Vent screws

[george121212]

Hi I have two of what look like combi boiler vents in the loft. Do the black screws stay open or closed?

Thanks

 

[Exedon]

Automatic air vents installed in a loft I would always screw down .
In fact I would have installed manual ones much less trouble.

 

[george121212]

Thanks for the reply. What do they do??
Why would one want to have them unscrewed?

 

[oldbuffer]

1. They are automatic and work rather like the float chamber in a carburettor.
2. The bowl contains a float with a needle valve at the top. As long as there is air in the bowl, the float drops, the needle valve opens and air get out.
3. When water fills the bowl, the float rises and the needle valve closes.
4. They have a great tendency to clog, and dribble water out continuously. Screw the cap down to stop the leak.
5. As Exedon says, the manual ones are less trouble in the long run, as well as being cheaper.

 

[ianmcd]

They are supposed to automatically vent any air, but they leak for fun , once the system is vented I always close the cap, there are no good brands they are all cheap crap, as already advised manual ones a re much better

 

[george121212]

Thanks for the explanation.
It sounds sensible to keep them closed.
Do I need to open them to vent? If so how regularly? Or best to leave them closed?

Thanks

 

[ianmcd]

Thanks for the explanation.
It sounds sensible to keep them closed.
Do I need to open them to vent? If so how regularly? Or best to leave them closed?

Thanks

just open them when you drain anything , then close again when filled, if you get a circulation problem open the cap you will instantly hear if there is air in there