I am thinking my 5" Britannia boiler is in need of some descaling treatment. I am contemplating filling it with vinegar but have not done this before on such a large boiler. Does anyone have any words of advice - concentration of vinegar, duration of treatment, amount of washing out etc.? Thanks in advance, Barrie Purslow WarringtonUK MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.