Dunham-Bush ACDX 120 - User Manual

Screw Type Air-Cooled Packages
Installation, Operation, and Maintenance Instructions
Form 6193A
ACDX/AUDX
TABLE OF CONTENTS
DESCRIPTION ........................................................................................................... PAGE NO.
Introduction & Product Identification .......................................................................................... 1
Physical Specifications .............................................................................................................. 2
Inspection .................................................................................................................................. 3
Rigging and Moving ................................................................................................................... 3
Location and Mounting .............................................................................................................. 3
Piping connections...............................................................................................................3 & 4
Multiple Chiller Water Connections ......................................................................................4 & 5
AUDX Condensing Unit Piping................................................................................................... 4
Electrical Connections ............................................................................................................... 6
ACDX Operation & Start-up .................................................................................................6 & 7
Maintenance .............................................................................................................................. 7
Slide Valve Unloading Operation................................................................................................ 8
Low Ambient Operation ............................................................................................................. 9
Fan Position Numbers .............................................................................................................. 10
Fan Cycling Sequence ............................................................................................................. 11
ACDX Sequence of Operation ................................................................................................. 12
Electrical Controls ........................................................................................................ 13, 14, 15
Field Control Wiring .........................................................................................................15 & 16
Star-Delta Starting Operation .................................................................................................. 16
Microcomputer Controller............................................................................................. 16 thru 23
Typical Wiring Diagram and Electrical Data .................................................................24 thru 30
Evaporator Water Pressure Drop ............................................................................................. 31
ACDX Refrigerant Piping Schematic ....................................................................................... 32
Condenser Clearance Requirements....................................................................................... 33
Rigging Instructions ................................................................................................................. 34
Point Loading ...................................................................................................................... 35-40
Trouble Shooting Guide ........................................................................................................... 41
Start-up Check List .................................................................................................................. 42

Summary

Location and Mounting

Piping Connections

Electrical Connections

General Electrical Connection Precautions

Air Cooled Package Chiller Start-Up

System Start Up

Procedures for requesting a startup representative and initial system checks.

Maintenance

Compressor Maintenance

Oil level checks, recommended oils, and repair considerations.

Slide Valve Unloading System

Low Ambient Operation

Condenser Head Pressure Control

Cooler Freeze Protection

Protects the cooler from freezing with heat tape and insulation.

Sequence of Operation (Typical)

Preliminary Sequence

Stage 1 Starting

Stage 2 Starting

Stage 1 Shutdown

Stage 2 Shutdown

Safety Controls

Electrical Controls

Field Control Wiring

Remote Chiller Wiring

Microcomputer Controller

General Description

Microcomputer Hardware Precautions

Safety measures for handling and working with microcomputer boards.

Operation of LCD Display NC25-4

To Display Data from the Menu

To Reset All Control Points to Computer Control

To Display Alarms

To Become Authorized

To Alter Setpoint Data

To Calibrate Temperature and Pressure Sensors

To Revise Unit Schedule of Operation (Optional)

ACDX;AUDX Package Control

Capacity Control of Screw Compressors

Automatic Control

How the system automatically adjusts compressor capacity based on load.

Manual Control

Staging of Compressors

Compressor Current Limiting

Ramp Control

Manual Lead;Lag Selection

Compressor Start Delay

Anti-Recycle Timing

Low Pressure Safety

High Pressure Safety

Freeze Safety

High Oil Temp Safety

Alarm Output

Fan Control

Chilled Water Reset (Optional) and Customer Control Interlock

Hot Gas Bypass Control (option)

Compressor Power Control (No-Stop Alarm) and Unit Schedule

Sensor Alarm Shutdown

External Shutdown Indication (No-Run Alarm)

Fast Unload Solenoid Control

Low Suction;Discharge Differential Alarm

High Motor Temperature Safety

Low Chiller Flow Alarm

High Discharge Pressure Unload

Low Suction Pressure Unload

ACDX;AUDX Condenser Clearance

Troubleshooting Guide

Chiller Unit Will Not Start

Common causes and remedies for a unit failing to start.

Compressor Hums But Does Not Start

Compressor Cuts Out on Low Pressure Safety Control

Diagnosing issues causing low-pressure safety shutdowns.

Compressor Cycles on High Pressure Control

Identifying causes for frequent high-pressure safety cutouts.

Causes and Prevention of Freeze-Up

Factors leading to freezing and preventative measures.

Start-Up Check List

Dunham-Bush ACDX 120 Specifications

General

Brand	Dunham-Bush
Model	ACDX 120
Category	Chiller
Language	English