Thanks - and we clocked your lid from this very useful topic, so will be asking for a new lid on Monday. We're a (hopefully) certified Passivhaus heated by low temp underfloor and have two Dual 4 PCM34s alongside the 12, heated by a low temp Daikin and primarily used for pre-heating the water heading for the 12 which is solar/electric heated, but also for the underfloor subject to some issues being clarified. One thing we were trying to find out, so far unsuccessfully, is whether Sunamp have any similar deployments, but maybe some one here will have a similar set-up.