Hitachi RAS-(2-6)HVNP1(E), Service Manual

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3 Piping work and
refrigerant charge
87
SMGB0087 rev.0 - 12/2013
3
Step 2: Additional refrigerant charge calculation for indoor unit (W
2
(kg))
When the outdoor unit is combined with indoor units RPI-(8/10)HP allowed (1 unit system combination only), it´s necessary
an additional refrigerant charge (W
2
) = 1kg/unit. For indoor units lower than 8 HP, an additional refrigerant charge it’s not
needed.
Indoor unit capacity Additional refrigerant charge (W
2
(kg))
≥ 8 HP 1
< 8 HP 0
Step 3: Calculation of total additional refrigerant charge (W (kg))
a. For all UTOPIA units except RAS-(8-12)HN(P/C)(E)
Put weight W
1
and W
2
calculated in step 1 and step 2 into the following formula:
W = W
1
+ W
2
System example (W) = + = kg
b. For UTOPIA units RAS-(8-12)HN(P/C)(E)
In case of RAS-(8-12)HN(P/C)(E), it must be used the following formula:
W = W
1
+ W
2
- C
System example (W) = + – = kg
C: Compensation value (kg) (Refer to the following table)
Model Compensation value (C (kg))
RAS-8HN(P/C)E 1.6
RAS-10HN(P/C)E 2.0
RAS-12HN(P/C) 2.0
C A U T I O N
Do not exceed the allowed maximum additional charge
Step 4: Charging work
Charge refrigerant (R410A) into the system according to the instructions in the Service Manual.
Step 5: Total refrigerant charge of the system (W
TOT
(kg))
The total refrigerant charge of this system is calculated by the following formula:
W
TOT
= W + W
0
System example (W
TOT
) = + = kg
W
0
is the outdoor unit refrigerant charge before shipment previous explained, and it’s shown in its specific table.
Finally, record the refrigerant charge quantity in order to facilitate maintenance and servicing activities.
Total additional charge W
kg
kg
Total ref. charge of this system
Date of ref. charge work
Year
Month
Day