Pipe Connection; Flaring Work - Mitsubishi Electric Mr. Slim MXZ-2A20NA Manual De Instrucciones

SELECTING PIPE SIZE
The diameter of connection pipes differs according to the type and capacity of indoor units. Match the diameters
of connection pipes for indoor and outdoor units according to the following table.
Model Pipe size for indoor unit Allowable
name [mm (in.)] connection pipe size
09 Liquid pipe ø6.35 (1/4) ø6.35 (1/4)
12 Gas pipe ø9.52 (3/8) ø9.52 (3/8)
Liquid pipe ø6.35 (1/4) ø6.35 (1/4)
15
Gas pipe ø12.7 (1/2) ø12.7 (1/2)
* Connections at outdoor unit are described as unit A and B below corresponding to the indication on
each valve.
• If the diameter of connection pipes does not match the diameter of pipe end connections, use optional
different-diameter joints.
• When connecting the model 15, use optional different-diameter joints MAC-A454JP because the valve size
of gas pipes for the outdoor unit is ø9.52 mm (3/8 in.).
PIPING PREPARATION
1 If you use commercially available copper pipes, use the following table for pipe specifications.
Outside diameter Minimum Wall thickness
mm (in.)
Liquid pipe ø6.35 (1/4)
Gas pipe ø9.52 (3/8)
Gas pipe ø12.7 (1/2)
2 Ensure that the 2 refrigerant pipes are insulated to prevent condensation.
3 Refrigerant pipe bending radius must be 4 in. or more.
CAUTION:
Be sure to use the insulation of specified thickness. Excessive thickness may cause incorrect installa-
tion of the indoor unit and lack of thickness may cause dew drippage.
5-3

FLARING WORK

• Main cause of gas leakage is defect in flaring work.
Perform flaring work correctly in the following procedure.
1. Pipe cutting
• Cut the copper pipe correctly with pipe cutter.
2. Burrs removal
• Completely remove all burrs from the cut cross
section of the pipe.
• Put the end of the copper pipe downward to pre-
vent burrs from dropping in the pipe.
3. Putting nut on
• Remove flare nuts attached to indoor and outdoor
units, then put them on pipe having completed
burr removal.
(not possible to put them on after flaring work)
• Flare nut for R410A pipe may differ from R22 pipe
depending on the diameter of pipe.
Valve size for outdoor unit
mm (in.)
Liquid pipe
Å UNIT
Gas pipe
Liquid pipe
ı UNIT
Gas pipe
Insulation thickness
Insulation material
mm (in.) mm (in.)
0.80 (0.0315) 8 (5/16) Heat resisting from
0.80 (0.0315) 8 (5/16) plastic 0.045 Specific
gravity
0.80 (0.0315) 8 (5/16)
No good
Good
Copper
Tilted Uneven Burred
90°
pipe
Copper pipe
Burr
Spare
reamer
Pipe cutter
Flare nut
Copper pipe
4. Flaring work
• Carry out flaring work using flaring tool as shown below.
Outside diameter
mm inch
ø6.35 1/4
ø6.35 (1/4)
ø9.52 3/8
ø9.52 (3/8)
ø12.7 1/2
ø6.35 (1/4)
ø9.52 (3/8)
Firmly hold copper pipe in a die in the dimension shown in the
table above.
5. Check
• Compare the flared work with the figure below.
• If flare is noted to be defective, cut off the flared section
and perform flaring work again.
5-4

PIPE CONNECTION

Note:
Fasten a flare nut with a torque wrench as specified in the table below.
When fastened too tight, a flare nut may be broken after a long period and cause a leakage of refriger-
ant.
1. Indoor unit connection
• Connect both liquid pipe and gas pipe to indoor unit.
- Apply a thin coat of refrigeration oil to the seat surface of pipe.
- For connection, align the center of both pipe and union, then tighten the first 3 to 4 turns in flare nut by
hand.
- For tightening the union part of the indoor unit side, use the table below as a standard and tighten
the flare nut with two wrenches. Excessive tightening damages the flared section.
Pipe diameter
mm inch
ø6.35 1/4
ø9.52 3/8
ø12.7 1/2
2. Outdoor unit connection
• Connect pipes to the pipe joint part of the stop valve in the same method as the indoor unit.
- For tightening, use the same tightening torque applied for indoor unit and tighten the flare nut with
torque wrench or spanner.
INSULATION AND TAPING
1 Cover piping joints with pipe cover.
2 For outdoor unit side, surely insulate every piping including valves.
3 Using piping tape E, apply taping starting from the entry of outdoor unit.
• Fix the end of piping tape E with adhesive tape.
• When piping has to be arranged through above ceiling, closet or area where the temperature and humidity
are high, wind additional commercially sold insulation for prevention of condensation.
6
Flaring tool
A
Flare tool for R410A
0.06 to 0.08
0.06 to 0.08
0.08 to 0.10
Die
Copper pipe
Smooth all around
Even length
all around
Tightening torque
ft. · Ib
10 to 13
25 to 30
36 to 42
Clutch type
A
York
Die
Copper pipe
Flare nut
Inside is shining without any scratches