Refrigerant Piping & Refrigerant Charge - Hitachi RCIM-2.0FSN Installation And Operation Manual

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11. REFRIGERANT PIPING & 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 HVRN1 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.
Gas line
Liquid line
Liquid stop valve
Outdoor unit
Gas Stop valve
Manifold
gauge
Vacuum
cylinder
Example of Evacuation and Refrigerant Charge for HVRN1
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.
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.
Nitrogen tank
(For Air Tight Test & Nitrogen
blow during brazing)
If a large