poor you and the Op was asking for opinions and no Sunvic is not the choice of most professional installers, we all have our preferences but few would say that Sunvic would be their first choiceThe original post mentioned 'cylinder', from that I would expect vented anyway. However I wasn't responding to that post, rather the one which I actually quoted discussing Sunvic units -where I expressed my own experience of them which was entirely relevant, informed appropriate and accurate. Sunvic's actuators are no better, no worse than many of the other spring return units on the market - they all of poor reliability.
My first post here and already you are insulting.