Hitachi SET FREE-Serie Bedienungsanleitung Seite 55

PIPING WORK AND REFRIGERANT CHARGE
Caution for opening stop valve
1 Do not apply an excessive force after fully opening the
spindle. (Tightening Torque: < 5.0N.m).
2 Tighten securely the caps according to the properly
tightening torque each spindle valve is opened.
a. Operate the compressor in the cooling mode and charge
the additional refrigerant from the check joint of the liquid
stop valve (acceptable error must be within 0.5 kg). At
this time, keep the liquid stop valve slightly opened
8.7.1 Maximum permitted concentration of hydrofluorcarbon (HFC) refrigerant
!
D a n G e r
• Fitters and the designers of the installations must strictly
observe local and national legislation, and local codes regarding
safety requirements in the event of refrigerant leaks.
• In the event of a leak, the gas will spread around the room,
displacing the air, and could therefore result in asphyxia.
• Special attention should be given to areas where the refrigerant
may be deposited and stay in the room, such as basements or
similar, as it is heavier than air.
The R410A refrigerant gas, used in the equipment, is fireproof
and not toxic.
The maximum permitted concentration of HFC R410A gas in
the air is 0.44 kg/m , in accordance with standard EN378-1.
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Therefore, efficient measures should be adopted to ensure the
concentration of R410A gas in the air is kept below 0.44 kg/m
the event of a leak.
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Calculation of the refrigerant concentration
1 Calculate the total quantity of refrigerant R (kg) charged
in the system; to do so, connect all the indoor units of the
rooms in which you wish to have air conditioning.
2 Calculate the volume V (m
3 Calculate the refrigerant concentration C (kg/m
according to the following formula:
R / V = C
R: total quantity of refrigerant charged (kg).
V: volume of the room (m ).
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C: concentration of refrigerant (= 0.44 kg/m
45 PMML0479 rev.2 - 02/2018
) of each room.
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) of the room
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for R410A gas).
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b. After the refrigerant is charged, fully open the liquid stop
valve and the gas stop valve.
c. Calculate securely the additional refrigerant quantity for
charging. If the quantity of additional refrigerant is not
correct, it may cause compressor failure. The additional
refrigerant must be charged in a liquid condition.
d. Refrigerant charge from check joint of gas stop valve may
lead to compressor failure. Be sure to charge refrigerant
from the check joint of liquid stop valve.
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Countermeasures in the event of refrigerant
leaks
Pay attention to the critical gas concentration to avoid accidental
refrigerant gas leakage before installing air conditioning
systems.
In the case that the calculated critical concentration is higher
than the maximum permissible concentration of HFC gas
(R410A) in air, take the following actions.
1 Provide each effective opening at the wall or door for
ventilation to next door so that the critical gas concentration
can be maintained lower than the above value. (Provide an
opening more than 0.15% of floor surface at the lower part of
a door.)
2 Opening without shutter to permit the circulation of fresh air
in
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in the room.
3 A fan with a capacity of at least 0.4 m
of Japanese refrigerant ( = volume displaced by the
compressor / 5.7 m
(gas leakage detector) in the air conditioning system which
uses the refrigerant.
/minute per tonne
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/h) or greater, connected to a gas sensor
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