Mitsubishi Electric American Standard NAXMMX20A122A Serie Notice D'installation page 6

3. FLARING WORK AND PIPE CONNECTION
3-1. FLARING WORK
1) Cut the copper pipe correctly with pipe cutter. (Fig. 1, 2)
2) Completely remove all burrs from the cut cross section of
pipe. (Fig. 3)
• Aim the copper pipe downward while removing burrs to
prevent burrs from dropping in the pipe.
3) 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.)
4) Flaring work (Fig. 4, 5). Firmly hold copper pipe in the
dimension shown in the table. Select A inch (mm) from
the table according to the tool selected.
5) Check
• Compare the flared work with Fig. 6.
• If flare is noted to be defective, cut off the flared section
and do flaring work again.
Pipe diameter B
[inch (mm)] [inch (mm)]
1/4 (ø6.35) 21/32 (17)
3/8 (ø9.52) 7/8 (22)
1/2 (ø12.7) 1-1/32 (26)
5/8 (ø15.88) 1-5/32 (29)
3-2. PIPE CONNECTION
1) Apply a thin coat of refrigeration oil (G) to the flared ends of the pipes and the
pipe connections of the outdoor unit.
2) Align the center of the pipe with that of the pipe connections of the outdoor unit,
then hand tighten the flare nut 3 to 4 turns.
3) Tighten the flare nut with a torque wrench as specified in the table.
• Over-tightening may cause damage to the flare nut, resulting in refrigerant
leakage.
• Be sure to wrap insulation around the piping. Direct contact with the bare piping
may result in burns or frostbite.
3-3. 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.
• Stop the end of piping tape (E) with tape (with adhesive agent attached).
• When piping have to be arranged through above ceiling, closet or where the
temperature and humidity are high, wind additional commercially sold insulation
to prevent condensation.
4. PURGING PROCEDURES, LEAK TEST, AND TEST RUN
4-1. PURGING PROCEDURES AND LEAK TEST
1) Remove service port cap of stop valve on the side of the outdoor unit gas pipe.
(The stop valves are fully closed and covered in caps in their initial state.)
2) Connect gauge manifold valve and vacuum pump to service port of stop valve
on the side of the outdoor unit gas pipe.
3) Run the vacuum pump. (Vacuumize for more than 15 minutes.)
4) Check the vacuum with gauge manifold valve, then close gauge manifold
valve, and stop the vacuum pump.
5) Leave as it is for one or two minutes. Make sure the pointer of gauge manifold
valve remains in the same position. Confirm that pressure gauge shows -14.7
psi [Gauge] (-0.101 MPa).
6) Remove gauge manifold valve quickly from service port of stop valve.
7) Fully open all stop valves on the gas pipe and the liquid pipe. Operating without
fully opening lowers the performance and this causes trouble.
8) Refer to 1-2., and charge the prescribed amount of refrigerant if needed. Be
sure to charge slowly with liquid refrigerant. Otherwise, composition of the
refrigerant in the system may be changed and affect performance of the air
conditioner.
9) Tighten cap of service port to obtain the initial status.
10) L eak test
En-5
Clutch type
A [inch (mm)]
Clutch type tool for R410A Clutch type tool for R22
0 to 0.02 0.04 to 0.06
(0 to 0.5) (1.0 to 1.5)
Good
Copper
pipe
Tilted Uneven Burred
Fig. 1
Flaring tool
Die
Flare nut
Wing nut type
Fig. 4
Wing nut type tool for R22
0.06 to 0.08
(1.5 to 2.0)
0.08 to 1.0
(2.0 to 2.5)
WARNING
When installing the unit, securely
connect the refrigerant pipes before
starting the compressor.
CAUTION
When there are the ports which are
not used, make sure their nuts are
tightened securely.
*4 to 5 turns
*Close
*Open
Hexagonal wrench
Service port cap
(Torque 13.7 to
17.7 N•m, 140 to
180 kgf•cm)
Precautions when us-
ing the control valve
Body
Close
A
Open
Control
Service port
valve
No good
Copper pipe
Burr
Spare reamer
Fig. 2
Smooth all
around
Copper pipe
B
Fig. 5
Tightening torque
ft-Ib N•m
10 to 13 13.7 to 17.7
25 to 30 34.3 to 41.2
36 to 42 49.0 to 56.4
54 to 58 73.5 to 78.4
Compound pressure
–0.101MPa
Stop valve cap
gauge (for R410A)
(–760 mmHg)
(Torque 19.6 to
29.4 N•m, 200
to 300 kgf•cm)
Handle
Low
Stop valve
Vacuum pump
Stop valve
for LIQUID
(for R410A)
for GAS
When attaching the control valve
to the service port, valve core may
deform or loosen if excess pres-
sure is applied. This may cause
gas leak.
When attaching the control valve to
the service port, make sure that the
valve core is in closed position, and
Charge hose
then tighten part A. Do not tighten
(for R410A)
part A or turn the body when valve
core is in open position.
Pipe cutter
Fig. 3
Inside is shin-
ing without any
scratches.
Even length
all around
Fig. 6
kgf•cm
140 to 180
350 to 420
500 to 575
750 to 800
Pressure gauge
(for R410A)
Gauge manifold
valve (for R410A)
Handle High
Charge hose
(for R410A)