EN - 16
Table 7
3-5. Refrigerant charge
Calculation of amount of additional refrigerant charge
•
Table 6 shows the refrigerant charge at factory shipping time. Additional refrigerant must be added according
to the size and length of the tubing. If a water heat exchanger unit is installed, provide an additional refrigerant
charge for the connecting line portion. (Use the values in Table 5 to calculate liquid tube size and length.)
Table 5 Quantity of additional refrigerant charge
Table 6
Liquid tube size (mm)
Additional charge
quantity per meter (g/m)
Type
Quantity of refrigerant
charge when shipped (kg)
Ø6.35
26
45.0 kW
10.5
Ø9.52
56
56.0 kW
11.5
Ø12.7
128
71.0 kW
Ø15.88
185
85.0 kW
Ø19.05
259
Ø22.22
366
Required additional refrigerant charge (g) =
456 × (A) + 366 × (B) + 259 × (C) + 185 × (D) + 128 × (E)
+ 56 × (F) + 26 × (G) + Unit additional charge amount (H)
(A) = total length in meters of 25.4 mm diameter liquid tubing
(B) = total length in meters of 22.22 mm diameter liquid tubing
(C) = total length in meters of 19.05 mm diameter liquid tubing
(D) = total length in meters of 15.88 mm diameter liquid tubing
(E) = total length in meters of 12.7 mm diameter liquid tubing
(F) = total length in meters of 9.52 mm diameter liquid tubing
(G) = total length in meters of 6.35 mm diameter liquid tubing
(H) = Unit additional charge amount (Table 7)
•
Be careful to charge accurately according to refrigerant weight.
•
Charging procedure
Evacuate the system, close the gauge manifold at the gas tube side to ensure that no refrigerant enters the
gas tube side, then charge the system with liquid refrigerant at the liquid tube side. While charging, keep all
valves fully closed. The compressor can be damaged if liquid refrigerant is added at the gas tube side.
•
If the system does not accept the predetermined quantity of refrigerant, fully open all valves and run the
system (either heating or cooling). While the system is running, gradually add refrigerant at the low pressure
side by slightly opening the valve on the cylinder just enough so that the liquid refrigerant is gasi
fi
ed as it is
sucked into the system. (This step is normally only needed when commissioning the system.)
All outdoor unit valves should be fully open.
•
When charging is completed, fully open all valves.
•
Avoid liquid back-
fl
ow when charging with R410A refrigerant by adding small amounts at a time.
Type
Unit additional
charge amount (kg)
45.0 kW
–
56.0 kW
0.5
71.0 kW
2.5
85.0 kW
11.0*
1
*1 When connecting a water heat
exchange unit, the value is 10.0 kg.
00-Installation̲All.indb 16
00-Installation̲All.indb 16
2012/09/07 9:32:41
2012/09/07 9:32:41
