Page 15
mrcool.com
Unit Installation
Outdoor Unit Model
Liquid Pipe Gas Pipe
Size of Fitting Pipe
Maximum
Pipe Length
Maximum Drop
between indoor and
outdoor units
3/8 in 3/4 in
98.4 ft
(30 m)
49.2 ft
(15 m)
MDUO18024036
MDUO18048060
INSTALLATION METHOD
Connect the refrigerant lines to the unit first. When bending a refrigerant pipe, be careful not to
kink or crimp the pipe. DO NOT overtighten the screw nut, otherwise leakage may occur. The
outside of the refrigerant pipe should have a layer of insulating cotton to protect it from
mechanical damage during installation, maintenance and transportation.
Refrigerant lines should adopt water-proof insulating material. The pipe wall thickness should be
0.5-1.0 mm and able to withstand 6.0 MPa. Excessive length of the refrigerant lines will negatively
affect cooling and heating performance. Attempt to minimize refrigerant line length when
possible.
When the drop between indoor and outdoor units is larger than 32 ft (10 m), an oil return bend
should be added every 19.69 ft (6 m).
Be extremely careful not to dent or damage the piping while bending them away from the unit. Any
dents in the piping will affect the unit’s performance.
LINE SET SIZE
MUST MATCH
SERVICE VALVE
CONNECTION
DO NOT CRIMP SERVICE VALVE
CONNECTOR IF PIPE IS
SMALLER THAN CONNECTOR
3
Conventional Line Set Installation
For installation with a No-Vac® Quick Connect® Line Set, refer to the next section starting on page 24
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