User manual | Air-Cooled Scroll Compressor Water Chillers Installation, Operation and Maintenance Manual

"Illustrations and data cover 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"

AGZ 010A through 034A IOMM AGZ1

Introduction

General Description

McQuay air-cooled water chillers are complete, self-contained automatic refrigerating units. Every unit is completely assembled, factory wired, charged, and tested. Each unit consists of air-cooled condensers, Copeland Compliant Scroll



hermetic compressor, brazed plate-to-plate evaporator, and complete refrigerant piping. Liquid line components include sight-glass/moisture indicator, solenoid valve, and thermal expansion valve. Other features include a compressor heater, and evaporator heater for chilled water freeze protection.

The electrical control center includes all equipment protection and operating controls necessary for automatic operation. Condenser fan motors are three-phase (except single-phase on No. 1 fan with

SpeedTrol option) and started by their own contactors and have inherent overload protection. The compressor has solid-state motor protection for inherent thermal overload protection except Model

AGZ 010 that has internal line breakage.

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 to be sure it agrees with the power supply available. Units are shipped FOB factory and McQuay is not responsible for physical damage after unit leaves the factory.

Note: Unit shipping and operating weights are listed on pages 13 and 14.

Installation

Note: Installation is to be performed by qualified personnel who are familiar with local codes

and regulations, especially concerning refrigerant release to the atmosphere.

WARNING

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

Handling

Be careful to avoid rough handling of the unit. Do not push or pull the unit from anything other than the base. Block the pushing vehicle away from the unit to prevent damage to the sheet-metal cabinet

and end frame (see Figure 1).

To lift the unit, lifting slots are provided in the base of the unit. Arrange spreader bars and cables to

prevent damage to the condenser coils or cabinet (see Figure 2).

IOMM AGZ1 AGZ 010A through 034A

Figure 1, Suggested Pushing Arrangement

Blocking required across full width

Figure 2, Suggested Lifting Arrangement

Location

Unit Placement

AGZ units are for outdoor applications and can be mounted on a roof or at ground level. Set units on a solid and level foundation. For roof-mounted applications, install the unit on a steel channel or Ibeam frame to support the unit above the roof. For ground level applications, install the unit on a substantial base that will not settle. A one-piece concrete slab with footings extended below the frost line is recommended. Be sure the foundation is level (within 1/2” [13 mm] over its length and width).

The foundation must support the operating weights listed in the Physical Data Tables on pages 13 and

14.

Since its operation is affected by wind, the unit should be located so that its length is parallel with the prevailing wind. If this is not practical, use field fabricated wind deflectors.

Service Access

Each end of the unit must be accessible after installation for periodic service. Compressors, filterdriers, and liquid line solenoid valve are accessible from the end of the unit. High-pressure, lowpressure, and motor protector controls are on the compressor. Most operational, safety and starting controls are located in the unit control box.

The fan deck with the condenser fans and motors can be removed from the top of the unit.

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

Clearances

The flow of air to and from the condenser coil must not be limited. Restricting airflow or allowing air recirculation will result in a decrease in unit performance and efficiency. There must be no obstruction above the unit that would deflect discharge air downward where it could be recirculated back to the inlet of the condenser coil. The condenser fans are propeller type and will not operate with ductwork on the fan outlet.

Install the unit with enough side clearance for air entrance to the coil and for servicing. Provide service access to the evaporator, compressors, electrical control panel and piping components as shown in

Figure 3. Do not block access to the unit

with piping or conduit.

Do not allow debris to accumulate near the unit. Air movement may draw debris into the condenser coil causing air starvation.

Give special consideration to low ambient operation where snow can accumulate.

Keep condenser coils and fan discharge free of snow or other obstructions to permit adequate airflow.

Figure 3, Clearance requirements

4 Ft.

(1220mm)

Clearance for

Service Access

4 Ft. (1220mm)

Clearance for Air Inlet

4 Ft. (1220mm)

Clearance for Air Inlet

4 Ft.

(1220mm)

Clearance for

Service Access

The recommended minimum side clearance between two units is 8 feet (2440mm).

Sound Isolation

The low sound levels of the AGZ chiller are 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.

Use flexible electrical conduit to isolate sound through electrical conduit. Spring isolators are effective in reducing the low amplitude sound generated by the Discus semi-hermetic compressors and for unit isolation in sound-sensitive areas.

The unit must not be installed in a pit or enclosure that is deeper or taller than the height of the unit unless extra space is provided. The minimum clearance on each side of the unit is 6 feet (1828mm) when installed in a pit. The pit cannot be deeper than the unit.

The minimum clearance to a side wall or building taller than the unit height is 6 feet (1828mm) provided no solid wall above 6 feet (1828mm) tall is closer than 12 feet (3658mm) to the opposite side of the unit.

AGZ 010A through 034A

Vibration Isolators

Vibration isolators are recommended for all roof-mounted installations or wherever vibration transmission is a consideration. The isolators can be purchased from McQuay by the part numbers shown in the table.

The unit should be initially on shims or blocks at the listed free height. When all piping, wiring, flushing, charging, etc. is completed, the springs are adjusted upward to loosen the blocks or shims that are then removed.

A rubber anti-skid pad is part of the isolator. Installation of spring isolators requires flexible piping connections and at least three feet of flexible conduit to avoid straining the piping and transmitting vibration and noise.

Table 1, Recommended Vibration Isolators

AGZ UNIT

010A – 034A

ISOLATOR

TYPE

Rubber-in-shear

ISOLATOR

PART NO.

021639703

021639701

010A – 017A

020A – 034A

Spring Isolators

047792726

047792727

Note: See dimension drawing for location of isolators

NUMBER

REQUIRED

KIT of FOUR

PART NO.

350014857

350014835

350014839

LOCATION

LF, RF

LB, RB

All

LF, RF

LB, RB

ISOLATOR

DESCRIPTION

RP-3 Green

RP-3 Red

CP-1-26

CP-1-27

CP-1-26

Control

Panel

Corner Weights

AGZ

Unit

Model

010A

013A

017A

020A

025A

029A

034A

RF LF RB LB

261 367 159 223

372 526 184 260

402 568 200 282

484 621 226 291

499 646 232 301

621 647 326 339

678 784 334 386

Chilled Water System

Water Piping

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. Consider the following when installing water piping:

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. Install drains at the lowest points in the system.

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

4. A means of maintaining adequate system water pressure (expansion tank or regulating valve).

5. Temperature and pressure indicators located at the unit to aid in unit servicing. Pressure gauge taps must be installed in the chilled water inlet and outlet piping or as shown in Figure 4.

6. A strainer or other means of removing 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 keep system performance up.

7. A 40-mesh strainer is required in the water line just before the inlet of the evaporator. This will help prevent foreign material from entering and decreasing the performance of the evaporator.

CAUTION

If separate disconnect is used for the 110V supply to the evaporator heating cable, mark the disconnect clearly to ensure disconnect is not accidentally shut off during cold seasons. This could cause a failure of the evaporator.

8. The brazed plate evaporator has a thermostat and heating cable to prevent freeze-up down to

-20

F (-29

C). It is suggested that the heating cable be wired to a separate 110V supply circuit.

As shipped from the factory, the heating cable is wired to the control circuit. Protect all water piping to the unit from freezing.

9. If the unit is used as a replacement chiller on a previously existing piping system, flush the system thoroughly before unit installation. Regular water analysis and chemical water treatment on the evaporator is recommended immediately at equipment start-up.

10. 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. Reset the freezestat and low leaving water alarm temperatures. The freezestat is factory set to default at 38

F (3.3

C). Reset the freezestat setting to approximately 4 to 5 degrees F (2.3 to 2.8 degrees C) below the leaving chilled water setpoint

temperature. See the section titled “Glycol Solutions” on page 9 for additional information

concerning glycol.

11. Perform a preliminary leak check before insulating the piping and filling the system.

12. Piping insulation should include a vapor barrier to prevent condensation and possible damage to the building structure.

Figure 4, Typical Field Evaporator Water Piping

Air

Vent

Strainer

Inlet

Vibration

Eliminators

Isolation

Valves

Outlet

Flow

Switch

Drain

NOTES:

1. Chilled water piping within the unit enclosure must be insulated in the field.

2. Piping should be supported independently of the unit and be installed per local codes.

AGZ 010A through 034A

System Volume

It is important to have adequate water volume in the system to provide an opportunity for the chiller to sense a load change, adjust to the change and stabilize. As the expected load change becomes more rapid, a greater water volume is needed. The system water volume is the total amount of water in the evaporator, air handling products and associated piping. If the water volume is too low, operational problems can occur, including rapid compressor cycling, rapid loading and unloading of compressors, erratic refrigerant flow in the chiller, improper motor cooling, shortened equipment life and other undesirable occurrences.

For normal comfort cooling applications, where the cooling load changes relatively slowly, we recommend a minimum system volume of five minutes times the flow rate (GPM). For example, if the design chiller flow rate is 120 GPM, we recommend a minimum system volume of 600 gallons

(120 GPM x 5 minutes).

Since there are many other factors that can influence performance, systems may successfully operate below these suggestions. However, as the water volume decreases below these suggestions, the possibility of problems increases.

Variable Chilled Water flow

Variable chilled water flow systems are not recommended for this class of equipment due to limited unloading capability.

Flow Switch

Mount a water flow switch in the leaving water line to shut down the unit when water flow is interrupted.

Figure 5, Flow Switch Installation

A flow switch is available from McQuay

(part number 017503300). It is a “paddle” type switch and adaptable to pipe sizes down to 1 1/4” (32mm) nominal. Certain minimum flow rates are required to close

the switch and are listed in Table 2. Install

the switch as shown in Figure 5. Connect

the normally open contacts of the flow switch in the unit control center at terminals

4 and 5. 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. Follow installation instructions provided with the flow switch. Calibrate the flow switch to open at one-half of nominal flow rate.

NOTE: Differential pressure switches are not recommended for outdoor installation.

Table 2, Flow Switch Settings

Pipe Size

Minimum

Adjustment

Maximum

Adjustment

Flow

Flow inch mm gpm

Lpm gpm

Lpm

1 1/4

4.8

18.2

3.0

11.3

7.7

29.1

5.9

22.3

1 1/2

6.3

22.7

3.6

13.6

10.0

37.9

7.0

26.5

9.9

37.5

5.9

22.3

15.8

59.8

11.0

41.6

2 1/2

15.3

57.9

9.5

36.0

23.7

89.7

17.0

64.3

24.4

92.4

15.4

58.3

35.5

134.4

29.2

110.5

102

33.3

126.0

21.1

79.9

61.4

232.4

37.7

142.7

AGZ 010A through 034A IOMM AGZ1

Water Connections

The unit has 3-inch holes for the chilled water piping to enter the unit. The connections are made to the evaporator water connections located within the unit. Water piping within the unit must be field insulated.

Refrigerant Charge

All units are designed with HCFC-22. See the nameplate for specific refrigerant used. Units are shipped with an operating charge. The operating charge (using HCFC-22) for each unit is shown in in

the Physical Data Tables on pages 13 and 14.

Unit Component Location

Control Panel

Tandem Scroll

Compressors

IOMM AGZ1

Evaporator

Charging Valve

Solenoid Valve, Expansion Valve

Optional Hot Gas Bypass Valve Filter Drier

Glycol Solutions

The use of glycol antifreeze solutions will decrease unit capacity and increase the pressure drop through the cooler. See Product Manual PM AGZ1 for specific ratings and correction factors.

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.

Evaporator Water Flow and Pressure Drop

Evaporator flow rate must fall between the minimum and maximum values shown in the evaporator

pressure drop curve, Figure 6. Flow rates outside of these limits result in a chilled water Delta-T

outside the operating range of the controller.

Measure the chilled water pressure drop through the evaporator at field-installed pressure taps. It is important not to include the effect of valves or strainers in these readings.

Varying chilled water flow through the evaporator while the compressors are operating is not recommended.

AGZ 010A through 034A

Figure 6, Evaporator Water Pressure Drop Curve

AGZ 010

AGZ 020

AGZ 025

AGZ 029

AGZ 034

AGZ 013

AGZ 017

AGZ

Model

010

013

017

020

025

029

034

Minimum Flow

Flow Rate gpm L/s

Pressure Drop ft. kPa

15.0

0.9

2.4

7.1

19.5

1.2

24.0

1.5

30.0

1.9

34.5

2.2

1.5

1.7

2.3

1.8

4.5

5.0

6.8

5.3

40.7

2.6

49.8

3.1

1.7

1.6

5.0

4.7

Nominal Flow

Flow Rate gpm L/s

Pressure Drop ft. kPa

24.0

1.5

5.8

17.3

31.2

2.0

38.4

2.4

48.0

3.0

55.2

3.5

3.7

4.1

5.6

4.3

11.0

12.2

16.7

13.0

65.0

4.1

79.7

5.0

4.0

3.9

12.1

11.7

Maximum Flow

Flow Rate gpm L/s

Pressure Drop

ft. kPa

40.0

2.5

15.2

45.5

52.0

64.0

80.0

92.0

3.3

4.0

5.0

5.8

9.6

10.7

14.5

11.4

28.9

32.1

43.4

34.3

108.4

6.8

132.8

8.4

10.9

32.6

10.4

31.2

AGZ 010A through 034A IOMM AGZ1

Control Layout and Operation

Control Center

All electrical controls are enclosed in a weatherproof control center with tool-locked, hinged access doors. The left-hand section contains the microprocessor controller and control input and output terminals. All high-voltage components are located on the right side of the panel.

ON/OFF Switch

Control

Transformer

24-Volt Trans.

MicroTech II

SpeedTrol Location

Field Connection

Terminals

Non-Fused Disc.

Power Block

Fan

Contactors

Fan

Protection

Compressor Contactors

Start-up and Shutdown

Pre Start-up

1. The chilled-water system should be flushed and cleaned. Proper water treatment is required to prevent corrosion and organic growth.

2. Open all electric disconnects and check all electric connections for tightness.

3. Inspect all water piping for flow direction and correct connections at the evaporator.

4. Verify thermostat water temperature sensor is installed in the leaving water line (supply to building). On all AGZ units the sensor well and sensor are factory mounted.

5. Check compressor oil level. The oil level should be visible in the oil sightglass.

6. Check voltage of the unit power supply and make certain voltage is within

10% of nameplate rating. Check unit power supply wiring for proper ampacity and a minimum insulation temperature of 75

C. Check for proper phasing using a phase sequence meter.

7. Verify all mechanical and electrical inspections have been completed according to local codes.

8. Open control stop switch S1(off). Turn on the main power and control disconnect switches. This will energize crankcase heaters. Wait at least 24 hours before starting up unit.

9. Open all water flow valves and start the chilled water pump. Check all piping for leaks and vent the air from the evaporator as well as from the system piping. Flush the evaporator and system piping to obtain clean, noncorrosive water in the evaporator.

Start-up

1. Set temperature controller to the desired chilled water temperature. Set the chilled water

Delta-T.

2. Start auxiliary equipment by turning on the following: time clock (if present), ambient thermostat and/or remote on/off switch, chilled water pump.

3. If the controller calls for cooling, the unit will begin the start-up sequence.

4. After running the unit for a short time, check the oil level in the compressor (1/4 to 1/3 of the glass), rotation of fans, and flashing in refrigerant sightglass.

IOMM AGZ1 AGZ 010A through 034A

5. Verify superheat temperature is at the factory setting of 8 to 12 degrees F (4.4 to 6.7 degrees C).

6. After system performance has stabilized, complete the current AGZ Start-Up Form (obtainable from the local McQuay sales office) to establish inception of warranty benefits. Return the form to McQuay International through your sales representative.

Sequence of Operation

The following sequence of operation is typical for Models AGZ 010A through AGZ 034A. It can vary depending upon options.

Start-Up

With the control circuit power on, 115V power is applied through the control circuit fuse F1 to the compressor crankcase heaters, the compressor motor protections and the primary of the 24V control circuit transformer. The 24V transformer provides power to the microprocessor controller.

When a remote time clock, manual switch, or the unit controller turns on the chilled water pump, the flow switch closes and satisfies the flow requirement. If the chilled water temperature is above the stage-on temperature, and all equipment protection devices are closed, the unit will start. The controller will operate the unit in response to the leaving chiller water temperature, reset signals that may be present and any equipment protection signals that may occur.

Equipment Protection Alarms

The following conditions will shut down the unit and activate the alarm circuit:

•

No evaporator water flow

•

High condenser pressure

•

Phase voltage protection (Optional)

•

Evaporator freeze protection

Low evaporator pressure

Motor protection system

Outside ambient temperature

Sensor failures

The following alarms will limit unit operation:

•

Condenser pressure stage down, unloads unit at high discharge pressures

•

Low ambient lockout, shuts off unit at low ambient temperatures

•

Low evaporator pressure hold, holds stage #1 until pressure rises

•

Low evaporator pressure unload, shuts off stage #2

Unit Enable Selection

Enables unit operation from local keypad, digital input, or Building Automation System.

Unit Mode Selection

Selects standard cooling, ice, glycol, or test operation mode.

Condenser fan control

Control of condenser fans is provided by the MicroTech II controller. The control steps condenser fans based on discharge pressure.

Shutdown

As the leaving water control is satisfied, it will stage off the lag compressor unloading the unit. The second stage will de-energize the liquid line solenoid valve SV1 and shut off the lead compressor.

The compressor crankcase heaters will energize when the compressors shut off, keeping the small

amount of refrigerant in the plate heat exchanger from migrating to the compressor. See page 38 for

detailed explanation of compressor staging.

AGZ 010A through 034A IOMM AGZ1

Physical Data

Table 3, Physical Data, AGZ 010A through 017A

PHYSICAL DATA

010A

AGZ MODEL NUMBER

013A 017A

BASIC DATA

Unit Capacity @ ARI Conditions (1), Tons (kW)

Number Of Refrigerant Circuits

Unit Operating Charge, R-22, Lb. (kg)

Cabinet Dimensions, LxWxH, In.

Cabinet Dimensions, LxWxH, (mm)

Unit Operating Weight, Lb. (kg)

Unit Shipping Weight, Lb. (kg)

Add'l Weight If Copper Finned Coils, Lb. (kg)

COMPRESSORS

Type

Nominal Tons Per Compressor

Oil Charge Per Compressor, Oz. (g)

9.8 (34.3)

22.0 (10.0)

73.6 x 46.3 x 50.8

220 (99.7)

13.3 (46.6)

24.0 (10.9)

73.6 x 46.3 x 50.8

220 (99.7)

Scroll

6.0 / 6.0

60 (1701)

Scroll

7.5 / 7.5

140 (3969)

CAPACITY REDUCTION STEPS - PERCENT OF COMPRESSOR DSPLACEMENT

Standard Staging 0 – 50 – 100 0 – 50 – 100

CONDENSERS - HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLING

Coil Face Area, One of Two Sides, Sq. Ft. (M

) 30.3 (2.8) 30.3 (2.8)

Finned Height x Finned Length, In.

Finned Height x Finned Length, (mm)

84 x 52

(2134) x (1321)

84 x 52

(2134) x (1321)

Fins Per Inch x Rows Deep

Pumpdown Capacity Lb. (kg)

16 x 2

35.3 (16.0)

16 x 2

35.3 (16.0)

15.9 (55.7)

31.0 (14.1)

73.6 x 46.3 x 50.8

(1869) x (1176) x (1289) (1869) x (1176) x (1289) (1869) x (1176) x (1289)

1090 (495) 1340 (608) 1450 (658)

1160 (527) 1400 (636) 1515 (688)

220 (99.7)

Scroll

9.0 / 9.0

140 (3969)

0 – 50 – 100

30.3 (2.8)

84 x 52

(2134) x (1321)

16 x 3

50.3 (22.8)

CONDENSER FANS - DIRECT DRIVE PROPELLER TYPE

Number Of Fans - Fan Diameter, In. (mm)

Number Of Motors - HP (kW)

Fan And Motor RPM, 60 Hz

60 Hz Total Unit Airflow, CFM (l/s)

DIRECT EXPANSION EVAPORATOR - BRAZED PLATE-TO-PLATE

2 – 26 (660)

2 – 1.0 (0.75)

1140

13950 (6584)

Connection Size Victaulic, In. (mm)

Water Volume, Gallons (L)

Maximum Refrigerant Working Pressure, psig (kPa)

Maximum Water Pressure, psig (kPa)

NOTE:

Nominal capacity based on 95°F ambient air and 54°F/44°F water range.

2 (51)

.94 (3.6)

450 (3103)

350 (2413)

2 – 26 (660)

2 – 1.0 (0.75)

1140

13950 (6584)

2 (51)

1.66 (6.3)

450 (3103)

350 (2413)

2 – 26 (660)

2 – 1.0 (0.75)

1140

12000 (5664)

2 (51)

2.00 (7.6)

450 (3103)

350 (2413)

IOMM AGZ1 AGZ 010A through 034A

Table 4, Physical Data, AGZ 020A through 034A

PHYSICAL DATA

020A

AGZ MODEL NUMBER

025A 029A 034A

BASIC DATA

Unit Capacity @ ARI Conditions (1), Tons (kW)

Number Of Refrigerant Circuits

Unit Operating Charge, R-22, Lb. (kg)

Cabinet Dimensions, LxWxH, In.

Cabinet Dimensions, LxWxH, (mm)

Unit Operating Weight, Lbs. (kg)

Unit Shipping Weight, Lbs. (kg)

Add'l Weight If Copper Finned Coils, Lb. (kg)

COMPRESSORS

20.4 (71.4)

1700 (772)

350 (159)

22.7 (79.5)

1750 (794)

350 (159)

28.2 (98.7)

2000 (908)

435 (197)

34.0 (119.0)

34.0 (15.4) 36.0 (16.3) 47.0 (21.3) 50.0 (22.7)

106.2x 46.3 x 50.8 106.2x 46.3 x 50.8

106.2x 46.3 x 58.8

(2697) x (1176) x

(1289)

1620 (735)

(2697) x (1176) x

(1289)

1675 (760)

(2697) x (1176) x

(1493)

1930 (876)

(2697) x (1176) x

(1493)

2180 (990)

2230 (1012)

435 (197)

Type

Nominal Horsepower

Oil Charge Per Compressor, Oz. (g)

Scroll

10.0 / 13.0

140 (3969)

Scroll

13.0 / 13.0

140 (3969)

CAPACITY REDUCTION STEPS - PERCENT OF COMPRESSOR DISPLACEMENT

Standard Staging 0 – 45 - 100 0 – 50 – 100

CONDENSERS - HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLING

Coil Face Area, One of Two Sides, Sq. Ft. (M

)

Finned Height x Finned Length, In.

Finned Height x Finned Length, (mm)

49.0 (4.6)

84 x 84

(2134) x (2134)

49.0 (4.6)

84 x 84

(2134) x (2134)

58.3 (5.4)

100 x 84

58.3 (5.4)

100 x 84

(2545 ) x (2134) (2545 ) x (2134)

Fins Per Inch x Rows Deep 16 x 2 16 x 2 16 x 3 16 x 3

Pumpdown Capacity lb. (kg) 53.1 (24.0)

CONDENSER FANS - DIRECT DRIVE PROPELLER TYPE

53.1 (24.0) 90.7 (41.1) 92.8 (42.0)

Number Of Fans - Fan Diameter, In. (mm)

Number Of Motors - HP (kW)

Fan And Motor RPM, 60 Hz

60 Hz Total Unit Airflow, CFM (l/s)

3 – 26 (660)

3 – 1.0 (0.75)

1140

20925 (9877)

DIRECT EXPANSION EVAPORATOR - BRAZED PLATE-TO-PLATE

Connection Size Victaulic, In. (mm) 2 (51)

Water Volume, Gallons (L)

Max. Refrigerant Working Pressure, psig (kPa)

2.16 (8.2)

450 (3103)

Maximum Water Pressure, psig (kPa) 350 (2413)

NOTE:

Nominal capacity based on 95°F ambient air and 54°F/44°F water range.

3 – 26 (660)

3 – 1.0 (0.75)

1140

20925 (9877)

2 (51)

3.05 (11.5)

450 (3103)

350 (2413)

Scroll

15.0 / 15.0

140 (3969)

0 – 50 – 100

3 – 26 (660)

3 – 1.0 (0.75)

1140

19800 (9346)

2 (51)

4.00 (15.1)

450 (3103)

350 (2413)

Scroll

20.0 / 20.0

296 (8392)

0 – 50 – 100

3 – 26 (660)

3 – 1.0 (0.75)

1140

19800 (9346)

2 (51)

5.55 (21.0)

450 (3103)

350 (2413)

AGZ 010A through 034A IOMM AGZ1

Electrical Data

Field Wiring

Wiring must comply with all applicable codes and ordinances. Warranty is void if wiring is not in accordance with specifications. Copper wire is required for all power lead terminations at the unit.

AGZ 010A through AGZ 034A units have single point power connection. A single field supplied fused disconnect is required. The control transformer is factory mounted.

If the evaporator heater is on a separate disconnect switch from the main unit power supply, the unit may be shut down without defeating the freeze protection provided by the evaporator heater.

Table 5. AGZ 010A – 034A Electrical Data Single Point

AGZ

Unit

Size

Volts Hz.

Minimum

Circuit

Ampacity

(MCA)

010A

013A

017A

020A

025A

029A

034A

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

See "Electrical Notes" on page 18.

103

110

136

175

Field Wire

Power Supply

Quantity

Wire

Gauge

Quantity

Hub

Nominal

Size

In. (mm)

1.00 (25)

1/0

2/0

1.50 (38)

1.25 (32)

1.00 (25)

1.25 (32)

1.00 (25)

1.25 (32)

1.00 (25)

1.50 (38)

1.00 (25)

Field Fuse Size or HACR Breaker Size

Recommended Maximum

125

150

200

100

125

150

175

100

225

110

100

IOMM AGZ1 AGZ 010A through 034A

Table 6, AGZ 010A – 034A Compressor and Condenser Fan Motor Amp Draw

AGZ

Unit

Size

Volts Hz.

Rated Load Amps

Compressors

No. 1 No. 2

Fan

Motor

(Each)

010A

013A

017A

020A

025A

029A

034A

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

See "Electrical Notes" on page 18.

18.6

9.0

7.4

23.7

12.5

9.1

29.9

15.3

11.6

33.6

16.5

13.7

41.0

21.8

17.3

52.6

23.7

21.7

5.8

2.8

3.0

5.8

2.8

3.0

5.8

2.8

3.0

5.8

2.8

3.0

5.8

2.8

3.0

5.8

2.8

3.0

5.8

2.8

3.0

18.6

9.0

7.4

23.7

12.5

9.1

29.9

15.3

11.6

41.0

21.8

17.3

41.0

21.8

17.3

52.6

23.7

21.7

No. of

Fan

Mtrs

23.7

21.4

10.7

11.5

23.7

21.4

10.7

11.5

23.7

21.4

10.7

11.5

23.7

21.4

10.7

11.5

23.7

21.4

10.7

11.5

23.7

21.4

10.7

11.5

Fan

Motor

(Each)

Locked Rotor Amps

Compressors

Across-The-Line

No. 1 No. 2

23.7

21.4

10.7

11.5

156

189

232

125

100

278

127

100

189

232

125

100

350

158

125

350

158

125

425

187

148

448

225

180

350

158

125

425

187

148

448

225

180

AGZ 010A through 034A IOMM AGZ1

Table 7, AGZ 010A – 034A Field Wiring Data, Single Point Power

Wiring to

Standard Power Block Terminal

AGZ

UNIT

SIZE

Volts HZ.

Maximum

Terminal

Amps (1)

Connector Wire Range

(Copper Wire Only) (3)

Wiring to

Optional Disconnect Switch

Disconnect

Size (2)

Connector Wire Range

(Copper Wire Only) (3)

010A

013A

017A

020E

025A

029E

034A

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

208

230

460

575

175

335

175

14 GA – 2/0

6 GA – 400 kcmil

14 GA – 2/0

NOTES:

1. "Size" is the maximum amperage rating for the terminals or the main electrical device.

2. "Size" is the disconnect part number and not the amperage rating for the terminals or the main electrical device.

3. "Connection" is the range of wire sizes that the terminals on the electrical device will accept.

See page 18 for additional Electrical Notes.

200

160

200

160

200

160

100

175

N/A

200

175

8 GA – 2/0

14 GA – 1 GA

8 GA – 2/0

14 GA – 4 GA

14 GA – 1 GA

6GA – 300 kcmil

14 GA – 4 GA

14 GA – 1 GA

6GA – 300 kcmil

8 GA – 1/0

6GA – 300 kcmil

8 GA – 1/0

6GA – 300 kcmil

8 GA – 1/0

-----

6GA – 300 kcmil

IOMM AGZ1 AGZ 010A through 034A

Notes for “Electrical Data Single Point"

1. Field Fuse Size for recommended and maximum is based on use of a time-delay fuse.

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 including the control transformer.

3. Since the control transformer is furnished, no separate 115v power is required.

4. If a separate 115V power supply is used for the control circuit, then the wire sizing amps is 2

Amps.

5. Recommended power lead wire sizes for 3 conductors per conduit are based on 100% conductor ampacity in accordance with NEC. Voltage drop has not been included. Therefore, it is recommended that power leads be kept short. All terminal block connections must be made with copper (type THW) wire.

6. Single conductors should be used for power connections as listed under “Recommended Power

Lead Wire Size.”

7. “Recommended Fuse Sizes” are selected at approximately 150% to 225% of the largest compressor RLA, plus 100% of all other loads in the circuit.

8. “Maximum Fuse Sizes” are selected at approximately 225% of the largest compressor RLA, plus

100% of all other loads in the circuit.

9. The recommended power lead wire sizes are based on an ambient temperature of 86°F.

Ampacity correction factors must be applied for other ambient temperatures. Refer to the

National Electrical Code Handbook.

Power Limitations:

1. Voltage within 10% of nameplate rating.

2. Phase imbalance within 3%.

Notes for “Compressor and Condenser Fan Amp Draw”:

1. Compressor RLA values are for wiring sizing purposes only but do not reflect normal operating current draw at rated capacity.

Notes for “Field Wiring Data” - Single Point Power:

1. Single point power supply requires a single disconnect to supply electrical power to the unit.

This power must be fused.

2. All field wiring to unit power block or non-fused disconnect switch must be copper.

3. All field wire size values given in table apply to 75°C rated wire per NEC.

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

Figure 7, AGZ 010A through AGZ 034A, Typical Field Wiring Diagram

3 PHASE

POWER

SUPPLY

DISCONNECT

(BY OTHERS OR

FACTORY OPTION)

UNIT MAIN

TERMINAL BLOCK

FUSED CONTROL

CIRCUIT TRANSFORMER

GND LUG

TO COMPRESSOR(S)

AND FAN MOTORS

120 VAC

OPTIONAL REMOTE

120 VAC CONTROL POWER

SEPARATE EVAPORATOR

HEATER POWER

OPTION

120VAC

(BY OTHERS)

DISCONNECT

(BY OTHERS)

DISCONNECT

(BY OTHERS)

10A

FUSE

(BY OTHERS)

10A

FUSE

(BY OTHERS)

TB1

TB1-20

CONTROL

CIRCUIT

FUSE

IF SEPARATE EVAPORATOR

HEATER POWER OPTION

IS USED - REMOVE

MECHANICAL JUMPER

BETWEEN TB1-5 AND

TB1-6 & TB1-15 AND

TB1-16

120 VAC

CHW PUMP RELAY

(BY OTHERS)

120 VAC 1.0 AMPS MAX

ALARM BELL

OPTION

FIELD WIRED

120 VAC

ALARM BELL

RELAY

TIME

CLOCK

OFF

AUTO

REMOTE STOP

(BY OTHERS)

CHW FLOW SWITCH

--MANDATORY--

(BY OTHERS)

MANUAL

NOR. OPEN PUMP AUX.

CONTACTS (OPTIONAL)

ICE MODE SWITCH

(BY OTHERS)

330258401

4-20 MA FOR

CHW RESET

(BY OTHERS)

OFF

AUTO

MANUAL

TB2

GND

843

IF REMOTE STOP CONTROL

IS USED, REMOVE LEAD 843

FROM TERM 25 TO 35.

Rx-/Tx-

J11

Rx+/Tx+

GND

COMMUNICATION

PORT

Note: See control and power wiring diagrams on unit control panel for specific unit information.

AGZ 010A through 034A

Dimensional Data

Figure 8, AGZ 010A through 017A

ACCESS

PANEL

14.59

(370.59)

3.00

(78.20)

QTY. 2

EVAP.

INLET

EVAP.

OUTLET

31.70

(805.18)

11.27

(286.26)

AGZ

Unit Size

AGZ 010

AGZ 013

AGZ 017

27.8 (706.1)

24.3 (617.2)

24.4 (619.8)

5.11 (129.79)

0.875 (22.23)

POWER ENTRY

KNOCKOUT

(OTHER SIDE)

0.875

(22.23)

CONTROL

ELECTRICAL

KNOCKOUT

39.63

(1006.6)

24.00

(609.6)

AIR

FLOW

49.06

(1246.12)

46.20

(1173.48)

73.57

(1868.68)

21.12

(536.45)

Center of Gravity

Inches (mm)

22.7 (576.6)

22.5 (571.5)

22.4 (569.0)

3.88 (98.55)

MOUNTING HOLES

QTY. 4 01.00

19.2 (487.7)

19.1 (485.1)

AIR

FLOW

46.14

(1171.96)

CONTROL

PANEL

ACCESS

DOORS

ACCESS DOOR

30.91

(785.11)

MOUNTING

HOLES

7.75

(196.85)

Evaporator Connection

Size

Inch Victaulic

POWER

ENTRY

51.00

(1295.40)

AIR

FLOW

Figure 9, AGZ 020A through 034A

ACCESS

PANEL

14.59

(370.59)

3.00

(76.20)

QTY. 2

EVAP.

INLET

EVAP.

OUTLET

31.70

(805.18)

11.27

(286.26)

5.11 (129.79)

0.875 (22.23)

POWER ENTRY

KNOCKOUT

(OTHER SIDE)

0.875

(22.23)

CONTROL

ELECTRICAL

KNOCKOUT

AIR

FLOW

49.0

(1246.12)

MOUNTING HOLES

QTY. 6 01.00 (25.40)

106.15

(2696.21)

49.06

(1246.12)

46.20

(1173.48)

21.12

(536.45)

3.88

(98.55)

AIR

FLOW

46.14

(1171.96)

CONTROL

PANEL

ACCESS

DOORS

POWER

ENTRY

ACCESS DOOR

AIR

FLOW

30.91

(785.11)

MOUNTING

HOLES

7.75

(196.85)

AGZ

Unit Size

AGZ 020

AGZ 025

AGZ 029

AGZ 034

Dimensions

Inches (mm)

B C X

Center of Gravity

Inches (mm)

24.0 (609.6) 39.6 (1006.6) 51.0 (1295.4) 33.8 (858.5) 22.4 (569.0)

24.0 (609.6) 39.6 (1006.6) 51.0 (1295.4) 33.7 (856.0) 22.2 (564.0)

33.0 (838.2) 47.6 (1209.8) 59.0 (1498.6) 36.5 (927.1) 23.1 (586.7)

33.0 (838.2) 47.6 (1209.6) 59.0 (1498.6) 35.0 (889.0) 23.1 (586.7)

20.2 (513.1)

20.1 (510.5)

22.6 (574.0)

21.4 (543.6)

Evaporator

Connection Size

Inch Victaulic

AGZ 010A through 034A IOMM AGZ1

System Maintenance

General

On initial start-up and periodically during operation, it will be necessary to perform certain routine service checks. Among these are taking electric leg readings. Some readings are readily available on the MicroTech II display.

Lubrication

No routine lubrication is required on the AGZ units. The fan motor bearings are of the permanently lubricated type and require no lubrication.

Electrical Terminals

WARNING

Electric shock hazard. Turn off all power before continuing with following service.

Normal heating and cooling of the wire will cause terminals to loosen. Retighten all power electrical terminals every six months.

Condensers

Condensers are air-cooled and constructed with 3/8” (9.5mm) O.D. internally finned copper tubes bonded in a staggered pattern into slit aluminum fins. No maintenance is ordinarily required except the occasional removal of dirt and debris from the outside surface of the fins. Use locally purchased foaming condenser coil cleaners for periodic cleaning of the coil. Condenser cleaners may contain harmful chemicals, be careful when using cleaners. Care should be taken not to damage the fins during cleaning. All chemical cleaners should be thoroughly rinsed from the coils.

Refrigerant Sightglass

Observe the refrigerant sightglass monthly. A clear glass of liquid indicates adequate sub-cooled refrigerant charge in the system to ensure proper feed through the expansion valve. Bubbling refrigerant in the sightglass indicates the system is short of refrigerant charge. Sub-cooling should be verified to prevent overcharging. Refrigerant gas flashing in the sightglass could also indicate an excessive pressure drop in the line, possibly due to a clogged filter-drier or a restriction elsewhere in the system. The sightglass indicates what moisture condition corresponds to a given element color. If the sightglass does not indicate a dry condition after about 12 hours of operation, the refrigerant or oil should be tested for moisture.

IOMM AGZ1 AGZ 010A through 034A

Standard MicroTech II Controller

Overview ............................................................................. 23

General Description .............................................................23

Compressor Motor Description ....................................... 23

FanTrol Head Pressure Control ....................................... 23

Inputs/Outputs ................................................................ 24

Setpoints ........................................................................24

Equipment Protection Alarms ......................................... 26

Limit Alarms .................................................................. 26

Unit Enable .................................................................... 26

Unit Mode Selection ....................................................... 27

Low Ambient Start ......................................................... 27

Automatic Adjusted Range Limits .................................. 28

Compressor Staging Parameters ...................................... 28

Using the Controller ............................................................ 30

Display and Keyboard.....................................................30

Getting Started..................................................................... 30

Menu Screens ................................................................. 31

Menu Matrix .................................................................. 33

View Screens Defined..................................................... 34

Alarm Screens Defined ...................................................36

Set Screens Defined........................................................ 36

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

Overview

MicroTech II’s state-of-the-art design will not only permit the chiller to run more efficiently, but will also simplify troubleshooting if a system failure occurs. Every MicroTech II controller is programmed and tested prior to shipment to contribute to a trouble-free start-up.

Operator-friendly

The MicroTech II menu structure is separated into three distinct categories, which provide the operator or service technician with a full description of current unit status, control parameters, and alarms. Security protection prevents unauthorized changing of the setpoints and control parameters.

MicroTech II continuously performs self-diagnostic checks, monitoring system temperatures, pressures and protection devices, and will automatically shut down a compressor or the entire unit should a fault occur. The cause of the shutdown will be retained in memory and can be easily displayed in plain English for operator review. The MicroTech II chiller controller will also retain and display the time the fault occurred. In addition to displaying alarm diagnostics, the MicroTech II chiller controller also provides the operator with a warning of limit (pre-alarm) conditions.

Staging

The two scroll compressors are staged on and off as a function of leaving chilled water temperature.

Lead/lag is automatic and switched every ten starts.

General Description

Compressor Motor Protection

AGZ 013 – 034: The solid-state compressor motor protector module incorporates a 2-minute “time-

off” relay utilizing the bleed-down capacitor principle. Any time the protection system opens or power to the module is interrupted, the 2-minute “time-off” delay is triggered and the module will not reset for two minutes. Once the 2-minute period has passed the motor protector contacts M1 and M2 reset, provided the protection system is satisfied and power is applied to the module.

Note: If the power circuit is broken once the 2-minute period is passed, the pilot circuit will

reset without delay when power is reapplied.

AGZ 010: The model AGZ 010 compressor has internal line breakage with automatic reset.

FanTrol Head Pressure Control

FanTrol is the standard method of head pressure control that automatically cycles the condenser fan motors in response to condenser pressure. This function is controlled by the microprocessor, maintains head pressure and allows the unit to run at low ambient air temperatures down to 35

(1.7

C). Fans are staged as follows:

Table 8, Fan Staging Pressures

Fan Two-Fan Unit Three-Fan Unit

Stage #1 On 150 psig, Off with unit On 150 psig, Off with unit

Stage #2 On 290 psig, Off 170 psig On 290 psig, Off 170 psig

Stage #3 On 310 psig, Off 180 psig

Note: Fan #1 is on with first compressor above 75

F (24

C).

AGZ 010A through 034A

Inputs/Outputs

Table 9, Inputs and Outputs

Analog Inputs

# Description

Reset of Leaving Water Temperature

Evaporator Refrigerant Pressure

Condenser Refrigerant Pressure

Leaving Evaporator Water Temperature

Outside Ambient Temperature

Analog Outputs

1 None

Description

Digital Inputs

Description

Unit OFF Switch

Remote Start/Stop

Evaporator Water Flow Switch

Motor Protection

Ice Mode Switch

Phase Voltage Fault

Open

Digital Outputs

# Description

Alarm

Evaporator Water Pump

Liquid Line

Motor Control Relay #1

Motor Control Relay #2

Condenser Fan #1

Condenser Fan #2

Condenser Fan #3

Signal Source

4-20 mA Current

0.1 to 0.9 VDC

Thermister (10k at 77

F, 25

Thermister (10k at 77

F, 25

Signal

0 VAC (Stop)

0 VAC (No Flow)

0 VAC (Fault)

0 VAC (Normal)

0 VAC (Fault)

Load

Alarm Indicator

Pump Contactor

Solenoid

Starter

Fan Contactor

Output Signal

Output OFF

Alarm OFF

Pump OFF

Cooling OFF

Compressor OFF

Fan OFF

Range

0-(10 to 80°F)

0 to 132 psi

3.6to 410 psi

-58 to 212°F

Signal

24 VAC (Auto)

24 VAC (Start)

24 VAC (Flow)

24 VAC (No Fault)

24 VAC (Ice)

24 VAC (No Fault)

Range

Output ON

Alarm ON

Pump ON

Cooling ON

Compressor ON

Fan ON

Setpoints

The setpoints shown in Table 10 are battery-backed and remembered during power off, are factory set

to the Default value, and can be adjusted within the value shown in the Range column.

The PW (password) column indicates the password level that must be entered in order to change the setpoint. Passwords are as follows:

O = Operator [0100]

M = Manager, M level settings are not normally changed for chilled water air-conditioning applications.

AGZ 010A through 034A IOMM AGZ1

Table 10, Setpoints

Description

Unit

Unit Enable

Unit Mode

Control Source

Default

OFF

COOL

Available Modes COOL

Display Units

Language

Evap LWT (COOL & GLYCOL)

Ice LWT (ICE)

Evap Delta T

Startup Delta T

* Condenser Fans Stages

* Phase Voltage Protection

* SpeedTrol Option

Staging

Stage Up Delay

Stage Down Delay

Timers

Evap Flow Proof

Low Evap Pressure Delay

Start-Start

Stop-Start

Alarms

Evaporator Freeze

Low Evap Pressure

Low Evap Pressure-Hold

Low Evap Pressure-Unload

High Condenser Stage Down

High Condenser Pressure

* Low Ambient Lockout

Condenser Fans

Fan Stages

Stage #1 On

Stage #2 On

Stage #3 On

Stage #1 Off

Stage #2 Off

Stage #3 Off

Sensor Offsets

Evaporator Refrig Press Sensor Offset

Condenser Refrig Press Sensor Offset

Leaving Evaporator Water Temp Sensor

Outside Ambient Temperature Sensor

(*) These items are factory set prior to shipment.

F/psi

ENGLISH

44. 0

40. 0

10. 0

2.0

120

5 sec

30 sec

15 min

5 min

36.0

58 psi

59 psi

370 psi

380 psi

35.0

150psi

290 psi

310 psi

Off

170 psi

180 psi

00.0 psi

0.0

SWITCHES

Range

OFF, ON

COOL

COOL w/Glycol

ICE w/Glycol

TEST

SWITCHES, KEYPAD,

NETWORK

COOL

COOL w/GLYCOL

COOL/ICE w/GLYCOL

TEST

F/psi

ENGLISH,

20.0 to 60.0

20.0 to 40.0

6.0 to 16.0

1.0 to 10.0

2,3

N,Y

20 to 240 sec

10 to 60 sec

3 to 120 sec

15 sec to 30sec

10 to 60 min

3 to 20 min

18 to 42

30 to 60 psi

31 to 65 psi

365 to 375 psi

380 to 390 psi

–2 to 60

2-3

140 to 200 psi

230 to 330 psi

Off with Stage #1

150 to 200 psi

-20.0 to 20.0 psi

-5.0 to 5.0

IOMM AGZ1 AGZ 010A through 034A

Equipment Protection Alarms

Equipment protection alarms execute rapid compressor shutdown.

The following table identifies each equipment protection alarm, gives the condition that causes the alarm to occur, and states the action taken because of the alarm. If the alarm is auto-clearing, the reset condition is shown below. Otherwise, the alarm is manually reset, requiring the operator to clear the alarm.

Table 11, Shutdown Alarms

Description

No Evaporator Water Flow

Low Evaporator Pressure

High Condenser Pressure

Motor Protection

Phase Voltage Protection

(opt)

Low Ambient Restart Fault

Evaporator Freeze Protect

Leaving Evaporator Water

Temperature Sensor Fault

Evaporator Pressure Sensor

Fault

Condenser Pressure Sensor

Fault

Outside Ambient

Temperature Sensor Fault

NOTE: SP=SetPoint

Occurs When:

Evap Pump State = RUN and Flow Switch

Digital Input = No Flow and time greater than

Evap Flow Proof SP

Evaporator Press < Low Evap Pressure SP start

Low Evap Pressure Time Delay – if after Time

Delay if Evap Press > SP continue else stop

Condenser Press > High Condenser Pressure

Digital Input = High Motor Temperature

On Power Up – Delay 150 Sec. before checking

If Phase Voltage Protection = Y, Then Digital

Input = Phase/Voltage Problem

Failed three consecutive low ambient start attempts

Evap LWT < Evaporator Freeze SP

Sensor shorted or open

Sensor is open or shorted

Action

Taken

Rapid Stop

Reset

Flow Switch

Closes

Manual

Phase/Voltage

Input Returns to Normal

Manual

Limit Alarms

The following alarms limit the operation of the chiller in some way as described in the Action Taken column. These alarms are auto-clearing based on reaching the conditions in the reset column.

Table 12, Limit Alarms

Description

Condenser Pressure

Stage Down

Low Ambient

Lockout

Low Evaporator

Pressure – Hold

Low Evaporator

Pressure – Unload

NOTE: SP = Set Point

Occurs When:

Pressure > High Condenser Stage

Down setpoint

Any compressor is running AND

Outside Ambient < Low Amb Lockout

Pressure < Low Evap Pressure–Hold setpoint

Pressure < Low Evap Pressure–

Unload setpoint

Action Taken

Shutoff

Stage #2

Shutoff Stages #1

& #2

Hold @

Stage 1

Shutoff

Stage 2

Reset

Condenser Press drops below (SP – 100psi)

Outside Ambient > Low

Amb Lockout

(SP + 5ºF)

Evap Press rises above

(SP + 8psi)

Evap Press rises above

(SP + 10 psi)

Unit Enable

Enabling and disabling the chiller is controlled by the Unit Enable Setpoint with options of OFF and

ON. This setpoint can be altered by the Unit Off Input, Remote Input, keypad entry, or BAS request.

The Control Source setpoint determines which source can change the Unit Enable setpoint with options of SWITCHES, KEYPAD, or NETWORK

Changing the Unit Enable Setpoint can be accomplished according to the following table.

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

Table 13, Unit Enable Conditions

Unit Off

Input

OFF x

Control Source

Set Point x

SWITCHES

KEYPAD

NETWORK

Remote Input x

OFF

X x

OFF

ON NETWORK ON

NOTE: An “x” indicates that the value is ignored

Keypad Entry x x x

OFF

ON x x x

BAS Request x x x x x

OFF x

Enable

OFF

Unit Mode Selection

The overall operating mode of the chiller is set by the Unit Mode Setpoint with options of COOL,

COOL w/Glycol, ICE w/Glycol, and TEST. This mode setting can be altered by the keypad, BAS, and Mode input. Changes to the Unit Mode Set Point are controlled by two additional setpoints.

•

Available Modes Setpoint: Determines the operational modes available at any time with options of COOL, COOL w/Glycol, COOL/ICE w/Glycol, and TEST.

•

Control Source Setpoint: Determines the source that can change the Unit Mode Set Point with options of KEYPAD, NETWORK, or SWITCHES.

Changing the Unit Mode Setpoint can be accomplished according to the following table.

Table 14, Unit Mode Selection

Control Source

Set Point

Mode

Input

Keypad Entry x x

SWITCHES

KEYPAD

NETWORK

NETWORK x x x

OFF

ON x x x x x

NOTE: An “x” indicates that the value is ignored.

x x x x

COOL w/Glycol

ICE w/Glycol x x x

BAS

Request x x x x x x

COOL

ICE x

Available Modes

Set Point

COOL

COOL w/Glycol

COOL/ICE w/Glycol

TEST

Unit Mode

COOL

COOL w/Glycol

ICE w/Glycol

COOL w/Glycol

ICE w/Glycol

COOL w/Glycol

ICE w/Glycol

TEST

Low Ambient Start

If SpeedTrol = N, the unit will start in the normal operation. If the SpeedTrol = Y then starting will follow table below. This step will bypass the “Low Evaporator Pressure” alarm until Low Ambient

Start is completed.

Low Ambient Start Method

Table 15, Low Ambient Start Sequence

Description

Check #1

Check #2

Check #3

Check #4

Occurs When:

After 15 Seconds after starting Lead Compressor, If the

Evap Press is < 28 take Action or else continue

After 15 Seconds after Check #1, If the Evap Press is < 38 take Action or else continue

After 15 Seconds after Check #2, If the Evap Press is < 48 take Action or else continue

After 15 Seconds after Check #3, If the Evap Press is <

Low Evap Pressure SP take Action or else continue in normal operation

Action Taken

Rapid Stop – See Low Ambient

Re-Start below

Rapid Stop – See Low Ambient

Re-Start below

Rapid Stop – See Low Ambient

Re-Start below

Rapid Stop – See Low Ambient

Re-Start below

Low Ambient Restart

If the Evap Pressure fails during the low-ambient start, the controller will wait until the anti-cycle timers expire then try to restart. It will allow unit to attempt to start 3 times. If the unit starts successfully, the counter is reset. If it fails to start on the third attempt, the Low Ambient Restart

Alarm Fault (Manual Reset) will be activated.

AGZ 010A through 034A

Automatic Adjusted Limits

The following setpoint ranges will be adjusted automatically based on selected options or mode of operation.

Evaporator Leaving Water Temperature

Mode

Unit Mode = Cool

Unit Mode = Cool w/ Gycol

Evaporator Freeze Temperature

Mode

Unit Mode = Cool

Unit Mode = Cool w/Glycol,

Ice w/ Glycol

Low Evaporator Pressure

Mode

Unit Mode = Cool

Unit Mode = Cool w/Glycol,

Ice w/ Glycol

Low Evaporator Pressure Hold and Unload

Mode

Unit Mode = Cool

Unit Mode = Cool w/Glycol,

Ice w/ Glycol

Low Ambient Lockout Temperature

SpeedTrol

SpeedTrol = N

SpeedTrol = Y

Range

40 to 60

20 to 60

Range

36 to 42

18 to 42

Range

55 to 60 Psig

30 to 60 Psig

Range

55 to 65 Psig

31 to 65 Psig

Range

35– 60

-2 – 60

Compressor Staging Parameters

The following table gives the rules for staging the two compressors. This is further explained in the

MENU section of the manual.

Cool, Glycol

Description

Stage #1 ON

Stage #2 ON

Occurs When:

Lvg Evap T > Evap LWT SP + (CB/2) +

Startup Delta T

After Stage Up Delay times out then, LVG

Evap T > Evap LWT SP + (CB/2)

Stage #2 OFF

Stage #1 OFF

After Stage Down Delay times out then, LVG

Evap T < Evap LWT SP - (CB/2)

After Stage Down Delay times out then, LVG

Evap T < Evap LWT SP - (CB/2)

Note: CB (Control Band) = Evap Water Delta T x .6

Action Taken

Lead Compressor ON

Lag Compressor ON

Lag Compressor OFF

Lead Compressor OFF

ICE

In ICE mode, the controller stages ON the compressors to stage 2 as shown above until the LWT is < the ICE LWT SP. At this point compressors #1 and #2 shut down simultaneously.

Compressor Lead/ Lag

The compressor designated as the lead will be the first to start and the last to shut off. Lead/lag designation is switched based on the number of starts. After 10 starts on Compressor #1 as lead,

Compressor #2 starts as Lead for 10 starts, and then the cycle is repeated.

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

Capacity Overrides

The following conditions will override the capacity control when the chiller is in the cool and ice modes.

Low Evaporator Pressure

If the unit is running at stage 1 and the evaporator pressure drops below the Low Evaporator

Pressure-Hold setpoint, the unit will hold at stage 1. This condition will inhibit the unit from loading until the evaporator pressure reaches the hold setpoint plus 8 psi.

If the unit is running at stage 2 and the evaporator pressure drops below the Low Evaporator

Pressure-Unload setpoint, the unit will unload to stage 1. This condition will inhibit the unit from loading until the evaporator pressure reaches the hold setpoint plus 10 psi.

Maximum LWT Rate

The maximum rate at which the leaving water temperature can drop shall be limited at all times by the

Maximum Rate setpoint (2

F/Minute). If the rate exceeds this setpoint, capacity increases shall be held at Stage 1. This limit is not adjustable through the keypad and does not have a presence in any alarm menu.

Discharge Pressure Stage Down

If the unit is running at stage 2 and the condenser pressure rises above the High Condenser Pressure

Stage Down setpoint, the unit will unload to stage 1. This condition will inhibit the unit from loading until the condenser pressure drops below the unload setpoint less 100 psi.

Digital Output Control

Each digital output is controlled according to the following rules and in accordance with whether the unit is in normal operation or TEST (test mode). All outputs are initialized to OFF at power on.

Alarm – (J12 – NO1)

This output is turned ON when any “EQUIPMENT PROTECTION ALARMS” occur. It is turned

OFF when all alarms have been cleared.

Evaporator Pump – (J12 – NO2)

The Evaporator Water Pump output is ON if the Evap State is set to START or RUN.

Liquid Line Solenoid – (J12 – NO3)

This output is ON when the Compressors are ON. It is OFF for all other cases.

Motor Control Relay #1, #2 – (J13 – NO4, J13 – NO5)

This output is ON when the Compressors are ON. It is OFF for all other cases.

Fan #1, #2, & #3 – (J13 – NO6, J14 – NO7, J15 – NO8)

Condenser Fans Staging is based on Condenser pressure as selected Fan Stage On & Off setpoints.

Evaporator Water Pump State Control (Evap State)

Power ON

TEST: Unit =OFF or Unit =ALARM

RUN

OFF

TEST: Unit Enable =

OFF

TEST: Flow OK for

30 Seconds

TEST: Unit Enable = ON

START

The state-transition diagram shown to the left controls operation of the evaporator pump.

A state variable (Evap State) shall be used to maintain the current state (OFF, START, or RUN).

The 30-second timer shall start when flow is first indicated by the

Evaporator Water Flow Switch digital input. This timer will reset if flow is lost before reaching 30 seconds, and it will restart when flow is again detected.

AGZ 010A through 034A

After flow has been present for 30 seconds, the pump state can transition to RUN. In this state, flow has been established so the “No Evap Water Flow” alarm will be active if the flow switch input is

OFF for more than the Evap Flow Proof time. The pump remains in the RUN state until the unit status equals off or alarm.

Using the Controller

4x20 Display & Keypad

Layout

The 4-line by 20-character/line liquid crystal display and 6-key keypad are shown below.

Figure 10, Display (in MENU mode) and Keypad Layout

Key to Screen Pathway

MENU Key

Air Conditioning

<

ALARM

VIEW

SET

ARROW Keys ENTER Key

Note that each ARROW key has a pathway to a line in the display. Pressing an ARROW key will activate the associated line when in the MENU mode.

Getting Started

There are two basic procedures to learn in order to utilize the MicroTech II controller:

1. Navigating through the menu matrix to reach a desired menu screen and knowing where a particular screen is located.

2. Knowing what is contained in a menu screen and how to read that information or how to change a setpoint contained in the menu screen.

Navigating Through the Menus

The menus are arranged in a matrix of screens across a top horizontal row. Some of these top-level screens have sub-screens located under them. The general content of each screen and its location in

the matrix are shown in Figure 12. A detailed description of each menu begins on page 33.

There are two ways to navigate through the menu matrix to reach a desired menu screen.

One is to scroll through the matrix from one screen to another using the four ARROW keys.

The other way is to use shortcuts to work through the matrix hierarchy. From any menu screen, pressing the MENU key will take you to the top level of the hierarchy. The display will show

ALARM, VIEW, and SET as shown in Figure 10. This corresponds to the second row of screens on

Figure 12. One of these groups of screens can then be selected by pressing the key connected to it via

the pathway shown in Figure 10.

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

For example, selecting ALARM will go the next row of menus under ALARM (ALARM LOG or

ACTIVE ALARM). Selecting VIEW will go the next level of screens under VIEW (VIEW UNIT

STATUS or VIEW UNIT TEMP). Selecting SET will go to a series of screens for looking at and changing setpoints.

MENU Key

The MENU key is used to switch between the shortcut method (known as the MENU mode and as

shown in Figure 10) and scrolling method (known as the SCROLL mode). The MENU mode is the

shortcut to specific groups of menus used for checking ALARMS, for VIEWING information, or to

SET setpoint values. The SCROLL mode allows the user to move about the matrix (from one menu

to another, one at a time) by using the four ARROW keys. A typical menu screen is shown in Figure

11.

Pressing the MENU key from any menu screen will automatically return you to the MENU mode as

shown in Figure 10.

Figure 11, Display in the Shortcut (SCROLL) Mode and Keypad Layout

MENU Key

Air Conditioning

VIEW UNIT STATUS

Unit = COOL

Compr. #1/#2=OFF/OFF

Evap Pump = RUN

ARROW Keys

ENTER Key

Menu Screens

Various menus are shown in the controller display. Each menu screen shows specific information; in some cases menus are used only to view the status of the unit, in some cases they are used for checking and clearing alarms, and in some case they are used to set setpoint values.

The menus are arranged in a matrix of screens across a top horizontal row. Some of these top-level screens have sub-screens located under them. The general content of each screen and its location in

the matrix are shown in Figure 12. A detailed description of each menu begins on page 33.

The ARROW keys on the controller are used to navigate through the menus. The keys are also used to change numerical setpoint values contained in certain menus.

Changing Setpoints

Pressing the ENTER key changes the function of the ARROW keys to the editing function as shown below:

LEFT key Default, changes a value to the factory-set default value.

RIGHT key Cancel, cancels any change made to a value and returns to the original setting.

UP key Increment, increases the value of the setting

DOWN key Decrement decreases the value of a setting.

These four edit functions are indicated by one-character abbreviation on the right side of the display

(this mode is entered by pressing the ENTER key).

AGZ 010A through 034A

Most menus containing setpoint values have several different setpoints shown on one menu. When in a setpoint menu, the ENTER key is used to proceed from the top line to the second line and on downward. The cursor will blink at the entry point for making a change. The ARROW keys (now in the edit mode) are used to change the setpoint as described above. When the change has been made, press the ENTER key to enter it. No setting is changed until the ENTER key is pressed.

For example, to change the chilled water setpoint:

1. Press MENU key to go to the MENU mode (see Figure 10).

2. Press SET (the UP Key) to go to the setpoint menus.

3. Press UNIT SPs (the Right key) to go to setpoints associated with unit operation.

4. Press the DOWN key to scroll down through the setpoint menus to the third menu which contains

Evap LWT=XX.X

5. Press the ENTER key to move the cursor down from the top line to the second line in order to make the change.

6. Use the ARROW keys (now in the edit mode as shown above) to change the setting.

7. When the desired value is achieved, press ENTER to enter it. The cursor will automatically move down.

At this point, the following actions can be taken:

1. Change another setpoint in this menu by scrolling to it with the ENTER key

2. Using the ENTER key, scroll to the first line in the menu. From there the ARROW keys can be used to scroll to different menus.

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

Figure 12, Menu Matrix

"MENU"

VIEW UNIT

STATUS

UNIT

VIEW UNIT

TEMP

"VIEW" MENUS

COMP

VIEW COMP VIEW COMP #2

#1 STATUS STATUS

REFRIGERANT

VIEW EVAP/COND PRESS (1)

VIEW EVAP APPROACH (2)

⇐

Continued

⇐

(Right side of matrix continued from above)

FANS

VIEW FAN

STAGING

"ALARM" MENUS

ALARM LOG (LAST)

TYPE, TIME

ALARM LOG

(NEXT TO LAST)

ALARM LOG

(SECOND TO LAST)

ALARM LOG

LAST 25 SHOWN

⇓

ACTIVE ALARM

(1)

TYPE, TIME

SET UNIT SPs, (1)

MODE

"SET" MENUS

SET COMP

SPs (1)

STOP/START

ACTIVE ALARM SET UNIT SPs, (2)

(2)

TYPE, TIME

ADDITIONAL

MODE

COOL/GLYCOL/

ICE

SET COMP

SPs (2) INTER-

STAGE

SET LIMIT

ALARMS (2)

FREEZE/ FLOW

ACTIVE ALARM SET UNIT SPs, (3)

(3)

CLEAR/VIEW

TEMP EVAP LWT

SET UNIT SPs, (4)

MISC

SET UNIT SPs, (5)

CLOCK

SET UNIT SPs, (6)

ENGLISH

SET UNIT SPs, (7)

PROTOCOL

SET UNIT SPs, (8)

EVAP OFFSET

SET UNIT SPs, (9)

COND OFFSET

SET UNIT SPs,

(10) LWT OFFSET

SET UNIT SPs,

(11) AMBIENT

OFFSET

SET UNIT SPs,

(12) ENTER

PASSWORD

SET LIMIT

ALARMS (1)

EVAP PRESS

SET LIMIT

ALARMS (3)

COND PRESS

SET LIMIT

ALARMS (4)

PHASE/VOLT

LOW AMB

LOCKOUT

SET LIMIT

ALARMS (5)

LOW EVAP PR

SET FANS (1)

STAGES

FANTROL

SET FANS (2)

STAGE ON

SET FANS (3)

STAGE OFF

Menu Structure (Hierarchical)

As discussed previously, a hierarchical menu structure can be used to access the various screens. One to twelve levels are used with two or three being typical. Optionally, the last menu selection can access one of a set of screens that can be navigated with the UP/DOWN ARROW keys (see the scrolled menu structure below).

AGZ 010A through 034A

Menu selection is initiated by pressing the MENU key that changes the display from a regular data screen to a menu screen. Menu selections are then made using the arrow keys according to labels on the right side of the display (the arrows are ignored). When the last menu item is selected, the display changes to the selected data screen. An example follows showing the selection of the “VIEW

COMPRESSOR (n) screen.

Suppose the initial screen is as below or any other menu screen:

A L A R M L O G

( d a t a )

After pressing the MENU key, the top level menu screen will show:

< ALARM

< VIEW

< SET

After pressing the “VIEW” menu key, a menu screen will show:

VIEW < UNIT

< COMPRESSOR

< REFRIGRANT

< FANS

Selection of any of these will advance to the appropriate data menu. For example, after pressing the

“REFRIGERANT” menu button, the selected data screen will show:

VIEW REFRIG

PSI

°°°°

F

SAT EVAP XXX.X XX.X

SAT COND XXX.X XX.X

The ARROW keys will automatically return to the “scroll” mode at this time.

Screen Definitions VIEW

This section contains information on each screen. The menu screens are in order of the matrix in

Figure 12, going from left to right and then down when there are sub-menus. Many menus are self-

explanatory.

VIEW UNIT

VIEW UNIT STATUS

Unit = AUTO

Compr.#1/#2=OFF/OFF

Evap Pump = RUN

Unit states can be OFF, AUTO, and ALARM as determined from the Unit State variable, the Unit

Mode setpoint, the Unit Enable and the presence of an alarm.

Compressor states can be OFF/OFF, ON/OFF, OFF/ON, and ON/ON.

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

VIEW UNIT TEMP

°°°°

F

Evap LWT = XX.X

°°°°

F

Outside Amb = XX.X

°°°°

F

LEW Target = XX.X

°°°°

F

LEW Target is the chilled fluid setpoint. It is the temperature that the controller controls to. Evap

LWT is the chilled fluid (usually water) temperature leaving the evaporator..

VIEW COMPRESSORS

VIEW COMP#1

State = OFF LEAD

Hours = XXXXX

Starts = XXXXX

VIEW COMP#2

State = OFF LAG

Hours = XXXXX

Starts = XXXXX

VIEW REFRIGERANT

VIEW REFRIG (1)

psi

°°°°

F

SAT EVAP XXX.X XX.X

SAT COND XXX.X XX.X

VIEW REFRIG (2)

Evap Approach=XX.X

°°°°

F

Approach is the difference between the leaving fluid temperature and the saturated evaporator temperature. It is an indication of the evaporator efficiency; an increasing approach temperature indicates decreasing heat transfer efficiency

VIEW FANS

Stages ON = 2 of 3

AGZ 010A through 034A

Screen Definitions – ALARM

ALARM ACTIVE (X)

Alarm Description hh:mm:ss dd/mmm/yyyy

OR

ALARM ACTIVE (X)

No more alarms

Press ENTER to clear all active alarms

If the unit is off on a shutdown alarm or running but in a limit alarm condition, the cause and date will appear in the upper screen. If there is a simultaneous occurrence of more than one alarm, the others will appear in additional screens below this one, accessed by the DOWN ARROW. Either type alarm will light a red light in back of the LEFT-KEY. The light will go out when the fault is cleared.

To clear the fault, scroll down to the last screen and press ENTER. If other faults have appeared, they will all be cleared at the same time.

ALARM LOG (1)

High Condenser Press

hh:mm:ss d/mmm/yyyy

The last 25 alarms, either shutdown or limit, are shown in this menu with subsequent menus stored under it. ARROW DOWN from this menu will go to the next-to-last alarm, ARROW DOWN again will go to the second from last, and so on through the last 25 occurrences. The screens are numbered

(1), (2), (3), etc.

Screen Definitions – SET

Changing setpoints; in general, setpoints are changed as follows:

1. Select the desired menu by scrolling through SET menus with the UP and DOWN ARROWS.

2. When the desired menu is selected, select the desired entry by moving between lines using the

ENTER key.

3. If a numerical value is being changed, use the INCREMENT key (UP ARROW) to increase or the DECREMENT key (DOWN ARROW) to decrease the value of the setpoint.

If a word type setpoint (for example, YES or NO) is to be selected, the choices are loaded into the menu and selected by scrolling through the available setpoint options using the UP ARROW key.

4. Enter the desired value or word into the controller by pressing the SET key.

AGZ 010A through 034A IOMM AGZ1

SET UNIT SPs

SET UNIT SPs (1)

Unit Enable=OFF

Mode=COOL

Source=KEYPAD

Unit Enable is an external signal or a keypad setting that keeps the unit off when the setting is OFF and allows it to run if there is a call for cooling. The source for the signal is selected in the 4 th

line and can be:

1. KEYPAD, in which case the selection is made in line 2 and would be normally selected as ON.

This is the normal setting when no external signals are controlling the unit.

2. SWITCHES, in which an external switch is wired across terminals #25 and #35. (See wiring

diagram page 19).

3. NETWORK, used with BAS signal, which is wired to the three communication ports.

Unit Mode settings can be

1. COOL, normal setting used with chilled water air-condition applications.

2. COOL w/GLYCOL, used with low temperature, glycol applications. It allows a lower LWT setpoint to be used.

3. ICE w/GLYCOL, used with ice storage systems, allows changing from chilled glycol operation to lower temperature ICE operation. In ICE, the unit runs at full load until the ICE setpoint is reached, at which time the unit shuts off. A three-position switch wired to terminals #28 and #38

initiates the change from glycol cooling to making ice. (See wiring diagram on page 19.)

SET UNIT SPs (2)

Available Modes

=COOL w/Glycol

Set w/ FP Switch Off

Available Modes settings can be COOL, COOL w/Glycol, ICE w/Glycol, or TEST as selected from the available modes imbedded in the menu. The 4 th

line is a reminder that the ON/OFF switch on the front panel (FP) must be in the OFF position before the MODE can be changed. This prevents a mode change while the unit is operating.

SET UNIT SPs (3)

Evap LWT = XX.X

°°°°

F

Ice LWT = XX.X

°°°°

F

EvapDeltaT= XX.X

°°°°

F

IOMM AGZ1 AGZ 010A through 034A

SET UNIT SPs (4)

StartDelta= XX.X

°°°°

F

Staging

StartDelta is the number of degrees above the temperature setting that determines when the lead compressor starts. Compressor start and stop is determined by the dead band and StartDelta settings.

The dead band is automatically set of 60% of the EvapDeltaT selected in menu 3 above. For example, for settings of:

EvapDelta T = 10

F (Dead Band = 6

F) StartDelta = 2

F LWT = 40

EWT 50.0°F

For a warm start-up the lead compressor will start at any temperature above 45

F. The lag will start after the start interval has timed out. The chilled water

Evap Delta-T Set

LWT Set

10.0°F

40.0°F

Start Delta-T

45.0°F

43.0°F

½ DB

40.0°F

37.0°F temperature will begin to be pulled down. At 37

F the lag compressor will shut off. If the temperature climbs above 37

F within the StageDownTimer setting (default at 30 sec.), the lead compressor will remain on. This would be normal operation. If for some reason the temperature does not rise, the lead compressor will also shut off. The lead compressor will start when the chilled water temperature reaches 45

SET UNIT SPs (5)

CLOCK

dd/mmm/yyyy

hh:mm:ss

SET UNIT SPs (6)

Units =

°°°°

F/psi

Lang = ENGLISH

Units settings are only °F/psi at the present time. °C/kPa will be available later.

Lang (Language) settings can be only ENGLISH at present.

SET UNIT SPs (7)

Protocol = NONE

Ident Number=001

Baud Rate=9600

Protocol selection for BAS will be available in June 2002.

SET UNIT SPs (8)

Evaporator Refrig

Press Sensor

Offset= 00.0 psi

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

The pressure offsets on menus 8 and 9 and the temperature offsets on menus 10 and 11 correct the controller's display of the parameters. The sensors used in these units have a high degree of repeatability but may need correction (offset). An accurate pressure gauge or thermometer is used to determine the correct temperature or pressure. A positive or negative offset value is then entered to make the controller reading agree with the measured value.

SET UNIT SPs (9)

Condenser Refrig

Press Sensor

Offset= 00.0 psi

SET UNIT SPs (10)

Leaving Evaporator

Water Temp Sensor

Offset= 00.0

F

SET UNIT SPs (11)

Outside Ambient

Temperature Sensor

Offset= 00.0

F

SET UNIT SPs (12)

ENTER PASSWORD XXXX

Active Password

Level:None

Two four-digit passwords provide OPERATOR and MANAGER levels of access to changeable parameters. The passwords are preprogrammed into the controller. The Operator Password is 0100.

Either password must be entered using the ENTER PASSWORD (12) screen before a protected setting can be changed.

This screen can be accessed either through the SET OTHER menu or by simply pressing the ENTER key while on one of the SET screens. The controller will automatically go from the screen with the setting change to this screen. After the correct password has been entered, the controller will automatically return to the original set screen.

Once a password has been entered, it remains valid for 15 minutes after the last key-press.

SET COMP SPs

SET COMP SPs (1)

Stop-Start =XXmin

Start-Start =XXmin

This menu sets the anti-recycle timers. Stop-Start is the time required before starting a compressor after it has stopped. Start-Start is the time required before starting a compressor after the last time it has started. It recommended that these default values not be changed.

AGZ 010A through 034A

SET COMP SPs (2)

InterStageUp=XXXsec

InterStageDn=XXXsec

InterStageUp is the time delay since the last stage change before a compressor can stage on.

InterStageDn is the time delay since the last stage change before a compressor can stage off normally

(not by an alarm).

SET LIMIT ALARMS

SET ALARM LMTS (1)

LowEvPrHold=XXXpsi

LowEvPrUnld=XXXpsi

LowEvPrStop=XXXpsi

The LowEvPrHold and LowEvPrUnld have the same default value of 59 psi. If two compressors are running, the LowEvPrUnld is in effect and the lag compressor will be shut off to unload the unit. If one compressor is running, the LowEvPrHold is in effect and the lag compressor is prevented from starting, thereby holding the unit capacity.

The last action to take place is the shutoff of all compressors running when the LowEvPrStop setting is reached (default is 58 psi).

SET ALARM LMTS (2)

Evap Freeze= XX.X

°°°°

F

LowEvpPrDelay=XXs

EvapFlowProof=XXXsec

Evap Freeze (the unit freeze protection shutdown) is actually a stop alarm and shuts off the unit when the LWT reaches 36

F. It is cleared by going to the CLEAR ALARM menu in the ACTIVE ALARM hierarchy.

LowEvPrDelay is a time delay on the low pressure trip that reduces nuisance low-pressure trips. The default setting is 30 seconds.

EvapFlowProof is the flow switch interlock. Closing the flow switch and therefor proving the existence of chilled water flow resets this trip.

SET ALARM LMTS (3)

HighCondPr = XXXpsi

HiCondStgDn = XXXpsi

HighCondPr (the unit high-discharge-pressure shutdown) is a stop alarm that shuts off the unit when the discharge pressure reaches the setting. The default setting is 380 psi. The HiCondStDn is a limit alarm that unloads the unit in an attempt to prevent total shutdown from the HighCondPr. The stage down is set at 370 psi.

SET ALARM LMTS (3)

PhaseVoltage=YES/NO

LowAmbientLock=XX

°°°°

F

AGZ 010A through 034A IOMM AGZ1

IOMM AGZ1

LowAmbientLock prevents unit operation below the setting. If the unit is equipped with the standard

FanTrol pressure-activated control, the available range is 35

F to 60

F with a default of 35

F. With the optional SpeedTrol variable speed control, the range becomes –2

F to 60

F with default of 0

Input to line 3 of the next screen, SET FANS SP (1), informs the controller which type of control is installed and which range of setting to allow.

SET FANS STAGES

SET FANS SPs (1)

Fans = 2

Speedtrol = NO

The Fans line tells the controller the number of fans on the unit. The UP ARROW toggles between 1,

2, and 3. 1 is not used; 2 should be used for Models AGZ 010, 013, and 017; and 3 should be used for AGZ 020, 025, 029, and 034.

Speedtrol tells the controller whether the optional SpeedTrol is installed in the unit. The UP

ARROW toggles between YES and NO. The setting changes the range available: YES = 35

F to

F, with 35

F being the recommended setting; NO = -2

F to 60

F, with 0

F being the recommended setting.

SET FANS SPs (2)

Stage ON psi

#1 #2 #3

150 290 310

SET FANS SPs (2)

Stage ON psi

#1 #2

150 290

SET FANS SPs (3)

Stage Off psi

#1 #2 #3

UNIT 170 180

SET FANS SPs (3)

Stage Off psi

#1 #2

UNIT 170

These two menus set the on and off staging pressures for the fans. The left-hand two are for three-fan units, the right-hand two are for two-fan units. The default values are shown in the boxes. These settings are used with both FanTrol and SpeedTrol. SpeedTrol takes effect when the last fan is running after FanTrol cycles off the others.

Editing, Review

Editing is accomplished by pressing the ENTER key until the desired field is selected. This field is indicated by a blinking cursor under it.. The arrow keys shall then operate as defined below.

CANCEL ................... Reset the current field to the value it had when editing began.

DEFAULT ................. Set value to original factory setting.

INCREMENT ............ Increase the value or select the next item in a list.

DECREMENT ........... Decrease the value or select the previous item in a list.

During edit mode, the display shall show a two-character-wide menu pane on the right as shown below.

SET UNIT SPs (X) <D

(data) <C

(data) <+

(data) <-

Additional fields can be edited by pressing the ENTER key until the desired field is selected. When the last field is selected, pressing the ENTER key switches the display out of “edit” mode and returns the ARROW keys to “scroll” mode.

AGZ 010A through 034A

Service

WARNING

Disconnect all power before doing any service inside the unit. Failure to do so can cause serious personal injury.

CAUTION

Service on this equipment is to be performed by qualified service personnel with special regard to regulations concerning release of refrigerant to the atmosphere.

Note: Repeated tripping of safety controls must be investigated and corrected.

Thermostatic Expansion Valve

The expansion valve is responsible for allowing the proper amount of refrigerant to enter the evaporator regardless of cooling load. It does this by maintaining a constant superheat. (Superheat is the difference between refrigerant temperature as it leaves the evaporator and the saturation temperature corresponding to the evaporator pressure.) Typically, superheat should run in the range of 8

F to 12

F (4.4

C to 6.6

C).

The superheat setting can be adjusted by removing the cap at the bottom of the valve to expose the adjustment screw. Turn the screw clockwise (when viewed from the adjustment screw end) to increase the superheat setting and counterclockwise to reduce superheat. Allow time for system rebalance after each superheat adjustment.

The expansion valve, like the solenoid valve, should not normally require replacement, but if it does the unit must be pumped down by following the steps involved when changing a filter-drier.

If the problem can be traced to the power element only, unscrew the element from the valve body without removing the valve, but only after pumping the unit down.

Filter-Driers

If the pressure drop across the filter-drier is in the 6 to 10 psi range, it should be monitored and changed when the pressure drop reaches 10 psi. To change the liquid line sealed filter, de-energize the unit and pump out the refrigerant. After changing the filter-drier, check for leaks before recharging and returning unit to operation.

Liquid Line Solenoid

The liquid line solenoid valve does not normally require any maintenance. It may, however, require replacement of the solenoid coil. The solenoid coil may be removed from the valve body without opening the system by disconnecting power to the unit. The coil can then be removed from the valve body by simply removing the nut or snap ring located at the top of the coil.

AGZ 010A through 034A IOMM AGZ1

Optional Controls

SpeedTrol Head Pressure Control

The SpeedTrol method of head pressure control operates in conjunction with FanTrol by modulating the motor speed on system #1 fan in response to condenser pressure. By reducing the speed of the last fan as the condensing pressure falls, the unit can operate to 0

F (-18

C) ambient air temperature.

The SpeedTrol fan motor is a single-phase, 230/460 volt, thermally protected motor specially designed for variable speed operation. The solid-state speed control is mounted in the unit control panel and is connected to a Schrader fitting on the liquid line. The control is factory-set to start modulating fan speed at 230 psig, and it will maintain a minimum condensing pressure of 170 to 180 psig. Minimum starting voltage for SpeedTrol motors is 120 volts.

A low ambient timer function is included in the microprocessor. When the solenoid valve and lead compressor are energized by the controller, the low pressure cutout control is bypassed and the compressor is allowed to start with the low pressure control open.

After about 2-3/4 minutes, the time delay will open and the low pressure cutout function is again operable. If the system has not built up enough evaporator pressure to close the low pressure setting, the compressor will stop.

Due to the vertical condenser design, it is recommended that the unit be oriented so that prevailing winds blow parallel to the unit length, thus minimizing effects on minimum ambient operation. If it is not practical to orient the unit in this manner, a wind deflector should be constructed.

Hot Gas Bypass

Hot gas bypass is a system for maintaining evaporator pressure at or above a minimum value. The purpose for doing this is to keep the velocity of the refrigerant as it passes through the evaporator high enough for proper oil return to the compressor when cooling load conditions are light. It also maintains continuous operation of the chiller at light load conditions.

The solenoid valve should be wired to open whenever the liquid line solenoid valve is energized.

This can be accomplished by wiring the hot gas solenoid (SV5) in parallel with the liquid line solenoid at terminals 14 and 16. The pressure-regulating valve is factory-set to begin opening at 58

PSIG (32

F for R-22) when the air-charged bulb is in an 80

F ambient temperature. The bulb can be mounted anywhere as long as it senses a fairly constant temperature at various load conditions. The compressor suction line is one such mounting location. It is generally in the 50

F to 60

F range.

The chart below indicates that when the bulb is sensing 50

F to 60

F temperatures, the valve will begin opening at 54 PSIG. This setting can be changed as indicated above, by changing the pressure setting, remove the cap on the bulb and turn the adjustment screw clockwise. To lower the setting, turn the screw counterclockwise. Do not force the adjustment beyond the range it is designed for, as this will damage the adjustment assembly.

The regulating valve opening point can be determined by slowly reducing the system load (or increasing the required chiller water temperature setting indicated on the unit thermostat), while observing the suction pressure. When the bypass valve starts to open, the refrigerant line on the evaporator side of the valve will begin to feel warm to the touch.

IOMM AGZ1 AGZ 010A through 034A

WARNING

The hot gas line may become hot enough to cause injury in a very short time, be careful during valve checkout.

On installations where the condensing unit is remote from the evaporator, it is recommended that the hot gas bypass valve be mounted near the condensing unit to minimize the amount of refrigerant that will condense in the hot gas line during periods when hot gas bypass is not required.

Figure 13, Hot Gas Bypass Piping

Suction Line

Hot Gas Bypass

Solenoid Valve

Discharge

Line

Hot Gas

Bypass Valve

Adjustable

Remote Bulb

External Equalizer

Connection to Suction

Side of Evaporator

To Evaporator Inlet

After Expansion Valve

Figure 14, Hot Gas Bypass Adjustment

REMOTE BULB ADJUSTMENT RANGE

MAXIM

FACTO

RY SET

MINIMU

TING

30 40 50 60 70 80

TEMP (°F) AT BULB LOCATION

90 100 110

AGZ 010A through 034A IOMM AGZ1

Troubleshooting Chart

Table 16, Troubleshooting Chart

PROBLEM POSSIBLE CAUSES

1. Main switch open

2. Fuse blown, breakers open

COMPRESSOR WILL

NOT RUN

COMPRESSOR NOISY

OR VIBRATING

HIGH DISCHARGE

PRESSURE

LOW DISCHARGE

PRESSURE

HIGH SUCTION

PRESSURE

LOW SUCTION

PRESSURE

UNIT WILL NOT LOAD

OR UNLOAD

LOAD/UNLOAD

INTERVAL TOO

SHORT

COMPRESSOR

LOSES OIL

MOTOR OVERLOAD

RELAYS OPEN OR

BLOWN FUSES

COMPRESSOR

THERMAL SWITCH

OPEN

3. Thermal overloads tripped

4. Defective contactor or coil

5. System off by safety device

6. No cooling required

7. Liquid line solenoid will not open

8. Motor electrical problem

9. Loose wiring

1. Refrigerant flooding compressor

2. Improper line support

3. Worn compressor

1. Noncondensables in system

2. Refrigerant overcharge

3. Fan not running

4. Dirty condenser coils

5. FanTrol out of adjustment

1. Faulty condenser control

2. Low refrigerant charge

3. Low suction pressure

1. Excessive load

2. Expansion valve overfeeding

1. Lack of refrigerant

2. Evaporator dirty

3. Clogged filter-drier

4. Expansion valve malfunctioning

5. Low condensing temperature

1 Faulty controller sensor/broken wire

2. Stages not set for application

1. Erratic water thermostat

2. Insufficient water flow

1. Lack of refrigerant

2. Suction superheat too high

3. Crankcase heater burned out

1. Low voltage during high loads

2. Defective or grounded motor wiring

3. Loose power wiring

4. High condensing temperature

5. Unbalanced voltage

1. Operating beyond design conditions

POSSIBLE CORRECTIVE STEPS

1. Close switch

2. Check electrical circuits and motor windings for shorts. Check for overloads and loose connections.

Replace fuse or reset breaker.

3. Check unit when back on line, auto reset

4. Repair or replace

5. Determine cause and correct

6. None, should start on call for cooling

7. Repair or replace coil

8. Check motor for open or short circuit, or burnout

9. Check all wire junctions. Tighten all terminals.

1. Check expansion valve setting

2. Relocate or add supports

3. Replace

1. Remove with authorized procedures

2. Remove excess

3. Check electrical circuit

4. Clean coil

5. Adjust FanTrol setting

1. Check condenser control operation

2. Check for leaks. Add refrigerant

3. See low suction pressure steps below

1. Reduce load or add capacity

2. Check remote bulb. Regulate superheat

1. Check for leaks. Repair and replace refrigerant.

2. Clean chemically

3. Replace

4. Check and adjust for proper superheat

5. Check discharge pressure control settings

1. Replace

2. Adjust thermostat setting

1. Replace

2. Adjust flow

1. Check for leaks and repair

2. Adjust superheat

3. Replace crankcase heater

1. Check supply voltage

2. Replace compressor

3. Check all connections and tighten

4. See steps for high discharge pressure

5. Check voltage. Contact power company.

1. Add facilities so conditions are within allowable limits

IOMM AGZ1 AGZ 010A through 034A

AGZ 010A through 034A IOMM AGZ1

Post Office Box 2510, Staunton, Virginia 24402 USA

•

(540) 248-0711

•

www.mcquay.com

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