Hitachi FSG Series, Technical Catalogue

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13
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REFRIGERANT PIPING AND REFRIGERANT CHARGE
13.6. REFRIGERANT CHARGING QUANTITY
13.6.1. GUIDE OF ADDITIONAL REFRIGERANT
CHARGE CALCULATION (R407C)
Although refrigerant has been charged into this unit, it is
required that additional refrigerant should be charged
according to piping length and indoor units.
1. Determine an additional refrigerant quantity to the
following procedure, and charge it into the system.
2. Record the additional refrigerant quantity to facilitate
service activities thereafter.
Calculating Method of Additional Refrigerant Charge
(W Kg)
Additional Refrigerant Charge Calculation for Liquid Piping
(W
1
kg). See example for models RAS-20FXG1 and fill in
the following table.
Pipe Diameter Total Piping Length Additional Charge (kg)
Æ
22.2
(0) x 0.390 = 0
* (0) x 0.300
Æ
19.05
** – x 0.280
= 0
* (30) x 0.195
Æ
15.88
** – x 0.190
= 5.85
Æ
12.7
(0) x 0.120 = 0
Æ
9.54
(14+4+12+3+3+9+3+2) x 0.065 = 3.25
Æ
6.53
(6+2+3) x 0.026 = 0.286
Example Additional Charge W
1
Total = 9.386 kg
* Except for RAS-24/30FSG1
** Only for RAS-24/30FSG1
Pipe Diameter Total Piping Length Additional Charge (kg)
Æ
22.2
x 0.390 =
* x 0.300
Æ
19.05
** x 0.280
=
* x 0.195
Æ
15.88
** x 0.190
=
Æ
12.7
x 0.120 =
Æ
9.54
x 0.065 =
Æ
6.53
x 0.026 =
Actual system Additional Charge W
1
Total = = kg
* Except for RAS-24/30FSG1
** Only for RAS-24/30FSG1
Additional Refrigerant Charge Calculation for Indoor Unit
(W
2
kg).
– Additional refrigerant charge is NOT necessary for one
refrigerant system unless the number of indoor unit
exceeds N units. Table 2 shows the necessary refrigerant
quantity.
$
ATTENTION:
For RAS-24FSG1 and RAS-30FSG1 is NOT
necessary refrigerant charge for indoor units.
– Determine the number of indoor units that require the
additional charge from table 1 and the following formula.
Number of
Indoor
Units
Number of Indoor Units
that do not require the
additional refrigerant
charge
N
Indoor units
that require the
additional
charge
Example 6 – 4 = 2
This System – =
– Calculate the required additional charge (W
2
kg) for the
units from the bigger capacity to smaller as shown in
table 3.
– Calculate the required additional charge (W kg) from
following formula:
Total Qty of additional charge W = W
1
+ W
2
:
Example W = 9.386 + 5.2 = 14.586 kg
W = + = kg
§
Charging Work:
Charge Refrigerant (R407C) into the system according to
the instructions described in the “Installation Manual”
§
Record of additional charge:
Record the Refrigerant Charge quantity in order to
facilitate maintenance and servicing activities.
Total Additional Charge W kg
Total Ref. Charge of this System kg
Year Month Day