19
7. System Design
7-1.Refrigerant Piping System
■
Sample connection
■
Pipe selection
■
Amount of refrigerant charge
Refrigerant for extension piping is not included at factory shipment. Add an appropriate amount of refrigerant for each
system on site. Write down the size and the length of the piping in each system as well as the amount of added
refrigerant on the outdoor unit as a reference for servicing.
■
Calculating the amount of refrigerant to be added
• The amount of refrigerant that is necessary for extension piping is calculated based on the size and the length of the
liquid piping.
• Use the following formula to figure out the amount of refrigerant to be added.
• Round up the calculation result to the nearest 0.1 kg. (e.g., If the result is 16.08 kg, round up the .08 to .1 , which
yields 16.1 kg.)
Caution
Charge Liquid Refrigerant
Filling the equipment with gas refrigerant will result in a power loss due to transformation of refrigerant in the tank.
500 model indoor unit : When
ø
15.88 pipes are used and the piping length is 150 m
150(m) x 0.2(kg/m)+4.0kg=34.0kg
✻
Refrigerant charge
calculation
✻
Amount of charged
refrigerant at factory shipment
✻
Sample calculation
Outdoor unit
model
Charged
refrigerant
amount(kg)
9.5
P250
22.0
P500
Outdoor unit
L
L
H
A
Outdoor unit
L
H
A
Indoor unit
Indoor unit
Liquid pipe size
Total length of the
ø
15.88 pipes x 0.2
Liquid pipe size
Total length of the
ø
9.52 pipes x 0.06
(m) x 0.2(kg/m)
+
(m) x 0.06(kg/m)
+
Total capacity of
connected indoor units
Amount for the indoor unit
P250 model
2.0kg
✻
2 kg x 2 when connected to a
system with two outdoor units
P500 model
4.0kg
<Connection to a system with one outdoor unit>
500 model indoor unit : When
ø
9.52 pipes are used and the piping length is 80 m
80(m) x 0.06(kg/m)+2.0kg=6.8kg
(Amount for the extension pipe to each outdoor unit)
<Connection to a system with two outdoor unit>
Farthest piping length(L)
Height difference between indoor
and outdoor units (H)
50 m or less (40 m if outdoor unit is below indoor unit,
15 m if outside temperature is 10˚C or below)
150 m or less in actual length
Allowable piping
length
Allowable height
difference
<Refrigerant system with one outdoor unit>
<Amount of refrigerant to be added>
<Refrigerant system with two outdoor units>
Outdoor unit model
Liquid pipe size
Gas pipe size
P250
P500
✻
1 Use
ø
12.7 pipes when the pipe
length exceeds 90 m.
ø
9.52
✻
1
ø
15.88
ø
22.2
ø
28.58
