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WaterTight

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Did I hear someone on here say that if bunging the vent and feed of a tank you should also make sure automatic air vents are closed? Is this true? I thought air would only go one way with them.

If it's true how do you close them? And also, presuming you might not find all of them - do they constitute much of a risk?

Or did I mis-read and they were talking about something else you must do when bunging? And if so, what would that be?

Thanks
 
WaterTight said:
Did I hear someone on here say that if bunging the vent and feed of a tank you should also make sure automatic air vents are closed? Is this true? I thought air would only go one way with them.

If it's true how do you close them? And also, presuming you might not find all of them - do they constitute much of a risk?

Or did I mis-read and they were talking about something else you must do when bunging? And if so, what would that be?

Thanks
Click to expand...

Once the pressure in the system drops the float in the vent can drop so your system won't be bunged, and will allow air in.
 
Gotcha, so how do you close them? Not touched one before. I see some are sold as demountable for maintenance.
 
Well yeah. I remember working in a loft with my old boss and he installed one in the far corner, in what would normall be pitch black, behind a tuft of loft insulation, because that was the highest point that part of the installation..
 
best to fit them in visable possitions as they tend to leak and need changing.
 
Ok. Two questions still remain. How do you turn them off / shut them off? And when using bungs do you hunt through every inch of pipework in loft etc to find them all or take a punt?
 
they have a cap on them, most look like the black valve cap on a bycle tyre, just screw it down,
i think on open vented systems they dont need them as air vents through the vent pipe, may be one on top of the boiler. with cealed sytems with pipe work in loft u will probably just have to trace the pipework untill u find them
 
Ok cheers. So with a vented system a cursory peek around the loft and in the airing cupboard would probably suffice?
 
When you hve bunged the system and think you have closed all the AAVs you still need to release the system pressure before you go cutting into any pipe. You release system pressure by attaching a hose to drain valve and letting water out, if the system is successfully bunged the flow from the drain valve will gradually slow down and stop after about a minute, if not, air is getting in somehow and the system is draining.

Please feel free to ask any questions about bunging the system as it is something i do all the time

Sorry about the typos, just finished my first bottle of wine for the evening
 
As stoke mentioned your average well designed/installed open system should not have or need AAV's, but a few problem systems may have had them fitted to cope with the odd airlock. Just have a quick butchers round the pipework then fire away with your bungs. Sometimes the black caps have been completely removed. If I change an AAV I keep some of the old caps for times like this. Or you could just stick a bit of bluetack over the relief hole.
 
morning gents. need to bung my F&E TANK. what type of bung do i buy . someone did say an expanding bung [comes with a wing nut?] is safes tto use. soemone else said a parsnip!!
 
Gassmanxxr1,
Do you bung a system when you work alone? I've seen some posts that recommend having a bucket buddy on hand.
The tip about releasing the system pressure is a good one, too; makes a lot of sense, after all cutting into a pipe is a BIG commitment (-:
I've not tried it yet, I understand the theory well enough but it's that first time nerves that get me. It's like an aircraft flying, you can see it, but really it's just magic that keeps it up!
TerryH
 
Yep i work alone mate. The best thing to do first off is crack open a compression joint if poss, if you get a gusher then just tighten it up.

After you've tried doing it a few times and have confidence you will be glad about all the time saved and airlocks missed
 
GasmanxxxR1 said:
Yep i work alone mate. The best thing to do first off is crack open a compression joint if poss, if you get a gusher then just tighten it up.

After you've tried doing it a few times and have confidence you will be glad about all the time saved and airlocks missed
Click to expand...

this is what I do, but remember on certain pipes you might have a little bit of water. if it is on a seperate drop with no drain valve for instance
 
I worry about bunging tanks, the reason for this is.

1. they might pop out if there is reverse pressure or if not in properly
2. F & E tanks are dirty and last thing i want to do is get my self covered in muck before i have even started work.
3. cold water tanks are clean and don't want to contaminate it with my dirty hands
 
Thanks for all the useful tips, gents.
On Saturday I have a trv to fit, so will try bunging the system (vented) first. I've copied out all your advice..... so heart beating rapidly and attempting to look confident, I'll give it a try.
I'm reluctant to drain down because the boiler is an old Potterton Flamingo, which will probably never work again once disturbed. ): and as you all say, it's an awful lot of work for one trv.
Say a little prayer for me!!!!
TerryH
 
Hi TERRY - i have a big thank you to say to all the pros / experienced guys on here. I recently bunged my open vented system yo chang etwo rad valves . the same job that you are doing on saturday. Yes, I was nervouse also!! this is how I bunged. But I am in no position to advise!! but this is what I did and it worked, appropriately shaped potato 9a slim potato not a fat one in the expansion pipe. I then used masking tape a few wraps round to get a good seal. In the feed pipe I put the top of a silicon sealeant tube!! The lid you screw off before you use the sealant.. Now this lid was kind of "splined" on the outside, so i got a wood chisel and chiselled off the "splines" If you get a lid without the splines obviously you wont need to do this! after chiselling off the splines, I found that it fiteed into fee hole perfectly! The bung held while change the rad valves. I even left the bung in for a week to show my mate what I did. The bung did not hold absolutely water tight, but all it was was a very slow drip .I easily fitted my rad valves, even with this very slow drip. But best thing to use , to bung both expansion and feed pipe is probably a cork or rubber bungs - if you can find any round the house!! I couldn't. it you happy to spend money, its called a "drain easy kit" aat the plumbers merchants - someting like £15 at plumbase!! a lot of money for two rubber bungs!! all the best mate. Nigel - firs timer - and thanks again to the pofessional for taking their time to input into these forums.
 
not many open vented systems have aav's mate as they should be designed out
 
did not turn on the central heating while bunged. However, the boiler was used to heat water for showering. Does the expansion pipe, [the one that drops over the F&E tank] act for the hot water also [in addition to the central heating]? I also have an expansion pipe dropping over my cold water feed tank, and this expansion pipe appears to come into the loft from a ceiling hole in the area of the bathroom.
 
Thanks again.....
Nijjy, well, my mind boggles! :D Thanks for the advice. I'm using a 22mm speedfit end-stop on the vent pipe and have a choice of conical bung or expanding bung on the F&E tank, I'll see what the connector looks like. The sealant top could be good in an emergency, provided it isn't one of those with a pre-drilled end !
Fuzzy, thanks. I know what you mean but being a great pessimist I'm going to have a quick check. You're right, the vent to the F&E SHOULD be the highest point and therefore any AAV's should not be needed in an open vented system.

I have NO intention of leaving bungs in for a week :D
Thanks, gents,
TerryH
 
By the time you lot have decided which size bung to use and whether to use a carrot, potato, piece of beetroot or whatever wouldn't it have been quicker to have drained the system?
:ninja:
 
might have been, but the government are asking us not to waste water! I am also thinking , if you close valves on all rads that you are not working on, then the only water u lose is that in the pipe work, in the F&E tank, and in the rad that you ARE working on, right? so prbably , what 6 - 9 buckest full??
 
i'd leave the valves alone unless they are new'ish. turn off a bunch of valves and i bet one of them leaks on re-filling.
 
watertight, thanks for that, will bear it in mind for any future work. on a different matter, I noticed that my cold water tank [in loft] is not covered. No lid or any type of cover. I did put some clean cardboard over it actually. are cold water tanks meant to remian uncovered? Look at the dust that could fall in over time. Lofts are dusty areas. [In fact my [much smaller] F&E tank has a polystyrene cover. any comments on this?
 
nijjy said:
watertight, thanks for that, will bear it in mind for any future work. on a different matter, I noticed that my cold water tank [in loft] is not covered. No lid or any type of cover. I did put some clean cardboard over it actually. are cold water tanks meant to remian uncovered? Look at the dust that could fall in over time. Lofts are dusty areas. [In fact my [much smaller] F&E tank has a polystyrene cover. any comments on this?
Click to expand...

Tank should be covered, to protect from birds, bugs and I believe diseases (not sure about diseases).
me and my brother made one out of wood. but don't use mdf or ply woiod as these deteriate over time, obviously plastic is better with a hole for vent to slot into.
 
Well I've found (and posted up on here a photo of) a very dead rat in a CWST. So my advice would be to make a better job of a lid than a bit of cardboard!!!

PS - the rat was like sludge, and when I syphoned the water off, I hoovered it up.....hope no ones eating while reading this!!

Oh and yes Jase it should really have a vent too.
 
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