Remote Control 3 Phase Power Water pump

My friend has a pump that supplies his farm with water. The motor on the pump is 3.5kw and is 3 phase power. The pump fills a 5000 litre tank which lasts about a day. The on-off switch is roughly 1000m away from his house (no line of sight, lots of trees in-between). Recently, he wanted to know would he be able to connect it to the switch so that he can switch the pump on and off from home 1000m away? Why didn’t he choose remote control system to control the water pump?
I thought the method was feasible for him. So I suggested that he should buy a long range remote control system.
After several days, he showed me his device and installation.
With external extend antenna, this remote control unit can be long range controller. Transmitting distance is about 1000m. But how to remote control 3 phase power water pump? Besides the transmitter and receiver, we should prepare a relay which is applied to the pump, my friend told me. Here is the relay.

Let’s see how to install and operate.
Step 1, the relay should be connected to the receiver. Then three live wires are connected to the relay and power supply.
Step 2, another three live wires to connect the relay and water pump.
Step 3, power to the receiver. Pressing the big button of the transmitter, the receiver will receive an “ON” signal to instruct the reply and pump to pump water into the tank. Pressing the small button of the transmitter, the receiver will receive an “OFF” signal to instruct the reply and pump stop pumping water.