Modena 80e combi boiler high pressure problem

The pressure on my Modena 80e combi boiler is normally just over the 1 bar level but lately it seems to be rising by itself!

It went as high as 3 bar yesterday - I bled some water from some radiators and the pressure went back down to 2 bar. When I looked again this morning the pressure was back at nearly 3 bar!

I have checked the filler "tap" and it seems to be tight off.

Help! Has anyone any idea what the problem might be and would running the boiler with high pressure cause a problem?

Thanks very much for any advice.

remove the silver hose to be sure

as said remove filling loop.

check expansion vessel.see faq

worst case is holed heat exchanger filling heating.

good luck getting the right 1 got 3 wrong 1`s last week.long leg/short leg etc.