Hitachi RASC-10HNPE, Руководство по обслуживанию, Страница: 302 / 306

11 Maintenance notes
Pump-down method for replacing the compressor
SMGB0091 rev.2 - 11/2015 292
11.6 Pump-down method for replacing the compressor
No. Procedure Remarks
1 Turn off the main switch of the RASC unit. -
2
Remove the covers, the thermistor, the crankcase heater,
the power wirings, and other items according to the chapter
“9. Servicing” .
Make sure that the terminal part of the detached power supply
wires is not exposed by the winding insulation tape and other
items.
3
Attach the manifold to the check joint of the high-pressure
side and the low-pressure side of the RASC unit.
-
4 Turn on the main switch of the RASC unit. -
5
Set the exclusion of the compressor by setting the DSW so
that a broken compressor will not work.
You can set the exclusion of the compressor by setting the
DSW1-4 in ON position.
-
6
The compressor replacing mode is performed:
-
The DSW1-4 on the RASC unit PCB → ON (The
cooling is run).
-
This operation is performed for up to a maximum of ten
minutes.
-
If the inverter compressor is excluded, the operation
starts after three minutes.
7
The operation finishes when one of the following conditions
occurs:
1
Ten minutes have passed and STP is displayed in
seven segments.
2
"
08
" is displayed in seven segments.
3
When Ps< 0.1MPa is continued for one minute, in ten
minutes STP is displayed in seven segments and the
operation finishes.
-
The operation may finished when any of the conditions
1) to 3) occurs.
8 Close the liquid stop valve completely.
To avoid the spillage of all the refrigerant if the check valve is
broken.
9
Check for a leakage of the check valve on the discharge
gas side:
-
DSW4-4 (enforced stoppage of the compressor) →
ON, so that the compressor will not run although
the running command is sent from the remote
control switch.
-
Check that variation of Ps on the RASC unit PCB
is 17 seconds. Make sure that the Ps increase
is within 0.03 MPa in two minutes after the Ps
increase at the stoppage (during approximately five
minutes). Also make sure that Pd>Ps.
0.03 MPa
or smaller
2 minutes
Time
Ps
-
When you stop the compressor for replacing:
-
You can check the leakage of the check valve by means
of the Ps variation because the SVA opens so that
the discharge gas side of the inverter compressor can
connect to the low-pressure side.
-
0.03 MPa / 2 minutes is within the permissible limits for
the check valve on the discharge gas side.
-
The leakage of the check valve may cause an incorrect
brazing, due to the gas pressure at the brazing of the
discharge piping.
-
If the compressor-replacing mode is performed again,
set the DSW4-4 to OFF and keep the DSW4-4 at the
OFF side during ten minutes. Then, start according to
the procedure number 6.
10
Collect the refrigerant by means of the refrigerant
collection:
-
Perform either A or B, depending on the process
10.
a.
The leak rate at the process 10 is within the
specification → Collect the refrigerant only at the
low-pressure side.
b.
The leak rate at the process 10 is greater than the
specification → Collect all the refrigerant of the
RASC unit side by means of the machine.
-
The discharge of the refrigerant in the atmosphere
is strictly forbidden. Make sure that the refrigerant is
collected by the collector.
-
Keep a note of the quantity of the collected refrigerant.