I have a Vaillant VCW 282E model,15yrs old.Recently I noticed the water pressure going down from 1.5 to 0 in less than 8 hours. Could it be due to a leakage (some pipes are under concrete) or could there be other reasons for this to happen. Heat exchanger replaced recently.What happens if I continue to put the heating on without refilling to 1.5 bar.Is there a reputable leak finder in Newham. Thanks

john, February 2010

check the saftey valve it could be leaking from there, if so the pressure vessel may need recharging and possibly the saftey valve replacing

daz, February 2010

I have a similar problem to John. Water pressure falls about 1 bar in 12-15 hours, then the system has to be topped up. I have examined all water pipe connections and radiators but found no leaks so the only component I can thik of next is the boiler There are no obvious signs of water leakage so could it be the heat exchangers, diverter valve?.
Any help would be greatly appreciated.

G.K., February 2010