DAB pump with filter or without – is the filterball set worth it
Pump DAB with filter or without – is the filterball set worth it?
When a customer is looking for a circulation pump for home heating, most of the attention is directed to power, energy class or mounting dimensions. A filter? For many, it is a secondary matter – something to be addressed "if needed". From practice, I know that this approach is the cause of unnecessarily shortened service intervals, premature failures and several times more expensive repairs. In this article, we will take a close look at what a filterball set is, how it works, in which cases it is really necessary and when a standard installation without a filter is sufficient – and most importantly, whether the extra cost for the version with a filter is worth it financially.
Why the cleanliness of heating water is so important
A circulation pump in a heating system is not a simple device – it works continuously, year after year, at temperatures ranging from cold starts in autumn to maximum performance in January. The internal rotor, bearings and seals of the pump are designed to work with relatively clean water. The reality of most older (and some newly built) houses, however, is different.
Heating water in a closed circuit contains various impurities:
- Magnetite (black sludge) – iron oxide (Fe₃O₄), which is formed by the corrosion of steel radiators, pipes and boiler heat exchangers. It is the most common and aggressive enemy of pumps.
- Copper and scale – coarse solid particles from old pipes, welding residues or mechanical impurities left during installation.
- Calcium and water hardness – in areas with hard water, calcium carbonate deposits settle on all hot surfaces.
- Plastic and rubber fragments – microscopic particles from seals, hoses or plastic fittings.
- Biological impurities – although less common in a closed system, they can form biofilms during long periods of inactivity or insufficient air venting.
These impurities circulate throughout the system. When they get into the pump, they abrasively affect the rotor and internal bearings. Magnetite is also ferromagnetic – it sticks to metal parts of the rotor, reduces the clearance between the rotor and the pump housing, and the pump gradually loses performance. In extreme cases, the rotor can seize completely – and the pump is beyond repair.
What exactly is a filterball set – construction and principle
A filterball set (sometimes also called a filter with ball valves or a mounting set with a filter) is a compact mounting unit designed for the installation of a circulation pump. In one unit, it combines:
- Two ball valves (shut-off valves) – one on the inlet and one on the outlet pipe of the pump. They allow the pump to be isolated and replaced without the need to drain the entire system.
- Filter body (mesh filter / magnetic filter) – the built-in filter medium captures solid impurities and magnetic particles (magnetite) before they enter the pump. Most filterball sets for DAB pumps use a combination of a mesh filter (fineness 100–300 µm) and a permanent magnet to capture magnetite.
- Seals and transition fittings – standardized connection (typically G 1½" or according to the specific pump model), suitable for all common pipes in heating.
The principle of operation is simple: water flowing from the return pipe into the pump passes through the filter medium. Coarse impurities are caught by the mesh, ferromagnetic particles are attracted by the magnet. The result – the pump receives significantly cleaner water than it would without a filter.
It is important to know where the filter is located in the set: always on the inlet side of the pump (i.e., on the return pipe of the heating circuit), not on the outlet side. This way, the filter is hydraulically correctly integrated and at the same time easy to clean – just close the ball valves, unscrew the filter cover and clean the mesh without draining the entire system.
Standard kit with flange vs. Filterball kit – a concrete comparison
Let's look at a specific example from the DAB pump portfolio. The model KIT with flange DAB.EVOSTA2 40-70/180 is a standard promotional kit, where you get the pump together with the mounting flange and shut-off valves – but without filtration. This kit is more affordable and fully functional for systems where the water is in good condition.
On the other hand, KIT with flange DAB.EVOSTA2 40-70/180 – FILTERBALL is an extended version of the same kit, where a magnetic-screen filter is added to the standard flange. The pump, performance, and energy class are identical. The difference is solely in the presence and protective function of the filter.
The price difference between these two kits in practice is in the range of tens of euros. It is not a sum that would ruin a household budget. The question is whether this investment is meaningful in your specific case.
Comparison table: Kit without filter vs. Filterball kit
| Feature | Kit without filter | Filterball kit |
|---|---|---|
| Shut-off valve on both sides | ✔ | ✔ |
| Protection against coarse impurities | ✘ | ✔ |
| Capture of magnetite (magnetic filter) | ✘ | ✔ |
| Servicing of the filter without draining the circuit | – | ✔ |
| Suitability for older steel piping | Risky | ✔ Yes |
| Suitability for new plastic piping | ✔ Yes | ✔ Yes |
| Higher initial investment | no | yes (~20–50 €) |
| Longer expected pump lifespan | Depends on water | ✔ Higher |
When a Filterball kit is really necessary
This is a question I address practically with every pump replacement. Based on experience from many customer cases, I know that there are situations where the filter is not a luxury, but a basic condition for reliable pump operation.
1. Older house with steel radiators and steel piping
If your house was built before the year 2000 and the heating system has never been completely renovated – meaning you are still using the original steel radiators, galvanized or black steel pipes and original fittings – the heating water is very likely heavily contaminated with magnetite. When you unscrew the flange during the replacement of an old pump and see a black oily substance, it is exactly magnetite. Without a filter, the new pump will end up the same way as the old one – only slowly and subtly losing performance until the rotor gets stuck.
2. Pump replacement after a failure caused by impurities
If the old pump showed signs of clogging (noise, thermal fuse, loss of flow) and during disassembly there was clearly sludge inside, installing a new pump without a filter is a gamble. The system is contaminated and without a filter, the new pump will be in the same condition within a few seasons.
3. Systems with domestic hot water (combination boilers, storage tanks)
In systems where the pump serves not only heating but also hot water heating via a plate heat exchanger, the requirements for water purity are even stricter. Impurities can cause clogging of the heat exchanger, which means both hot water and heating will fail simultaneously.
4. Areas with hard water and scaling
Certain areas of Slovakia (e.g. part of the Záhorská lowland, the central Slovakia region) have significantly harder water. Even though the system is closed and the water is nominally not refilled, with every bleeding or leak, new hard water with dissolved minerals enters, which precipitate as carbonate deposits when heated.
5. Systems with cast iron or mixed materials
Cast iron boiler bodies and older cast iron radiators are less dramatically affected by corrosion than steel, but even from them small metal particles and rust are released, which damage the pump bearings.
When a kit without a filter is sufficient
Of course, not every system requires a filter. There are situations where a standard kit without a filter is a perfectly sufficient choice:
- New construction with plastic piping (PEX, PE-RT, copper) – systems built after 2010, where the entire piping is made of plastic or copper and the radiators are aluminum or steel (not cast iron). There are minimal impurities and most of them are caught during the first system flush.
- System where an external magnetic filter is already installed – if there is a professional separator of impurities from another manufacturer (Fernox, Spirovent, Caleffi etc.) already installed on the return pipe (usually at the boiler), an additional filter in the pump flange is not necessary.
- Fresh complete system renovation – if the system was completely drained, mechanically cleaned (possibly chemically flushed) and filled with new inhibitor, the water quality should be at an acceptable level.
- Short-term temporary installation – a temporary solution for a season before a planned comprehensive system reconstruction.
Economic analysis: how much does the decision without a filter cost you
Let's do a simple economic analysis. We assume a standard single-family house with a steel piping system and old radiators.
Scenario A – installation without a filter:
- New DAB EVOSTA2 pump without a filter: approx. 130–160 € (kit with bypass)
- Estimated lifespan in a contaminated system: 5–8 years (instead of 15+ years in a clean system)
- After 7 years, pump replacement: +130–160 €, plumber's work: +50–80 €
- Total costs over 15 years: approx. 370–400 €
Scenario B – installation with a Filterball kit:
- DAB EVOSTA2 Filterball kit: approx. 150–200 €
- Annual filter cleaning (done manually, 15 minutes of work): 0 €
- Estimated pump lifespan in a protected system: 12–18 years
- Total costs over 15 years: approx. 150–200 € (no replacement needed)
This is, of course, a simplified model, but the basic economics are clear: the extra cost of the filter is paid back with the first saved pump replacement. We also don't include the saved costs of potential service calls, air venting after clogging, or resolving the consequences of a seized pump in the middle of the winter season.
Practical experience in the field – examples from customer cases
In my work in this area, I repeatedly encounter similar cases. Here are some typical scenarios:
Case 1 – Apartment building from the 80s, Bratislava: The customer ordered a replacement of the circulation pump because the old one had stopped working. When we disassembled the installation, the inside of the pump was covered with a compact layer of black magnetite – practically locking the rotor. The system had no filtration of any kind for the entire 35 years. We installed a new pump with a Filterball kit, and after the first two weeks of operation, we cleaned the filter – it had captured additional magnetite circulating in the system. After one year, the pump is still in perfect condition, and the customer cleans the filter himself once a year, during the heating season change.
Case 2 – New construction, plastic piping, aluminum radiators: The customer asked whether a filter was needed. The system was only one year old, with PEX piping and aluminum radiators. We recommended a standard kit without a filter, or the option to add a filter later. The water was clean during the first inspection. A filter is not a priority in such a case – but if the customer wanted peace of mind, we recommended at least a simple mesh filter on the boiler.
Case 3 – House after renovation, mixed system (old boiler, new radiators): This is a tricky combination. New aluminum radiators react with water alkalinely and release hydrogen (which is the cause of air venting problems). At the same time, the old steel boiler produces magnetite. The result – the water was full of mixed-type impurities. The Filterball kit was clearly the right choice. In addition, the customer received a recommendation to add a corrosion inhibitor and to check the water pH annually.
Filterball kit and backup power supply – a comprehensive solution
For those who want truly comprehensive protection for their heating system, it is also worth mentioning the extended kit KIT with bypass DAB.EVOSTA2 40-70/180 + backup power supply. This combination addresses two distinct risks at once: contamination of the heating water (filter) and power outages (backup power supply). In cases where uninterrupted heating operation is important – for example, in houses with stove inserts and water heat exchangers, where pump failure could lead to overheating – the backup power supply is as important as the filter. More on this topic can be found in the article Backup power supply for DAB pump – when and why to use it.
How to properly maintain the filter in the Filterball kit
The filter in the kit is not a one-time thing – it needs to be cleaned regularly. The good news is that every homeowner can do this without special tools or knowledge.
Filter cleaning procedure:
- Step 1: Close both ball valves in the kit (left and right). The pump is disconnected from the system.
- Step 2: Place a container or cloth under the filter cap. Carefully unscrew the cap of the filter body – usually a wrench or manual unscrewing is sufficient.
- Step 3: Remove the mesh insert and magnet (if included). Rinse them under running water or wipe off the dirt with a cloth. Thoroughly remove magnetite (black dust) – with a mesh filter, you can gently poke it with a brush.
- Step 4: Check the gasket on the cap. If it is cracked or worn, replace it.
- Step 5: Reinsert the insert, tighten the cap, and open the valves. Check the seal visually – are there any drops?
Recommended cleaning frequency: once a year (ideally at the beginning of the heating season) in new systems. In older systems with high contamination, the first two years every six months, until the system is "cleaned".
Filterball set and other DAB pump models
The Filterball principle is not exclusive to the EVOSTA2 model. You can apply the same logic to other models in the DAB range. For example, the pump DAB.EVOTRON 40/130 is an energy-efficient class A model suitable for smaller systems with lower head pressure – and the Filterball set is also recommended for it in older systems. The same applies to the simpler model DAB VA35/130 – this is a fixed-speed pump without electronic regulation, a cost-effective option for simple applications, where water cleanliness remains equally important.
If you are unsure which model is suitable for you, we recommend reading the article DAB EVOTRON vs EVOSTA2 – which pump to choose, where these two product lines are compared in detail. To correctly dimension the pump performance, visit the article What DAB pump performance do I need for my home.
Installation of the Filterball set – practical notes
The installation of the Filterball set is practically as demanding as the installation of a standard set with ball valves. A few practical notes:
- Filter orientation: The filter body must be oriented correctly – usually, the flow direction is indicated on the body (an arrow). Always install the filter on the return (cooler) pipe, before the pump inlet.
- Vertical vs. horizontal installation: Most Filterball sets for DAB pumps allow installation in both positions. With vertical installation (pump above the pipe), emptying the filter during cleaning is easier.
- Seals: Check that all seals (between the ball valve and the pump body, between the filter body and the pipe) are properly seated. New seals are usually part of the set.
- First start: After installation, open the valves gradually, check the sealing and bleed the pump according to the instructions. More about the installation process can be found in the article Installation of a circulation pump DAB step by step.
Most frequently asked questions (FAQ)
Do I need to clean the filter regularly, or is it a one-time thing?
The filter must be cleaned regularly – it is routine maintenance, not a one-time task. In practice, we recommend the first cleaning after 3–6 months of operation (to find out how much dirt the system produces), and then once a year at the beginning of the heating season. In older, heavily contaminated systems, cleaning may be necessary every 6 months in the first few years. Cleaning takes about 15–20 minutes and can be done by any homeowner without special tools.
Will the Filterball set also extend the lifespan of the boiler, not just the pump?
Yes, indirectly. The filter captures impurities before they enter the pump, but those impurities would otherwise circulate throughout the system – including the plate heat exchanger in the combi boiler, control valves, and the entire piping. Clean water reduces the risk of clogging the heat exchanger, reduces abrasive wear on all moving parts, and extends the life of the entire system. The Filterball set thus protects not only the pump, but also the boiler and the entire installation.
Can I install a Filterball set additionally to an existing pump without replacing the entire set?
It depends on the specific installation. If the pump is mounted with standard ball valves and unions, a filtered insert can be added between the union and the valve – but such a solution is more complicated and space-consuming. It is simpler to replace the entire set with a Filterball version when replacing the pump (or during planned maintenance). Therefore, when purchasing a new pump, it is always more advantageous to choose a Filterball set from the beginning.
Will the Filterball set catch limescale and water hardness deposits?
The mesh filter will catch carbonate deposits that have detached from surfaces (visible white or beige fragments). It will prevent these fragments from entering the pump. However, it will not prevent the formation of limescale on internal surfaces (boiler, heat exchanger) – for that, other methods are used, such as water treatment before filling the system (softening) or adding a limescale inhibitor. In areas with hard water, we recommend combining the Filterball set with chemical water treatment for the heating system.
The DAB EVOSTA2 pump has built-in protection – do I still need a filter?
Yes. The DAB EVOSTA2 has electronic protection against dry running and overheating, but it does not have mechanical filtration against impurities in the water. Electronic protection stops the pump when a problem occurs – but impurities in the system cause gradual wear, not sudden failure. The filter works preventively and in the long term, while electronic protection is only a last resort. These functions do not exclude each other, but complement each other.
Is the Filterball set suitable for low-temperature systems (heat pumps, floor heating)?
Absolutely yes – in low-temperature systems, filtration is even more important. Systems with heat pumps have a higher volume of water and slower flow rates, which means that impurities settle more. Floor heating also has very small pipe diameters, and any sediment causes local failures. The Filterball set is standard, not a luxury, when combined with a heat pump. For more information on selecting a pump for different types of systems, read the article How to choose a DAB circulation pump for heating.
Conclusion – Filterball set: a sensible investment with clear return on investment
After a thorough analysis, the answer to the initial question is clear: the Filterball set is worth it in most cases. It is not marketing – it is pure technical and economic logic. The additional cost compared to a standard set (usually 20–50 €) is paid back with the first saved pump replacement, the first saved service visit, or the first more thorough system cleaning that becomes unnecessary thanks to the filter.
If you have an old house, steel piping, cast iron radiators, or you are installing a pump after a failure caused by impurities – the Filterball set is not a question, but an answer. If you have a new build with plastic piping and the system is in good condition, a standard set will suffice, but the filter will not harm anything.
Decide based on the condition of your heating water. If you are unsure, take out the old filter or look at the water when bleeding – if it is dark and cloudy, the decision is clear. If you need help choosing a specific set, look at the products in the DAB category on atria.sk or read more professional articles in our Knowledge Centre, such as Common faults of DAB circulation pumps and their solutions or Cleaning and maintenance of DAB pumps – how to extend their lifespan.
Do you have a question about this topic?
Can't decide or are you dealing with a specific situation in your household? Write to us – we are happy to help.