Technical Information
SERVICE MANUAL
6. Function and Control
1.Function Control
1) Cooling mode
a. Turning on the unit for cooling operation, and if any one of the indoor units satisfy the cooling operation condition, the system will start
for cooling operation; and the electronic expansion valve, the outdoor fan and the compressor start operation.
b. When some of the indoor units satisfy the stop-condition while some indoor units does not satisfy the stop-condition, the compressor
does not stop, the compressor adjust the frequency according to demand. For the indoor unit with stop-condition satisfies, the
corresponding electronic expansion valve will be closed.
c. Change Cooling mode to heating mode
after the compressor stops.
d. 4-way valve
In this mode, the 4-way valve is closed.
e. Outdoor fan control in cooling mode
The outdoor fan starts before 5s of the starting of compressor. The outdoor fan will run in high speed after starting and then it will run in
set speed.
This mode is the same as cooling mode;
3) Heating mode
a. Turning on the unit for heating operation, If any one of the indoor unit satisfy the heating condition, the system will start to run in heating
mode
b. If all the indoor units satisfy the stop-condition, the compressor stops and the outdoor fan stops after 1min;
c. If only part of the indoor units satisfy the stop-condition, the compressor decrease the frequency immediately and operates according to
demand.
e. Defrosting function
direction, the frequency of compressor rises, and the unit will start defrosting under cooling cycle.
f. Oil-return control in heating mode
a)If the whole system runs in low frequency for a long time, the system will run a oil-return operation in high frequency, the oil-return
operation will runs for 60 second.
4) Fan mode
Only indoor fan run. Compressor, outdoor fan and 4-way valve are closed .
2.Protection Function
When the setting mode is different of different indoor unit, the unit runs in below status:
heating mode.
2) Overload protection
If the tube temperature at the high pressure side is higher than normal, the compressor frequency is restricted or decreased to normal
operation frequency.
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