Hitachi RAS-10HNCE, Инструкция по установке и эксплуатации

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PMML0251A rev.2 - 02/2013 32
Refrigerant piping & refrigerant charge
When the pressure is measured, use the check joint of gas stop
valve (A), and use the check joint of liquid piping (B) in the figure
below.
At that time, connect the pressure gauge according to the follow-
ing table because of high pressure side and low pressure side
changes by operation mode.
Cooling
Operation
Heating
Operation
Check Joint for Gas Stop Valve “A” Low Pressure High Pressure
Check Joint for Piping “B” High Pressure Low Pressure
Check Joint for Liquid Stop Valve “C”
Exclussive for Vacuum Pump
and Refrigerant Charge
N O T E
Be careful that refrigerant and oil do not splash to the electrical
parts at removing the charge hoses.
C
B
A
The gas stayed at O-ring
s c r e w p a r t i s o p e n e d
and may make sound
when removing the cap.
However, it is not gas
leakage.
4 Correct position of Triple Branch Pipe (Standard series only).
• Install the header horizontally
Sample: Triple Branch pipe
Gas piping
Liquid piping
13.4.3 Brazing work
C A U T I O N
Use nitrogen gas for blowing during pipe brazing. If oxygen, acet-
ylene or fluorocarbon gas is used, it will cause an explosion or
poisonous gas.
A lot of oxidation film will occur inside of tubes if no nitrogen
gas blowing is performed during brazing work. This film will be
flecked off after operation and will circulate in the cycle, resulting
in clogged expansion valves, etc. This will cause bad influence to
the compressor.
Use a reducer valve when nitrogen gas blowing is performed dur-
ing brazing. The gas pressure should be maintained within 0.03
to 0.05 Mpa. If a excessively high pressure is applied to a pipe, it
will cause an explosion.
13.4.4 Refrigerant charge
C A U T I O N
Do not charge OXYGEN, ACETYLENE, or other flammable and
poisonous gases into the refrigerant because an explosion can
occur. It is recommended that oxygen free nitrogen be charged
for these types of tests cycle when performing a leakage test or
an airtight test. These types of gases are extremely dangerous,
Insulate the unions and flare-nuts at the piping connection part
completely.
Insulate the liquid piping completely to avoid a decrease of per-
formance; if not, it will cause sweating on the surface of the pipe.
Charge refrigerant correctly. Overcharging or insufficient charging
could cause a compressor failure.
Check for refrigerant leakage in detail. If a large refrigerant leak-
age occurred, it would cause difficulty with breathing or harmful
gases would occur if a fire were being used in the room.
If the flare nut is tigthened too hard, the flare nut may crack after
a long time and cause refrigerant leakage.
Outdoor Units has been charged with refrigerant for 30m of actual
piping length. An additional refrigerant charged is required in sys-
tems with actual piping length longer than 30m.
1 Determine an additional refrigerant quantity according to the
following procedure, and charge it into the system.
2 Record the additional refrigerant quantity to facilitate service
activities thereafter.
C A U T I O N
When charging refrigerant accurately measure refrigerant to be
charged.
Overcharging or undercharging of refrigerant can cause compres-
sor trouble
In case of actual piping length less than 5 m, consult your distribu-
tor.
13.5 CAUTION OF THE PRESSURE BY CHECK JOINT
13.6 REFRIGERANT CHARGING QUANTITY
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