The heating system's expansion vessel fulfills important tasks. If it is defective, it can lead to several problems. Regular maintenance and repairs can prevent difficulties with the expansion tank and thus with heating.
Expansion vessel function
The expansion tank consists of a chamber that is divided into two areas by a membrane. One area is filled with water that can be fed to the heating system. There is gas in the other. This is usually nitrogen, as this can prevent corrosion.
When the water is heated, its volume increases. This moves the membrane. The gas is compressed. If the temperature drops again, the volume of the water also decreases. The membrane moves back and the gas again has more room to expand. This allows water to flow back into the heating circuit.
However, this is not possible in the event of defects or other problems.Signs
Signs of a defective expansion vessel or difficulties in the pressure equalization tank include:
- "gurgling" noises
- leaking water at the safety valve
- significant pressure fluctuations during heating
- lack of heating power, only slight warming
- cold or unevenly warm radiators
Membrane tear
A tear in the membrane between the chambers, which are filled with water and gas, is particularly problematic. In this case, the two substances can mix and the heating output drops considerably, while the pressure fluctuates strongly.
It is not possible to change the membrane. Instead, the entire expansion tank must be replaced. An installer should be consulted for this. However, the container can also
can be replaced if the correct procedure is followed.Wrong size
If the wrong size has been selected for the pressure equalization tank, the pressure cannot be equalized accordingly. In order to calculate the correct size, the design of the heating system must be taken into account. In addition, the following factors are also decisive:
- Amount of heating water
- operating temperatur
- Response pressure
A corresponding vessel can already be purchased very cheaply. The prices range between around 30 and 100 euros.
Wrong pressure
The working range of the pressure equalization tank must be adjusted correctly. Otherwise problems may arise. For the working area, it should be taken into account that it is at least 0.3 bar above the minimum pressure. Otherwise, negative pressure can occur, which can have a negative effect on the entire system.
Tip: Apps or PC programs that are included in the Usually offered directly by the manufacturer and designed for the respective heating system and the pressure equalization tank are.
If the operating pressure is too high, water will escape from the safety valve. A clear sign of this, in addition to the dripping valve, is also that high
There are heating water losses and the system has to be topped up again and again.
Another problem in the area of pressure can be the minimum pressure mentioned above. This leads to:
- Noises
- Reduced performance
- Shutdown of the boiler
As with an incorrectly set pre-pressure, the container can also fill up, so that no There is sufficient space if heated heating water is taken in with a larger volume must become.
Leaking valve
The safety valve is used to prevent overpressure if necessary and to drain water for this purpose. For this purpose, the valve is opened from a certain pressure and pressure is released.
However, if the valve is leaky, water will escape even at a significantly lower pressure and no corresponding operating pressure can be built up.
Wrong gas
If there is oxygen in the section for gas, this can lead to corrosion of the metal in the event of a leak or a leak. This in turn results in weak points and defects that can result in costly repairs and the purchase of spare parts. The gas container should therefore always be filled with nitrogen.
