Hitachi RCI Serie Manual De Instalación Y Funcionamiento página 31

12. PIPING AND REFRIGERANT CHARGE
CAUTION:
Use refrigerant R410A in the refrigerant cycle. Do not
-
charge oxygen, acetylene or other flammable and
poisonous gases into the refrigerant cycle when
performing a leakage test or an air-tight test.
These types of gases are extremely dangerous and
-
can cause an explosion. It is recommended that
compressed air, nitrogen or refrigerant be used for
these types of tests.
Check to ensure that no pressure exists inside the
-
stop valve before removing the flange.
Evacuation and Refrigerant Charge
Evacuation and refrigerant charging procedure should be
performed according to the following instructions.
The stop valve has been closed before shipment. However,
make sure that the stop valves are closed completely.
Connect the indoor unit and the outdoor unit with field-
supplied refrigerant piping.
Connect the gauge manifold using charging hoses with a
vacuum pump or a nitrogen cylinder to the check joints of
the liquid line and the gas line stop valve.
Check for any gas leakage at the flare nut connection, by
using nitrogen gas to increase the pressure at 4.15MPa for
HRNM outdoor units inside of the field-supplied piping.
Operate the vacuum pump for 1 to 2 hours until the
pressure decreases lower than a pressure of 756 mmHg in
vacuum.
For charging refrigerant, connect the gauge manifold using
charging hoses with a refrigerant charging cylinder to the
check joint of the liquid line stop valve.
Charge the proper quantity of refrigerant according to the
piping length (Calculate the quantity of the refrigerant
charge).
Fully open the gas line stop valve, and slightly open the
liquid line stop valve.
Charge refrigerant by opening the gauge manifold valve.
Charge the required refrigerant within the difference range
of ±0.5kg by operating the system in cooling.
Fully open the liquid line stop valve after completing
refrigerant charge.
Continue cooling operation for more than 10 minutes to
circulate the refrigerant.
Remove the "close" plate from the stop valve and hook the
attached "Open" plate at the stop valve.
PIPING AND REFRIGERANT CHARGE
Outdoor Unit
Gas Stop valve
Liquid Stop
valve
Gas Line
Liquid Line
Indoor Unit
Multi-Kit
Example of Evacuation and Refrigerant Charge for HRNM
NOTE:
Charge the refrigerant correctly after calculation.
-
Overcharge and insufficient charge of the refrigerant
may cause the compressor failure. Insulate the liquid
pipe for prevention of the capacity decrease according
to the ambient air conditions and the dewing on the
pipe surface by the low pressure.
Check to ensure that there is no gas leakage. When
-
large amount of the refrigerant leaks, the troubles as
follows may occur:
Oxygen deficiency
-
Generation of Harmful gas Due to Chemical
-
Reaction with fire.
Use thick gloves to protect your hands from liquid
-
refrigerant injuries when handling refrigerant.
CAUTION:
Check for refrigerant leakage in detail. If a large
refrigerant leakage occurs, it will cause difficulty with
breathing or harmful gases would occur if a fire was
being used in the room. An excess or a shortage of
refrigerant is the main cause of trouble to the units.
Charge the correct refrigerant quantity.
19
Nitrogen tank
(For Air Tight Test &
Nitrogen Blow during
Brazing)
Charging
Cylinder
Vacuum
cylinder
Indoor Unit