Heating System?

You have a leak, Nothing else would cause that problem, As it started shortly after the tank was fitted, check around that to start, wipe your hand around the joints, will not be much of a leak, as it takes months to drop, so very slight wet, look for signs of run down from the joints, Make sure all your radiators are bled of air. Check all 4 corners of radiators, even the blanking plug. But you have aleak.

SD
October 2011

find a new plumber, you need a heating engineer,the problem lies with the boiler ,a proper engineer will be able to pressure test the system,a fall in bar with the boiler isolated would indicate a leak in the piping network. hope this helps .

killerdanny
October 2011