Refrigerant Piping Work; Insulating Refrigerant Pipes; Drain Piping Work - Mitsubishi Electric CMB-P-NU-J1 Installation Manual

5.3. Refrigerant piping work

After connecting the refrigerant pipes of all indoor and outdoor units with the out-
door units' stop valves remained fully closed, evacuate vacuum from the outdoor
units' stop valve service ports.
After completing the above, open the outdoor units' stop valves. This connects
the refrigerant circuit (between outdoor and BC controller) completely.
How to handle stop valves is described on each outdoor unit.
Notes:
After pipe connection, be sure to check that there is no gas leakage,
using a leak detector or soap-and-water solution.
Before brazing the refrigerant piping, always wrap the piping on the main
body, and the thermal insulation piping, with damp cloths to prevent
heat shrinkage and burning the thermal insulation tubing. Take care to
Do not use leak-detection additives.
Warning:
refrigerating cycle when installing or moving. Mixing air may cause the
refrigerating cycle to reach abnormally high temperature, resulting in burst
pipes.
Caution:
Cut the tip of the indoor unit piping, remove the gas, and then remove the
brazed cap.
[Fig. 5.3.1]
A Cut here
B Remove brazed cap
A
B

5.4. Insulating refrigerant pipes

Be sure to wind heat-resisting polyethylene form of more than 20 mm [13/16
in] in thickness onto both liquid and gas pipes and also put it onto the joints
between indoor unit and insulating material so that there will be no gaps. Incom-
plete insulation may cause excess condensation or heat losses. Pay careful at-
tention, particularly when insulating above the ceiling.
[Fig. 5.4.1]
A Insulating material for pipes (not supplied)
Ⓒ
Ⓑ B Bind here using band or tape.
Ⓒ
Ⓐ
C Do not leave any opening.
D Lap margin: more than 40 mm
E Insulating material (not supplied)
Ⓓ
Ⓔ Ⓕ
Ⓖ F Unit side insulating material
G Minimum 20 mm
Insulation materials for the pipes to be added on site must meet the following
Outdoor unit High-pressure pipe: 10 mm or more
-BC controller
Low-pressure pipe: 20 mm or more
BC controller Pipe size 6.35 to 25.4 mm: 10 mm or more
-indoor unit
Pipe size 28.58 to 41.28 mm: 15 mm or more
Temperature resistance 100°C or above
Installation of pipes in a high-temperature high-humidity environment, such
as the top floor of a building, may require the use of insulation materials
The brazed connections must be covered with the insulations, its cutting
surface upward and fastened with the bands.
Insulate the pipe that protrudes from the BC controller if the pipe is not going
to be connected to other pipes.
[Fig. 5.4.2]
A Insulating material (not supplied)
Ⓐ Ⓑ
B Bind here using band or tape.

5.5. Drain piping work

1. Drain piping work
Ensure that the drain piping is downward (pitch of more than 1/100) to the
outdoor (discharge) side. If it is impossible to take any downward pitch, use
an optionally available drain-up mechanism to obtain a downward pitch of
more than 1/100.
Ensure that the drain piping is downward (pitch of more than 1/100) to the
outdoor (discharge) side. Do not provide any trap or irregularity on the way.
Ensure that any cross-wise drain piping is less than 20 m (excluding the
difference of elevation). If the drain piping is long, provide metal braces to
prevent it from waving. Never provide any air vent pipe. Otherwise drain may
be ejected.
Use a hard vinyl chloride pipe for drain piping.
Ensure that collected pipes are 10 cm [3-15/16 in] lower than the unit body's
drain port.
Do not provide any odor trap at the drain discharge port.
Put the end of the drain piping in a position where no odor is generated.
Do not put the end of the drain piping in any drain where ionic gases are
generated.
If the drain pipe is connected to only either of the two drain sockets, cover
the unused drain socket.
[Fig. 5.5.1]
Max. 20 m
1.5-2 m
Ⓑ
Ⓐ
Ⓚ
Ⓑ
Ⓓ
Ⓔ
Ⓕ
Ⓙ
Ⓗ
Correct piping
× Wrong piping
A Insulation (9 mm or more)
B Downward slope (1/100 or more)
C Support metal
K Air bleeder
L Raised
M Odor trap
Grouped piping
D PVC TUBE
E Make it as large as possible. About 10 cm.
F Indoor unit
G Make the piping size large for grouped piping.
H Downward slope (1/100 or more)
I O.D. ø38 PVC TUBE for grouped piping. (9 mm or more insulation)
J BC controller
1. Insert the adapter (not supplied) into the drain port.
2. Attach the drain pipe (PVC TUBE, not supplied).
(Attach the pipe with glue.)
3. Perform insulation work on the drain pipe (PVC TUBE) and on the socket
(including elbow).
4. Check the drainage.
5.
insulate the drain port.
Ⓕ
Ⓔ
Ⓐ
Ⓑ Ⓒ Ⓓ
2. Discharge test
After completing drain piping work, open the BC controller panel, and test drain
discharge using a small amount of water. Also, check to see that there is no wa-
ter leakage from the connections.
3. Insulating drain pipes
Caution:
Be sure to provide drain piping with heat inslation in order to prevent
excess condensation. Without drain piping, water may leak from the unit
causing damage to your property.
Ⓒ
Ⓛ
Ⓜ
Ⓓ Ⓓ
Ⓕ
Ⓖ
Ⓘ
A BC controller
B Tie band (not supplied)
C Drain socket NPT 3/4 in
D Adapter (not supplied)
E Drain pipe (not supplied)
F Insulating material (not supplied)
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