Oil Return Operation; Compressor Overheat Protection; Oil Return Operation In Heating; Input Protection Signal - Haier H-MRV Series Service Manual

9.1 According to the temperature measured by Td, the unit will adjust compressor frequency when
discharging temperature is overheat. When spraying refrigerant cannot efficiently decrease
discharging temperature, the system will make decrease-frequency protection.
9.2 When Td is over 110℃, the frequency will reduce 10Hz for every 120 seconds. When the output
frequency has become the low limit, Td is still over 110℃, the unit will stop.

10. Oil return operation

10.1 Oil return operation in cooling
Entering condition:
Indoor thermostat OFF time is over 30 minutes (after oil return operation, time again from
beginning).
In cooling mode, compressor runs for 1 hour in all (after oil return operation, time again from
beginning).
Operation procedure:
After oil return signal has been sent to indoor for 30 seconds, the unit will begin oil return operation.
Compressor running frequency is the oil return frequency, outdoor EEV open angle does not
change and quit oil return 4 minutes later, then resume the frequency before oil return operation,
finally, send oil return finish signal to indoor unit.

10.2 Oil return operation in heating

Entering condition:
Indoor thermostat OFF time is over 30 minutes (after oil return operation, time again from
beginning).
In heating mode, compressor runs for 1 hour in all (after oil return operation, time again from
beginning).
Operation procedure:
After oil return signal has been sent to indoor for 30 seconds, the unit will begin oil return operation.
Compressor running frequency is the oil return frequency, outdoor EEV open angle is the special
angle for heating oil return and quit oil return 4 minutes later, then resume the corresponding base
angle due to the indoor capacity.

11. Compressor overheat protection

Values saved in EEPROM:
Parameter
Over current protection
Over load protection
Overcurrent stall
protection
Overload fixed
frequency protection
value
Rated current

12. Input protection signal

High/low pressure switch protection:
When input of pressure switch is 0, that shows no protection.
When input of pressure switch is 1 for 1 minute, that shows high pressure protection, and
compressor stops, then there will be failure alarm signal. If alarm has been solved, the protection
Current protection data
Over_c (Pr-24)
Ov_load (Pr-23)
Oc_stall (Pr-26)
Ov_load2 (Pr-28)
Rate_c (Pr-20)
-103-
>a__WcU[S^ <[c >a`V[e[a`Wc
unit Data out of factory
% 130
% 106
% 96
% 100
A 13
Actual data
13*130%=16.9(A)
13*100%=13(A)
13*88%=11.5(A)
13*96%=12.5 (A)
13(A)