The risk of magnetite in circulator pumps with permanent magnets

Xylem, Lowara, magnetite, pump, pipes, pipework
Magnetite build-up on a circulator pump.

Circulator pumps with permanent-magnet motors are at increased risk of magnetite build-up, which badly affects the efficiency of pumps and central-heating systems — according to Xylem. In extreme cases, system efficiency can be reduced by 10 to 50%, and the increased power consumption does not meet the requirements of ErP 2009/125/EC Directive, which is the driving force between the increase in the use of high-efficiency circulators.

According to Xylem, the problems stem from a permanent-magnet motor attracting magnetite unless, as part of the pump design, the flow of water is separated from parts that are permanently magnetic.

Chiara Musola, AWS global product manager circulators at Xylem commented, ‘To combat this problem, we would recommend the flushing of the system together with an inhibiter and a magnetic dirt separator. In addition, circulator pumps fitted with “anti-block technology” have the capability to separate the main flow of the transferred liquid from the permanent magnetic parts, meaning the pump will never be susceptible to blockages from magnetite or sludge.’

For more information on this story, click here: October 2014, 103
Related links:
Related articles:



modbs tv logo

Heat pump market represents a colossal opportunity, says BESA

BESA’s head of technical Graeme Fox said the heat pump market represented “an absolutely colossal opportunity” for suitably qualified engineers but warned that the industry would have “to rapidly scale up capacity and needed considerable investment in additional skills to deliver all these hugely ambitious targets”.

Mitsubishi Electric launches modular R32 e-series chiller

Mitsubishi Electric has launched an R32 version of its popular e-series chillers, available in 150kW and 180kW units. 

Calendar