A mag filter, often referred to by other names such as magnetic separator, impurity separator, etc. - is a component of a heating or water installation, whose task is to capture metallic impurities circulating in the circuit. Most often these are magnetite particles, rust, and small pieces of metal (sometimes almost microscopic), which form as a result of corrosion of steel elements or general wear and tear of the metal components of the system. In practice, a magnetic filter very often also performs a protective function - it aims to stop the process of further system degradation, and in particular, to protect the more sensitive components of the system from these harmful particles.
An additional function of mag filters – known to only a few – is the possibility of introducing cleaning agents into the heating system through them (e.g. descalers or corrosion inhibitors), i.e. the so-called system flushing.
The basic construction of a magnetic filter is relatively simple, but very effective - provided that the basic element attracting metallic dirt is strong enough. This basic element is a magnet.
Therefore, a magnetic filter consists of:
The magnet is responsible for attracting ferromagnetic particles, while the housing design allows for the slowing down of the flow medium, which facilitates the settling of non-magnetic impurities as well, such as sand or sediment.
As a magnetic separator, the filter is most often installed on the return of the heating installation, before the boiler, heat pump, hydraulic coupling, or heat exchanger (heat exchangers are devices quite prone to clogging). Its task is to protect sensitive installation components from mechanical wear, clogging, and a decrease in efficiency. Regular removal of magnetite significantly extends the lifespan of the entire system - as well as individual components. Pumps are less prone to failure, heat exchangers are less likely to develop leaks, and boilers maintain full efficiency for longer.
An approach increasingly encountered among installers is using the magnetic filter to flush the installation. It is used during the initial system startup or when servicing older installations. During flushing, the filter intensively collects deposits, sludge, and fine impurities that have been detached from the pipe walls. This makes the cleaning process more effective and safer for the other components of the installation. Afterwards, the filter is often left in the installation, because unfortunately the process of system aging only intensifies over time, so the process of flushing the installation (old or worn) should be repeated cyclically.
The use of a magnetic filter as an impurity separator directly translates to:
In modern installations, the magnetic filter is no longer an add-on but becomes a standard protective element of the entire system. However, it is most recommended to install a magnetic filter in open systems.
Recommendations for installing impurity separators for gas boilers andheat pumps are also often encountered.
Every element inserted into an installation causes a certain pressure drop – this also applies to a magnetic filter. However, hydraulic resistance is generally marginal and does not have a significant impact on the system. Of course, unless any harmful circumstances occur, meaning resistance can increase for several reasons:
The dirtier the magnetic separator / impurity separator is, the greater the resistance it presents to the flowing water. However, generally, with proper selection, appropriate installation, and servicing – hydraulic resistance at a level that negatively impacts the installation should not occur.
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