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6. Connecting refrigerant pipes and drain pipes
6.1. Refrigerant piping work
This piping work must be done in accordance with the installation manuals for both
outdoor unit and BC controller (simultaneous cooling and heating series R2).
• Series R2 is designed to operate in a system that the refrigerant pipe from an
outdoor unit is received by BC controller and branches at the BC controller to
connect between indoor units.
• For constraints on pipe length and allowable difference of elevation, refer to the
outdoor unit manual.
• The method of pipe connection is brazing connection.
Caution:
• Install the refrigerant piping for the indoor unit in accordance with the fol-
lowing.
1. Cut the tip of the indoor unit piping, remove the gas, and then remove the brazed
cap.
[Fig. 6.1.1] (P.3)
2. Pull out the thermal insulation on the site refrigerant piping, braze the unit piping,
and replace the insulation in its original position.
Wrap the piping with insulating tape.
Note:
• When brazing the refrigerant pipes, be sure to braze, after covering a wet
cloth to the pipes of the units in order to prevent it from burning and
shrinking by heat.
[Fig. 6.1.2] (P.3)
• Pay strict attention when wrapping the copper piping since wrapping the
piping may cause condensation instead of preventing it.
[Fig. 6.1.3] (P.3)
Cautions On Refrigerant Piping
Be sure to use non-oxidative brazing for brazing to ensure that no foreign
matter or moisture enter into the pipe.
Be sure to apply refrigerating machine oil over the flare connection seating
surface and tighten the connection using a double spanner.
Provide a metal brace to support the refrigerant pipe so that no load is
imparted to the indoor unit end pipe. This metal brace should be provided
50 cm away from the indoor unit’s flare connection.
Warning:
Do not use refrigerant other than the type indicated in the manuals provided
with the unit and on the nameplate.
- Doing so may cause the unit or pipes to burst, or result in explosion or fire during
use, during repair, or at the time of disposal of the unit.
- It may also be in violation of applicable laws.
- MITSUBISHI ELECTRIC CORPORATION cannot be held responsible for mal-
functions or accidents resulting from the use of the wrong type of refrigerant.
Caution:
• Use refrigerant piping made of C1220 (Cu-DHP) phosphorus deoxidized
copper as specified in the JIS H3300 “Copper and copper alloy seamless
pipes and tubes”. In addition, be sure that the inner and outer surfaces of
the pipes are clean and free of hazardous sulphur, oxides, dust/dirt, shav-
ing particles, oils, moisture, or any other contaminant.
• Never use existing refrigerant piping.
- The large amount of chlorine in conventional refrigerant and refrigerator oil in
the existing piping will cause the new refrigerant to deteriorate.
• Store the piping to be used during installation indoors and keep both ends
of the piping sealed until just before brazing.
- If dust, dirt, or water gets into the refrigerant cycle, the oil will deteriorate and
the compressor may fail.
• Use Suniso 4GS or 3GS (small amount) refrigerator oil to coat the flare and
flange connection part. (For models using R22)
• Use ester oil, ether oil or alkylbenzene (small amount) as the refrigerator oil
to coat flares and flange connections. (For models using R410A or R407C)
- The refrigerant used in the unit is highly hygroscopic and mixes with water and
will degrade the refrigerator oil.
6.2. Drain piping work
• Ensure that the drain piping is downward (pitch of more than 1/100) to the out-
door (discharge) side. Do not provide any trap or irregularity on the way. (
1
)
• Ensure that any cross-wise drain piping is less than 20 m (excluding the differ-
ence 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 VP-25 (with an external diameter of 32 mm) for
drain piping.
• 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 gener-
ated.
[Fig. 6.2.1] (P.4)
1. Insert the drain hose (accessory) into the drain port.
The connecting part between the indoor unit and the drain hose may be discon-
nected at the maintenance. Fix the part with the accessory band, not be adhered.
2. Attach the drain pipe (O.D. ø32 PVC TUBE, field supply).
(Attach the pipe with glue for the hard vinyl chloride pipe, and fix it with the band
(small, accessory).)
3. Perform insulation work on the drain pipe (O.D. ø32 PVC TUBE) and on the
socket (including elbow).
[Fig. 6.2.2] (P.4)
7. Duct work
• When connecting ducts, insert a canvas duct between the main body and the
duct.
• Use non-combustible duct components.
• Install sufficient thermal insulation to prevent condensation forming on air inlet
and air outlet duct flanges, and air outlet ducts.
[Fig. 7.0.1] (P.4)
• Procedure for changing the bottom inlet to the front inlet.
Caution:
When the front inlet, the sound pressure level will be greater by approximately
5 dB than when the bottom inlet.
[Fig. 7.0.2] (P.4)
1. Remove air filter.
2. Remove the bottom plate.
3. Fit the front plate to the bottom of the body.
4. Fit air filter.
A
Cut here
B
Remove brazed cap
A
Cool by a wet cloth
A
Thermal insulation
B
Pull out insulation
C
Wrap with damp cloth
D
Return to original position
E
Ensure that there is no gap here
F
Wrap with insulating tape
A
Downward slope 1/100 or more
B
Drain hose (Accessory)
C
Indoor unit
D
Collective piping
A
Indoor unit
B
Tie band (accessory)
C
Band fixing part
D
Insertion margin
E
Drain hose (accessory)
F
Drain pipe (O.D. ø32 PVC TUBE, field supply)
G
Insulating material (field supply)
A
Air inlet
B
Air filter
C
Duct
D
Canvas duct
E
Access door
F
Wall
G
Air outlet
A
Filter
B
Front plate
C
Fan guard
VG79D813H01_en.book 10 ページ ２０１８年１２月１４日 金曜日 午前１１時２０分
