Lennox MLB048S4S User Manual

1
MINI-SPLIT SYSTEMS SERVICE MANUAL
Indoor and Outdoor Unit Information
100029
5/2022
Table of Contents
Indoor Unit Information ...................................3
1. M22A and M33C Cassette Non-Ducted Indoor Units ............... 3
1.1. ModelNumberIdentication ........................................................3
1.2. M22AIndoorUnitSpecications ..................................................3
1.3. M33CIndoorUnitSpecications .................................................4
1.4. M22AIndoorUnitDimensions .....................................................5
1.5. M33CIndoorUnitDimensions .....................................................6
1.6. M22AandM33CIndoorUnitClearances ....................................7
1.7. M22AandM33CIndoorUnitControlBoardSwitches
Location .......................................................................................8
1.8. M22AandM33CCondensateDrainTestProcedure ...................9
2. MMDB Ducted Indoor Units ......................................................10
2.1. MMDBModelNumberIdentication ..........................................10
2.2. MMDBIndoorUnitSpecications .............................................. 11
2.3. IndoorUnitBlowerData ............................................................12
2.4. MMDBIndoorUnitDimensions .................................................18
2.5. MMDBIndoorUnitClearances ..................................................19
2.6. CondensatePumpLift-MMDBandM22A/M33C .....................20
2.7. MMDBCondensateDrainTestProcedure.................................20
2.8. MMDBIndoorUnitGravityDrain ...............................................21
3. MWMC and 3WMC-036 Wall Mounted Indoor Units ............... 22
3.1. ModelNumberIdentication ......................................................22
3.2. IndoorUnitSpecications(009-012Ton)Units ......................23
3.3. IndoorUnitSpecications(018-030Ton)Units .......................23
3.4. IndoorUnitSpecications(3WMC) ...........................................23
3.5. IndoorUnitDimensions(MWMCand3WMC) ...........................24
3.6. IndoorUnitClearances(AllModelsandSizes) .........................25
3.7. MWMCand3WMC036S4UnitControlBoardSwitches
Location .....................................................................................25
3.8. DryModeOperation-MWMCand3WMC ................................26
3.9. TestRun-MWMCand3WMC ..................................................26
3.10. Double-CheckPipeConnections ...............................................26
3.11. AmbientTemperatureisBelow63°F(17°C) .............................27
4. MCFA and MCFB Ceiling / Floor Indoor Units ........................28
4.1. ModelNumberIdentication ......................................................28
4.2. IndoorUnitSpecications(018-048Ton)Units .......................28
4.3. IndoorUnitDimensions .............................................................29
4.4. IndoorUnitClearances ..............................................................30
4.5. MCFAandMCFBIndoorUnitControlBoardSwitches
Location .....................................................................................31
5. MFMA Floor Indoor Unit ...........................................................32
5.1. ModelNumberIdentication ......................................................32
5.2. IndoorUnitSpecications(012Ton)Unit ..................................32
5.3. IndoorUnitDimensions .............................................................33
5.4. IndoorUnitClearances ..............................................................33
6. Indoor and Outdoor Power and Communication
Wiring Requirements ............................................................... 34
6.1. Overview ....................................................................................34
6.2. WiringGuide ..............................................................................35
MCFA and MCFB
M22A and M33C
MMDB
MWMC and 3WMC036
MPC, 3PC, and MLB
Single Zone
MLB and MPC
Multi-Zone
MFMA
Please refer to service manual 100030 for indoor and
outdoor unit error codes and component diagnostics.

Lennox MLB048S4S Specifications

General

Brand	Lennox
Model	MLB048S4S
Category	Air Conditioner
Language	English

Summary

Indoor Unit Information

1.1. Model Number Identification

Explains how to identify indoor unit models through their nomenclature.

1.2. M22A Indoor Unit Specifications

2.2. MMDB Indoor Unit Specifications

6.2. Wiring Guide

Provides guidelines for wiring single-zone mini-split systems, including wire gauge.

Connection to Centralized Controller, ON/OFF and Alarm Devices

8.1. Set Indoor Unit Address for Centralized Control (Used with VRF Only)

Outdoor Unit Information

9.1. Model Number Identification

Explains the model number nomenclature for single and multiple zone outdoor units.

9.2. MPC Single-Zone Specifications (0.75 - 1.5 Ton)

9.5. MLB Single-Zone Specifications (0.75 - 2 Ton)

Indoor / Outdoor Unit Combinations

10.1. MPC Multi-Zone System Combinations

Lists valid combinations of MPC outdoor units with various indoor units and their capacities.

10.2. MLB Multi-Zone System Combinations

Lists valid combinations of MLB outdoor units with various indoor units and their capacities.

Refrigeration Pipe Work

11.1. MPC and 3PC Single-Zone Refrigerant Cycle Diagram

11.7. Single-Zone Piping Limitations

Details maximum and minimum line set lengths and elevation differences for single-zone systems.

11.8. Multi-Zone Piping Limitations

Details piping limitations for multi-zone systems, covering length and elevation.

MPC Multi-Zone Outdoor Unit Connections and Line Set Usage

Table 7. MPC018S4M

Table 8. MPC024S4M

Table 9. MPC030S4M

Figure 31. MPC036S4M

MLB Multi-Zone Outdoor Unit Connections and Line Set Usage

Table 11. MLB018S4M

Table 12. MLB030S4M

Table 13. MLB036S4M

Table 14. MLB048S4M

Installation Requirements

18.1. Torque Requirements

Specifies torque values for refrigerant pipe connections and additional tightening.

18.2. Pipe Length and Elevation

Details maximum piping length and height difference limits for system installation.

18.2.4. Air Purging using a Vacuum Pump

18.2.5. Adding Refrigerant if Pipe Length Exceeds Charge Less Pipe Length

Guides on adding refrigerant based on pipe length and elevation for optimal performance.

Start-Up

20.1. Adding Refrigerant - Single-Zone Systems

20.2. Adding Refrigerant - Multi-Zone Systems

Specifications and Operations

24. Pressure on Service Port

Provides pressure charts and data for cooling and heating modes based on temperature conditions.

24.3. Capacity Request Calculations

Explains how to calculate system capacity requests based on norm codes, HP, and temperature modifications.

24.4. Defrost Control

Details the conditions and logic for initiating defrost cycles based on coil temperature and run-time.

24.7. Outdoor Fan Control

Describes how the system controls outdoor fan speed based on ambient and coil temperatures.