These pumps are designed to work with clean liquids. The impeller can exist of bronze, iron or plastic material. These pumps are designed to work with temperatures at 80° to 120° Celcius. When the impeller is directly mounted on the motor shaft, the water pump can handle a flow up to 300 m³/h and for differential heads of up to 100 m. The casing can hadnle pressure up to 10 barg. The motor output exceeds 20 kW and can be over 100 kW.

Motors like this require lifting facilities. Close coupled pumps rely on the motor bearings to absorb axial thrust and radial loads. When the pipework has enough rigidity, it's possible to mount a smaller vertical compact pump directly in the pipework. A larger vertical compact pump has a foot to rest on. When the pump is mounted, it's important to make sure the motor isn't located under the pump.

Other than close coupled pumps, pump with bearing brackets don't have the same restrictions on suction pressure and sealing arrangements. The coupling between the pump and the motor is used as a baseplate for horizontal units. These units are slightly longer than the equivalent compact close coupled pump but more versatile.

Heating water pump

The heating water pump has a relatively low noise and vibration level. The pump has a noise level of approximately 25 dB(A) in a private house, up to 65 dB(A) for pumps in an insulated machine room. These different pump requirements are covered by:

• Heating circulation pumps, for central heating systems. All rotating parts are sealed within a stainless steel can. The stator windings are placed around the outside of the can and the rotating magnetic field passes through the can wall. The bearings are usually ceramic lubricated by the hot water, so no seals are necessary. Pump casings are usually cast iron or aluminium alloy with bronze or stainless steel impellers.
  
• The twin-pump packages, a pump casing with two built in pumps as a unit. The pumps can be operated for parallel or series operation. The pumps can run independently or together, because the unit includes a non-return valve system.
  
• Hot water-pumps for circulating domestic hot water in larger systems, so that the hot water is almost immediately available when opening the tap. The parts that have contact with the liquid are made of bronze or stainless steel. Both wet and dry motors are available.