Flaring Work And Pipe Connection; Purging Procedures, Leak Test, And Test Run - Mitsubishi Electric MXZ-2B52VA Installation Manual

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)
• Put the end of the copper pipe to downward direction as you
remove burrs in order to avoid to let burrs drop in the piping.
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 mm from the table according to the tool
you use.
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.
A (mm)
Pipe diameter Nut
Clutch Clutch
[mm (in.)] (mm)
type tool type tool
for R410A for R22
ø6.35 (1/4") 17
ø9.52 (3/8") 22
0 to 0.5 1.0 to 1.5
ø12.7 (1/2") 26
ø15.88 (5/8") 29
3-2. PIPE CONNECTION
• Fasten flare nut with a torque wrench as specified in the table.
• When fastened too tight, flare nut may brake after a long period and cause refrigerant leakage.
Outdoor unit connection
Connect pipes to stop valve pipe joint of the outdoor unit in the same manner applied for indoor unit.
• For tightening, use a torque wrench or spanner and use the same tightening torque applied for indoor unit.
WARNING
When installing the unit, securely connect the refrigerant
pipes before starting the compressor.
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 valve will not work in its initial state fresh out of
the factory, totally closed with cap on.)
2) Connect gauge manifold valve and vacuum pump to service port of
stop valve on the gas pipe side of the outdoor unit.
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 pointer gauge mani-
fold valve remains in the same position. Confirm that pressure gauge
shows –0.101 MPa [Gauge] (–760 mmHg).
6) Remove gauge manifold valve quickly from service port of stop
valve.
7) After refrigerant pipes are connected and evacuated, fully open all
stop valves on both sides of gas pipe and liquid pipe. Operating with-
out fully opening lowers the performance and this causes trouble.
8) Refer to 1-3., 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 af-
fect performance of the air conditioner.
9) Tighten cap of service port to obtain the initial status.
10) Leak test
Tightening torque
Wing nut
type tool N•m kgf•cm
for R22
13.7 to 17.7 140 to 180
1.5 to 2.0
34.3 to 41.2 350 to 420
2.0 to 2.5 49.0 to 56.4 500 to 575
- 73.5 to 78.4 750 to 800
*4 to 5 turns
*Open
Hexagonal wrench
Precautions when using
the control valve
Service
port
Control
valve
Open
Close
A
Body
Copper
pipe
Fig. 1
Copper pipe
Burr
Spare reamer
Pipe cutter
Fig. 3
Copper pipe
Die
Flare nut
Fig. 5
Stop valve
for GAS
Stop valve
*Close
cap (Torque
19.6 to 29.4
N•m, 200 to
300 kgf•cm)
Stop valve
for LIQUID
Service port cap
(Torque 13.7 to 17.7 N•m,
140 to 180 kgf•cm)
When attaching the control valve to
the service port, valve core may de-
form or loosen if excess pressure 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
then tighten part A. Do not tighten
part A or turn the body when valve
core is in open position.
Charge hose
(for R410A)
No good
Good
Tilted Uneven Burred
Fig. 2
Flaring tool
Clutch type Wing nut type
Fig. 4
Inside is shin-
ing without any
Smooth all
scratches.
around
Even length
all around
Fig. 6
Compound pressure
–0.101 MPa
gauge (for R410A)
(–760 mmHg)
Pressure gauge
(for R410A)
Gauge manifold
valve (for R410A)
Handle High
Handle
Low
Charge hose
(for R410A)
Vacuum pump
(for R410A)
5