Baxi Solo RS Pressure loss.....help??

[Gastel]

iv'e already rec'd help on a different problem...same boiler recently, anyway I have a baxi solo rs, sealed system with stand alone expansion vessel etc, noticed pressure drop on vessel and was having to top up every morning, replaced vessel and prv then boiler was overheating and cutting out, after investigation replaced faulty gate valve (by-pass) overheating problem sorted but pressure loss was still there! Doh...as house is drop fed d/stairs no obvious leaks shown thru ceiling, checked manifolds and everywhere else 10 fold anyway...nothing, so replaced vessel and prv again (peace of mind) and air eliminator which was passing water slightly, checked internals of boiler for any signs of leakage and bunged in a leak seal, now pressure loss is still there but only topping up once every 2 days......i'm selling house so really need to get this sorted, any help or ideas would be greatly appreciated,thanks.

 

[baxpoti]

Sealed system, if you keep putting water in it has to be going somewhere!

If you cannot find a leak, it may be, among other things, the primary coil in the cylinder,

 

[Gastel]

Did think about that but how would I know for sure? Think I might bung in another couple of leak seals & hope for the best......any other ideas would be appreciated,cheers.

 

[bster]

Is the system overpressurising whilst left over night or whilst CH is on and thus causing the PRV to open?

 

[Gastel]

No, don't think so....checked for dripping on PRV everymorning,what would cause the overpressurising if this was the case? The heating is off most of the night so don't think it would be the PRV, only other thing I can think of is the primarycoil on the cylinder like baxipoti said, is there a way I can test for this problem? Like some kind of dye inserted into the flow??