Hi, I have sealed system with Keston boiler and I have the system pressure set to 1.8 bars when cold (2.4 bar when hot). I know that it is much higher than the recommended 1-1.2 bars but the only reason I’ve set it to be so high is that if I set it on recommended pressure (e.g. 1 bar) I can hear gurgling noses in few radiators. When I increase the system pressure to 1.8 bar the noises disappear. My questions are: Is it a problem to run the system on such high pressure or if not can you suggest how can I make it run quietly at normal pressure? How much the expansion vessel air pressure shall be set to? The Expansion vessel is at the top of the system (at the airing cupboard) and the air pressure is set to 6psi when system pressure was 0 bar. The bypass valve is fully open and the boiler doesn’t have an adjustable temperature control only few thermostats which shut down the boiler if water heats to 80 degrees. Thanks you four help.