Multi F Max Bd Unit - LG MULTI F Engineering Manual

Multi-zone heat pump systems, 1.5 to 5 tons

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Table Of Contents

Table of Contents

MULTI

MAX

Branch Distribution Unit

General

Branch distribution units are designed for use with LG Multi F MAX (LMU480HV

and LMU540HV) outdoor units, and are internally piped, wired, assembled and

run-tested at the factory. The branch distribution unit is used as an intermedi-

ate refrigerant control device between the outdoor unit and the indoor units to

effectively and efficiently control the heating or cooling operation of the system

through the use of electronic expansion valves.

Refrigerant System

System is designed for use with R410A refrigerant. All refrigerant lines from the

outdoor unit to the branch distribution unit, and from the branch distribution unit to

the indoor units, must be field insulated. The units may be connected to optional

field-supplied and field-installed isolation valves for servicing without evacuating

the entire system.

Piping Capabilities

Maximum piping length from the branch distribution unit to the indoor unit is 49.2

equivalent feet. Maximum elevation difference between branch distribution unit

and indoor unit is 32.8 feet. Maximum elevation difference between two parallel

branch distribution units is 49.2 feet.

Electrical

Each branch distribution unit is designed to operate using 208–230/60/1 power

with voltage variances of ±10%.

Casing

The casing is designed to mount fully concealed above a finished ceiling, is manufactured of galvanized steel plate, and is internally

insulated. Branch distribution units do not require a condensate drain.

Port Assembly

Branch distribution units have a two-pipe system consisting of one vapor pipe and one liquid pipe. Units are available in a choice of two

(PMBD3620), three (PMBD3630) or four ports (PMBD3640 and PMBD3641); branch distribution units include two, two-positioned solenoid

valves per port. Each port for PMBD3620, PMBD3630, and PMBD3640 units connects to one indoor unit for a maximum nominal capacity of

24,000 Btu/h. For PMBD3641 units, ports A, B, C each connect to one indoor unit for a maximum nominal capacity of 24,000 Btu/h; port D

connects to one indoor unit for a nominal capacity of either 24,000 Btu/h or 36,000 Btu/h. Maximum nominal capacity per branch distribution

unit is 73,000 Btu/h. Two branch distribution units can be piped in parallel using accessory Y-branch kit PMBL5620.

Controls

The unit is provided with factory-installed control boards and an integral microprocessor to communicate with the main control board in the

outdoor unit. All power wiring / communication cable to be minimum 14 AWG, 4-conductor from the outdoor unit to the BD unit, and 14 AWG,

4-conductor from the BD unit to the indoor unit, stranded, shielded or unshielded (if shielded, it must be grounded to the chassis of the out-

door unit only), and must comply with applicable local and national codes.