Air trapped in system (advice please)

[ian-d]

Hi all, just signed up hoping for some assistance, so hopefully I can explain clearly enough.

We had problems with water rising to the top when flushing the toilet, which would then return to normal levels within seconds. Having explored further, I noticed water was remaining in the back of the shower, so had assumed a blockage further down. The noise of "glugging/gurgling" could be heard from the toilet when using the washing machine downstairs too.

However, when the plumber came out, he confirmed it was actually a problem with air pressure, and used an example where by he removed the plug from the shower and flushed the toilet, no water came up and it was working fine. He said that there was no blockage (didn't check) and that water should remain in the shower basin (below the part you stand on).

He checked some kind of air pipe in our loft and assumed the auto vent (which stops the smells leaking out!) wasn't working, so would get a replacement part. When that arrived, he removed the old one and tested the toilet and it worked fine, but when adding the new part, the same problem arose again.

The only assumption he could come to was that not enough air was getting into the system (think that is right) and the only solution will be to have a hole drilled through our outer wall from the loft, with some kind of air pipe installed. He said that something within the air system a number of houses share (we are detached!) must have changed which is why the problem appeared so unexpectadily.

What I cannot get my head around is why this is only affected the en-suite toilet/shower and not the toilet/sink/bath in the other bathroom, or toilet/sink in the downstairs cloakroom, or the kitchen.

Does what he has said make sense, or should I get someone else in to check? I'm just concerned that drilling a hole through the outer wall is an extreme measure to "force" more air in compared with doing the same through the existing system in the loft.

Hope someone can help.

 

[SimonG]

Sounds like a dodgy air admittance valve, which you say is in the loft. The only thing I would say is that although a new one has been tried, according to your post, just because something is new and out of box doesn't mean it will work. Have any neighbours had any plumbing/building works done recently? I can't remember the exact number but I think you can get away with only vented 1 stack in 6 to atmosphere. I'm sure somebody will correct me if I'm wrong.

 

[ian-d]

This is true, I could ask for them to try another valve just in case, as drilling through my outside wall is the last thing I want them to do! I don't understand how pulling air in from outside would be any different than from within the loft space, which isn't restrictive really.

Does it sound like air pressure is the problem, as I cannot work out why it would suddenly change and cause problems in the en-suite, yet not cause any issues in the other bathroom/cloakroom/kitchen?

 

[ian-d]

Any further help from any plumbing experts on here? Getting desperate to resolve before the plumber phones back to book in drilling holes in my house.

 

[SimonG]

Ian,

Your plumber is trying to do away with the air admittance valve and venting to atmosphere hence hole through wall or roof, can't do this into roof space smells gases etc,. Try another AAV and go from there.

Good luck

 

[ian-d]

Hi SimonG, so from what I have said, you think what the plumber has recommended makes sense, although trying another AAV first would be recommended? Is there no alternative to a hole in the wall should the AAV not be the issue, i.e. it couldn't be a blockage, or a trapped air pocket or something?

 

[SimonG]

Ian, Always difficult to say without seeing. But you said you had an issue, he removed AAV and the issue disappeared, replaced AAV and problem was back. Have any neighbours had any work done lately?
Could be worse, did a new build a few years ago, bison beam floor, and I priced waste pipework above finish floor level, he supplied all materials, top floor bathroom wouldn't work and stack had loft space AAV. I took AAV off and stack full of water. Went out to manhole and stack had never been connected underground. Turned out that the stack had been moved from back to front of house, builder used old drawings I used new. Somebody had driven piece of pipe into ground to identify where new stack went, and then builder filled hole in with 8 barrow loads of concrete. Took three days to fix.

 

[ian-d]

SimonG, nightmare situation but I guess given that mine seems to work ok without the AAV on that a blockage further down is less likely. No one around seems to have done any work, so don't think it is that. Would removing the AAV for a few hours possibly resolve the situation, albeit providing a shocking smell into the house, or does it sound like a problem only fixed by action by the plumber? I noticed when the kitchen sink was firing water out last night it didn't smell too nice, but I guess that would be normal anyway in such a situation; the toilet also brought a small amount of 'product' back up if you know what I mean!

 

[SimonG]

Ian, Maybe more to it then if it's coming back on you. I would expect the issues mentioned in your first post with the AAV not working correctly. Try for a while without it and flush toilets, run sinks etc., to see if everything works ok. Simon.

 

[philtheflush]

i wreckon there is a blockage somewhere if he hasn't looked thats the first thing to look for

 

[jase158]

Not being funny, but none of what he said has made any sense to me, "Air from other houses affecting your house" ????
Personnaly i would ask him more about why he thinks it is not a blockage first. I always start with a blockage and work my way round.

How ever, That said, He was there and he has been doing it for a while, so maybe he knows that it is a air problem.

 

[ian-d]

I might have got the wording wrong, so apologies, but he came to the conclusion by mentioning that a number of houses in a row on new developments often share and that probably only one house has a air value to the outside of the house; presumably he means sharing the drains or something, I don't know, but did ask me if I know of anyone doing any work, so I assume you'd be able to gather from that what exactly is shared.

No check for blocked drains was done, he just looked at it all and said water will stay in the shower outlet/pipe and when removing the AAV in the loft, there wasn't any sign of problem with water rising in the toilet, but as soon as a new AAV was installed, the problem was there again.

I really don't want a hole drilling to the outside of the house and cannot understand why it would be needed if the system had worked absolutely fine for 4 years until now. I'm really stuck!

 

[WaterTight]

As suggested before you can come to conclusion easy enough yourself. Remove the AAV yourself. Then flush toilets, run showers, empty sinks, do everything and monitor. If no problems occur his solution might be the only answer. If problems still occur there may be more to it and you could present him with reasons for your doubt.

 

[yorkieplumber]

tottaly agree with above, air admitance valves are ok, but you still need a vent into the atmosphere somewhere on the system, you cant beat the old way ie vent outside.

As suggested before you can come to conclusion easy enough yourself. Remove the AAV yourself. Then flush toilets, run showers, empty sinks, do everything and monitor. If no problems occur his solution might be the only answer. If problems still occur there may be more to it and you could present him with reasons for your doubt.

 

[fagsanbooz]

yes agree with watertight and yorkie, most modern developments use a soil stack system where 4 houses have AAV fitted in loft and 5th one has 'open vent pipe' to atmosphere (this is assuming it has been done properly). If 5th one has been 'modified' by 'capping off' or aav fitted then there is a lack of air for rest of soil system and underground drainage system to work effectively.
Do as watertight said and maybe check with immediate neighbours to see if they have any problems, also look up at roofs to see which house has the 'open vent pipe'.

 

[stevetheplumber]

i hate durgos they make the drains stink when you lift a manhole on an old victorian property if theres no blockage theres very little smell as the open vent ensures air flows through the drains
go to a new developement and lift a cover and the drains realy hum

 

[ian-d]

Appreciate all the comments guys and will be removing the AAV this weekend when I have the chance to run everything, washing machine, toilets, shower etc.

All that confuses me is why this problem has only just appeared after 4 years, and why no one else nearby is suffering from any problems, and why it isn't affected the whole house, just the en-suite and kitchen sink. Is there any kind of logical reason for this?

I had also thought about trying another AAV, just in case the new one the plumber tried was faulty, but I don't know!

 

[jase158]

I am A bit confused with the replies, How would the houses be joined / affecting each others house if the houses are detached, Unless it was underground?

and as above, wouldn't this be affecting all pipes and all houses in the row if it is because of this?

This problem make a lot more sense now, There is not enough air getting into the Soil Pipe. And this is why he says drill a hole through the wall.

Bit of a silly idea, But if they are connected underground, couldn't you drill holes into the outside pipe, meaning there will be air getting into it? lol. may mean a leak every time it rains hard, but saves the hole in the attic.
My point is, isnt there air getting into the underground drain?

 

[mredd]

Sounds like a partial blockage further down the line possible off of your property.

 

[kay-jay]

firstly i'm assuming that that as the problem only affects your en-suite that your w/c's are connected to seperate stacks.

the plumber was right in telling you that water should remain beneath your shower, this is simply a water seal to prevent the smell from the drains rising into your house. he was also correct in advising you that a possible cause of your problem is a combined underground waste system with only one external vent pipe. to answer your question about this ...if you live on a block and you are the furthest house from the one with the soil termination to the outside then you will be the most likely to suffer with pressure problems. however if the system previously worked fine and no neighbours have had any alterations done to the drainage system and at least one house is vented to the outside (which personally i suspect) then you really need to rule out a partial blockage.

as i see it, when the aav is removed and your w/c flushes fine it doesn't necessarily mean that there is no partial blockage it may simply represent the fact that an open pipe vents more efficiently than a aav, which in itself will vent efficiently enough providing there is no blockage. simply rod the soil pipe of the offending stack while the aav is removed, then refit the aav and try flushing w/c.

if this doesn't resolve your issue then unfortunately extending your soil pipe to vent outside is going to be your only option.

good luck and let us know how you get this resolved!


regards

KJ

 

[ian-d]

Right, I think I might be making some progress. I have two drain covers in my front garden (parellel to each other) which say "Osmadrain" on them. I managed to remove the threaded screws and there is a clear plastic protector inside the drain, which I presume is to stop stuff going down, and maybe prevent smells coming up. The one furthest away which heads downhill (kind of) is clear, but by looking through the very small hole that has been made in the plastic (not easy to see through it despite being clear) on the one closest to the house, it looks like there is tissue (maybe nappies - not ours) in the hole that points towards the side of the house with the en-suite, the rest of the pipe looks clear.

I ran the sink and shower and went to check, but nothing was coming through, so either the water doesn't go through that drain? or it is completely blocked up!

Does this sound like the right drains (appreciate the limited info)? Can I remove the clear plastic cover or should I leave it to the experts? I don't really fancy putting my hand down there, I've not had my dinner yet!

Still doesn't explain why the plumber didn't look and why the toilet appeared to work ok when the AAV was off.

 

[franz]

Dont put your hands down there,weilers disease.
Baby wet wipes are a pain because they dont dissolve quick enough same as other toilet wipe products.
Best get your plumber back ,he has the kit.

 

[fagsanbooz]

Right, I think I might be making some progress. I have two drain covers in my front garden (parellel to each other) which say "Osmadrain" on them. I managed to remove the threaded screws and there is a clear plastic protector inside the drain, which I presume is to stop stuff going down, and maybe prevent smells coming up. The one furthest away which heads downhill (kind of) is clear, but by looking through the very small hole that has been made in the plastic (not easy to see through it despite being clear) on the one closest to the house, it looks like there is tissue (maybe nappies - not ours) in the hole that points towards the side of the house with the en-suite, the rest of the pipe looks clear.

I ran the sink and shower and went to check, but nothing was coming through, so either the water doesn't go through that drain? or it is completely blocked up!

Does this sound like the right drains (appreciate the limited info)? Can I remove the clear plastic cover or should I leave it to the experts? I don't really fancy putting my hand down there, I've not had my dinner yet!

Still doesn't explain why the plumber didn't look and why the toilet appeared to work ok when the AAV was off.

Could be a seperate system of drainage! wwhere one does all your soils and wastes and the other does all the guttering and rainwater particularly if it's a modern development.

 

[ian-d]

Problem appears to have been solved. Was convinced the drain was blocked following looking down the manhole so called my home insurance as I have included emergency cover; the guy from homeserve had a look and pulled out a rock coated in toilet paper which had got wedged in the hole. No idea where that came from, but it is a new build and we had already dug up a full wheel barrow, spade and hard hat from the front garden! Anyway, toilet is flushing well and no more noises...happy days!

Going to phone the original plumber tomorrow and tell them they completely dismissed it being a blocked drain and were about to have me spend hundreds of pounds on drilling through my house wall to the outside! They better not try and charge me for the AAV they fitted or time spent getting it wrong! (obviously appreciate that these things are complicated, but he did dismiss drainage being an issue from the start and wouldn't look despite my asking!)

Thanks for all the help on here, appreciate all your comments, it helped me resolve this so thanks again.

 

[philtheflush]

first thing always to look at is a blockage in any case, glad you got it sorted