9.3 ADDITIONAL REFRIGERANT CHARGE CALCULATION
Although refrigerant has been charged into this unit in advance, additional refrigerant charge is required according to piping length.
Determine the additional refrigerant quantity according to the following procedure, and charge the system with it.
Record the additional refrigerant quantity to facilitate maintenance and servicing activities thereafter.
Calculating method of additional refrigerant charge (W kg)
No. Symbol Contents
Additional
charge (kg)
1 W1
Additional refrigerant charge calculation for liquid piping (W1 kg)
Pipe diameter (mm) Total piping length (m)
Refrigerant amount for 1m pipe
(kg/m)
Additional charge
(kg)
∅22.2
m × 0.36 =
∅19.05
m × 0.26 =
∅15.88
m × 0.17 =
∅12.7
m × 0.11 =
∅9.52
m × 0.056 =
∅6.35
m × 0.024 =
Total additional charge for liquid piping =
NOTE
In the case that the quantity calculated above is less than the minimum quantity indicated in the table below, adopt
the quantity in the table below as the additional refrigerant quantity for piping liquid, regardless of the piping length.
HP
5 6 8 10 12 14 16
Minimum additional charge of base unit (kg)
2.0 2.0 2.0 2.0 3.0 3.0 3.0
For combination of the units, adopt the total minimum quantity of each base unit as the minimum additional refriger-
ant quantity.
kg
2 W2
Additional refrigerant charge quantity for indoor unit (only for heat pump system) (W2 kg)
The additional refrigerant charge is required depending on the number of connected indoor units. Select the refriger-
ant quantity from the following table.
Additional refrigerant charge quantity (kg)
System Heat Pump Heat Recovery
Model RCI-2.0FSN3 RCI-2.5FSN3 RCI-3.0-6.0FSN3 RCI-2.0-6.0FSN3
Connectable
number
1 0.0 0.0 0.5 0.0
2 0.5 0.5 1.0 0.0
3 0.5 1.0 1.5 0.0
4 or more 1.0 1.5 2.0 0.0
kg
3 W3
Additional refrigerant charge calculation for indoor unit (W3 kg)
Additional refrigerant charge is 1kg/unit of 8HP and 10HP indoor unit.
Additional refrigerant charge of less than 8HP indoor units is not needed.
8 and 10HP Total Indoor Unit Numbers Additional Charge
× 1.0kg/unit =
kg
4 W4
The ratio of indoor unit connection capacity (indoor unit total capacity/outdoor unit capacity) additional charge
(W4 kg).
Determine the ratio of indoor unit connection capacity.
Condition Refrigerant amount
• I.U. Capacity Ratio is less than 100%: 0.0kg
• I.U. Capacity Ratio is more than 100%: 0.5kg
kg
5 W Calculation of additional charge (W kg) = W1 + W2 + W3 +W4 kg
51
PMML0294A rev.2 - 07/2014
Additional refrigerant charge
PMML0294A_rev.2_02-2014.indb 51 14/07/2014 12:28:31
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