Vailliant boiler pressure drop

[Tedd]

Turbomax VUW 242 / 1 E
System 4 yrs old
Losing 1 bar pressure over 48 hrs.
No radiator leaks, nor nothing.
Where is the pressure being lost???
Hot water pressure has steadily decreased over the years also???
Any help, much appreciated.

 

[andyman6]

should have pressure release valve piped outside, check for water at end of pipe, small drip could cause this in 24-48 hrs, pressure drop in hot water possibly scaled up internally especially in hard water areas