Mitsubishi Electric Mr. Slim PEAD-M35JA Installation Manual page 14

6. Refrigerant piping work
6.2. Flaring work
• Main cause of gas leakage is defect in flaring work.
Carry out correct flaring work in the following procedure.
6.2.1. Pipe cutting
[Fig. 6-2-1] (P.4)
a Copper tubes
b Good
c No good
d Tilted
e Uneven
f Burred
• Using a pipe cutter cut the copper tube correctly.
6.2.2. Burrs removal
[Fig. 6-2-2] (P.4)
a Burr
b Copper tube/pipe
c Spare reamer
d Pipe cutter
• Completely remove all burrs from the cut cross section of pipe/tube.
• Put the end of the copper tube/pipe to downward direction as you remove burrs in
order to avoid burrs drop in the tubing.
6.2.3. Putting nut on
[Fig. 6-2-3] (P.4)
a Flare nut
b Copper tube
• Remove flare nuts attached to indoor and outdoor unit, then put them on pipe/tube
having completed burr removal.
(not possible to put them on after flaring work)
• Use the flare nut included with this indoor unit.
6.2.4. Flaring work
[Fig. 6-2-4] (P.4)
a Flaring tool
b Die
c Copper tube
d Flare nut
e Yoke
• Carry out flaring work using flaring tool as shown below.
A (mm)
Pipe diameter
When the tool for R32/R410A
(mm)
is used
Clutch type
6.35 0 – 0.5
9.52 0 – 0.5
12.7 0 – 0.5
15.88 0 – 0.5
Firmly hold copper tube in a die in the dimension shown in the table at above.
• When reconnecting the detached refrigerant pipes, make sure to flare them again.
6.2.5. Check
[Fig. 6-2-5] (P.4)
a Smooth all around
b Inside is shining without any scratches
c Even length all around
d Too much
e Tilted
• Compare the flared work with a figure in right side hand.
• If flare is noted to be defective, cut off the flared section and do flaring work again.
14
Dimension
+0
B (mm)
-0.4
9.1
13.2
16.6
19.7
f Scratch on flared plane
g Cracked
h Uneven
i Bad examples
6.3. Pipe connection
[Fig. 6-3-1] (P.4)
• Apply a thin coat of refrigeration oil on the seat surface of pipe.
• For connection first align the center, then tighten the first 3 to 4 turns of flare nut.
• Use tightening torque table below as a guideline for indoor unit side union joint
section, and tighten using two wrenches. Excessive tightening damages the flare
section.
Copper pipe O.D. Flare nut O.D.
(mm)
ø 6.35
ø 9.52
ø 12.7
ø 15.88
Warning:
Be careful of flying flare nut! (Internally pressurized)
Remove the flare nut as follows:
1. Loosen the nut until you hear a hissing noise.
2. Do not remove the nut until the gas has been completely released (i.e.,
hissing noise stops).
3. Check that the gas has been completely released, and then remove the nut.
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.
Refrigerant pipe insulation
• After connecting refrigerant piping, insulate the joints (flared joints) with thermal
insulation tubing as shown below.
[Fig. 6-3-2] (P.4)
A Pipe cover (small) (accessory)
B Caution:
Pull out the thermal insulation on the refrigerant piping at the site, insert the flare nut to flare
the end, and replace the insulation in its original position.
Take care to ensure that condensation does not form on exposed copper piping.
C Liquid end of refrigerant piping
E Site refrigerant piping
G Pipe cover (large) (accessory)
I Pull
K Return to original position
M Plate on main body
O Ensure that there is no gap here. Place join upwards.
1. Remove and discard the rubber bung which is inserted in the end of the unit
piping.
2. Flare the end of the site refrigerant piping.
3. Pull out the thermal insulation on the site refrigerant piping and replace the
insulation in its original position.
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.
Tightening torque
(mm) (N·m)
17 14 – 18
22 34 – 42
26 49 – 61
29 68 – 82
D Gas end of refrigerant piping
F Main body
H Thermal insulation (field supply)
J Flare nut
L Ensure that there is no gap here
N Band (accessory)