McQuay ALR C Installation Manual

Installation and Operating Manual

Leaving Water Controller, AS-UNT33n-1

Applied to ALR C/D/E and WHR D/E

IOM UNT33n

Group: Chiller
Date: May 2000
Supersedes: IM 552

© 1996 McQuay International

Table of Contents

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

Specifications.....................................................................................4

Installation..........................................................................................5

Dimensional Data................................................................................6

Electrical Data.....................................................................................7

Operation...........................................................................................9

Additional Features............................................................................11

Settings And Adjustments.................................................................. 12

System Checkout and Troubleshooting .............................................. 13

Zone Terminal User's Guide.............................................................. 16

Zone Terminal Glossary.................................................................... 21

"McQuay" is a registered trademarks of McQuay International

"Illustrations and information cover McQuay International products at the time of publication and we reserve the right to make

changes in design and construction at anytime without notice"

2 IOM UNT33



1996 McQuay International

Introduction

This controller is the standard controller on ALR "C", "D" or “E” vintage and WHR "D" or "E"
vintage packaged chillers where control of leaving water temperature is desired. On these units with
the controller factory installed, the control is pre-set and calibrated and should not need any
adjustment other than the control setpoint.

For further information on the AS-UNT33n-1 Microprocessor based leaving water controller and
accessories contact McQuay International for specification sheets for each individual control.

The controller and sensor covered in this Installation and Operating Manual is also available as a
substitute replacement for earlier ALR and WHR units.

General Description

The AS-UNT33n-1 Microprocessor-based Leaving Water Control is designed to control multiple
capacity steps of cooling from a single sensor.

The AS-UNT33n-1 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 begin to de-energize.

There will be no energizing or de-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 Interstage On Delay
between stages. Each stage incorporates minimum on and off timers with a maximum cycle rate of six
cycles per hour.

CAUTION-Offering this control
device is not intended to imply that
rapid cycling of compressors is
condoned. If an application
produces rapid cycling, the control
and/or the application must be
reviewed and altered to prevent
compressor failure.

Table 1, Standard Control Characteristics

DESCRIPTION

AS-UNT-33n-1

Setpoint Range

Control Band Range

Interstage On Delay Between Stages 60 seconds
Minimum Off Time (each stage) 5 minutes
Minimum On Time (each stage) 60 seconds

Soft Start During Start-up

10°F to 60°F (-12°C to
+15°C) Adjustable
0°F to 10°F (0°C to 6°C)
Adjustable

50% command over 5
minutes

SETTING

Table 2, Controller Specific Characteristics

CONTROLLER

DESCRIPTION

AS-UNT330-1 4 or 6 Honeywell
AS-UNT332-1 8 Honeywell
AS-UNT334-1 4 or 6 Johnson Controls
AS-UNT336-1 8 Johnson Controls

IOM UNT33 3

NUMBER OF

STAGES

LEAVING WATER

SENSOR

Specifications

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

Number of Stages Selection:

Refer to Table 5, Figure 1 for stage selection

Temperature Ranges:

Ambient: -40°F to +150°F.

Humidity Rating:

5 to 90% RH non-condensing.

Leaving Water Sensor:

The Honeywell C7173Al017, Honeywell
C7170A1010, or Johnson Controls TE-6300-300
senses Leaving Water Temperature on control

terminals AI3 and AI3 COM.
coefficient of 3 ohms/Degree F; resistance of 1000
ohms at 70°F.
.

Table 3, Contact Rating

CONTACT VOLTAGE (V) INRUSH (VA) RUNNING (VA)

N.O. 24 240 60
N.C. 24 75 30
N.O. 120/240 750 75
N.C. 120/240 240 40

Table 4, Accessories

Model No.
Johnson TE-6313P-1 070312301 1 Outdoor Air Sensor Used for reset of Leaving Water Setpoint.

Johnson TE-6300-300 070312401 1 Immersion Sensor (30 ft. cord) Senses Leaving or Return Water Temperature.
Sensor Well 047441506 1 Immersion Well Used with TE-6300-300.
Johnson TE-6410S­2000
Johnson AS-ZTU330­1
Honeywell
C7173A1017
Honeywell
C7170A1010
Honeywell 121371A 048442403 1 Copper Immersion Well Used with C7173A1017 or C7170A1010.
Honeywell 121371E 048442404 1 Stainless Steel Immersion Well Used with C7173A1017 or C7170A1010.
Johnson AS-KIT100-0 1 Resistor Test Kit Used for field diagnostics.

McQuay

Part No.

070312801

070312701 1 Zone Terminal

048442405 1 Immersion Sensor (30 ft. cord) Sensing of Leaving Water Temperature.

048442402 1 Immersion Sensor (10 ft. cord) Sensing of Leaving Water Temperature.

Quantit

y

depends on

# of zones

Description Application

Zone Temperature Sensor Used for zone temperature reset.

Used for monitoring and local control of
designated points.

4 IOM UNT33

Installation

AS-UNT330-1

STANDARDS COMPLIANCE

The UNT Controller complies with the following standards:
* CSA C22.2 No. 205* UL 916 * IEEE 472
* IEEE 446 * VDE 0871 Class B * IEEE 587 Category A
* IEEE 518 * FCC Part 15, Subpart A, Cl. J * NEMA ICS 2, Part 2-230
All wiring must comply with local codes and ordinances:

1. Disconnect power before making connections to avoid electrical shock or equipment damage.

2. Check ratings given in the specification and on the product to make sure the controller fits the application.

3. Choose a location for the AS-UNT33n-1 controller that is not exposed to the weather and where controls,
connections, and the zone bus phone jack are accessible.

4. Mount the controller with three No. 8 screws through the mounting holes in the base. (See Figure 2.)

5. Install immersion well and sensor bulb in the Leaving Chilled Water piping as instructed by the installation manual
for the unit being controlled.

6. Connect 24 VAC to terminals marked 24 VAC and COM. CAUTION: Never spark the 24 V power leads to check for
power.

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

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 AI2 for the appropriate number of cooling stages. The AS-UNT330-1/AS-UNT334-1 is
factory set for 6 stages by Johnson Controls. The AS-UNT332-1/AS-UNT336-1 is factory set for 8 stages.

Table 5, Dipswitch Settings

Dipswitch Settings

Factory

Set

Stage

Select

Factory Set

AS-UNT33n-1 AI 1 AI 2 AI 3 AI 4 AI 5 AI 6

AS-UNT330-1 SW2 10 V • • • •
AS-UNT334-1 2 V • •

4 stage

SW1 T •
(set by others) V • • • • •
AS-UNT330-1 SW2 10 V • • • •
AS-UNT334-1 2 V • •

6 Stage

SW1 T • •

(Factory Set) V • • • •
AS-UNT332-1 SW2 10 V • • • • •
AS-UNT336-1 2 V •

8 Stage

SW1 T • •

(Factory Set) V • • • •

Figure 1, Analog Input Switches

C
D
V
5
1
+

A N A LO G I N PU TS

B IN A R Y IN

COM

PW R

I N

2 4V

B IN A R Y CO M

A C

BIN ARY INA NAL OGIN PUTS

BINA RY OUT PUT S

ANAL O G I N PU TS

1 2 3 4 5 6 1 2 3 4

A N A L OG I N P U TS

CO MM ON

B IN A RY OU TP U T
1 2 3 4 5 6 7 8

2 4V A C TO L OA D S

IOM UNT33 5

Dimensional Data

Figure 2, Dimensional Data

These relays are for the
7th and 8th stages.

COOL 8

COOL 7

7.78

8.95

SW2
SW1

ANALOG INPUTS BINARY IN

1.245.80

C
B

A
C
B
A

BINARY OUTPUTS

McQuay

RECIPROCATING
CHI LLER CONTROL

SETPOIN T

RESET

CON TROL BAND

COOL 6

COOL 5

COOL 4

COOL 3

COOL 2

COOL 1

C
B
A
C
B
A

C
B
A
C
B
A

C
B
A
C
B

A

8.95

9.23

0.89

14.90

= mounting holes

5.16

2.23

0.74

2.17

2.77

0.25

6 IOM UNT33

Electrical Data

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

Figure 3, Wiring Diagram

Note: See Additional Features on page 11 for explanation.

DEMAND LIMIT*

(1)

(2)

0-10 VDC

LEAVING

WATER SENSOR

SHUTDOWN*

COMP LEAD/LAG*

ICE MODE*

FLOW INTERLOCK

Indicates

*

optional
feature.

24VAC

(+)

AI CM

25

26

528

529

(-)

AI CM
AI CM
AI CM
AI CM

AI CM

+15VDC

24VAC
24VAC

24VAC
24VAC

24 C OM Z

VAC B U S

P5 P6

AI1
AI2
AI3

AI4
AI5

AI6

+15VDC

BI1
BI2

BI3
BI4

ANALOG INPUTS BINARY IN

DS

REF N 2 N 2

18

28

512/518

519

- +

P4

(1)
(2) Field connections must be made between TB3-18 and BI-4 for unit to operate.

NNotes:

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 between TB3-18 and Bl-4 for unit to operate.

3. If a time clock is desired, it should be installed between 24 VAC and Bl1. The time clock switch should be installed as follows:
Open to Run and Close to Stop.

Figure 4, Stage Relay Configuration

M cQuay

C ONT ROL BA ND

S ET PO I NT

RE SET

RECIPROCATING
CHILLER CONT ROL

COO L 6

COO L 5

COO L 4

COO L 3

COO L 2

COO L 1

C

B

A

C
B

A

C

B

A

C

B
A

C

B
A

C

B
A

C

B

A

Stage Relays

COM

NC

NO

Note: Refer to Unit Wiring

Diagram for Stage
Wiring.

IOM UNT33 7

Table 6, Wiring Location Cross Reference

Lead #

512 TB3-18 to TB3-29 (4,6,8 Stages) Not Needed (See Note 1 and 2)
518 TB3-29 to "TR" " TB3-18 to 24 VAC
519 "TR" " Common
522 Ground " Not Needed
524 "7" " Not Needed (See Note 3)
525 TB3-23 to TB3-24 " Not Needed
526 "6" " Not Needed (See Note 3)
527 "P" to "P1" " Not Needed or Zone Terminal Adjust

528 "T" "

529 "T1" "

400 OHM Resister "7" to "8" 4 Stages
600 OHM Resister "7" to "8" 6 Stages See Table 5
800 OHM Resister "7" to "8" 8 Stages

523 Ground 8 Stages Not Needed
535 "1" " Not Needed
536 "2" " Not Needed
537 "3" " Not Needed
538 "4" " Not Needed
539 "5" " Not Needed

Note 1: To install Flow Switch Contacts, connect between TB3-18 and UNT BI-4.
Note 2: To install Time Clock Contacts, connect between TB3-18 and UNT BI-1.
Note 3: The options are as follows. (Option A is standard; options B, C, and D require field download. See "Features Requiring

Configuration and/or Field Adjustment" section for more information):
A. The standard is Demand Limit Input. 0-10VDC signal is required. Connect leads to AI-1 and AI-CM on the

controller.

B. Johnson Controls Outdoor Air Sensor if Outdoor Air Reset is used.
C. Johnson Controls Zone Temperature Sensor if Zone Temperature Reset is used.
D. Johnson Controls Return Water Sensor if Return Water Reset is used.

Honeywell (H/W)

W7100G

Stages

AI-3 (JCI or H/W Leaving Water Sensor. See

Johnson Controls (JCI)

AS-UNT33n-1

appropriate sensor section)

AI-CM (JCI or H/W Leaving Water Sensor.

See appropriate sensor section)

8 IOM UNT33