Went to replace the broken pressure gauge for this boiler in Kingsbury London. Further investigation reveals more serious issues. Cracked main heat exchanger and split expansion vessel is the two sides of the same coin. Fan bearing was shouting at my ears, So the air pressure switch is not going to be very happy about it quite soon. Replacing the expansion vessel going to kill my knees & break me back since the boiler is two low to work with. Perhaps external expansion vessel is the easier and cost effective option. Repair or replace, well I leave it for the client to decide. Heat exchanger alone is odd £ 250 without even fitting it…….