Plumbing

Boiler loses pressure but never goes below 0.1 bar - ?

Anonymous user 03/03/2024 - 2.57 PM

Vaillant Ecotech installed Dec 2010 has always lost pressure but only once lost enough pressure to trigger an error. No matter how well we bleed radiators and refill the boiler, it always drops back down to 0.1 bar. Heating continues no problem at this pressure. We've had a plumber out twice to investigate with no progress so far. No drips from pressure release pipe (had a plastic bag over it for a week). No leaks from radiators and no obvious leaks in ceilings/floors. Logic dictates there's a leak somewhere, but where? And why not lose pressure completely? Any insights would be very helpful. Thanks in advance.