McQuay AS-UNT33n-1 Installation Manual

Installation and

MeQuw@

Microprocessor-Based

Leaving Water Control

Model AS-UNT33n-l

This controller is offered as an option on ALR “C vintage and WHR “D” vintage packaged chillers where control of Leaving Water Temperature is desired. On these units with the controlIer factory installed, the control is preset and calibrated and should not need any adjustment other than the control setpoint.

For further information on the AS-UNT33n-l microproces-

Maintenance Data

Bulletin No. IM 552

December, 1993

Form No. 573899Y

sor-based Leaving Water Controller and accessories contact SnyderGeneral Corporation for specification sheets for each individual control,

The controller and sensor covered in this installation and maintenance data bulletin are available as substitute replacements for earlier ALR and WHR units.

Table Of Contents

introduction—AS-UNT33n-l ................................................2

General Description .........................................................2

Standard Control Characteristics .........................................2

AS-UNT33n-l Specifications ...............................................2

AS-UNT33n-l Accessories ..................................................2

Installation ...........................................................................3

Standards Compliance .....................................................3

Dimensional Data .............................................................4

Mting ...............................................................................5

Operation .............................................................................7

Chiller System ..................................................................7

Leaving Water Temperature Control Operation ...............7

01993 SnyderGeneral Corporation

Johnson Controls Leaving Water Sensor ,...........................8

Hone~ell Leaving Water Sensor ........................................8

Additional Features ..............................................................9

Settings and Adjustments ..................................................l O

System Checkout and Troubleshooting .............................10

Features Requiring Factory Configuration .........................11

Reset Options ................................................................ll

Zone Terminal User’s Guide ..............................................l3

Introduction ....................................................................l3

Getting Started ..................................................................l4

Making Zone Terminal Adjustments ..................................15

Zone Terminal Glossary ....................................................l6

Introduction

General Description

The AS-UNT33n-l microprocessor-based leaving water control is designed to control multiple capacity steps of coolin9from a single sensor.

The AS-UNT33n-l operation is based on an adjustable setpoint and control band as shown in the “operation” section of this document. If the Leaving Chilled Water Temperature begins to rise to the desired setpoint plus control band/2 (upper limit), Cooling Stage 1 brings on the first stage of cooling. Additional stages of cooling will follow as long as the Leaving Water Temperature remains above the upper limit of the control

band. As the leaving water temperature begins to drop to

setpoint minus control band/2 (lower limit), cooling stages will

Standard Control Characteristics

Table 1: Standard Control Characteristics

DESCRIPTION

Setpoint Range

Control Band Range

Interstate On Delay Between Stages

Minimum Off Time (each stage) Minimum On Time (each stage) Soft Start During Start-up

AS-UNT33n-l

10”F to 60”F (-12-C to +15-C)

Adjustable

O-F to 10“F (O-Cto 60”) Adjustable

60 seconds 5 Minutes 60 Seconds 50% command over 5 minutes

SETTING

begin to de-energize.

There will be no energizing orde-energizing of cooling stages as long as the leaving water temperature is between the upper and lower limits of the control band. As a rule, anytime the leaving water temperature is above the upper limit of the control band, stages will be energized, and anytime the leaving water temperature falls below the lower limit of the control band, stages will be de-energized. At the initial start of the unit a time delay will occur. There is a 60-second Interstate On Delay between stages. Each stage incorporates minimum on and off timers with a maximum cycle rate of six cycles per hour.

Table 2: Controller Specific Characteristics

CONTROLLER DESCRIPTION

AS-UNT330-I AS-UNT332-I AS-UNT334-1 AS-UNT336-1

NUMBER OF

STAGES

4or6 8 4or6 8

LEAVING WATER

SENSOR Honeywell Honeywell Johnson Controls Johnson Controls

Caution: Offering this control device is not intended to imply that rapid cycling of compressors iscondoned by SnyderGeneral.

If an application produces rapid cycling, the control and/or the application must be reviewed and altered to prevent compressor failure.

AS-UNT33n-l

Electrical Ratings”:

Input voltage and frequency (terminals 24 VAC-COMMON) 20 to 30 VAC at 50/60 Hz (50 Hz requires download.)

Power Consumption: 25 VA at 24 VAC and 50/60 Hz Input Signal:

Honeywell sensor—positive temperature coefficient of 4.8 ohms/Degree F; resistance of 3484 ohms at 77”F. Johnson Controls sensor—positive temperature coefficient of 3 ohms/ Degree F; resistance of 1000 ohms at 70”F.

Number of Stages Selection:

Refer to Table 5, Figure 1 for stage selection.

Temperature Ranges:

Ambient: -40”F to +150°F.

AS-UNT33n-l Accessories

Model No. Johnson TE-6313P-1 Johnson TE-6300-300 070312401

Sensor Well 047441506 Johnson TE-6410S-200-0 070312801

Johnson AS-ZW330-1

Honeywell C7173AI 017

Honeywell C7170AI 010

Honeywell 121 371A 046442403 Honeywell 121371E Johnson AS-KITIOO-O

Page 2 I IM 552

McQuay Pert No. Quantity Description 070312301

070312701 1 Zone Terminal

048442405 046442402

048442404 1

1 Outdoor Air Sensor 1 1 Immersion Well

depends on Zone Temperature Sensor #of zones

1 Immersion Sensor (30 ft. cord) 1 Immersion Sensor (10 ft. cord)

1 Copper Immersion Well

1 Resetor Test Kit

Specifications

Humidity Rating:

5 to 90% RH noncondensing.

Leaving Water Sensor:

The Honeywell C7173AIOI 7, Honeywell C7170AI 010, or Johnson Controls TE-6300-300 senses Leaving Water Temperature on control terminals A13 and A13 COM.

Table 3: Contact Rating

CONTACT

N.O. NC, 24 NO. 120/240 NC, 120/240

Immersion Sensor (30 ft. cord) Senses Leaving or Return Water Temperature

Stainless Steel Immersion Well Used with C7173AI017 or C7I7OA1OIO

VOLTAGE (V)

Application Used for reset of Leaving Water Setpoint.

Used with TE-6300-300 Used for zone temperature reset

Used for monitoring and local control of designated points

Sensing of Leaving Water Temperature Sensing of Leaving Water Temperature Used with C7173AIO17 or C7170AIOI0

Used for field diagnostics.

INRUSH (VA)

240

75 750 240

RUNNING (VA)

60 30 75 40

Installation

Standards Compliance

The UNT Controller complies with the following standards:

● CSA C22.2 No. 205

● IEEE 446

● IEEE 518 ● FCC Part 15, Subpart A, Class J

● UL916

● VDE 0871 Class B “ IEEE 587 Category A

● IEEE 472

● NEMA ICS 2, Part 2-230

All wiring must comply with local codes and ordinances:

Disconnect power supply before making connections to

avoid electrical shock and/or equipment damage. Check ratings given inthe specification and on the product

2. to make sure the controller fits the application.

Choose a location for the AS-UNT33n-l controller that is

Do not run low-voltage wiring in the same conduit as linevoltage wiring (30 VAC or above) or wiring that switches power to highly inductive loads (such as contractors, coils, motors, or generators).

not exposed to the weather and where controls, connec-

tions, and the zone bus phone jack are accessible. Mount the controller with three No. 8 screws through the

4. mounting holes in the base. (See Figure 2,)

Install immersion well and sensor bulb in the Leaving

5. Chilled Water piping as instructed bythe installation manual for the unit being controlled.

Connect 24 VAC to terminals marked 24 VAC and COM.

CAUTION: Never spark the 24 V power leads to check for power.

7. Wire the compressor and capacity controls steps to the individual controller relay terminals as shown in the unit wiring diagram.

8. Adjust SW1 and SW2 on A12 for the appropriate number of cooling stages. The AS-UNT330-l/ASUNT334-1 is factory set for 6 stages by Johnson Controls. The AS-UNT332-l/AS-UNT336-l is factory set for 8 stages. Refer. o Table 5 and Figure 1.

Table 5: Dipswitch Settings

Oipswitch ettings

AS-UNT 13n-1 Al 1 A12

AS-UNT330-I

AS-UNT334-1

4 stage selection

(set by others)

AS-UNT330-1

AS-U NT334-1

6 stage selection

(set by others)

AS-UNT332-I

AS-UNT336-1

6 stage selection

(set by others)

10 v ●

SW2

Swl

SW2

v ● ●

10 v ●

Swl

T ●

10 v ● ●

SW2

Swl

Factory

Sat

●

I I

●

Stage Select

●

A13

—

●



●



—

●



—

●



●



—

Factorv Set

A14 A15 A16

● ● ●

Figure 1: Analog Input Switches

Ardog Inputswitches

IM 552 I Page 3

Dimensional Data

—

Figure 2: Dimensional Data

+mrL3L-

,Iuiuullin’u”i: II~lll_l I

II I&p--’

5.80

r 1-

‘1

1.24

—

~ = mounting holes

A 7il

o“ I

-1

Page4/ IM 552

DEMAND LIMIT*

(1)

0-10 VDC

LEAVING

SHUTDOWN*

COMP LEADILAG*

Wiring

Figure 3: Wiring Diagram

(+)

—

(-)

Al CM

~~ p

+15VDC +15VDC G

—— I

24VAC BI

A12

T ,

A16

B14 ~

(2)

FLOW INTERLOCK

* Indicates

optional feature.

(1) Sensor for Outdoor, Return Water, or Zone Temperature Reset options are connected to Al-1 and Al-CM.

(2) Field connections must be made betweenTB3-18 and BI-4 for unit to operate.

Figure 4: Stage Relay Configuration

24VAC

512/518

519 +

Note:

g;— g;. ;

❑

)

Refer to Unit Wiring Diagram for Stage Wiring.

IM 552/ Page 5

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