Pressure drop

[Scmitt26a]

Over a week would you expect to see any pressure drop on a Worcester Bosch 28 CDi? I have seen a very small drop over about a week after re-pressurizing the expansion tank and cleaning and re seating the PRV

 

[ianmcd]

the guage wil vary slightly depending what temperature the water in the boiler is at

 

[Blagard]

What do you call a very small pressure drop? Can you supply the figures?

 

[Scmitt26a]

The gauge read 1.5 bar when I refilled the system. It goes up to 1.9 to 2.0 bar when CH on. When CH off it now drops to about 1.2 bar. So nothing major but is this normal? Or is something wrong.