How to check the pressure in the expansion tank

If large pressure oscillations occur between the cold and hot system during the operation of the boiler, for example: on the cold system the pressure is 1 bar, and when the pressure rises to 2 bar, you should check the air pressure in the expansion tank - you probably need to top up the air or replace the expansion tank, which must be done by a professional, i.e. a heating installer. The reason is that checking and pumping up the expansion tank must be done when the water pressure in the system is 0bar, that is, when the hydraulic connection of the expansion tank is separated from the heating system. The air pressure in the expansion tank of Mikoterm block boilers is factory set to 1.5 bar. This allows for proper operation of the system with water pressure of 1.2 bar 1.5 bar.

If the hydraulic installation is high and it is necessary for the water pressure in the system to be, for example: 2 bar, before filling the system with water, it is necessary to raise the air pressure in the expansion vessel to the same value - in this case 2 bar, so that the compensation of the increase in pressure due to the expansion of the water during heating would work correctly.