Float switches are the commonest type of submersible pump accessories and come in numerous varieties. A float switch is used to detect the water level around a submersible pump. As the surrounding water reaches a pre-set depth, the switch triggers the pump to start working. If the water drops below a further pre-set depth, the pump switches off and stops working.
The main advantage of float switches is that they ensure that the pump will never run dry. Pump motors in submersible pumps need to be cooled by surrounding water. Once the water is not longer there, the pump can overheat and break down. Standard float switches are mechanical, also known as the free moving pendant type. They consist of a micro switch within a polypropylene casing. These switches work when the pump is installed in a sump or a tank and has at least 300 mm of free space surrounding the pump so that it can work correctly. The switches are available with 3, 5 or 10 metres of cabling.
There are separate hose kits available for Grundfos submersible pumps in lengths of 7, 10 and 20 metres and all of 1.25 inch diameter. More sophisticated magnetic float switches slide within a tube that is coupled to the body of the pump. These are ideal accessories in those locations where space around the pump is limited.
Foam filters are vital accessories for submersible pumps as most models do not come with the attachment any more. Their purpose is to keep small debris out of the pump and to avoid damaging the pumping system. Pump operators sometimes cut out a standard piece of foam to fit in the pump as a filter. However, it is a better idea to buy the accessory outright to avoid damage. The Grundfos foam filter is available for use with the KP 150 and 250 Grundfos submersible pump models.
