Ferroli sys 10-30 loosing water pressure

[Mikeycollins]

My 10 year old system is loosing water pressure. I don't detect any leaks, so far. I am hoping it is something simple. I am trying to locate where the pressure relief valve is situated, where should I be looking?

The expansion vessel is behind the boiler so if that has failed I take it that fitting an external expansion vessel would be simpler? Would I need a gas engineer to do that or a plumber?

Thanks for any help.

 

[ShaunCorbs]

would need a gas safe engy to repair the prv for you anyway so might be best to call one out