Haier AS072XVERA Service Manual page 49

<=90℃
Heating mode
100℃< discharging temp.
90℃< discharging temp.<=100℃
<=90℃
3.4 4-way valve control in heating
Protection when 4-way valve can not reverse in heating:
10 minutes later after compressor startup, if indoor coil average temp. is below 15degree and keeps for 1
minute, the unit will stop and occur the 4-way valve protection.
compressor ON
OFF
4-way valve ON
OFF
3.5 Electric heater control
If compressor has not run for a long time, the refrigerant will deposit on the bottom of compressor and mix
with the refrigeranr oil. When re-startup, because low pressure reduces, refrigerant will be segregated
from the refrigerant oil and cause soam in the oil, which will make compressor exhaust a lot of oil.
Therefore please stop heating the compressor bottom to ensure the low pressure in startup period should
not go down greatly.
Ambient temp. TA≤27degree, when compressor stops, the electric heater will be electrified.
When TA≥32degree, or compressor running, the electric heater will be off.
Heater ON
OFF
Ambient temp. TA(℃)
3.6 Control of liquid spray valve SV2:
According to the compressor discharging temp., open or close the SV2.
①Control condition:
A. In every mode (including defrosting and oil return operation), the control can work.
B. In 3 minutes after compressor startup, ignore the abnormal compressor suction and discharging value.
②3 minutes later after compressor startup, according to the discharging temp., the following procedure
will be taken:
Td≤90℃, SV2 close;
Td＞110℃, SV2 open.
③In 150 seconds when compressor stops, in order to keep the system in balanc, please open the liquid
spray valve SV2. 150 seconds later after compressor stops, SV2 close.
3.7 Control of defrosting in heating
In heating mode, defrosting temp. sensor will check the frosting condition of outdoor heat exchanger and
make defrosting control.
3.7.1 Enter condition:
①In heating mode, if the compressor has run for 10 minutes continously and run for 45 minutes in all, the
system will measure the defrosting temperature sensor Te and outdoor ambient temp. sensor TA, if the
below condition can be met for continous 5 minutes, the unit will enter defrosting operation:
Commercial Air Conditioner
-5degree/30seconds, and reduce to 0 degree gradually
Indoor modification angle
+50degree/30seconds, it will stop until up to the max. permitted
-5degree/30seconds, and reduce to 0 degree gradually
15s（E）
27
-49-
Model: AU18/222XFERA
AS072/092/122XVERA
opening angle
Keep the angle
2minutes and 55s
32