measure pressure drop through the evaporator and compare to flow as shown on page 34. Vibration eliminators are recommended in both the supply and return water lines.

Insulate chilled water piping to reduce heat loss and prevent condensation. Chillers not running in the winter should have their water systems thoroughly drained to protect against freezing. If the chiller operates year-round, or if the system is not drained for the winter, protect the chilled water piping exposed to outdoor temperature against freezing. Wrap the lines with a heater cable and add proper amount of glycol to the system to further protect the system.

Figure 16: Strainer Pressure Drop

Table 2: Strainer Data

AGZ Model

025-055 2.5 16.75 14 060-130 3.0 17.75 20 140-190 8.0 36.00 125

Strainer Size

(in.)

Strainer Plus Pipe

Length (in.)

Strainer

Weight (lbs)

Water Flow Limitations

Constant Flow

The evaporator flow rates and pressure drops shown on page

page 34 are for full load design purposes. The maximum flow

rate and pressure drop are based on a 6°F temperature drop. Avoid higher flow rates with resulting lower temperature drops to prevent potential control problems resulting from very small control bands and limited start up/shut off temperature changes.

The thermostat sensor is factory mounted in the leaving water well. If a field supplied and installed return water sensor is desired, install the sensor bulb in a field supplied well or strap to the outside of the water line.

Optional Inlet Strainer

An inlet water strainer kit is available to be field-installed, sized per Tabl e 2 and with the pressure drop show in

Figure 16. This pressure drop must be accounted for in the

total system pressure drop. The kit consists of:

• (1) Y-type 40% open area strainer with 304 stainless steel perforated basket, Victaulic pipe connections and strainer cap

• (1) Extension pipe with (2) Schrader fittings that can be used for a pressure gauge and thermal dispersion flow switch. The pipe provides sufficient clearance from the evaporator for strainer basket removal.

• (1) ½-inch blowdown valve

• (2) Victaulic clamps

The minimum flow and pressure drop is based on a full load evaporator temperature drop of 16°F. Evaporator flow rates below the minimum values can result in laminar flow causing freeze-up problems, scaling and poor control. Flow rates above the maximum values will result in unacceptable pressure drops and can cause excessive erosion, potentially leading to failure.

Evaporator Variable Flow

Reducing evaporator flow in proportion to load can reduce system power consumption. The rate of flow change should be a maximum of 10 percent of the flow per minute. For example, if the maximum design flow is 200 gpm and it will be reduced to a flow of 140 gpm, the change in flow is 60 gpm. Ten percent of 200 gpm equals 20 gpm change per minute, or a minimum of three minutes to go from maximum to minimum. Do not reduce flow lower than the minimum flows listed in the evaporator pressure drop section, page 45. The water flow through the vessel must remain between the minimum and maximum values listed on page 45. 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.

IM 1100 9

Installation and Application Information

Figure 17: Typical Piping, Brazed-Plate Evaporator (models AGZ025D-130D)

Figure 18: Typical Piping, Shell and Tube Evaporator (models AGZ140D-190D)

Water Piping

Piping for units with brazed-plate evaporators must have a drain and vent connection provided in the bottom of the lower connection pipe and to the top of the upper connection pipe respectively. These evaporators do not have drain or vent connections due to their construction.

Local authorities can supply the installer with the proper building and safety codes required for safe and proper installation.

Install piping with minimum bends and changes in elevation to minimize pressure drop. The following issues should be considered when designing and installing water piping:

1 Vibration eliminators to reduce vibration and noise

transmission to the building.

2 Shutoff valves are required to isolate the unit from the

piping during unit servicing.

10 IM 1100

3 Manual or automatic air vent valves at the high points of

the system. Drains must be installed at the lowest points in the system.

4 Adequate water pressure must be maintained (expansion

tank or regulating valve).

5 Temperature and pressure indicators located at the unit

are required to aid in unit servicing.

6 A 40-mesh strainer or other means of removing foreign

matter from the water before it enters the evaporator must be installed. The use of a strainer will prolong unit life and help maintain system performance.

7 Chilled water piping and strainer must be supported

independently from the unit.

Installation and Application Information

8 Models AGZ 025D through 130D require field-installed

drains and vents adjacent to the unit. Their brazed-plate evaporators are not so equipped.

9 Flush the system water piping thoroughly before making

connections to the unit evaporator. Design the water piping so the chilled water circulating pump discharges into the evaporator inlet.

10 The unit's evaporator has a thermostat and heater to

prevent freeze-up down to -20 F ( 29 C). The heating cable can be wired to a separate 115 V supply circuit. As shipped from the factory, the heating cable is wired to the control circuit. All water piping to the unit must also be protected to prevent freezing.

11 If the unit is used as a replacement chiller, flush the

system thoroughly before unit installation. Regular water analysis and chemical water treatment for the evaporator loop is recommended immediately at equipment start-up.

12 The total water volume in the system should be sufficient

to prevent frequent "on-off" cycling. Turnover rate should not be less than 4 minutes for normal variable cooling loads.

13 When glycol is added to the water system for freeze

protection, the refrigerant suction pressure will be lower, cooling performance less, and water side pressure drop greater. If the percentage of glycol is high, or if propylene is used instead of ethylene glycol, the added pressure drop and loss of performance could be substantial. When Glycol or Ice are selected as Unit Mode, the MicroTech II control will automatically reset the available range for the Leaving Water Temperature, Freezestat and Evaporator Pressure settings.

14 Reset the freezestat setting to 6 degrees F (3.3 degrees C)

below the leaving chilled water setpoint temperature after the glycol percentage is verified safe for the application. See the section titled "Glycol Solutions" on page 14 for additional information concerning glycol.

15 Perform a preliminary leak check before insulating the

piping and filling the system.

16 Piping insulation should include a vapor barrier to

prevent condensation and possible damage to the building structure.

Water Connections

Bring water piping to the evaporator through the side between the vertical supports. Provide taps for the connection of pressure gauges and thermometers in the inlet and outlet lines. Check the inlet and outlet labels on the unit against the certified drawings supplied on the job and be sure the water piping is hooked up correctly. Contact the McQuay sales office if any discrepancies exist.

System Water Volume Considerations

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 storage tank may have to be added to the system.

BAS should enable chiller only when there is a cooling demand.

Evaporator Freeze Protection

Evaporator freeze-up can be a concern in the application of aircooled water chillers. To protect against freeze-up, insulation and electric heaters are furnished with the unit. Models 140 through 190 have immersion heaters with a thermostat; models 025 through 130 have an external plate heater and thermostat. They protect the evaporator down to -20° F (-29° C) ambient air temperature. Although the evaporator is equipped with freeze protection, it does not protect water piping external to the unit or the evaporator itself if there is a power failure or heater cable burnout. Consider the following recommendations for additional protection.

1 If the unit will not be operated during the winter, drain

evaporator and chilled water piping and flush with glycol. Drain and vent connections are provided on the evaporator to ease draining.

2 Add a glycol solution to the chilled water system to

provide freeze protection. Freeze point should be approximately ten degrees (F) below minimum design ambient temperature.

3 The addition of thermostatically controlled heat and

insulation to exposed piping.

The evaporator heater cable is factory wired to the 115 volt circuit in the control box. This power should be supplied from a separate source, but it can be supplied from the control circuit. Operation of the heaters is automatic through the ambient sensing thermostat that energizes the evaporator heaters for protection against freeze-up. Unless the evaporator is drained in the winter or contains an adequate concentration of anti-freeze, the disconnect switch to the evaporator heater must not be open.

Temperature and Water Flow Limitations

Evaporator flow rates below the minimum values can result in laminar flow causing freeze-up problems, scaling and poor control. Flow rates above the maximum values will result in unacceptable pressure drops and can cause excessive erosion, potentially leading to failure.

IM 1100 11

Installation and Application Information

Low Ambient Operation

Compressor staging is adaptively determined by system load, ambient air temperature, and other inputs to the MicroTech III control. A low ambient option with fan VFD allows operation down to -10° F (-23° C). The minimum ambient temperature is based on still conditions where the wind is not greater than five mph. Greater wind velocities will result in reduced discharge pressure, increasing the minimum operating ambient temperature. Field installed hail/wind guards are available to allow the chiller to operate effectively down to the ambient temperature for which it was designed.

High Ambient Operation

AGZ-D units for high ambient operation (105ºF to 125 F, 40.1 C to 51.7 C) require the addition of the optional high ambient package that includes a small fan with a filter in the air intake to cool the control panel.

All units with the optional VFD low ambient fan control automatically include the high ambient option.

Flow Switch

All chillers require a chilled water flow switch to check that there is adequate water flow through the evaporator ant to shut

the unit down if there isn't. McQuay has two options for meeting this requirement.

1 A factory-mounted thermal dispersion flow switch. 2 A "paddle" type flow switch is available from McQuay

(part number 017503300) for field mounting and wiring. Certain flow rates are required to open the switch and are listed in Figure 3. Wire from switch terminals Y and R to the unit control panel terminals shown on the field wiring diagrams, page 36 and page 37. Mount the flow switch in the leaving water line to shut down the unit when water flow is interrupted. A flow switch is an equipment protection control and should never be used to cycle a unit.

Installation should be per manufacturer's instructions included with the switch . There is also a set of normally closed contacts on the switch that can be used for an indicator light or an alarm to indicate when a "no flow" condition exists. Freeze protect any flow switch that is installed outdoors. .

NOTE: Differential pressure switches are not recommended for outdoor installation. They can freeze and not indicate a noflow condition

Table 3: Flow Switch Minimum/Maximum Flow Rates

Pipe Size (NOTE !)

Min.

Adjst.

Max.

Adjst.

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

Flow

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

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 Lpm 0.8 1.1 2.2 2.8 4.3 11.4 22.9 35.9 38.6 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 Lpm 2.8 4.1 6.1 7.3 11.4 27.7 53.4 81.8 90.8

Drain Valves at Start-up

Model sizes AGZ 140 and larger have shell-and-tube evaporators. They are drained of water in the factory and shipped with evaporator drain plugs removed and stored in the control panel or with an open ball valve in the drain holes. The drain is located on the bottom of the vessel. Be sure to replace plugs or close the valves prior to filling the vessel with fluid.

12 IM 1100

Installation and Application Information

Glycol Solutions

The use of a glycol/water mixture in the evaporator to prevent freezing will reduce system capacity and efficiency, as well as increase pressure drop. The system capacity, required glycol solution flow rate, and pressure drop with glycol may be calculated using the following formulas and tables.

1 Capacity - Multiply the capacity based on water by the

Capacity correction factor from Tabl e 4 or Table 5.

2 Flow - Multiply the water evaporator flow by the Flow

correction factor from Tabl e 4 or Table 5 to determine the increased evaporator flow due to glycol. If the flow is unknown, it can be calculated from the following equation:

For Metric Applications - Use the following equation for metric applications:

3 Pressure drop - Multiply the water pressure drop from

Table 20, page 34 by Pressure Drop correction factor

from Tabl e 4 or Table 5 . High concentrations of propylene glycol at low temperatures may cause unacceptably high pressure drops.

4 Power - Multiply the water system power by Power

correction factor from Tabl e 4 or Table 5.

Test coolant with a clean, accurate glycol solution hydrometer (similar to that found in service stations) or refractto determine the freezing point. Obtain percent glycol from the freezing point table below. It is recommended that a minimum of 25% solution by weight be used for protection against corrosion or that additional compatible inhibitors be added. Concentrations above 35% do not provide any additional burst protection and should be carefully considered before using.

CAUTION

Do not use an automotive-grade antifreeze. Industrial grade glycols must be used. Automotive antifreeze contains inhibitors

which 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 4: Ethylene Glycol Factors Table 5: Propylene Glycol Factors

% E.G.

10 26 -3.3 0.998 0.998 1.036 1.097 20 18 -7.8 0.993 0.997 1.060 1.226 30 7 -13.9 0.987 0.995 1.092 1.369 40 -7 -21.7 0.980 0.992 1.132 1.557 50 -28 -33.3 0.973 0.991 1.182 1.791

Freeze Point

Capacity Power Flow PD

% P.G.

10 26 -3.3 0.995 0.997 1.016 1.100 20 19 -7.2 0.987 0.995 1.032 1.211 30 9 -12.8 0.978 0.992 1.057 1.380 40 -5 -20.6 0.964 0.987 1.092 1.703 50 -27 -32.8 0.952 0.983 1.140 2.251

Freeze Point

Capacity Power Flow PD

Operating and Standby Limits

Table 6: Operating Limits

Maximum standby ambient temperature 130°F (55°C) Maximum operating ambient temperature 105°F (40°C)

-with optional high ambient package (see information under High Ambient Operation‚ page 12 125°F (52°C) Minimum operating ambient temperature (standard control) 35°F (2°C) Minimum operating ambient temperature (with optional low-ambient control) -10°F (-23°C) Leaving chilled water temperature 40°F to 60°F (2°C to 16°C)

Leaving chilled fluid temperatures (with anti-freeze) - Unloading is not permitted with fluid leaving temperatures below 25°F (-4°C). When ambient air temperature is above 100º F, minimum leaving chilled fluid temperature (with antifreeze) is 25°F (4°C)

Operating chilled water delta-T range 6 to 16°F (-14 to -9°C) Maximum evaporator operating inlet fluid temperature 76°F (24°C) Maximum evaporator non-operating inlet fluid temperature 100°F (38°C)

15°F to 60°F (-9°C to 16°C)

Vibration and Sound Isolation

Vibration isolators are recommended for all roof-mounted installations or wherever vibration transmission is a

IM 1100 13

Installation and Application Information

consideration. The tables beginning page 23 list isolator loads for all unit sizes. Isolators are also recommended for slab installations, primarily to keep the unit base from resting its entire length directly on the slab.

Spring Isolator Installation

The unit should be initially installed on shims or blocks at the listed free height. When all piping, wiring, flushing, charging, etc. is completed, adjust the springs upward to load them and to provide clearance to remove the shims or blocks.

Installation of spring isolators requires flexible piping connections and at least three feet of conduit flex tie-ins. Piping and conduit must be supported independently of the unit.

Sound Isolation

The low sound level of the AGZ chiller is suitable for most applications. When additional sound reduction is necessary, locate the unit away from sound sensitive areas. Avoid locations beneath windows or between structures where normal operating sounds may be objectionable.

Reduce structurally transmitted sound by isolating water lines, electrical conduit and the unit itself. Use wall sleeves and rubber isolated piping hangers to reduce transmission of water or pump noise into occupied spaces. Spring isolators are effective in reducing the low amplitude sound generated by scroll compressors and for unit isolation in sound sensitive areas.

Compressor sound blankets are available as a factory or field installed option. They will reduce sound levels by two or three dB depending on unit size.

14 IM 1100