Heating system pressure loss

jacksmidth

Hello,
My Buderus Logamax Plus GB172-14 from 2011 is constantly losing water pressure without any visible sign of leakage neither from inside the boiler or its connections nor outside like pipes, radiators etc. I need to top it up sometimes even two times a day, which makes me very anxious of a big problem. I have already checked the expansion vessel for proper pressure and internal leak. Apparently, this one has no problem and even the internal Membran seems to be okay. I bleed the entire radiators after each top-up, but every now and then, I observe bleeding air from one of the radiators which I have just recently installed. This summer I had some renovations in the house and so that I replaced two very old radiators with a new one, where I had to drain the whole system and filled it again after finishing my job. Although I meticulously top the system up, bleed the radiators and so on, the problem persists. I also checked the PRV, and there is also not a single sign of leakage. Could someone help me there to spot the issue and get rid of it?

jacksmidth

jacksmidth