Mitsubishi Electric MSZ-LN18VG2V-E3

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INDOOR UNIT

SERVICE MANUAL

No. OBH766

REVISED EDITION-G

CONTENTS

1. TECHNICAL CHANGES ······························3

2. PART NAMES AND FUNCTIONS ··················5

3. SPECIFICATION ········································6

4. NOISE CRITERIA CURVE ····························8

5. OUTLINES AND DIMENSIONS ··················· 11

6. WIRING DIAGRAM ··································· 13

7. REFRIGERANT SYSTEM DIAGRAM ··········· 18

8. SERVICE FUNCTIONS ······························19

9. MICROPROCESSOR CONTROL ·················26

10. TROUBLESHOOTING ······························· 37

11. DISASSEMBLY INSTRUCTIONS ················· 55

PARTS CATALOG (OBB766)

MSZ-LN25VGW/V/B/R

MSZ-LN35VGW/V/B/R

MSZ-LN50VGW/V/B/R

MSZ-LN60VGW/V/B/R

OBH766 REVISED EDITION-F is void.

Outdoor unit service manual

MUZ-LN•VG Series (OBH767)

MUZ-LN•VGHZ Series (OBH768)

Revision G:

• MSZ-LN18VG2W -

SC1

ET2

ER2

MSZ-LN18VG2V/B/R -

MSZ-LN25/35/50VG2W/V/B/R -

SC1

ET3

ER3

and MSZ-LN60VG2W/V/B/R -

ET3

ER3

have been added.

Models

MSZ-LN18VGW/V/B/R -

MSZ-LN18VG2W -

ER1

EN1

ET1

SC1

ET2

ER2

MSZ-LN18VG2V/B/R -

EN1

ET1

MSZ-LN25VGW/V/B/R -

ER1

MSZ-LN25VG2W/V/B/R -

ER1

EN1

ET1

SC1

ER2

EN2

ET2

ET3

ER3

MSZ-LN35VGW/V/B/R -

ER1

MSZ-LN35VG2W/V/B/R -

ER1

EN1

ET1

SC1

ER2

EN2

ET2

ET3

ER3

MSZ-LN50VGW/V/B/R -

ER1

MSZ-LN50VG2W/V/B/R -

ER1

EN1

ET1

SC1

ER2

EN2

ET2

ET3

ER3

MSZ-LN60VGW/V/B/R -

ER1

MSZ-LN60VG2W/V/B/R -

ER1

ET1

ER2

ET2

ET3

ER3

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Overview

Function Description
Key Components and Features
Important Technical Specifications (Examples for MSZ-LN18VGW/VG2W, MSZ-LN25VGW/VG2W, MSZ-LN35VGW/VG2W, MSZ-LN50VGW/VG2W, MSZ-LN60VGW/VG2W)
Usage Features
Maintenance Features

This document is a service manual for Mitsubishi Electric split-type air conditioners, specifically for the MSZ-LN series indoor units. It covers various models including MSZ-LN18VGW/V/B/R, MSZ-LN25VGW/V/B/R, MSZ-LN35VGW/V/B/R, MSZ-LN50VGW/V/B/R, and MSZ-LN60VGW/V/B/R, as well as their VG2W/V/B/R variants with different revisions (E1, ER1, EN1, ET1, SC1, E2, ER2, EN2, ET2, E3, ET3, ER3). It also references outdoor unit service manuals for MUZ-LN-VG and MUZ-LN-VGHZ series.

Function Description

The MSZ-LN series indoor units are designed for air conditioning, offering both cooling and heating functions. They are compatible with outdoor units that feature low standby power control, enabling energy efficiency. The units incorporate a Wi-Fi interface for remote control via MELCloud, allowing users to monitor status and send commands.

Key Components and Features:

Air Filter: Filters incoming air.
Front Panel: The main visible cover of the indoor unit.
Air Inlet/Outlet: Where air enters and exits the unit.
Air Purifying Device: An optional component (Silverionized air purifier filter) for improving air quality by reducing fungi, viruses, mold, and allergens.
Horizontal and Vertical Vanes: Adjustable vanes that control airflow direction. Stepping motors control their rotation, speed, and angle.
i-see Sensor: Detects human presence and analyzes room temperature distribution for optimized airflow control and energy saving (Absence Detection mode).
Emergency Operation Switch: Allows basic operation (COOL/HEAT at 24°C, Med fan speed, VANE AUTO) if the remote controller is missing or faulty.
Remote Controller: Wireless remote for comprehensive control of operation mode, temperature, fan speed, vane direction, and various special functions.
Operation Indicator Lamp: Displays the unit's operational state (Lit for operation, Blinking for standby or abnormality, Not lit for off).
Electronic Control P.C. Boards: Indoor power P.C. board and indoor electronic control P.C. board manage the unit's functions.
Thermistors: Room temperature thermistor (RT11) and indoor coil thermistors (RT12, RT13) monitor temperatures for control and frost prevention.
Fan Motor (MF): Drives the indoor fan.
Vane Motors (MV1, MV2): Control horizontal and vertical vanes.
Varistor (NR11) and Fuse (F11): Electrical protection components.
Terminal Block (TB): For electrical connections.

Important Technical Specifications (Examples for MSZ-LN18VGW/VG2W, MSZ-LN25VGW/VG2W, MSZ-LN35VGW/VG2W, MSZ-LN50VGW/VG2W, MSZ-LN60VGW/VG2W):

Power Supply: Single phase 230 V, 50 Hz.
Power Input (W):
- Cooling: 20 (LN18), 24 (LN25/35), 29 (LN50), 40 (LN60)
- Heating: 29 (LN18), 27 (LN25/35), 34 (LN50), 40 (LN60)
Running Current (A):
- Cooling: 0.21 (LN18), 0.23 (LN25/35), 0.28 (LN50), 0.37 (LN60)
- Heating: 0.28 (LN18), 0.26 (LN25/35), 0.33 (LN50), 0.37 (LN60)
Dimensions (W × H × D): 890 x 307 x 233 mm.
Weight (kg): 14.5 (LN18W/VG2W), 15.5 (LN18V/B/R), 15 (LN50/60W/VG2W), 16 (LN50/60V/B/R).
Airflow (m³/h) - Super High:
- Cooling: 714 (LN18), 768 (LN25/35), 834 (LN50), 942 (LN60)
- Heating: 864 (LN18), 822 (LN25/35), 942 (LN50/60)
Sound Level (dB(A)) - Super High:
- Cooling: 42 (LN18/25), 43 (LN35), 46 (LN50), 49 (LN60)
- Heating: 45 (LN18/25), 45 (LN35), 47 (LN50), 49 (LN60)
Fan Speed (rpm) - Super High:
- Cooling: 1,030 (LN18), 1,090 (LN25/35), 1,160 (LN50), 1,280 (LN60)
- Heating: 1,190 (LN18), 1,150 (LN25/35), 1,280 (LN50/60)
Refrigerant Pipe: Ø6.35 (with heat insulator) and Ø9.52 (LN18-50) or Ø12.7 (LN60) (with heat insulator).

Usage Features

Timer Short Mode: For service purposes, reduces ON/OFF timer set time to 1 second per minute and compressor start-up time to 1 minute (after breaker ON).
Remote Controller Pairing: Allows assigning a unique number to each remote controller for individual control of up to 4 indoor units in a room.
Installation Position Setting: Configures the remote controller based on the indoor unit's position (Left, Center, Right) relative to walls/cabinets for optimized airflow.
Auto Restart Function: Memorizes operation settings (mode, temperature, fan speed) and automatically restarts the unit in the same mode after a power cut. Can be disabled by cutting jumper wire JR77.
Wi-Fi Interface Setting Up: Connects the unit to MELCloud via a router using WPS-PUSH mode or Access Point mode for remote control and monitoring.
Operation Modes:
- COOL: Standard cooling with coil frost prevention and low outside temperature operation.
- DRY: Dehumidification with similar controls to COOL mode.
- FAN: Fan-only operation.
- HEAT: Standard heating with cold air prevention control, high pressure protection, and defrosting.
- AUTO CHANGE OVER (AUTO MODE): Automatically switches between COOL and HEAT based on room temperature relative to the set temperature.
- AUTO VANE OPERATION: Horizontal vanes adjust automatically for optimal room temperature distribution. Vertical vanes also adjust.
- SWING Mode: Horizontal vanes swing vertically; vertical vanes swing horizontally.
- ECONO COOL: Automatically sets temperature 2°C higher in COOL mode while maintaining comfort through varied horizontal vane swings, saving energy.
- POWERFUL Mode: Automatically adjusts fan speed and set temperature for rapid cooling/heating.
- NIGHT MODE: Dims operation indicator, disables beep sounds, and limits outdoor unit noise level.
- AIR PURIFYING: Activates the built-in device to reduce airborne fungi, viruses, mold, and allergens.
- i-save: Saves preferred temperature, fan speed, and airflow direction settings for quick recall (2 groups: COOL/ECONO COOL/CIRCULATOR and HEAT).
- OPERATION LOCK: Locks the operation mode only, allowing other functions to be adjusted.
- CIRCULATOR: Circulates indoor air when the indoor temperature reaches the set temperature in HEAT mode.
- 3-MINUTE TIME DELAY: Prevents compressor restart for 3 minutes after shutdown to protect against overload.
- i-see CONTROL (Absence Detection): Automatically switches to energy-saving or auto-OFF mode when no human presence is detected.
- AIRFLOW CONTROL: Adjusts airflow based on occupant location (INDIRECT, DIRECT, EVEN).

Maintenance Features

Troubleshooting Flow Charts: Detailed procedures for diagnosing and resolving issues related to indoor/outdoor unit abnormalities, Wi-Fi interface problems, indoor fan motor errors, remote controller/P.C. board issues, serial signal errors, and air purifying power failures.
Failure Mode Recall Function: Memorizes abnormal conditions, allowing service personnel to recall failure details even if LED indications have disappeared.
Test Point Diagram and Voltage: Provides electrical diagrams and voltage values for key components to aid in troubleshooting.
Thermistor Characteristics: Charts showing resistance values of room and indoor coil thermistors at different temperatures for diagnostic purposes.
Disassembly Instructions: Step-by-step guides for removing various components, including the front panel, vanes, Wi-Fi interface, electrical box, P.C. boards, fan motor, and heat exchanger.
Indoor Coil Thermistor Fixing: Instructions for correctly mounting the indoor coil thermistor using clip-shape or holder-shape parts.
Refrigerant System Diagram: Illustrates the refrigerant flow and components.
Specified Refrigerant Use: Emphasizes using only the specified refrigerant to prevent damage or hazards.
Safety Precautions: Warnings regarding handling refrigerant, electrical parts, and capacitors during service.
Battery Replacement: Instructions for replacing remote controller batteries and resetting the microprocessor.