Replacing The Refrigerant Oil; No Clogging In Return Oil Circuit - Hitachi FSXN Series Service Manual

10 Servicing

10.9 Replacing the refrigerant oil

D A N G E R
• Turn OFF all the power source switches.
N O T E
• For servicing use the following tool:
- Adjustable wrench or spanner.

10.9.1 No clogging in return oil circuit

1 Remove the front service cover as described in the procedure
Removing the front service
2 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-.
3 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.
4 Connect the charge hose (for R410A) to the pressure check
joint to collect the refrigerant oil -D-.
5 Charge with nitrogen (0.15MPa) from the low pressure check
joint -E- and collect the refrigerant oil in the accumulator by
applying pressure for approximately 20 minutes.
N O T E
Make sure that the pressure of the high pressure check joint -A- is not abnormal when the nitrogen is charged.
6 Stop charging with nitrogen after the refrigerant oil is completely collected. Perform vacuuming from the low pressure
check joint -E- and add the same quantity as the collected refrigerant oil.
N O T E
When the collected refrigearnt oil is 3 L. or less, clogging may exist in the return oil circuit. In this case, replace
the return oil circuit as described in the procedure
7 When the procedure is finished, perform the vacumming again from the low pressure check joint -E- and recharge the
refrigerant. After recharging, open the stop valves.
N O T E
• Use a clean charge hose.
• Charge the refrigerant oil in a short period of time (approximately 20 minutes).
Use a container with a small opening so the refrigerant oil does not absorbe the moisture in the atmosphere.
308
SMGB0065 rev. 1 - 12/2010
cover, see on page 292.
Replacing the return oil
D
E
A
B
circuit, see on page 311.
C