where to fit an automatic air vent

[bobby_la_mesma]

I think you'll find that a forum is designed to reach many people and discuss the matter objectively. To get many answers and opinions e.g. the fact that the suppliers states one thing and you give another opinion.

Who's to say that the first answer given is not posted by a person who failed their plumbing course several times or is just a misinformed individual.

Thanks again for your insight? I would appreciate it further if you could stop posting here so I can continue to discuss the actual topic of the post!

 

[croydoncorgi]

If your boiler is GC number 47-311-71 (ie. a WB GREENSTAR 30CDi Conventional) I think YOU'll find that the 'air vent' referred to on page 10 of the manual you probably looked at is a pipe, not a valve!!

PS If it's NOT that boiler, what other 'WB 30CDi' are you referring to?

 

[bobby_la_mesma]

Hi

Thanks for further help. Yes you are right in what you said

"If your boiler is GC number 47-311-71 (ie. a WB GREENSTAR 30CDi Conventional) I think YOU'll find that the 'air vent' referred to on page 10 of the manual you probably looked at is a pipe, not a valve!! "

This is true but on the same page 10 it does say that an air vent is needed at the highest point on the system. Also, their web site for the same boiler shows an automatic air valve.

link

http://www.worcester-bosch.co.uk/index.php?fuseaction=product.detail&con_id=127781&detail_id=129082

This is why I'm confused and I just want to get it right while its drained, which I'm actually doing right this minute, to combine the vent and cold feed pipes.

I know from your opinion I'm being an idiot for keep asking, but I'm an electronics engineer so I can't draw from my own experiences to eliminate one or the other of the guidance notes.

Thanks

Rob

 

[gas4you]

The air vent that this diagram refers to is not one that is needed at the highest point in the system, but the standard air vent that is fitted on any indirect system on the flow to the hw cylinder after the zone valve.

This is just to eliminate any possibility of an air lock in the hw circuit as quite often the supply/flow to this goes 'back upwards' to the inlet tapping, therefore in theory creating a place for an air lock.

 

[bobby_la_mesma]

Hi

I should have done this first, but I've just called Worcester Bosh technical.

They agree with yourself not to fit an automatic air valve as the boiler will go into purge mode upon starting and vent all air in the system through its own self contained vent, inside the boiler.

Sorry for being an idiot and thanks for your help, all of you.

Rob

 

[croydoncorgi]

I think the WB illustration is wrong (differs from the Installation and Maint manual), or overkill, anyway. For practical purposes, all that's required at that point is (as G4Y says) a manual air-vent (abbrv 'AV') rather than an Automatic Air Vent (AAV). You'll notice the two diagrams have different keys for the same valve.

A key design requirement of the pipe layout for an open-vented system is that the pressures around the vent and cold-feed pipe connections are close to equal. This is SPECIFICALLY to prevent 'over-pumping' UP through the vent, or air being drawn down (actually, pushed down by atmospheric pressure) the vent.

IF your pipe layout approximates to the illustration, I'd be looking for a partial blockage where the cold-feed T-s onto the main Return (often happens!). Otherwise, there's a pipe layout problem.

 

[megawatt]

bobby_la_mesma: You originally asked about fitting an AUTOMATIC air vent (AAV) and everybody since has told you that you don't need one ... I also told you that the boiler you refer to actually has an AAV fitted (in the installation instructions which you've referred to).

If you'd asked about fitting a manual air vent the responses would have been quite different ... Fit as many as you like wherever you like!

But getting arsey with people posting free help for you isn't really a great way to get the best out of a forum

MW

 

[al-yeti]

muppet ----->cc

 

[Agile]

Who's to say that the first answer given is not posted by a person who failed their plumbing course several times or is just a misinformed individual.

The first answer was given by a staff service engineer from one of the manufacturers. Whilst he hides his identity and can be a bit touchy you as a householder should expect that he knows 1000 times more than you do and respect his advice.

Many householders who take an interest in their heating installations will quickly be able to realise just why an open vented system does not need an AAV !

Do you pay your solicitor or accountant or dentist and them go and pay another because you dont trust what the first has told you?

The professionals on this site are usually fairly obvious because of their consistant and well explained good advice, and they give it all for free too!

I like diagnosing faults from these postings because they are like crosswords, limited clues with cryptic words and the real answer is not always the obvious one!

Tony Glazier

 

[Dan Robinson]

Some people just won't be told

 

[croydoncorgi]

muppet ----->cc

& your point is???

 

[bobby_la_mesma]

Guys

Just to update you all. Changing the pipes around to a combined Vent and cold feed has stopped air being drawn into the system through the vent pipe. My system does not need any additional air vents, manual or automatic.

Thanks for the guidance, Sorry for the arguments

Rob

 

[megawatt]

Glad it worked out okay in the end