Overhaul Work; Vacuuming Procedure; Vacuuming - Hitachi RCUE40AG2 Service Manual

Maintenance

6.9. Overhaul work

6.10. Vacuuming Procedure

6.10. Vacuuming Procedure

6.10. Vacuuming Procedure

CAUTION
If vacuum grade
is not decreased
to –755mmHg in
1 hour, confi rm
if there is no
leakage or if water
is not in the pipes,
and then keep
vacuuming other
1 hour.
pag. 170
SMGB0003 rev.0 - 11/2006
Perform the work according to "Dissolution and Composition Manual of Hitachi Half Sealed
Screw Compressor".
When compressor is removed from refrigeration cycle, high pressure part should be separated
between projecting part fl ange of compressor and upper cover of oil separator. Do not
be separated between check valve and projecting part fl ange of compressor, or collected
refrigerant is ejected.
Projecting part fl ange of Projecting part fl ange of Projecting part fl ange of
Check valve Check valve Check valve
compressor compressor compressor compressor compressor
Separate from Separate from Separate from
this part this part this part
Upper cover of Upper cover of Upper cover of
oil separator
Although refrigerant is collected to airside heat exchanger by the above collection operation,
it is necessary to be vacuumed due to that refrigerant cycle of low pressure side pipe and of
water side heat exchanger are open.
Vacuum should be performed in the following 2 positions.
Stop valve for refrigerant insertion ((D) part)
−
Check joint of compressor suction side ((E) part)
−
*Capillary for compound gauge in low pressure side is installed in check joint. This
capillary should be removed from check joint.
Vacuuming procedure is shown in the following.

6.10.1. Vacuuming

Manifold valve, vacuuming pump and vacuuming gauge for R407C are connected.
−
Operate vacuuming pump for at least 1~2 hours until vacuum grade be below
−
–755mmHg (5Torr).
pressure
atmosphere
pressure
Vacuum
(1~2 hrs)
Confi rmation of vacuum
−
Vacuum gauge should be used to measure a target vacuum, however, it is
impossible to read the vacuum gauge installed in the manifold very accurately.
It is recommended to use a digital vacuum measure device, available in the
market.
Remove these Remove these Remove these Remove these
bolts fi rstly bolts fi rstly bolts fi rstly
Abnormal
(leakage, water
in pipes)
Connect to (D)
(E) parts
Leave
(1 hour)
Do not remove these bolts
or refrigerant is ejected or refrigerant is ejected
Check valve
Projecting part fl ange of compressor Projecting part fl ange of compressor Projecting part fl ange of compressor Projecting part fl ange of compressor
Upper cover of oil separator Upper cover of oil separator Upper cover of oil separator Upper cover of oil separator Upper cover of oil separator Upper cover of oil separator
Manifold valve
for vacuuming
(Refrigerant
tank for R407C)
Vacuuming pump
(prevention of adverse
current)