Control To The Compressor; Control To The Fan; Control To The 4-Way Valve; Control To The Water Pump - Gree LSQWRF35VM/NhA-M Service Manual

2.3.3 Control to the compressor

"First on, first off"/ "first off, first on" control indicates the numbered compressor which is started/
stopped firstly will then be stopped/started firstly.

2.3.4 Control to the fan

The fan will start when the unit is turned on and will stop when the compressor is turned off. During
defrosting, the fan does not work but will back to working when defrosting exists.
2.3.5 Control to the 4–way valve
At the cooling mode, the 4–way valve will not work when the unit goes for defrosting or the unit is off.
At the heating mode, the 4–way valve will work when the unit is turned on or defrosting quits.

2.3.6 Control to the water pump

When there is demand for any single unit, the water pump will start. When there is no demand for all
water pumps, the water pump will stop.

2.3.7 Control to the electric expansion valve

The electric expansion valve will be initialized when the controller is powered on for the first time.
After the compressor has been started, the electric expansion valve starts to adjust its opening angle.

2.3.8 Protection

Recoverable protection
◆
The unit will stop when it receives no signal from the controller. Once there is any communication fault
for any unit, all compressors of this unit will stop and then the water pump will follow.
Irrecoverable protection
◆
(1) Protection against high pressure for the compressor 1/2
When it is detected that the high pressure cutoff of the compressor 1/2 is tripped off, compressor 1/2
will stop immediately. If both compressors are closed, their fans will be delayed to stop. In this case,
the control panel will display an alarm symbol, which should be cleared manually for resuming normal
operation.
(2) Protection for the flow switch
When it is detected for some unit that the flow switch is opened, this unit will stop. When protection for
the flow switch occurs for all unit, all compressors and water pumps will stop.
(3) Fault of communication
When a single unit does not receive any signal from the controller, this unit will stop automatically. For
the unit with communication fault, when all its compressors stop and then the water pump will follow.
(4) Protection against phase loss/reversal
When there is phase loss or reversal for power supply, power for the main board will be cut off directly.
In this case, there is nothing for the main board.
(5) Protection for abnormal 4–way valve
When it is detected that the entering water temperature is 4°C higher than the leaving water
temperature and the leaving water temperature continuously goes down, the control panel will display this
fault.
Unit Control
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