Quick one folks. I have a spare potable water expansion vessel kicking around our unit. Rather than skip it, I was wondering if I can use it for a sealed CH circuit? I know you can't do it the other way round but my understanding is potable water expansion vessels are built to a better standard, i.e. mould resistant membrane. What do you guys reckon? If in doubt I will chuck it in the skip but would prefer not to waste it tbh.