Haier MRV II AV08NMVERA, Startup Manual

GRUPAd.o.o.

37

(7) Oil return operation control

1. Entering condition

When any one of compressor has run for 8 hours, the system will enter oil return operation.

* When compressor running frequency is over 90Hz for 10 minutes continuously, the oil return time will

be cleared.

* In defrosting operation, when compressor running frequency is over 90Hz for 5 minutes continuously,

the oil return time will be cleared.

2. Oil return procedure in cooling mode:

1) After the compressor frequency enters 90Hz, in the course, if the discharging pressure or discharging

temperature is too high, the reducing frequency protection will be prior.

2) The standby outdoor will start up, and its frequency is 90Hz.

3) Outdoor EEV will be fully open.

4) Outdoor fan motor will be controlled as the cooling mode.

5) Indoor fan: the running fan will keep running, and the stop fan will still stop.

6) Indoor EEV: in oil return operation, the running indoor EEV is always controlled as the overheat state.

In oil return operation, for the stop indoor, its EEV open angle is 5 before the oil return; during oil return,

open angle is 100 and will not be adjusted; at the end of oil return, the EEV is close.

7) 4-way valve: OFF

8) Sub-cooling valve OFF, but if the discharging temperature is over 100degree, the system will control

the sub-cooling valve, and open 100 steps, then it will control the valve according to the discharging

temperature.

9) Oil return quit condition

After oil return, the system will enter refrigerant elimination.

3. Oil return procedure in heating mode:

1) After the compressor frequency enters 90Hz, in the course, if the discharging pressure or discharging

temperature is too high, the reducing frequency protection will be prior.

2) The standby outdoor will start up, and its frequency is 90Hz.

3) Outdoor EEV will be fully open, 1400 steps; after oil return is over, EEV open angle is 200 steps, 2

minutes later, the system will adjust the open angle as over heat state.

4) Outdoor fan motor will be controlled as the cooling mode.

5) Indoor fan OFF

6) Indoor EEV: In oil return operation, for the stop indoor, its EEV open angle is 60 before the oil return;

during oil return, open angle is 100 and will not be adjusted; at the end of oil return, indoor EEV will be off.

For the running indoor, before oil return, indoor EEV will be adjusted as over heat state, in the oil return,

the open angle will be 100 compulsorily, and will not be adjusted; after oil return is over, EEV open angle

will be back to 350 the base data in heating mode and 10 minutes later, the system will adjust the over

heat state.

7) 4-way valve OFF, after oil return is over, it is ON.

8) Sub-cooling valve OFF, but if the discharging temperature is over 100degree, the system will control

the sub-cooling valve, and open 100 steps, then it will control the valve according to the discharging

temperature.

9) Oil return quit condition

OR

after 5 minutes

AND

OR

Td   CT+20  C for 10 seconds continuously

TS

-

ET

5

C

for 10 seconds continuously

after 2 minutes