The Junkers boiler expansion vessel absorbs the pressure changes in the boiler due to the increase in water temperature when we heat it, thus preventing the maximum pressure at which our system can work from being exceeded and avoiding problems in our appliances or circuits and its wear due to excess pressure.

The pressure is determined by the safety valve. The normal working pressure of a heater is around 1.5 bar.

In case of malfunction, to check if the internal globe of the glass has been broken or punctured, simply act on the internal mechanism of the valve, exerting pressure on the core with a tool, for example a screwdriver, and check what comes out. air . If what comes out is water, it means that the internal membrane is broken and the water has completely filled the glass; On the other hand, if air escapes, the membrane should still be intact and it is only necessary to precharge the expansion vessel with gas or air again.

You can also check the pressure of the glass using the pressure gauge of a tire inflator. This process must be carried out with the boiler or installation empty of water so that it indicates the real air pressure.