LG FM21AH UE3 User Manual

Multi Air Conditioner
SVC MANUAL(General)
MODEL : Multi-Inverter Type
CAUTION
Before Servicing the unit, read the safety precautions in General SVC manual.
Only for authorized service personnel.
Internal Use Only
http://biz.lgservice.com

LG FM21AH UE3 Specifications

General

Brand	LG
Model	FM21AH UE3
Category	Air Conditioner
Language	English

Summary

Part 1 General Information

Safety Precautions

Essential safety guidelines for servicing and handling the air conditioner.

Part 3 Control Logic

Compressor Control

Principles of compressor operation, starting, and frequency control.

Step(Frequency) Control

Reversing Valve Operation

Defrosting Control Algorithm

Part 4 Test Run

Pre-Test Run Checks

Essential pre-operational checks to ensure proper installation and safety.

Test Run Flow Chart

Step-by-step guide for conducting a test run and troubleshooting.

Test Running Procedures

Detailed procedures for performing test runs on different unit types.

Part 5 Trouble Shooting

Self-diagnosis Function

How the unit self-diagnoses errors and indicates them via LEDs or displays.

Pumping Down Procedure

Procedure for safely collecting refrigerant into the outdoor unit.

Evacuation Process

Process for removing air and moisture from the refrigerant circuit.

Gas Charging Procedure

Method for charging the system with the correct amount of refrigerant.

Cycle Part Troubleshooting

Electronic Parts Troubleshooting

Step-by-step guide for diagnosing and fixing issues with electronic components.