Refrigerant System Engineering - LG MULTI F LMU183HV Installation Manual

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REFRIGERANT SYSTEM ENGINEERING

Proper system operation depends on the installer using utmost care while assembling the piping system. The following pages are an over-

view of best practices when installing the refrigerant piping system.

No Pipe Size Substitutions

Use only the pipe size selected by the LATS HVAC pipe system design software. Using a different size is prohibited and will result in a

system malfunction or failure to work at all.

No In-line Refrigeration Components

Components such as oil traps, solenoid valves, filter-driers, sight glasses, tee fittings, and other after-market accessories are

permitted on the refrigerant piping system between the outdoor units and the indoor / heat recovery units. LG HVAC systems are provided

with redundant systems that make sure oil is properly returned to the compressor. Sight-glasses and solenoid valves will cause vapor to form

in the liquid stream. Over time, driers will deteriorate and introduce debris into the system. The designer and installer must verify the refriger-

ant piping system is free of traps, sagging pipes, sight glasses, filter driers, etc.

Field-Provided Isolation Ball Valves

LG maintains a neutral position on using isolation valves in LG HVAC refrigerant piping systems. LG does not endorse any manufacturer of

isolation valves. It is recognized that installing isolation valves will simplify future maintenance requirements, and, if used, considerations

must be taken including, but not limited to, the following:

• Pressure drops for any component used, including isolation valves, must be known in equivalent pipe length and calculated into the total

and segment equivalent piping lengths and compared to product design limitations.

• In all cases, materials must be suitable for the application and any applicable codes, including, but not limited to, diameter and wall thick-

ness continuity per ACR standards.

Failure to do so will cause significant performance degradation. Proper leak checks must be performed. Using isolation valves does not

automatically void any LG product warranty, however, a limited warranty will be voided in whole or part must any field supplied accessory fail

in any way that causes product failure.

Using Elbows

Field-supplied elbows are allowed if they are long radius and designed for use with R410A refrigerant. The designer and installer, however,

must be cautious with the quantity and size of fittings used, and must account for the additional pressure losses in equivalent pipe length

calculation for each branch. The equivalent pipe length of each elbow must be added to each pipe segment in the LATS program.

Pipe Bends

When bending soft copper, use long radius bends. Refer to the "Radii of Coiled Expansion Loops and Developed Lengths of Expansion

Offsets" table for minimum radius specifications.

Due to our policy of continuous product innovation, some specifications may change without notification.

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