Mitsubishi Electric MXZ-8A140VA Manuel D'installation page 7

5. Installing the refrigerant piping
5.3. Addition of refrigerant
• Additional charging is not necessary for this unit if the total pipe length
(b1+b2+a1+a2+a3+a4+a5+a6+a7+a8) does not exceed 40 m.
• If the total pipe length exceeds 40 m, charge the unit with additional R410A
refrigerant according to the permitted pipe lengths in the chart below.
* When the unit is stopped, charge the unit with the additional refrigerant through
the liquid stop valve after the pipe extensions and indoor unit have been
vacuumized.
When the unit is operating, add refrigerant to the gas check valve using a
safety charger. Do not add liquid refrigerant directly to the check valve.
* After charging the unit with refrigerant, note the added refrigerant
amount on the service label (attached to the unit).
Refer to the "1.5. Using R410A refrigerant air conditioners" for more information.
Table 1
Total piping length
(b1+b2+a1+a2+a3+a4+a5+a6+a7+a8)
Additional refrigerant charging amount
I In case of using 1-branch box
Flare connection employed. (No. brazing)
A
B
I In case of using 2-branch boxes
2 branches pipe (joint)
: optional parts.
A A
A
B B
Fig. 5-2
(1)Valve size for outdoor unit
For liquid
For gas
(2)Valve size for branch box
Liquid pipe
Å UNIT
Gas pipe
Liquid pipe
ı UNIT
Gas pipe
Liquid pipe
Ç UNIT
Gas pipe
Liquid pipe
Î UNIT
Gas pipe
Liquid pipe
‰ UNIT
Gas pipe
* 3-branch type : only Å, ı, Ç unit
A
Fig. 5-3
41 - 50 m 51 - 70 m 71 - 90 m 91 - 115 m
0.6 kg 1.4 kg 2.2 kg 3.2 kg
Branch box
B B B
Branch box #1
B B
Branch box #2
ø9.52 mm
ø15.88 mm
ø6.35 mm
ø9.52 mm
ø6.35 mm
ø9.52 mm
ø6.35 mm
ø9.52 mm
ø6.35 mm
ø9.52 mm
ø6.35 mm
ø12.7 mm
Conversion formula
1/4 F ø6.35
3/8 F ø9.52
1/2 F ø12.7
B
5/8 F ø15.88
3/4 F ø19.05
If connecting an indoor unit with ø9.52 liquid pipes (model number 71 or more for M-
and S-Series and model number 60 or more for P-Series), the additional refrigerant
charging amount in Table 1 must be corrected (add the following ∆R value from the
value given in Table 1).
Additional refrigerant charging correction amount
∆R=0.01 [kg/m] × ø9.52 branch pipe (liquid pipe) total length [m]
Example) b1=20 m, b2=25 m
Indoor unit A
Indoor unit B
Indoor unit C
Indoor unit D
Total piping length : b1+b2+a1+a2+a6+a7=95 m
→ According to Table 1, the additional refrigerant charging amount is 3.2 kg.
Because indoor units with ø9.52 liquid pipes are connected (indoor units A and D in
this example), the additional refrigerant charging amount must be corrected.
Additional refrigerant charging correction amount
∆R=0.01 [kg/m] × ø9.52 branch pipe (liquid pipe) total length (a1+a7)
=0.01 × (12+13 m)
=0.25 kg
Therefore, the additional refrigerant charging amount is 3.2 kg + 0.25 kg = 3.45 kg.
5.4. Selecting pipe size (Fig. 5-2)
A
The piping connection size differs according to the type
and capacity of indoor units. Match the piping connec-
Liquid (mm) ø9.52
tion size of branch box with indoor unit.
If the piping connection size of branch box does not
match the piping connection size of indoor unit, use op-
B
tional different-diameter (deformed) joints to the branch
Gas (mm) ø15.88
box side. (Connect deformed joint directly to the branch
box side.)
Different-diameter joint (optional parts) (Fig. 5-3)
Connected pipes diameter
Model name
MAC-A454JP ø9.52
MAC-A455JP ø12.7
MAC-A456JP ø12.7
PAC-493PI ø6.35
PAC-SG76RJ-E ø9.52
Piping preparation
B
1 Table below shows the specifications of pipes commercially available.
Outside diameter Insulation thickness
mm
6.35
9.52
12.7
15.88
2 Ensure that the 2 refrigerant pipes are insulated to prevent condensation.
3 Refrigerant pipe bending radius must be 100 mm or more.
Caution:
Be sure to use the insulation of specified thickness. Excessive thickness may
cause incorrect installation of the indoor unit and branch box, and lack of thick-
ness may cause dew drippage.
2-branch pipe (Joint) : Optional parts (According to the connection method,
you can choose the favorite one.)
Model name
MSDD-50AR-E
MSDD-50BR-E
I Installation procedure (2 branches pipe (Joint))
Refer to the installation manuals of MSDD-50AR-E and MSDD-50BR-E.
ø9.52 Liquid pipe a1=12 m
ø6.35 Liquid pipe a2=11 m
ø6.35 Liquid pipe a6=14 m
ø9.52 Liquid pipe a7=13 m
B
Diameter A Diameter B
mm mm
→ ø12.7
ø9.52
→ ø9.52
ø12.7
→ ø15.88
ø12.7
→ ø9.52
ø6.35
→ ø15.88
ø9.52
Insulation material
mm
8
8 Heat resisting foam plastic
8 0.045 specific gravity
8
Connection method
flare
brazing
mm
ø12.7
ø9.52
ø15.88
ø9.52
ø15.88
7