Or you could simply fit a 3 bar Caleffi PRV , once the system hits 60 psi the water will return to tank
Did anything ever become of your heater panes?
I sold a grand total of 2 in the end , I didn’t bother to push it at the time as Covid made it really hard to get all the bits to make it .
It has had a total revamp now , more compact and a lot more heat .
I’m now in the process of adapting it to heat hot tubs and run central heating
Other than that I now work part time on the windows and make garden statuary the rest of the time , but that’s another story