Lennox MLB Series

INSTALLATION
INSTRUCTIONS
©
2024 Lennox Industries Inc.
Dallas, Texas, USA
WARNING
Improper installation, adjustment, alteration, ser vice or
maintenance can cause property damage, personal
injury or loss of life.
Installation and service must be performed by a li censed
professional HVAC installer (or equivalent) or a service
agency.
WARNING
The clean Air Act of 1990 bans the intentional venting of
refrigerant (CFCs, HCFCs, and HFCs) as of July, 1992.
Approved methods of recovery, recycling or reclaiming
must be followed. Fines and/or incarceration may be
levied for non-compliance.
CAUTION
As with any mechanical equipment, contact with sharp
sheet metal edges can result in personal injury. Take
care while handling this equipment and wear gloves and
protective clothing.
General
These instructions are intended as a general guide and
do not supersede local or national codes in any way.
Authorities having jurisdiction should be consulted before
installation.
The MWMC wall-mounted indoor units are matched with
an outdoor heat pump unit to create a mini-split system
that uses HFC-410A refrigerant.
MLB/MPC Outdoor Units
with MWMC Indoor Units
SINGLE-ZONE MINI-SPLIT SYSTEMS
(115V and 208/230V) --
Wall-Mounted Indoor Unit
507545-07 04/2024
Supersedes 02/2024
Table of Contents
General .....................................................................................1
Included Parts...........................................................................2
Model Number Identication .....................................................3
Indoor / Outdoor Unit Match-Ups..............................................4
System Dimensions ..................................................................5
Outdoor Units ................................................................................................... 5
Indoor Units ...................................................................................................... 8
Wall Mounting Plates ........................................................................................ 9
System Clearances ................................................................11
Outdoor Unit ................................................................................................... 11
Indoor Unit ...................................................................................................... 11
Torque Requirements for Caps and Fasteners.......................12
Indoor Unit Installation ............................................................12
Unit Placement Considerations ...................................................................... 12
Determining Wall Mounting Plate Location .................................................... 12
Installation of Wall Mounting Plate ................................................................. 13
Installation of Wall Sleeve .............................................................................. 13
Installation of Indoor Unit on Wall Mounting Plate .......................................... 13
Indoor Unit Condensate Piping Connections ................................................. 14
Outdoor Unit Installation .........................................................14
Placement Considerations ............................................................................. 14
Direct Sunlight, Rain, Snow and Ice Protection .............................................. 15
Prevailing Winds ............................................................................................. 16
Buried Refrigerant Pipe Protection ................................................................. 16
Outdoor Unit Condensate Piping .................................................................... 16
Securing the Outdoor Unit .............................................................................. 17
Refrigerant Piping Connections ..............................................17
Leak Test and Evacuation ......................................................19
Leak Test ........................................................................................................ 19
Triple Evacuation Procedure .......................................................................... 20
Wiring Connections ................................................................20
Outdoor Unit .................................................................................................. 20
Indoor Unit ...................................................................................................... 20
Unit Start-Up ...........................................................................28
Adding Refrigerant for Longer Line Set ..................................29
Troubleshooting ......................................................................29
I-Clean Feature.......................................................................30
Test Run .................................................................................31
Pre-Checks ..................................................................................................... 31
Procedure ....................................................................................................... 31
Double-Check Pipe Connections ................................................................... 31
If Ambient Temperature is below 60°F (16°C) ................................................ 31
Dry Mode Operation (Dehumidication) .................................31
Procedure ....................................................................................................... 31
Sequence of Operation .................................................................................. 31
Humidity Control .....................................................................32
Intelligent Eye Function .........................................................32
THIS MANUAL MUST BE LEFT WITH THE OWNER
FOR FUTURE REFERENCE

Lennox MLB Series Specifications

General

Brand	Lennox
Model	MLB Series
Category	Indoor Furnishing
Language	English

Summary

General Information

General Guidance

General installation guidance and disclaimer about local codes and refrigerant.

Included Parts

Lists all components included in the indoor and outdoor unit packages for installation.

Model Identification & Match-Ups

Explains model numbering and compatible indoor/outdoor unit combinations.

Unit Specifications

System Dimensions

Provides dimensional diagrams and specifications for outdoor and indoor units.

Wall Mounting Plates

Shows dimensions and mounting details for indoor unit wall plates.

System Clearances

Specifies minimum required clearances for outdoor and indoor units for proper operation.

Installation Procedures

Indoor Unit Installation & Placement

Guidelines for indoor unit placement, wall plate location, and mounting.

Indoor Unit Condensate Piping

Instructions for correctly connecting and ensuring proper drainage of the indoor unit condensate line.

Outdoor Unit Installation & Placement

Guidance on outdoor unit placement, protection from elements, and securing methods.

Refrigerant Piping & Connections

Steps for making refrigerant line connections, including pipe sizing, flaring, and insulation.

System Testing & Wiring

Leak Test & Evacuation

Procedure for leak testing and evacuating the refrigerant system to remove non-condensables and moisture.

Triple Evacuation Procedure

Step-by-step guide for performing a triple evacuation to ensure system purity.

Wiring Diagrams & Connections

Instructions and diagrams for electrical wiring connections and system diagrams.

Operation & Troubleshooting

Unit Start-Up

Essential pre-energization checks and steps to safely start up the HVAC unit.

Refrigerant Charge Adjustment

Guidance on calculating and adding extra refrigerant for extended line sets.

Special Features & Modes

Explanation of I-Clean, Test Run, Dry Mode, Humidity Control, and Intelligent Eye.