Midea MOU-12FN1-QD0 Installation Manual page 18

Refrigerant Piping Connection Instructions
CAUTION
The branching pipe must be installed
•
horizontally. An angle of more than 10° may
cause malfunction.
DO NOT install the connecting pipe until
•
both indoor and outdoor units have been
installed.
Insulate both the gas and liquid piping to
•
prevent water leakage.
Step1: Cut pipes
When preparing refrigerant pipes, take extra
care to cut and flare them properly. This will
ensure efficient operation and minimize the
need for future maintenance.
1. Measure the distance between the indoor
and outdoor units.
2. Using a pipe cutter, cut the pipe a little
longer than the measured distance.
CAUTION
DO NOT deform pipe while cutting. Be extra
careful not to damage, dent, or deform the pipe
while cutting. This will drastically reduce the
heating efficiency of the unit.
1. Make sure that the pipe is cut at a perfect
90° angle. Refer to Fig. 7.1 for examples of
bad cuts.
90°
Oblique
 Page 18 
Rough
Warped
Fig. 7.1
Step 2: Remove burrs.
Burrs can affect the air-tight seal of refrigerant
piping connection. They must be completely
removed.
1. Hold the pipe at a downward angle to
prevent burrs from falling into the pipe.
2. Using a reamer or deburring tool, remove
all burrs from the cut section of the pipe.
Point down
Fig. 7.2
Step 3: Flare pipe ends
Proper flaring is essential to achieve an airtight
seal.
1. After removing burrs from cut pipe, seal
the ends with PVC tape to prevent foreign
materials from entering the pipe.
2. Sheath the pipe with insulating material.
3. Place flare nuts on both ends of pipe.
Make sure they are facing in the right
direction, because you can't put them on
or change their direction after flaring.
See Fig. 7.3
Flare nut
Copper pipe
Fig. 7.3
4. Remove PVC tape from ends of pipe when
ready to perform flaring work.
5. Clamp flare form on the end of the pipe.
The end of the pipe must extend beyond
the flare form.
Flare form
Fig. 7.4
Pipe
Reamer
Pipe