My R30 drops in pressure from about 2 Bar to zero in a few days and consiquently no hot water after topping up with the fill loop everything is fine No fault codes and the CH works ok. there is staining around the relief valve on the expansion tank could this be the problem?
either prv isn't seating properly leaking (see spit pipe outside) or if pressure rises over 3 bar when heating is on expansion vessel is u/s and excess pressure will vent off
