The Grundfos CU200 electronic connection and control unit also provides the safe connection points between the solar array and the submersible pump and motor.   In addition, the CU200 has input control circuits for a pressure switch, level switch, radio telemetry on/off switch, or flow switch so that the pump can operate automatically to fill a storage tank.   When a pressure switch is installed and the tank is full, the float valve in the tank closes, the pressure builds up, the pressure switch switches and, the CU200 controller turns the pump off.   When the water level in the tank falls, the float valve opens, the pressure in the pipework falls, the pressure switch switches and, the CU200 controller turns the pump on.   The CU200 also includes a visual display which shows when the pump is pumping water, a visual display when the tank is full and, a “Fault” code if there is a problem.   Supplied with weatherproof cable glands, stainless steel screws in the cover, external on/off switch and a weatherproof cover to protect the electronics.

The CU 200 control unit is a combined status, control and communication unit specifically developed for the SQFlex system. Furthermore, the CU 200 enables connection of a level switch, flow switch or, pressure switch for automatic operation.

The CU 200 incorporates weatherproof gland cable entries for:

• power supply connection from the solar array,

• pump connection,

• earth cable connection,

• level switch, or flow switch, or, pressure switch connection.

Communication between the CU 200 and the pump takes place via the pump power supply cable. This is called mains borne signaling (or Power Line Communication), and this principle means that no extra cables between the CU 200 and the pump are required.  It is possible to start, stop and reset the pump by means of the on/off button located on the front of the CU200 unit.

The CU 200 control unit offers:

• System monitoring with visual displays,

• Alarm indication with visual display,

The following indications allow the operation of the pump to be monitored:

• Water reservoir is full (level switch, flow switch, pressure switch)

• Pump is running - sequential green arrows show movement,

• Input power in watts and killowatts, 

The CU 200 offers the following alarm indications:

• Dry running - (low water level which will stop the pump),

• Service needed in case of:

- No contact to pump

- Over voltage

- Over temperature

- Overload.