Ferroli 77 FF pressure drop

Hi,

I have an old Ferroli 77 FF that has started playing up since we started using it this autumn. I pressure the system to the recommended 1 bar when the heating is off and the pressure holds steady. When the heating cuts in the pressure rises until it gets to 3 bar then the relief valve lets some water out. As a consequence, the pressure when cold is left at around 0.2 bar but the heating will still cut in. The whole system seems to be working fine apart from having to top up the pressure. I had a look in the manual to see where the displacer unit was but it says that it's an optional part, and on my boiler there isn't one.
My Questions are:
1, Why does the heating still work when there is virtually no pressure?
2, Why is the system going up to 3 bar?
3, Why is there no displacer on the boiler, should there be one somewhere else on the system?

Thanks in advance, Dave.

C'mon Dave, put your hand in your pocket & spend some of that moneyon a new boiler!!

Arctic Bob

you said it m8 AN OLD FERROLI they were rubbish when they first came out .