Refrigerant Piping Work - Mitsubishi Electric SEZ-KD09 Installation Manual

6. Refrigerant piping work

6.1. Refrigerant pipe
[Fig. 6-1] (P.3)
a Indoor unit
b Outdoor unit
Refer to the outdoor unit Instruction Manual for restrictions on
the height difference between units and for the amount of additional refrigerant
charge.
Avoid the following places for installation where the air conditioner malfunction is
liable to occur.
• Where there is too much oil in the air such as for machines or cooking.
• Salty environments as seaside areas.
• Hot-spring areas.
• Where sulfide gas exists.
• Other special atmospheric areas.
• This unit has flared connections on both indoor and outdoor sides. (Fig. 6-1)
• Refrigerant pipes are used to connect the indoor and outdoor units as shown in the
figure below.
• Insulate both refrigerant and drainage piping completely to prevent condensation.
Piping preparation
• Refrigerant pipes 3, 5, 7, 10 and 15 m [5 ft] are available as optional items.
(1) The specifications of commercially available pipes.
Outside diameter
Model Pipe
mm inch
SEZ- For liquid 6.35 1/4
KD09 For gas 9.52 3/8
SEZ- For liquid 6.35 1/4
KD12 For gas 9.52 3/8
SEZ- For liquid 6.35 1/4
KD15 For gas 12.7 1/2
SEZ- For liquid 6.35 1/4
KD18 For gas 12.7 5/8
(2) Ensure that the two refrigerant pipes are well insulated to prevent condensation.
(3) Refrigerant pipe bending radius must be 10 cm [3-15/16 in] or more.
Caution:
Use insulation of specified thickness. Excessive thickness prevents storage
behind the indoor unit and smaller thickness causes condensation.
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. Cutting the pipes
[Fig. 6-3] (P.3)
a Copper tubes
b Good example
c Bad examples
d Tilted
e Uneven
f Burred
• Use a pipe cutter cut the copper tube correctly.
6.2.2. Burr removal
[Fig. 6-4] (P.3)
a Burr
b Copper tube/pipe
c Spare reamer
d Pipe cutter
• Completely remove all burrs from the cut section of pipe/tube.
• Point the end of the copper tube/pipe to downward direction as you remove burrs in
order to avoid burrs drop in the tubing.
10
Min wall Insulation Insulation
thickness thickness material
0.8 mm [1/16 in] 8 mm [11/32 in]
0.8 mm [1/16 in] 8 mm [11/32 in]
0.8 mm [1/16 in] 8 mm [11/32 in]
0.8 mm [1/16 in] 8 mm [11/32 in] Heat-resistant
0.8 mm [1/16 in] 8 mm [11/32 in] foam plastic,
0.8 mm [1/16 in] 8 mm [11/32 in] 0.045 specific
0.8 mm [1/16 in] 8 mm [11/32 in] gravity
1.0 mm [1/16 in] 8 mm [11/32 in]
6.2.3. Putting nut on
[Fig. 6-5] (P.3)
a Flare nut
b Copper tube
• Remove flare nuts attached to indoor and outdoor unit, then attach them on pipe/
tube after burr removal.
(not possible to attach them on after flaring work)
6.2.4. Flaring work
[Fig. 6-6] (P.3)
a Flaring tool
b Die
c Copper tube
d Flare nut
e Yoke
• Carry out flaring work using flaring tool as shown below.
Pipe diameter A (mm [in])
(mm [in]) When the tool for R410A is used
Clutch type
6.35 [1/4] 0 to 0.5 [0 to 1/32]
9.52 [3/8] 0 to 0.5 [0 to 1/32]
12.7 [1/2] 0 to 0.5 [0 to 1/32]
15.88 [5/8] 0 to 0.5 [0 to 1/32]
Firmly hold copper tube in a die in the dimension shown in the table at above.
6.2.5. Check
[Fig. 6-7] (P.3)
a Smooth
b Inside is shiny without any scratches
c Even length
d Too much
e Tilted
• If flare is defective, cut off the flared section and repeat.
6.3. Pipe connection
[Fig. 6-8] (P.3)
• Apply a thin coat of refrigeration oil on the surface of pipe.
• When connecting, first align the center, then tighten the flare nut 3 to 4 turns.
• 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 [in])
ø6.35 [1/4] 17 [11/16]
ø9.52 [3/8]
ø12.7 [1/2] 26 [1-1/32]
ø15.88 [5/8] 29 [1-5/32]
Warning:
Be careful of removing the flare nut! (Internally pressurize can cause them to
burst off.)
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., hiss-
ing 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 following the same proce-
dure as the indoor unit.
• For tightening, use a torque wrench or spanner, and use the same tightening torque
procedure for indoor unit.
Dimension
+0
B (mm [in])
-0.4 [-1/32]
9.1 [3/8]
13.2 [17/32]
16.6 [21/32]
19.7 [25/32]
f Scratch on flared plane
g Cracked
h Uneven
i Bad examples
Tightening torque
(mm [in]) (N·m)
14 - 18
22 [7/8] 34 - 42
49 - 61
68 - 82