Air-to-water Heat Pump Split Versati
26
SPLIT TYPE
unit and the 4-way valve will stop. Over-temperature protection will exit when the leaving water temperature is
lower than the over-temperature protection temperature. Then, the main unit will resume normal operation.
2.3.2 Water Heating by the Solar System
When the solar water heating system is equipped but temperature difference ( it is the difference of solar panel
temperature and the actual water tank temperature) for startup is not satisfied, the water pump of the solar system
will not start. When the temperature difference is satisfied, the water pump will start. However, when it is detected
that the water tank temperature reaches the set point, or the entering/leaving water temperature difference of the
solar panel is too small, then this water pump will stop running.
2.4 Shutdown
There are three kinds of shutdown conditions: normal shutdown, shutdown with some error, shutdown for
protection
Shutdown sequence: for normal shutdown, the compressor lowers its frequency firstly to the minmum value,
while for shutdown with some error or for protection, the compressor will stop directly.Then, the electronic
expansion valve turns to the maximum opening angle; the fan stops after the compressor has stopped; the water
pump of the main unit stops after the compressor has stopped; the electronic expansion valve turns the maximum
opening angle to the fixed opening angle.
During shutdown under the heating and water heating modes, the 4-way valve will be powered off after the
compressor has stopped.
For shutdown owing to some error (except the communication error) or protection, the 4-way valve will keep the
power-on status.
For shutdown owing to communication between the unit and the wired controller, the 4-way valve will be
powered off some timer later.
For shutdown with some error or for protection, the electronic expansion valve will keep the maximum opening
angle.
2.5 Control to the Compressor
When the unit is controlled by the leaving water temperature, the output frequency of the compressor is adjusted
by the difference between the actual water temperature and the leaving water temperature set point. When the
unit is controlled by the room temperature, the output frequency of the compressor is adjusted by the difference
between the actual room temperature and the room temperature set point.
2.6 Control to the Fan
Under the cooling mode, the operating frequency of the fan is adjusted according to pressure at the high
pressure side. Under the heating or water heating mode, the operating frequency of the fan is adjusted according
to the pressure at the low pressure side. During defrosting, the fan stops and resumes operation when defrosting
ends up.
2.7 Control to the 4-way Valve
The 4-way valve always keeps on under the cooling mode and will off after the compressor starts up under the
heating or water heating mode. When the unit comes into defrosting, the 4-way valve will be on and resume the
off status when defrosting ends up. For shutdown under the heating mode, the 4-way valve will be closed after the
compressor stops.
2.8 Control to the Water Pump
The water pump firstly will run at the initialized speed and then adjust the speed according to the entering/
leaving water temperature difference. When the temperature difference is large, the fan runs at the high speed.
When the temperature difference is small, the fan runs at the low speed.
