Mitsubishi Electric American Standard NAXMMX48A182A Serie Manuel D'installation page 7

5. Installing the refrigerant piping
5.2. Pipe length and height difference (Fig. 5-1)
Flared connections
• This unit has flared connections on each indoor unit and branch box and outdoor
unit sides.
5.3. Additional refrigerant charge
Additional refrigerant charge
Refrigerant for the extended piping is not included in the outdoor unit when the unit is
shipped from the factory. Therefore, charge each refrigerant piping system with addi-
tional refrigerant at the installation site. In addition, in order to carry out service, enter
the size and length of each liquid pipe and additional refrigerant charge amounts in
the spaces provided on the "Refrigerant amount" plate on the outdoor unit.
* When the unit is stopped, charge the unit with the additional refrigerant through
the liquid stop valve after the pipe extensions and indoor units have been vacu-
umized.
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.
Calculation of additional refrigerant charge
• Calculate the additional charge using the liquid pipe size and length of the ex-
tended piping and total capacity of connected indoor units.
• Calculate the additional refrigerant charge using the procedure shown to the right,
and charge with the additional refrigerant.
• For amounts less than 0.1 kg, round up the calculated additional refrigerant
charge.
(For example, if the calculated charge is 6.01 kg, round up the charge to 6.1 kg.)
■
In case of using 1-branch box
Flare connection employed. (No. brazing)
A
B
■
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
A UNIT
Gas pipe
Liquid pipe
B UNIT
Gas pipe
Liquid pipe
C UNIT
Gas pipe
Liquid pipe
D UNIT
Gas pipe
Liquid pipe
E UNIT
Gas pipe
* 3-branch type : only A, B, C unit
A
Fig. 5-3
Branch box
B B B
Branch box #1
B B
Branch box #2
ø9.52 mm (3/8 inch)
ø15.88 mm (5/8 inch)
ø6.35 mm (1/4 inch)
ø9.52 mm (3/8 inch)
ø6.35 mm (1/4 inch)
ø9.52 mm (3/8 inch)
ø6.35 mm (1/4 inch)
ø9.52 mm (3/8 inch)
ø6.35 mm (1/4 inch)
ø9.52 mm (3/8 inch)
ø6.35 mm (1/4 inch)
ø12.7 mm (1/2 inch)
Conversion formula
1/4 F ø6.35 (1/4)
3/8 F ø9.52 (3/8)
1/2 F ø12.7 (1/2)
B
5/8 F ø15.88 (5/8)
3/4 F ø19.05 (3/4)
• Remove the valve cover of the outdoor unit, then connect the pipe.
• Refrigerant pipes are used to connect the branch box and outdoor unit.
<Additional Charge>
Calculation of refrigerant charge
Pipe size Pipe size
Liquid pipe Liquid pipe
+
ø6.35 ø9.52
(m) × 19.0 (g/m) (m) × 50.0 (g/m)
(0.21 (oz/ft)) (0.55 (oz/ft))
Included refrigerant amount when shipped from the factory
Included refrigerant amount
4.8 kg (10 lbs, 9 oz)
<Example>
Outdoor model : NAXMPH48A182A
Indoor 1 : model 24
2 : model 15
3 : model 09
4 : model 09
The total length of each liquid line is as follows:
ø9.52 : A + a = 30 + 15 = 45 m (148 ft)
ø6.35 : b + c + d = 10 + 10 + 20 = 40 m (131 ft)
The total capacity of connected indoor unit is as follows:
24 + 15 + 09 + 09 = 57
<Calculation example>
Additional refrigerant charge
19.0 50.0
+ 45 ×
40 ×
1000 1000
(131 × 0.21 + 148 × 0.55 + 106 = 215 oz)
5.4. Selecting pipe size (Fig. 5-2)
Conversion formula
A
ø9.52 mm
Liquid
(3/8 inch)
B
ø15.88 mm
Gas
(5/8 inch)
Different-diameter joint (optional parts) (Fig. 5-3)
Connected pipes diameter
Model name
MAC-A454JP-E ø9.52 (3/8) → ø12.7 (1/2)
MAC-A455JP-E ø12.7 (1/2) → ø9.52 (3/8)
MAC-A456JP-E ø12.7 (1/2) → ø15.88 (5/8)
B
PAC-493PI ø6.35 (1/4) → ø9.52 (3/8)
PAC-SG76RJ-E ø9.52 (3/8) → ø15.88 (5/8)
Piping preparation
1 Table below shows the specifications of pipes commercially available.
Outside diameter Insulation thickness
mm (inch)
6.35 (1/4)
9.52 (3/8)
12.7 (1/2)
15.88 (5/8)
2 Ensure that the 2 refrigerant pipes are insulated to prevent condensation.
3 Refrigerant pipe bending radius must be 4" (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
thickness 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
■
Installation procedure (2 branches pipe (Joint))
Refer to the installation manuals of MSDD-50AR-E and MSDD-50BR-E.
Total capacity of
connected indoor units
+
– 27
28 – 54
55 – 62
A : ø9.52 30 m (99 ft)
a : ø9.52 15 m (49 ft)
b : ø6.35 10 m (33 ft)
c : ø6.35 10 m (33 ft)
d : ø6.35 20 m (66 ft)
+ 3.0 = 6.1 kg (rounded up)
B
The piping connection size differs according to
the type and capacity of indoor units. Match the
piping connection 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 optional different-diameter (deformed)
joints to the branch box side. (Connect deformed
joint directly to the branch box side.)
Diameter A
mm (inch) mm (inch)
ø9.52 (3/8)
ø12.7 (1/2)
ø12.7 (1/2)
ø6.35 (1/4)
ø9.52 (3/8)
Insulation material
mm (inch)
8 (5/16)
8 (5/16)
Heat resisting foam plastic 0.045
specific gravity
8 (5/16)
8 (5/16)
Connection method
flare
brazing
Amount for the
indoor units
1.5 kg (53 oz)
2.5 kg (88 oz)
3.0 kg (106 oz)
At the
conditions
below:
Diameter B
mm (inch)
ø12.7 (1/2)
ø9.52 (3/8)
ø15.88 (5/8)
ø9.52 (3/8)
ø15.88 (5/8)
7