McQuay MMC075B - User Manual

Questions and Answers

P
Pedro BishopAug 9, 2025
Why is my McQuay Air Conditioner not cooling properly?
- S
  Sarah Bailey MDAug 9, 2025
  If your McQuay Air Conditioner is running but not cooling effectively, several factors could be the cause. First, make sure the thermostat isn't set too high; try resetting it. Ensure all doors and windows are completely closed. If these steps don't help, there might be an obstruction blocking the unit's inlet or outlet; remove any objects you find. For issues such as a dirty condenser coil or insufficient refrigerant, it is best to contact your local dealer.
T
thamptonAug 17, 2025
What to do if both fan and compressor on my McQuay MMC075B Air Conditioner don't work?
- W
  wporterAug 17, 2025
  If neither the fan nor the compressor is working on your McQuay Air Conditioner, there are a few things you can check. First, there may be a power failure; the unit should resume operation when the power supply is restored. Also, the starter may have tripped; try resetting it. Finally, inspect the fuse in the power switch or operating unit and replace it if it's blown.
B
Brian BenitezAug 25, 2025
How to fix a McQuay MMC075B Air Conditioner when the fan is not working?
- T
  tony19Aug 26, 2025
  If the fan on your McQuay Air Conditioner isn't working, start by checking the power supply. If the power supply is fine, the issue might be a faulty fan capacitor or fan motor, in which case you should contact your local dealer. Another potential cause is a faulty switch, which would need to be changed.
M
Mr. John Allen Jr.Sep 1, 2025
What to do if McQuay MMC075B Air Conditioner fan works, but the compressor doesn't?
- R
  Randy SextonSep 1, 2025
  If the fan on your McQuay Air Conditioner is working, but the compressor isn't, there are a few potential reasons. First, the thermostat setting might be too high; try resetting it. It's also possible that the dual pressure control has tripped; in this case, reset the pressure control. For compressor or compressor contractor issues, contact your local dealer.

Summary

Nomenclature System

Features

General Specifications

Compressor Details

Details the high-efficiency, refrigerant-cooled hermetic compressor features.

Safety Controls

Outlines high/low pressure cut-outs and crankcase heater for compressor protection.

Operating Guide

Specifications

Specifications (Continued)

Compressor Specifications

Lists compressor type, power supply, and protection devices.

Heatpump Specifications (Cooling)

Performance Characteristics

Cooling Capacity Data

MDB075 B vs MMC075 B Cooling Data

Cooling capacity data for MDB075B vs MMC075B models.

MDB100 B vs MMC100 B Cooling Data

Cooling capacity data for MDB100B vs MMC100B models.

Cooling Capacity Data (Continued)

MDB125 B vs MMC125 B Cooling Data

Cooling capacity data for MDB125B vs MMC125B models.

MDB150 C1;C2 vs MMC150 C Cooling Data

Cooling capacity data for MDB150C1/C2 vs MMC150C models.

MDB250 B2 vs MMC125 B x 2 Cooling Data

Cooling capacity data for MDB250B2 vs MMC125B x 2 models.

MDB400 B4 vs MMC100 B x 4 Cooling Data

Cooling capacity data for MDB400B4 vs MMC100B x 4 models.

MDB500 B4 vs MMC125 B x 4 Cooling Data

Cooling capacity data for MDB500B4 vs MMC125B x 4 models.

MDB750 B5 vs MMC150 C x 5 Cooling Data

Cooling capacity data for MDB750B5 vs MMC150C x 5 models.

MDB150 B1;B2 vs MMC150 C;075 B x 2 Cooling Data

Cooling capacity data for MDB150B1/B2 vs MMC150C/075B x 2.

MDB200 B2 vs MMC100 B x 2 Cooling Data

Cooling capacity data for MDB200B2 vs MMC100B x 2 models.

MDB300 B3 vs MMC100 B x 3 Cooling Data

Cooling capacity data for MDB300B3 vs MMC100B x 3 models.

MDB450 B3 vs MMC150 C x 3 Cooling Data

Cooling capacity data for MDB450B3 vs MMC150C x 3 models.

MDB600 B4 vs MMC150 C x 4 Cooling Data

Cooling capacity data for MDB600B4 vs MMC150C x 4 models.

Heatpump Performance Data

MDB075 BR vs MMC075 CR Heatpump Data

Heatpump performance data for MDB075BR vs MMC075CR.

MDB100 BR vs MMC100 BR Heatpump Data

Heatpump performance data for MDB100BR vs MMC100BR.

Heatpump Performance Data (Continued)

MDB125 BR vs MMC125 BR Heatpump Data

Heatpump performance data for MDB125BR vs MMC125BR.

MDB200 BR2 vs MMC100 BR x 2 Heatpump Data

Heatpump performance data for MDB200BR2 vs MMC100BR x 2.

MDB300 BR3 vs MMC100 BR x 3 Heatpump Data

Heatpump performance data for MDB300BR3 vs MMC100BR x 3.

MDB400 BR4 vs MMC100 BR x 4 Heatpump Data

Heatpump performance data for MDB400BR4 vs MMC100BR x 4.

MDB150 BR2 vs MMC075 CR x 2 Heatpump Data

Heatpump performance data for MDB150BR2 vs MMC075CR x 2.

MDB250 BR2 vs MMC125 BR x 2 Heatpump Data

Heatpump performance data for MDB250BR2 vs MMC125BR x 2.

MDB350 BR3 vs MMC100 BR + MMC125 BR x 2 Heatpump Data

Heatpump performance data for MDB350BR3 vs MMC100BR + MMC125BR x 2.

Power Table

Power Table (Continued)

MDB150 C1 vs MMC150 C Power Data

Power data for MDB150C1 vs MMC150C models.

MDB250 B2 vs MMC125 C x 2 Power Data

Power data for MDB250B2 vs MMC125C x 2 models.

MDB500 B4 vs MMC125 B x 4 Power Data

Power data for MDB500B4 vs MMC125B x 4 models.

MDB200 B2 vs MMC100 B x 2 Power Data

Power data for MDB200B2 vs MMC100B x 2 models.

MDB400 B4 vs MMC100 B x 4 Power Data

Power data for MDB400B4 vs MMC100B x 4 models.

Drive Package Selection Example

Outlines And Dimensions (Indoor)

Outlines And Dimensions (Outdoor)

Wiring Diagrams (Cooling)

MDB 075 B - MMC 075 C Cooling Wiring

Wiring Diagrams (Heatpump)

Export Indoor Wiring Diagrams

MDB 125 CR Export Wiring Diagram

Refrigerant Circuit Diagram

Installation (Indoor)

Preliminary Site Survey

Indoor Installation (Continued)

Operational Check Procedures

Electrical Connection Precautions

General precautions for electrical connections, grounding, and wiring safety.

Installation (Outdoor)

Outdoor Unit Location Requirements

Requirements for outdoor unit placement to ensure optimal cooling capacity and airflow.

Field Piping Guidelines

Maximum Pipe Length and Bends

Guidelines on pipe length, bends, and elevation differences to maintain performance.

Vacuuming And Charging

Vacuuming Procedure

Charging Procedure

System Refrigerant Charge Level Guidelines

Cooling Only Refrigerant Charge

Refrigerant charge levels for cooling-only models based on pipe size and model.

Heatpump Refrigerant Charge

Refrigerant charge levels for heatpump models based on pipe size and model.

Servicing And Maintenance

CAUTION Statements

CAUTION FOR USE

Maintenance Procedures

General Maintenance Recommendations

Recommendations for proper and regular maintenance for optimal performance.

Outdoor Heat Exchanger Cleaning

Operation

Electrical Connection Guidelines

Regulations and precautions for electrical connections, wiring, and supply.

General Operation Precautions

Operational Checks

Sequential Controller Configuration

Compressor Number Configuration

Heater Number Configuration

Troubleshooting Guide

Common Troubleshooting Issues

Lists common problems, probable causes, and suggested actions for troubleshooting.

No Cooling Troubleshooting

Evaporator Fan Motor Issues

Condenser Fan Motor Issues

Compressor Contactor Issues

Insufficient Cooling Troubleshooting

Compressor Cycling Issues

Compressor Overcurrent Relay Issues

Thermostat Faults

High Discharge Pressure Troubleshooting

Condenser Airflow Issues

Low Discharge Pressure Troubleshooting

Condenser Airflow and Fan Cycling

High Suction Pressure Troubleshooting

Low Suction Pressure Troubleshooting

Evaporator Airflow Issues

Noisy Operation Troubleshooting

Compressor Noise Sources

Evaporator Fan Noise Sources

Part List

MDB 075 B Indoor Part List

Part list for MDB 075B indoor unit, cooling model, horizontal discharge.

Part List (Continued)

MDB400 B4 Indoor Part List

Part list for MDB400B4 indoor unit.

MMC075 B Outdoor Part List

Part list for MMC075B outdoor unit, vertical air discharge.

MMC125 B Outdoor Part List

Part list for MMC125B outdoor unit.

MMC150 C Outdoor Part List

Part list for MMC150C outdoor unit.

MMC075 CR Outdoor Part List

Part list for MMC075CR outdoor unit.

McQuay MMC075B Specifications

General

Brand	McQuay
Model	MMC075B
Category	Air Conditioner
Language	English

Related product manuals

McQuay MMC075B - User Manual

Table of Contents

Questions and Answers

Summary

Nomenclature System

Features

General Specifications

Compressor Details

Safety Controls

Operating Guide

Specifications

Specifications (Continued)

Compressor Specifications

Heatpump Specifications (Cooling)

Performance Characteristics

Cooling Capacity Data

MDB075 B vs MMC075 B Cooling Data

MDB100 B vs MMC100 B Cooling Data

Cooling Capacity Data (Continued)

MDB125 B vs MMC125 B Cooling Data

MDB150 C1;C2 vs MMC150 C Cooling Data

MDB250 B2 vs MMC125 B x 2 Cooling Data

MDB400 B4 vs MMC100 B x 4 Cooling Data

MDB500 B4 vs MMC125 B x 4 Cooling Data

MDB750 B5 vs MMC150 C x 5 Cooling Data

MDB150 B1;B2 vs MMC150 C;075 B x 2 Cooling Data

MDB200 B2 vs MMC100 B x 2 Cooling Data

MDB300 B3 vs MMC100 B x 3 Cooling Data

MDB450 B3 vs MMC150 C x 3 Cooling Data

MDB600 B4 vs MMC150 C x 4 Cooling Data

Heatpump Performance Data

MDB075 BR vs MMC075 CR Heatpump Data

MDB100 BR vs MMC100 BR Heatpump Data

Heatpump Performance Data (Continued)

MDB125 BR vs MMC125 BR Heatpump Data

MDB200 BR2 vs MMC100 BR x 2 Heatpump Data

MDB300 BR3 vs MMC100 BR x 3 Heatpump Data

MDB400 BR4 vs MMC100 BR x 4 Heatpump Data

MDB150 BR2 vs MMC075 CR x 2 Heatpump Data

MDB250 BR2 vs MMC125 BR x 2 Heatpump Data

MDB350 BR3 vs MMC100 BR + MMC125 BR x 2 Heatpump Data

Power Table

Power Table (Continued)

MDB150 C1 vs MMC150 C Power Data

MDB250 B2 vs MMC125 C x 2 Power Data

MDB500 B4 vs MMC125 B x 4 Power Data

MDB200 B2 vs MMC100 B x 2 Power Data

MDB400 B4 vs MMC100 B x 4 Power Data

Drive Package Selection Example

Outlines And Dimensions (Indoor)

Outlines And Dimensions (Outdoor)

Wiring Diagrams (Cooling)

MDB 075 B - MMC 075 C Cooling Wiring

Wiring Diagrams (Heatpump)

Export Indoor Wiring Diagrams

MDB 125 CR Export Wiring Diagram

Refrigerant Circuit Diagram

Installation (Indoor)

Preliminary Site Survey

Indoor Installation (Continued)

Operational Check Procedures

Electrical Connection Precautions

Installation (Outdoor)

Outdoor Unit Location Requirements

Field Piping Guidelines

Maximum Pipe Length and Bends

Vacuuming And Charging

Vacuuming Procedure

Charging Procedure

System Refrigerant Charge Level Guidelines

Cooling Only Refrigerant Charge

Heatpump Refrigerant Charge

Servicing And Maintenance

CAUTION Statements

CAUTION FOR USE

Maintenance Procedures

General Maintenance Recommendations

Outdoor Heat Exchanger Cleaning

Operation

Electrical Connection Guidelines