Refrigerant And Water Piping - Hitachi RWM-2.5NE Instruction Manual

REFRIGERANT AND WATER PIPING

4 REFRIGERANT AND WATER PIPING
4.1 GENERAL NOTES BEFORE PERFORMING PIPING WORK
• Prepare locally-supplied copper pipes.
• Select the piping size with the correct thickness and correct
material able to withstand sufficient pressure.
• Select clean copper pipes. Make sure that there is no dust
or moisture inside the pipes. Blow the inside of the pipes
with oxygen free nitrogen to remove any dust and foreign
materials before connecting them.
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N O T E
A system with no moisture or oil contamination will give maximum
performance and lifecycle compared to that of a poorly prepared system.
Take particular care to ensure that all copper piping is clean and dry
internally.
• Cap the end of the pipe when pipe is to be inserted through
a wall hole.
• Do not put pipes on the ground directly without a cap or vinyl
tape at the end of the pipe.
4.2 REFRIGERANT CIRCUIT
4.2.1 Refrigerant charge
The R410A refrigerant is factory charged in the outdoor unit with
a refrigerant charge amount for 30 m of piping length between
outdoor and indoor unit. The maximum refrigerant piping length
is 30 m, so additional refrigerant charge is not required.
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N O T E
Refer to the outdoor unit Installation and operation manual to charge the
R410A refrigerant inside the indoor unit.
4.2.2 Precautions in the event of gas
refrigerant leaks
The installers and those responsible for drafting the
specifications are obliged to comply with local safety codes and
regulations in the case of refrigerant leakage.
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C A U T I O N
• Check for refrigerant leakage in detail. If a large refrigerant leakage
occurred, it would cause difficulty with breathing or harmful gases
would occur if a fire were in the room.
• If the flare nut is tightened too hard, it may crack over time and cause
refrigerant leakage.
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Maximum permitted concentration of HFCs
The refrigerant R410A (charged in the outdoor unit) is an
incombustible and non-toxic gas. However, if leakage occurs
and gas fills a room, it may cause suffocation.
6 PMML0336B rev.1 - 03/2016
• If piping installation is not completed until next day or over
a longer period of time, braze off the ends of the piping
and charge with oxygen free nitrogen through a Schrader
valve type access fitting to prevent moisture and particle
contamination.
• It is advisable to insulate the water pipes, joints and
connections in order to avoid heat loss and dew
condensation on the surface of the pipes or accidental
injures due to excessive heat on piping surfaces.
• Do not use insulation material that contains NH3, as it can
damage copper pipe material and become a source of future
leakage.
• It is recommended to use flexible joints for the water piping
inlet and outlet in order to avoid vibration transmission.
• Refrigerant circuit and Water circuit must be performed and
inspected by a licensed technician and must comply with all
relevant European and national regulations.
• Proper water pipe inspection should be performed after
piping work to assure there is no water leakage in the space
heating circuit.
The maximum permissible concentration of HFC gas according
to EN378-1 is:
Refrigerant Maximum permissible concentration (kg/m
R410A
The minimum volume of a closed room where the system is
installed to avoid suffocation in case of leakage is:
System combination
2 HP
2.5 HP
3 HP
4 HP
5/6 HP
8 HP
10 HP
The formula used for the calculation of the maximum allowed
refrigerant concentration in case of refrigerant leakage is the
following:
R R: Total quantity of refrigerant charged (kg)
— = C V: Room volume (m³)
V C: Refrigerant concentration
If the room volume is below the minimum value, some effective
measure must be taken account after installing to prevent
suffocation in case of leakage.
)
3
0.44
Minimum volume (m )
3
3.2
3.5
3.9
7.5
7.8
11.4
12.1