what about foam lining the plenum? Trying some of the foam flow adjusters is worth a try tho- air can do some pretty wierd things in a tube and slightly increasing or decreasing the pressure might help...
the screenshot shows heating on, not DHW.
regardless, if it's anything like the setup in the Carel, there are four places setpoint is stored-
User Mask
Timezone. Adding anything here overrides user mask
Fan mode/ weather comp (default for DHW is 50 btw). Need to go into the engineers pages for that.
and the App. In my experience the App displays the Usermask data *until* the unit is actually running?
Bedding is only for supporting the pipe and the diagram reflects that. If the pipes are shallow then there's another section to read w/ concrete casing or slabs over the top for protection?
are you reading the tank temperature off the controller, or off some other thermometer on the tank? Or the flow temp? Certainly on our iVT9 the flow exceeds tank setpoint so the top of the tank ends up quite a bit warmer than setpoint...
Do you actually see the tank actively heating to 50c or does it soak up a bit after shutting down @45?
the bubbling and splashing are both louder than the pump. Remember the pump (which is quiet already tbh) is sitting on a foam pad inside a sealed housing, under a double-skinned manhole cover...
that's the point, we *don't* put the render against the window, we already have the upright DPC there as a barrier...
edit: and remember also it's a check reveal so there's less exposed frame to work to