What do you mean? are you talking about the water pressure? if so then you need to use the filling loop and bring the pressure up to about 1.5 bar max then bleed radiators of air and then bring pressure back up to 1.5 bar. But why have you lost pressure maybe leak or faulty pressure relief valve. You need to supply more info. If not sure then get a plumber!
daz71, November 2008
