Hi. First I want to introduce myself my name is Mariano. I'm new to this boiler. The problem I have is with a Caldaia s30f boiler installed in a house with 1 radiant earthenware floor. The boiler turned off (cold) has normal pressure (1 - 1.5 bar) but after a few minutes of operation when raising the water temp (44c *) the pressure goes to about 3bar. When the boiler is turned off it drops immediately. To avoid working at that pressure, I open the drain valve, the pressure drops to 2 or 2.5 bar, but when it goes out, it drops too 0 or 0.5 and marks error E8. What can I do or what is the fault. Thanks in advance for taking the time