Refrigerant Pipe And Drain Pipe Specifications; Connecting Refrigerant Pipes And Drain Pipes; Refrigerant Piping Work - Mitsubishi Electric PFAV-P250VM-E Manuel D'installation

5. Refrigerant pipe and drain pipe specifications

To avoid dew drops, provide sufficient antisweating and insulating work to the
refrigerant and drain pipes.
When using commercially available refrigerant pipes, be sure to wind
commercially available insulating material (with a heat-resisting temperature of
more than 100 °C and thickness given below) onto both liquid and gas pipes.
Be also sure to wind commercially available insulating material (with a form
polyethylene's specific gravity of 0.03 and thickness given below) onto all pipes
which pass through rooms.
Use thermal insulating material to insulate piping connections inside the unit.
5.1. Refrigerant pipe and drain pipe specifications
[Fig. 5.1.1] (P.4)
A Blow duct flange
B Front intake (P250·P500 models only)
C Suction duct flange (P300-F·P600-F models only)
D Refrigerant pipe (liquid)
F Drain pipe
H Refrigerant pipe (liquid)
* The pipe positions are the same on both the left and right
Model
Item
Liquid pipe ø9.52 × Thickness 0.8mm (Pipe type-O)
Refrigerant pipe
(Brazing
ø22.2 × Thickness 1.0mm (Pipe type -
connection)
Gas pipe
1/2H or H)
Rc1, ø34 steel pipe, hard vinyl chloride
Drain pipe pipe VP-25
(with an external diameter of 32mm)

6. Connecting refrigerant pipes and drain pipes

 Do not connect outdoor units other than the specified type.
 Be sure to connect the indoor unit and outdoor unit on a one-to-one
basis.

6.1. Refrigerant piping work

This piping work must be done in accordance with the installation manuals for
both outdoor unit.
• With this air conditioner, the refrigerant pipe from the outdoor unit is
connected to each indoor unit.
• For constraints on pipe length and allowable difference of elevation, refer to
the outdoor unit manual.
• The method of pipe connection is brazing connection.
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.
 Remove the filter before performing brazing work.
 When brazing pipes, take care that the flame of the torch does not come
into contact with any surrounding material (rubber, glass wool, wires, etc.).
 When connecting the locally procured pipes for the indoor unit, expand
the pipes or use pipe connections.
 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 brazing connection.
Warning:
When installing and moving the unit, do not charge it with refrigerant other
than the refrigerant specified on the unit.
- Mixing of a different refrigerant, air, etc. may cause the refrigerant cycle to
malfunction and result in severe damage.
Caution:
• Use refrigerant piping made of phosphorus deoxidized 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, shaving particles, oils, moisture, or any other
contaminant.
E Refrigerant pipe (gas)
G Refrigerant pipe (gas)
I Drain pipe
P250·P300-F
1 Select the thickness of insulating material by pipe size.
Pipe size
6.4 mm to 25.4 mm
28.6 mm to 34.9 mm
2 If the unit is used on the highest story of a building and under conditions of
high temperature and humidity, it is necessary to use pipe size and insulating
material's thickness more than those given in the table above.
3 If there are customer's specifications, simply follow them.
[Fig. 5.1.2] (P.4)
A Blow duct flange
C Refrigerant pipe (gas)
E Drain connection hole (upper)
Refrigerant pipe inlet (gas)
1
Refrigerant pipe inlet (liquid)
2
P500·P600-F
ø15.88 × Thickness 1.0mm (Pipe type-O)
ø28.58 × Thickness 1.0mm (Pipe type -
1/2H or H)
Rc1-1/4, ø42.7 steel pipe, hard vinyl
chloride pipe VP-30
(with an external diameter of 38mm)
• 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.
P250·P300-F models
Braze the supplied pipe to the unit, following the instructions below.
* Direct the brazing torch flame away from the thermistor and LEV wiring.
(1) Remove the front bottom panel, filter, and service panel.
(2) <To route the pipe from the right>
Punch out the knockout hole for the refrigerant pipe on the right.
<To route the pipe from the left>
Punch out the knockout hole for the refrigerant pipe on the left.
(3) Cut off the charging pipe (indicated with X in the figure) on the closed-end
gas pipe to release the nitrogen gas inside the pipe (shown in [Fig. 6.1.1],
viewed from the direction of A).
(4) Remove the closed-end pipes from the gas and the liquid pipes in
[Fig. 6.1.1].
Perform brazing either through the maintenance access hole on the left
side or from the front of the unit.
(5) Braze the supplied pipe and the field-supplied pipe through the
maintenance access hole on the left side or from the front of the unit as
shown in [Fig. 6.1.2] and [Fig. 6.1.3].
Note 1: When routing the pipe from the right, take the following steps to
braze the pipe to the unit.
Field-supplied pipe connection [Fig. 6.1.3]  Supplied pipe
connection [Fig. 6.1.2]
Note 2: Direct the brazing torch flame away from the surrounding parts
when brazing the field-supplied pipe to the unit.
(6) Install the pipe cover as shown in [Fig. 6.1.3].
Insulating material's thickness
More than 10 mm
More than 15 mm
B Suction duct flange
D Refrigerant pipe (liquid)
F Drain connection hole (lower)
Parts
ø75 Knockout hole
ø43 Knockout hole
P750·P900-F
ø19.05 × Thickness 1.0mm (Pipe type-
1/2H or H)
ø34.93 × Thickness 1.2mm (Pipe type-
1/2H or H)
Upper: Rc1-1/4, ø42.7 steel pipe, hard
vinyl chloride pipe VP-30
(with an external diameter of
38mm)
Lower: Rc1, ø34 steel pipe, hard vinyl
chloride pipe VP-25
(with an external diameter of
32mm)
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