When Should You Use Bronze or Stainless Steel Circulator Pumps?

Posted On Posted on 28th June, 2022 by Don

Circulator pumps are typically required to move liquid around a heating or hot water system. Whilst there are many different types of circulator pumps, the main materials used to form the volutes and impellers are generally cast iron, bronze or stainless steel.

If your business operates circulator pumps on secondary hot water (the water going to hot water taps or into a manufacturing process), then it should be constructed from either bronze or stainless steel as these materials will not contaminate the discharging water. Unlike cast iron, materials like bronze and stainless steel are not corroded by water, which means it won’t rust and release contaminants into the water supply.

However, if you have a hot water primary pump, then these do not need to be bronze or stainless steel. This is due to the positioning of the heating system: primary pumps are connected to the heating side of the system (not the mains side) and therefore water quality and contamination are not a primary concern as they do not pose any risks to the users.


To find out if you have a bronze or stainless-steel pump, this can be identified by:

  • Checking the manufacturer’s model. Typically, they would have a B for bronze or a N for stainless steel in their coding.
  • Simply looking at the colouring of the volute. Stainless steel being a grey or shiny silver and bronze being a gold or metallic brown.
  • Using a magnet, you can test the volute (not the motor) to see if it’s magnetic or not. If it is not magnetic it is more likely to be a bronze or stainless-steel pump. If it is magnetic, it’s most like a cast iron pump.

If you need support or assistance identifying coding on your circulator pump, then get in touch with the Dura Pump team.

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