Gree UM600PH/A-M, Service Manual

Page: 68 / 121

GREE Duct type Ducted Type Split Air-Conditioner Units
68
5.2 Allowable Length and Fall for Refrigerant Pipe In IDU and ODU
Model
Pipe dimension (mm)
Max pipe length
(m)
Max height difference between
indoor unit and outdoor unit (m)
Gas pipe Liquid pipe
UMLD400W/A-M(P)
UMD400PH/A-M(P)
Ф 25.4 Ф 12.7 50 30
UML500H/A-M(P)
UM500PH/A-M(P)
Ф 34.9 Ф 15.9 50 30
UML600H/A-M(P)
UM600PH/A-M(P)
Ф 34.9 Ф 15.9 50 30
5.3 Design of Oil Loop
5.3.1 Purpose of Setting Oil Loop
If big fall exist in the pipe, in order to prevent the problem that the refrigeration oil can’t return to the
compressor effectively, oil loop must be set in the vertical pipeline.
5.3.2 Principle of setting Oil Loop
When there’s a difference between IDU and ODU, for the vertical gas pipe, an oil loop shall be
installed every 10m from the bottom up.
Oil loop shall adopt two U-shaped loops or one O-shaped loop, the height is 3
～
5 times the size of
pipe diameter.
5.3.3 Lnstallation Notices for Oil Loop
For the vertical gas pipe, an oil loop shall be installed every 10m from the bottom up, meanwhile, the
lowest/highest point of the vertical pipe shall be set with oil loop and check loop.
5.3.4 Manufacture Requirement for Oil Loop and Check Loop
Setting and manufacture method of oil loop is as follows:
(1) Set the oil loop as U-shape or O-shape;
(2) If ODU is below IDU, it’s needless to set oil loop at the lowest/highest point of the vertical pipe;
if ODU is above IDU, then oil loop and check loop must be set separately at the lowest/highest
point;
(3) Manufacture size of oil loop is as follows: