Refrigerant Piping For Separated Outdoor Units; Trapping; Maximum Pipe Length From First Odu Y-Branch To Farthest Odu; Elevation Difference Between Outdoor Units - LG Multi IV Engineering Manual

Refrigerant Piping for Separated Outdoor Units

Dual-frame and triple-frame systems should be installed with all outdoor units located next to each other. In conditions where the dual-frame
or triple-frame outdoor units need to be separated, the following rules must be followed:
1. Measurements.
All measurements should be made from the union center of the outdoor unit Y-branch.
2. Maximum pipe length from first outdoor unit Y-branch to farthest outdoor unit.
Total pipe length from the first outdoor unit Y-branch to the piping connection at the
farthest outdoor unit must not exceed thirty-three (33) feet.

3. Elevation difference between outdoor units.

The elevation difference between the highest and lowest elevation outdoor unit must
not exceed sixteen (16) feet.

Trapping

1. When required, all traps must be inverted type
a. Heat pump outdoor units would be trapped
in the suction vapor line, and heat recovery
outdoor units would be trapped in the high AND
low pressure vapor lines.
b. Inverted traps are defined as any piping that
pipe it elevates from.
Figure 39: Traps for Heat Pump and Heat Recovery Units.
Heat Pump
Suction
Liquid
To IDUs
Figure 40: Close Up of An Inverted Oil Trap.
©
LAYOUT BEST PRACTICES
General Information / Guidelines
Figure 36: Y-branch Measurement Location.
Figure 37: Maximum PIpe Length from First ODU
Y-branch to Farthest ODU.
To IDUs / HRUs s
33 Feet
(Max.)
Figure 38: Elevation Difference Between Outdoor
Units.
To IDUs /
HRUs
High Pressure Vapor
Low Pressure Vapor

Oil Trap

8 inches
16 Feet
(Max)
/
Heat Recovery
Liquid
To IDUs
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