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McQuay ACZ 016A - User Manual

McQuay ACZ 016A
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Installation, Operation and Maintenance Manual
IOMM ACZ1
Group:
Chiller
Part Number
: 330262002
Effective:
December 2001
Supersedes:
New
Air-Cooled Scroll Condensing Units
ACZ 010A – ACZ 039A
10 to 43 Tons, 35 to 150 kW
R-22, 60 Hertz

Table of Contents

Questions and Answers

  • J
    jacquelinecharlesAug 17, 2025
    What to do if the McQuay Heat Pump compressor will not run?
    • C
      Charles DickersonAug 17, 2025
      If the McQuay Heat Pump compressor will not run, first ensure the main switch is closed. Check for blown fuses or open breakers, inspecting electrical circuits and motor windings for shorts, overloads, and loose connections; replace the fuse or reset the breaker if necessary. Also, check if thermal overloads have tripped (they auto reset). Inspect the contactor or coil for defects and repair or replace if needed. Determine if a protection device has shut the system off and correct the cause. If no cooling is required, the compressor should start on a call for cooling. Check if the liquid line solenoid will not open and repair or replace the coil if needed. Inspect the motor for open or short circuits, or burnout. Finally, check all wire junctions and tighten all terminals.
  • D
    darlene41Aug 19, 2025
    What to do if my McQuay ACZ 016A has high discharge pressure?
    • C
      Charles MuellerAug 20, 2025
      If your McQuay Heat Pump has high discharge pressure, it could be due to several reasons. First, there might be noncondensables in the system, which should be removed using authorized procedures. Another cause could be a refrigerant overcharge, so remove the excess. Check if the fan is running and inspect the electrical circuit. Dirty condenser coils can also cause this issue, so clean the coil. Lastly, the FanTrol might be out of adjustment, so adjust the FanTrol setting.
  • D
    David TerryAug 23, 2025
    Why is my McQuay ACZ 016A compressor noisy or vibrating?
    • T
      Tommy TorresAug 23, 2025
      If your McQuay Heat Pump compressor is noisy or vibrating, it may be due to refrigerant flooding the compressor, so check the expansion valve setting. Another cause could be improper line support, in which case you should relocate or add supports. Finally, the compressor might be worn, requiring replacement.
  • R
    Rose CoxAug 26, 2025
    What causes motor overload relays to open or blown fuses in McQuay ACZ 016A?
    • M
      michaelcarrollAug 26, 2025
      Motor overload relays opening or blown fuses in your McQuay Heat Pump can be caused by several factors. These include: 1. Low voltage during high loads, in which case you should check the supply voltage. 2. Defective or grounded motor wiring, requiring you to replace the compressor. 3. Loose power wiring, so check all connections and tighten them. 4. High condensing temperature (see steps for high discharge pressure). 5. Unbalanced voltage, so check the voltage and contact the power company.
  • S
    Shannon AyersAug 28, 2025
    What to do if my McQuay ACZ 016A has low suction pressure?
    • M
      Michele AndersonAug 28, 2025
      If your McQuay Heat Pump has low suction pressure, it could be due to a lack of refrigerant, so check for leaks and repair and replace the refrigerant. Another cause could be a dirty evaporator, which needs to be cleaned chemically. A clogged filter-drier can also cause this, so replace it. Additionally, the expansion valve might be malfunctioning; check and adjust for proper superheat. Low condensing temperature can also be a factor; check discharge pressure control settings.
  • H
    hannahparkerAug 31, 2025
    Why is my McQuay ACZ 016A's compressor losing oil?
    • D
      Denise MirandaAug 31, 2025
      If your McQuay Heat Pump's compressor is losing oil, it could be due to a lack of refrigerant, so check for leaks and repair them. Another cause could be suction superheat being too high, so adjust the superheat. Lastly, the crankcase heater might be burned out, requiring replacement.
  • B
    blaneSep 3, 2025
    What causes low discharge pressure in a McQuay Heat Pump?
    • K
      Kyle Hill MDSep 3, 2025
      Low discharge pressure in a McQuay Heat Pump can be caused by a faulty condenser control, so check the condenser control operation. It can also be caused by a low refrigerant charge, so check for leaks and add refrigerant. Another possible cause is low suction pressure; see the low suction pressure steps.
  • M
    Mark HouseSep 5, 2025
    What causes high suction pressure in a McQuay ACZ 016A?
    • J
      John SotoSep 5, 2025
      High suction pressure in a McQuay Heat Pump can be caused by an excessive load, so reduce the load or add capacity. It may also be caused by the expansion valve overfeeding, so check the remote bulb and regulate superheat.
  • M
    Mathew JuarezSep 8, 2025
    What causes a McQuay ACZ 016A unit to not load or unload?
    • J
      Jessica DudleySep 8, 2025
      If a McQuay Heat Pump unit will not load or unload, it could be due to a faulty controller sensor or a broken wire, requiring replacement. Another cause could be stages not set for the application, so adjust the thermostat setting.
  • W
    William MichaelSep 12, 2025
    Why does my McQuay Heat Pump have a short load/unload interval?
    • M
      melissawilsonSep 12, 2025
      If your McQuay Heat Pump has a load/unload interval that is too short, it could be due to an erratic thermostat, in which case you should replace it. Another cause could be insufficient water flow, so adjust the flow.

Summary

Introduction

Inspection Procedures

Guidelines for checking units upon arrival for damage and correctness.

Installation Guidelines

Instructions for qualified personnel on unit installation.

Handling Precautions

Advice on safely moving and lifting the unit.

Location and Placement

Service Access Requirements

Ensuring accessibility to unit components for service.

Clearances and Airflow

Condenser Airflow Management

Importance of maintaining unobstructed airflow for efficiency.

Refrigerant Piping Best Practices

Piping Introduction and Concerns

Importance of proper piping for system reliability and performance.

Suction Line Design Guidelines

Recommendations for sizing and routing suction lines.

Refrigerant Piping Design

Suction Line Sizing Calculation

Steps to determine appropriate suction line sizes.

Liquid Line Design

Liquid Line Sizing Criteria

Factors influencing liquid line sizing and selection.

Unit Start-up and Shutdown Procedures

Pre Start-up Checklist

Essential checks before initial unit operation.

Unit Start-up Sequence

Step-by-step instructions for starting the unit.

Electrical Data and Wiring

Field Wiring Requirements

General rules for field wiring connections.

Single Point Power Wiring

Electrical Wiring Diagram

Typical Field Wiring Diagram

Schematic illustrating electrical connections.

MicroTech II Controller Features

Compressor Staging and Protection

How compressors are staged and protected.

FanTrol Head Pressure Control

MicroTech II Controller Setpoints & Alarms

Detailed Setpoint Table

Comprehensive list of configurable setpoints.

Equipment Protection Alarms

Alarms that trigger rapid compressor shutdown.

MicroTech II Controller Alarms

Shutdown and Limit Alarms

Conditions causing unit shutdown or limiting operation.

MicroTech II Controller Menu Operations

Understanding Menu Screens

Process for Changing Setpoints

Step-by-step guide to modifying setpoint values.

MicroTech II Controller Setpoint Adjustment

Example of Setpoint Change

A practical example of changing a unit setpoint.

MicroTech II Screen Definitions - Alarm

Active Alarms Display

Information on current unit alarms.

Alarm Log Access

MicroTech II Screen Definitions - Set

Setpoint Adjustment Procedures

General steps for modifying setpoints.

MicroTech II Limit Alarms Configuration

Low Evaporator Pressure Limits

Setting thresholds for low evaporator pressure alarms.

Evaporator Freeze and Flow Proof Alarms

Configuring freeze protection and flow interlocks.

High Condenser Pressure Limits

Setting thresholds for high condenser pressure alarms.

Service and Maintenance

Thermostatic Expansion Valve

Role in maintaining superheat for compressor life.

Filter-Drier Maintenance

Troubleshooting Common Issues

Compressor Operation Problems

Diagnosing and resolving issues like not running or noise.

Pressure Related Issues

Troubleshooting high/low discharge and suction pressures.

Unit Loading Problems

Addressing issues with unit loading or unloading intervals.

Compressor Oil Loss

Diagnosing and fixing compressor oil loss.

Electrical Fault Diagnosis

Troubleshooting motor overloads, blown fuses, and thermal switches.

McQuay ACZ 016A Specifications

General IconGeneral
BrandMcQuay
ModelACZ 016A
CategoryHeat Pump
LanguageEnglish

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