Table of contents
- Expansion tank - function
- signs
- membrane rupture
- Wrong size
- Wrong pressure
- Leaking valve
- Wrong gas
The expansion tank of the heating system fulfills important tasks. If it is defective, this can result in several problems. Regular maintenance and repairs can prevent problems with the expansion tank and thus with heating.
Expansion tank - function
The expansion tank consists of a chamber divided into two areas by a diaphragm. One area is filled with water that can be fed to the heating system. The other has gas. This is usually nitrogen, as this can prevent corrosion.
When water is heated, its volume increases. This moves the membrane. The gas is compressed. If the temperature decreases again, the volume of the water also decreases. The membrane moves back and the gas has more room to expand again. This also allows water to flow back into the heating circuit. However, this is not possible in the case of defects or other problems.
signs
Signs of a defective expansion tank or problems in the surge tank include:
- "gurgling" noises
- escaping water at the safety valve
- significant pressure fluctuations during heating
- lack of heating power, only slight warming
- cold or unevenly warm radiators
membrane rupture
A rupture in the membrane between the chambers, which are filled with water and gas, is particularly problematic. Because in this case, the two substances can mix and the heating power drops significantly, while the pressure fluctuates greatly.
Changing the membrane is not possible. Instead, the entire expansion tank must be replaced. An installer should be consulted for this. However, the container can also be replaced by yourself if the correct procedure is observed.
Wrong size
If the wrong size was 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 important:
- amount of heating water
- operating temperatur
- response pressure
A corresponding vessel can already be purchased very cheaply. Prices range between around 30 and 100 euros.
Wrong pressure
The working range of the expansion tank must be adjusted correctly. Otherwise problems may arise. For the working area, it should be considered that this 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 in the Usually offered directly by the manufacturers and designed for the respective heating system and the pressure expansion tank are.
If the operating pressure is too high, water will escape from the safety valve. In addition to the dripping valve, a clear sign of this is that there are high heating water losses and the system has to be refilled accordingly.
Another problem in the area of pressure can be the already mentioned minimum pressure. This leads to:
- noises
- Decreased performance
- shutdown of the boiler
Just as with an incorrectly set initial pressure, the container can also fill up, so that no there is sufficient space if heated heating water is included with a larger volume must become.
Leaking valve
The purpose of the safety valve is to prevent excess pressure if necessary and to drain water for this purpose. For this purpose, the valve is opened from a certain pressure and the pressure is released.
However, if the valve is leaking, 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 gas section, it can corrode the metal in the event of 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 tank should therefore always be filled with nitrogen.
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