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How to solve some most common heating issues

A maintained, well-adjusted and clean heating system will ensure cost-effective and carefree operation. However, if you neglect it, it may happen that radiators heat less, unevenly, or are noisy. Heating costs can then rise significantly without you knowing it, because the heating elements are suprisingly cold. Thermal comfort decreases, but the risk of a serious malfunction or accident, on the contrary, increases. Therefore, problems need to be solved in a timely manner.

Check out the five most common heating system problems and their solutions.

Aerated radiators

Aeration is the most common problem with heating. Although the solution is very easy, many people underestimate or do not vent at all. How does air even get into the heating liquid and what can it cause?

Oxygen is a natural part of water, so it is not possible to completely remove it. In this natural quantity, however, it is not dangerous for the health of the heating. Problematic is the air that gets into the heater during filling or through various connections and pumps. This air is undesirable and causes:

  • corrosion of metal parts of the heater,
  • worsened heating efficiency,
  • uneven heating,
  • cavitation noise.

Venting is done either manually using venting valves, or automatically with the help of air separators that are installed permanently, so you don't have to think about venting at all.

Non-ventilated radiators heat less, but more expensive. 


Corrosion significantly shortens lifes of heating systems and increases the risk of cracks, leaks and accidents.

The most common is the oxygen corrosion, which is caused again by air in the heating system. Solution is therefore regular venting of the system. Galvanic corrosion is then caused by the presence of different materials with different electropositivity. The entire system (radiators, pipes, joints, boiler) should therefore be built from a single material.

Microbial corrosion is the result of metabolism of microorganisms in the water. This problem is mainly present in heating systems with untreated water from their own sources. Therefore, water from a well or a borehole must always be properly treated before being used for heating.

Heating liquid of low quality

It is also necessary to focus on the quality of the operating fluid - specifically on its composition and possible types of pollution. In general, water contamination in can be divided into magnetic and non-magnetic.

Non-magnetic impurities is mainly scale. Scale is a heat insulator, its deposits reduce heating efficiency and limit the flow of water. Water hardness can be chemically adjusted, but only after professional consultation, as softening also affects pH of the water, which can lead to corrosion.

Magnetic impurities (particles of magnetite, metal chips, etc.) are naturally released from the heating system. You can remove it very effectively using a magnetic filter.

Another possible contamination is microbial contamination. Bacteria in the water create a biofilm, which, like scale, reduces the efficiency of heat transfer and clogs the individual components of the heating.

Seizing of a pump and other components

If water pollution in the heating system is not dealt with, your circulation pump may seize up, or control valves or heat exchangers of the boilers may become blocked.

In particular, modern low-energy pumps are very susceptible to this type of failure, as they contain a magnet. This makes the pump run more efficiently and reduces energy costs, but at the same time catches magnetic impurities that are present in the water. If seizing occurs, it is usually necessary to replace the pump.

Flamco dirt separator with magnet.

Leaking fluid

Especially after filling the system with water, it is necessary to check whether there are any leaks. However, re-check regularly during the entire heating season. Leaky joints cause not only damp spots and mold, but also air penetration into the heating system. And as we mentioned above, air leads to reduced heating efficiency and corrosion.

If the sealing problem is not fixed immediately, it will get worse and may even end in an accident. Therefore, if you detect a leak, call a heating engineer immediately, never try to repair leaking joints yourself. Unprofessional intervention could irreparably damage your heating system.

Five steps to a perfectly maintained heating system

Maintenance of the heating system is not complicated if you follow 5 basic rules:

  1. Don't neglect the heating system design. Heating engineer should design suitable construction materials and dimensions of the system and pay attention to the quality of joints and seals during installation.
  2. Always use magnetic filters for heating, which continuously clean the heating water of solid impurities. Clean the magnetic filter once a year.
  3. Before a heating season, vent all radiators, adjust the system and, after filling, check functionality and seals.
  4. During the entire season regularly check the temperature of radiators, pressure in the heating system and sealing of the joints.
  5. Never tamper with the heating system yourself. In case of problems, call a heating engineer.