5. What is the cause of noise in radiators?

The heating system is often the source of noise in different forms and with different causes of its origin. The heating body itself is not the single cause of noise almost any time.
If it is represented by the sound similar to splashing or murmur of water, it is probably caused by incorrect venting of the radiator. Each radiator should be equipped with own bleeder plug and should be suitable inclined. Venting should be located at the highest point, on the opposite side to the valve. In older systems, the venting of radiators is designed by the reverse layout of bodies, which means that the highest point is at place of connection - next to the valve. In this way air can escape to the riser and to leave the system at the highest point. The new control valves that are controlled by thermostatic heads usually represent a larger obstacle than the classical closing valves. In case of a higher volume of air in the body, for example in repeated filling after repair, venting is slow, and often it is not successful to 100%. We can help using partial releasing of the valve thread and releasing the captured air. It is not good to neglect the venting of bodies. In addition to reduction of heat capacity, the increased risk of corrosion is threatened.

Methods of radiator venting:

  1. to the riser
  2. through vent valves
Spôsob odvzdušnenia radiátorov

Fizzle to hiss occurs very frequently. It is caused by high difference of pressure on control valves. The valves close water flow rate to the radiators depending on adjustment of thermostatic heads. When closing the valves, the flow rate cross section is reduced and in this way the difference of pressure upstream and downstream valves is also increased. In this way velocity of liquid flowing through the valve is increased. The correctly designed system must response to these pressure changes and to equalize the pressure changes through the control valves located on risers. If it is not the case, unpleasant hissing noise is generated that is very unpleasant and disturbing mainly in the nigh hours. Noise can be even more intensive in case when heating water includes air bubbles. Sometimes it is sufficient to open the valve more, some other time; noise does not disappear even in its maximum opening. The intervention by the expert is necessary for remedy of this phenomenon, the change of the system of differential pressure equalization is often necessary.

Tapping, knocking or scrunching are the noises that are most frequently caused by heat dilatation of the supply line. When heated, the pipeline is dilated, and if passages between individual floors or rooms have been bricked, without possibility of free movement of the pipeline, tension originates resulting in noise. This takes place on risers or branches intended for connection of individual bodies. Temperature of medium is changed here due to opening and closing of the valve during control. Remedy is not simple. During the building work, it is necessary to take into account the dilatation of the pipeline and to allow free movement for it. Additional solution of the situation is based on localization of problematic points and subsequent demolition of firmly laid pipelines and filling with flexible seating. In case of radiators, partial solution is based on the use of suspension cantilevers that allow movement in the horizontal direction.

Korad VKL

Ventil Kompakt left (VKL)
Korad VKP

Ventil Kompakt right (VKP)

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