Thanks for all this everyone. The detail design of the dangerous bit (woodburner to thermal store, panels to thermal store, heat dumps etc) will be handled by others at installation time of that part of the system. Interesting hearing the discussions of the various different ways of emergency dumping excess heat- useful in case someone starts gilding the lily at install time.
The original question (DHW in plastic or copper)- I'll do the bits I'm on at the moment in copper and leave the tricky arsey wiggly connection bit to the HETAS approved installers.
The original question (DHW in plastic or copper)- I'll do the bits I'm on at the moment in copper and leave the tricky arsey wiggly connection bit to the HETAS approved installers.