What is a submersible pump?

  • What is a submersible pump?
  • What type of submersible pump should I buy?
  • How does a submersible pump work?

What is a submersible pump?

A submersible pump is one that has to be immersed in water, and is normally used to drain water.  These pumps are used in situations that involve flooding, such as rising groundwater in cellars or basements, flooded boats, or flooded areas.

Submersible pumps come in different models, and they distinguish themselves mainly in terms of the water that needs to be pumped, for example, clean-water submersible pumps,  which are used for rainwater. Other models are dirty-water or wastewater submersible pumps that are able to process water that contains sand, soil, and residue, or heavy-duty models that can process even coarser materials such as large solid particles. The impeller at the bottom of the pump processes solid particles by cutting them up so that they can be easily drained.

Submersible pumps are supplied with or without a float, though a float is handy if the pump needs to switch on or off automatically. If a space has to be drained completely dry, this will need to be done manually. The pump has to be switched off in time to prevent it from running dry. Some models are fitted with both a manual and an automatic mode (float switch).

What type of submersible pump should I buy?

There are different types of submersible pumps that can easily be tailored to the type of water/fluids needing to be pumped. Situations may arise that make draining water difficult, but there is usually a solution. For example, if a space needs to be drained completely dry, a submersible puddle pump is perfect for the job. Sometimes these spaces are very limited in terms of size, and therefore special internal floats/float switches have been developed so that the pump can continue operating automatically. These pumps have also been kept small in size so that they can be placed in a sump pit.

Another specific model in this range is the saltwater submersible pump. They are often used on farms for draining faecal matter, and there are many additional solutions for problems involving these situations. Because faecal matter contains caustic substances that may affect the pump and its rubber seals,  these special submersible pumps are fully protected against these substances.

How does a submersible pump work?

The pump has a suction grid fitted to the bottom, through which water is drawn directly into the pump. The water is then transferred through the pump body to the delivery connection, through which the water can leave the pump. The delivery connection has a discharge hose or tube attached to it so that the water can be drained. The pump can be partly or completely immersed in water, because it cools itself with the water it pumps. As a result, running dry can damage a submersible pump. This is why no submersible pump is capable of draining a surface completely dry in automatic mode (using a float), but some models are able to do so in manual mode. They drain to the point that just a few drops need to be mopped up. In principle, it is the most simple model in this category of water pumps. The hose is screwed onto the pump, the plug is inserted into the socket, and the pump does its job, or starts as soon as the float is activated.