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Is it dangerous to have it closed thank you for the replyIts meant to be slightly loose, to allow air to escape. However, as they nearly always leak after a while you often find them closed.
Oh ok mine has always been openOpen for filling / draining
normal operation closed
Reply to the thread, titled "Automatic air vent screw" which is posted in Air Sourced Heat Pumps Advice Forum on Plumbers Forums.
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