Hitachi UTOPIA R410A Series - 8.4 REFRIGERANT CHARGE

Use two spanners here
for pipe connection
Do not work with two
spanners here.
Refrigerant leakage
shall occur
! CAUTION
• Atthetestrun,fullyopenthespindleandballstopvalve.
• Ifnotfullyopened,thedeviceswillbedamaged.
• Donotattempttoturnservicevalverodbeyonditsstop.
• Donotloosenthestopring.Ifthestopringisloosened,itisdangerous
sincethespindlewillhopout.
• Anexcessorashortageofrefrigerantisthemaincauseoftrouble
totheunits.Chargethecorrectrefrigerantquantityaccordingtothe
descriptionoflabelattheinsideofservicecover.
• Checkforrefrigerantleakageindetail.Ifalargerefrigerantleakage
occurs,itwillcausedifcultywithbreathingorharmfulgaseswould
occurifarewasbeingusedintheroom.
8.3 BRAZING WORK
! CAUTION
• Usenitrogengasforblowingduringpipebrazing.Ifoxygen,acetylene
oruorocarbongasisused,itwillcauseanexplosionorpoisonous
gas.
• A lot of oxidation lm will occur inside of tubes if no nitrogen gas
blowingis performed duringbrazingwork. This lmwillbeecked
offafteroperationandwillcirculateinthecycle,resultinginclogged
expansionvalves,etc.Thiswillcausebadinuencetothecompressor.
• Useareducervalvewhennitrogengasblowingisperformedduring
brazing. The gas pressure should be maintained within 0.03 to
0.05MPa.Ifaexcessivelyhighpressureisappliedtoapipe,itwill
causeanexplosion.
8.4 REFRIGERANT CHARGE
! CAUTION
• Do not charge OXYGEN, ACETYLENE, or other ammable 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 are-nuts at the piping connection part
completely.
• Insulate the liquid piping completely to avoid a decrease of
performance;ifnot,itwillcausesweatingonthesurfaceofthepipe.
• Charge refrigerant correctly. Overcharging or insufcient charging
couldcauseacompressorfailure.
• Checkforrefrigerantleakageindetail.Ifalargerefrigerantleakage
occurred, it would cause difcultywith breathing or harmful gases
wouldoccurifarewerebeingusedintheroom.
• Ifthearenutistightenedtoohard,thearenutmaycrackaftera
longtimeandcauserefrigerantleakage.
8.5 CAUTION OF THE PRESSURE BY CHECK JOINT
When the pressure is measured, use the check joint of gas stop

below.
At that time, connect the pressure gauge according to the
following 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”
Exclusive for vacuum pump and
refrigerant charge
? NOTE
Becarefulthatrefrigerantandoildonotsplashtotheelectricalpartsat
removingthechargehoses.
C
B
A
There may be gas
trapped at the “O-ring
screw” part, which may
produce a sound when
released upon removal
of the cap.
However, this is not a
gas leakage.
Refrigerant piping & refrigerant charge
PMML0545 rev.2 - 04/2021
11
EN