Hitachi FS3 Series, Service Manual

Page: 234 / 240

5
4
FIELD WORK INSTRUCTION
5.6. SELECT GUIDE OF DRAIN PIPE FOR INDOOR UNIT
n
Selecting Method of Drain Pipe Diameter
1. Calculation of Drain Flow Volume
Calculate from that the drain flow volume is
approximately 3 (I/hr) per 1HP of the indoor unit
nominal capacity.
For Example:
Common drain pipe for four 2HP indoor units and four
2.5HP indoor units.
Total Horse Power of
Indoor Unit
4
™
2HP + 4
™
2.5 HP=18HP
Total Drain Flow Volume
18HP
™
3 (l/hr
™
HP) =
54 (l/hr)
2. Select Drain Pipe from Table A and B
Horizontal Common Pipe
with Slope 1/50
VP30 for above Example
Horizontal Common Pipe
with Slope 1/100
VP30 for above Example
Vertical Common Pipe VP30 for above Example
Table A. Permissible Drain Flow Volume of Horizontal Vinyl
Pipe
Permissible Flow Volume (I/hr]
JIS Symbol
Inner Diameter
(mm)
Slope=1/50 Slope=1/100
VP20 20 39 27
VP25 25 70 50
VP30 31 125 88
VP40 40 247 175
VP50 51 472 334
NOTE
VP20 and VP25: Not Applicable to Common Pipe
VP30, 40 and 50: Applicable to Common Pipe
Table B. Permissible Drain Flow Volume of Vertical Vinyl
Pipe
JIS Symbol
Inner Diameter
(mm)
Permissible Flow Volume (I/hr]
VP20 20 220
VP25 25 410
VP30 31 730
VP40 40 1400
VP50 51 2760
VP65 67 5710
VP75 77 8280
NOTE
VP20, 25 and 30: Not Applicable to Common Pipe
VP40, 50, 65 and 75: Applicable to Common Pipe
5.7. CAUTION ON REFRIGERANT LEAKAGE
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Maximum Permissible Concentration of H(C)FC Gas
The refrigerant R407C (or R22), charged in the SET-FREE
FSG system, is an incombustible and non-toxic gas.
However, if leakage occurs and gas fills a room, it may
cause suffocation.
The maximum permissible concentration of H(C)FC gas,
R407C in air is 0.3 kg/m³ according to the refrigeration and
air conditioning facility standard (KHK S 0010) by the KHK
(High Pressure Gas Protection Association) Japan.
Therefore, some effective measure must be taken to lower
the R407C concentration in air below 0.3 kg/m³, in case of
leakage.
n
Calculation of Refrigerant Concentration
1. Calculate the total quantity of refrigerant R (kg)
charged in the system connecting all the indoor units
of rooms to be air-conditioned.
2. Calculate the room Volume V (m³) of each room.
3. Calculate the refrigerant concentration C (kg/m³) of the
room according to the following equation:
R
— = C
V
R: Total Quantity of Charged Refrigerant (kg)
V: Room Volume (m³)
C: Refrigerant Concentration (
ˆ
0.3 kg/m³)
n
Countermeasure for Refrigerant Leakage According
to KHK Standard
The facility shall be arranged as follows referring to the
KHK standards, so that the refrigerant concentration will be
bellow 0.3 kg/m³.
1. Provide a shutterless opening which will allow fresh air
to circulate into the room.
2. Provide a doorless opening of 0.15% or more size to
the floor area.
3. Provide a Ventilator, Linked with a gas leak detector,
of 0.4 m³/min or more ventilating capacity per
Japanese Refrigeration Ton (=compressor
displacement m³/h/8.5(R22) or 9.8(R407)) of the air
conditioning system utilizing refrigerant R-22.
RAS-5FSG 2.15 ton RAS-5FS3 2.48 ton
RAS-8FSG 3.74 ton RAS-8FS3 4.31 ton
RAS-10FSG 4.01 ton RAS-10FS3 4.63 ton
RAS-16FSG 5.78 ton RAS-16FS3 6.66 ton
RAS-20FSG 7.36 ton RAS-20FS3 8.49 ton
4. Pay a special attention to the place, such as a
basement, etc., where refrigerant can stay, since
refrigerant is heavier than air.
1/25 ~ 1/100 Down-Slope
Common Drain Piping
(Horizontal)
Connecting Pipe Shall
be Downward
Common Drain Piping
(Vertical)
>
100m
m