Baxi boiler valves

[schematicgnu]

Hey, im having a problem with a Baxi boiler which is constantly loosing pressure. It heats up water and radiators (only if thermostats are up high), but noticed under the boiler there is 3 valves... The 2nd one is what we've used to refill the system cos it dropped down to zero. On the loop pipe(?) both valves are now closed, but the main one under the boiler is still open along with the other 2.. is this right or should this be closed too?

Thanks.

 

[diesel_ltd]

your boiler needs to be between 1 and 1.5 bar when its cold if it keeps loosing pressure then its one of three things;

1. you got a leak somewhere?
2. your pressure relief valve is letting by?
3. your expansion vessel has lost it charge or split the diapham

post a pic of the pipes you are talking about