Hi, I hope somebody can help!

I have an unvented system that constantly drops pressure. There are no visible leaks (3 years dropping) and a couple of so called plumbers have tried to no avail to fix it. I have to keep the filling loop slightly open to keep the pressure around 2 bar. If not it drops to zero within a day. My hunch is that it is leaking into the water tank, is this likely/possible? As there is no other leaks anywhere.

Help!!

Simon (Cheshire), November 2008

i dont think it will be leaking into it then matey ! the unvented cyliner is under a higher pressure [ prob 3bar ] so if there was a leak in the coil [causing the two to mix ]the cylinder water would push into the boiler system causing the boiler pressure to rise not fall !! understand me ?
what boiler do you have ?

matt, November 2008

Hi Matt

It is a Protea unvented system

Simon, November 2008

what type of cylinder do you have ... unvented mains pressure or tank feed [from loft etc] ?

matt, November 2008

Cheers for the quick response Matt

It is neither the underfloor (has been isolated) or the expansion outlet easily monitored. If it is leaking in the cylinder (as I suspect) would the hot water colour be tarnished as that is what the last plumber said?

Simon, November 2008

do u mean u have a sealed boiler system ? if you are losing pressure it can only be 3 things , a pipe/rad leaking [poss under the floor ], the relief pipe outside leaking or depending on the boiler model ,the boiler could be leaking internally

matt, November 2008