Hitachi RAS-10FSXN - Clogging in Return Oil Circuit

10.9.2 Clogging in return oil circuit
1 Remove the front service cover as described in the procedure
Removing the front service cover, see on page 292.
2 Remove the
electrical box wiring and electrical box stay as
described in the procedures Removing the electrical box for
RAS-(8-12)FSXN, see on page 295, Removing the electrical
box for RAS-(14-18)FSXN, see on page 295, Removing the
electrical box stay for RAS-(8-12)FSXN, see on page 296 and
Removing the electrical box stay for RAS-(14-18)FSXN, see on
page 296.
3 Close the following stop valves.
a Heat pump system: Close the high pressure gas stop valve
-A- and the liquid stop valve -C-.
b Heat recovery system: Close the high pressure gas stop
valve, the low pressure gas stop valve -B- and the liquid
stop valve -C-.
4 Collect the outdoor unit refrigerant from the low pressure check
joint -E- and the high pressure check joint -F-. Make sure that
the pressure will not increase at this time.
N O T E
If the
pressure increases, collect all the refrigerant in the
refrigerant circuit.
5 Remove the flare nut that connects with the return oil circuit and the outlet port of the oil separator -J-. Also remove the
flare nut -I- from the upper part of the return oil circuit and connect the charge hose to the flare nut for the oil separator
outlet port (size 1/4). -H- return oil capillary.
N O T E
When the
flare nut of the oil separator outlet port -G- and the flare nut of the upper part of the return oil circuit
-I- are removed, the oil refrigerant can overflow. Prepare an oil pan to collect the refrigerant oil before removing.
RAS - (8-12) FSXN RAS - (14-18) FSXN
J
H
G
I
I
H
J
G
6 Charge with
nitrogen (0.15 MPa) from the flare nut of the upper part of the return oil circuit -I- and collect the refrigerant
oil in the oil separator -J-.
N O T E
Collect the refrigerant oil from the return oil circuit and from the oil separators one by one.
A
B
C
D
E
10 Servicing
309
SMGB0065 rev. 1 - 12/2010
10