Prevent mechanical failures in the heating system

In many cases, mechanical failure is due to dirt or magnetite particles collecting in parts of the system, such as radiators, valves and other parts.


Getting to the core of the problem

Magnetite and dirt pose real problems for heating systems. Magnetite is a mineral that can occur in the water of heating or hot water systems. Over time, metal components corrode, releasing particles that are heavier than water. It’s often seen in the form of black sludge in radiator water, particularly in the lower parts of heating systems.

Something that can become a problem

Magnetite can settle in pipes, the boiler, system valves or even the pump. The sludge that builds up over time will eventually restrict flow or block water flow, potentially causing breakdowns. 

Handling magnetite issues the Grundfos way

Magnetite only occurs when there’s oxygen in the system, so the first step is to check for leaks. We recommend that water used in the heating system meets the requirements of accepted water quality standards, such as the German standard VDI 2035. 

Based on many years of circulator and heating system experience, we have built up a solid knowledge on magnetite and how much a pump installation can tolerate. Whether integrated into boilers, heat pumps or stand alone, Grundfos circulators are designed, constructed and tested to withstand magnetite and general dirt particles. During design and development, we have a dedicated magnetite test at our testing facilities. The overall design and construction of our circulators ensures resistance to impurities such as magnetite:

  • All bearings and shafts are made from ceramic and carbon materials, which do not attract magnetite
  • Flow conditions are designed to minimise large particles in the rotary can and ensure lubrication and cooling of internal components
  • To ensure a high level of protection against system impurities, the entire surface of the rotor is clad in stainless steel. 

To further protect against blockage some Grundfos circulators feature control functions, such as ‘automatic de-blocking’ and ‘summer mode’ to reduce the likelihood of problems. In certain circulators we also include a de-blocking screw that allows you to free a stuck shaft if severely blocked.

BENEFITS of avoiding magnetite in the heating system:

  • Reduce stress on the systems mechanical parts
  • Minimise start-up problems after seasonal downtime