I have a combi boiler that is letting by on the filling loop. Can stop it and is relatively gradual ( 1 bar to 3 bar in 4 hours).No easy way to isolate mains as stop cock isnt working properly. Also needs full drain down as filling loop has been put straight into flow pipework so no easy fix for tonight. My question is when the pressure exceeds a certain bar count will it automatically go through the boiler overflow pipe. Also will it do this if i keep the boiler switched off?
