Hitachi RAS-8FSNM - Page 23

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(6) Additional Refrigerant Charge
If total piping length is move than 30m, it is necessary additional refrigerant charge as follows.
2. Charging Work
3. Record of Additional Charge
Record the refrigerant charging quantity in order to facilitate maintenance
and servicing activities.
Total refrigerant charge of this system is calculated in the following formula.
1. Calculating Method of Additional Refrigerant Charge (W kg)
Although refrigerant has been charged into this unit, it is required that additional refrigerant be charged according
to piping length.
A. Determine an additional refrigerant quantity according to the following procedure, and charge it into the system.
B. Record the additional refrigerant quantity to facilitate service activities thereafter.
Additional Refrigerant Charge Calculation
See Example for Model RAS-12FSNM(Q), and fill in the following table.
Additional Charge W = W
1
- P
= 3.1 - 2.0 = 1.1 (kg)
Total Ref. Charge of This System = W + W
0
This System = + = kg
Charge refrigerant (R410A) into the system as follows.
(1) For charging refrigerant, connect the gauge mani-fold using charging hoses with a refrigerant cylinder to the check joint
of the liquid line stop valve.
(2) Fully open the gas line stop valve and slightly open the liquid line stop valve.
Charge refrigerant by opening the gauge mani-fold valve.
(3) Charge the required refrigerant by operating the system in cooling.
Ensure to charge correct volume by utilizing a weight scale. An excess or shortage of refrigerant is the main cause
of trouble to the units.
Fully open the liquid line stop valve after completing refrigerant charge.
<Table 1>
NOTE:
W
0
is outdoor unit ref. charge before shipment.
RAS-8FSNM(Q) 5.0
RAS-10FSNM(Q) 5.5
RAS-12FSNM(Q) 6.5
Outdoor Unit
W
0:
Outdoor Unit
Ref. Charge (kg)
Pipe Diameter (mm) Total Piping Length (m) Additional Charge (kg)
φ12.7 ..... (10) x 0.12 = 1.2
φ9.53 ..... (5 + 5 + 5 + 5) x 0.07 = 1.4
φ6.35 ..... (10 + 10) x 0.03 = 0.6
Total Piping Length 50m Additional Charge W
1
= 3.2 (kg)
Pipe Diameter (mm) Total Piping Length (m) Additional Charge (kg)
φ12.7 ..... x 0.12 =
φ9.53 ..... x 0.07 =
φ6.35 ..... x 0.03 =
Total Piping Length m Additional Charge W = (kg)
kg
kg
Total Ref. Charge of This System
Date of Ref. Charge Work
Day Month Year
Total Additional Charge W
No. 3No. 1
No. 2No. 0
φ9.53x5mφ12.7x10m
φ9.53x5m
φ6.35x10m
RAS-12FSNM(Q)
φ9.53x5m
φ9.53x5m
φ6.35x10m
<Example>