Swapped a conventional system for a new Worcester boiler and changed every rad. After a week when the system was on a radiator was half cold so i bled lots of air. Then refilled pressure to 1 bar but it now zooms back to 0 bar overnight each time - but heating and hot water still seems to work. Didn't have pressure problem with old system. Searched for leaks but can't see one. Boiler firm say might be pipes for 2 rads in my lounge in a concrete floor so are coming to put new surface pipes in but i'm worried the problem will still be there and i'll have ugly surface pipes. Completely at a loss. Can i just leave boiler at low pressure or will i hurt the boiler? Do i just top up every other day for evermore? Is it something the boilermen did and can i expect them to solve it or is it my pipework and i'm stuck with it? Or have i hurt the boiler because i bled a radiator when the heating was on and, if so, what might be wrong with it?
