Auto Air Vent Srew Cap Loose Or Tight !!!

[Invisible-Man]

Hi,
Seems to be a vast variation of opinion to whether the Auto Air Vent plastic screw cap should be left permanently loose or screwed tight after the initial pressuring of a combination boiler, to try and go with the majority what are your opinions today may I ask?

Many thanks

 

[kevplumb]

loose or it can't auto air vent

 

[ChrisR]

Loose.
Unless it leaks, then you can close it until you replace it as long as you check it frequently.

 

[Invisible-Man]

Wonder why Honeywell say to screw down tight afterwards?

 

[kevplumb]

Wonder why Honeywell say to screw down tight afterwards?

good point don't make any sense to me

 

[corgiman]

I always use a AAV like a thumb vent and tighten it after venting as the bleedin (no pun intended) always leak.

 

[Invisible-Man]

Wonder why Honeywell say to screw down tight afterwards?

good point don't make any sense to me

Thats what I thought, also when purchasing replacement today from proper boiler part shop (not plumber merchant) I asked the same question and was told to screw tight!

Like you say, it would not be an Auto Air Vent!

I did in fact go with an educated guess and used the leave loose option!

 

[Slugbabydotcom]

Wonder why Honeywell say to screw down tight afterwards?

good point don't make any sense to me

Well I didn't believe it and had to check it out on page 2 HERE

Where AAV's have been fitted in boilers I can't say I have seen one yet where it didn't say to loosen the cap. Maybe some of them do and I havent noticed.

 

[oilman]

I always use a AAV like a thumb vent and tighten it after venting as the bleedin (no pun intended) always leak.

I agree.

 

[Paul Barker]

Some boilers don't even use an aav which has a cap, or cap is not provided. Non state to shut it after initial use.

I think they should stick a manual vent on top of the boiler.

 

[dan the man]

yup it seems all different. some have caps, some dont. some say leave open some dont.

Do what u feel

If an exisiting istalation with no air probs i shut it,if new i leave it open to get rid of last bits of air.

 

[Chivas69]

I know this is an old thread
BUT
If I've closed one of these valves by mistake, and air has got into my system (by draining a pipe) , could this be the cause of my rads not heating up?
Cheers

 

[ALCPlumbing]

It obviously could be. Depends on the amount of air that entered the system. Are the upstairs radiators the ones that are cold. Are they hot at the bottom?