Plumbing problem: foul drain smell in kitchen after using upstairs en-suite

grumbler

Lorian said:

Also check the Air Admittance valve is actually pulling in air when the on-suite toilet is flushed. 

MikeJXE said:

Looking back at your query, in my opinion Dyno Rod back up my theory that the upstairs bathroom is sucking out the sink trap due to a faulty air admittance valve

Yes, on second thought I think this can happen, although far less likely on the ground floor than on the first floor.

diystarter7

SarahB1 said:

diystarter7 said:

How long have you been there?
Have you noted the smells since mivig in?
Or have you had recent alterations, and or new toilet/basin fitted etc

Are you 100% the stench is coming from where you think it is? As it times it may be another place

do the smell happen with hot and cold water?

If its only hot water it could be a rat/etc is dead lying against a hot pipe/etc and speaking the smell.

Many years ago and I posted about this a couple of weeks ago - we lived in what is called an up and over pre 1900 mid terraced house in London - massive house, split level ground floor, mid and upper levels. At times around the smae time of the day there was a stench between the door to the dining room and gas/elec cupbaord under the stairs. I though there was damp we could not see or dead rate etc under the floorboard. The stench happend as i said around a certtin time about 5/30 6pmish but oly in hot waether.  

We had a bathroom and toiet and a toilet upstairs and in hotter weather small windows were left open to cool the house.
Then I thought I'd close the windows and see if hot smell arrived around the usal times it did not - tried a few times could not work it out and then went outside - it was next door cocking fish and their extractor was at the back of the house and our open windows where in the U shape gap between the up and over houses and we were getting their fish smells land in the lowest parts of our hose and as the door was closed there and small space the smells gathers. There was me thinking it was a dead rat/drains etc.

So smell around with you nose and ask others to help to IF the exact location of the smell and when it happens EG turn on/this and the other is it hot/cold/etc

Thanks for this - the smell only arrives after we use the en-suite, either flush the toilet or use the sink/shower

I'm no expert but its the set up/piping in the ensuite I'm almost 100% sure about this.
whatever they did with the pipes, must be wrong.

Try using the basin alone one day, see it that results i smell
Then the toilet the next day and as above
then the shower and as above

If its just the one easier to resolve if its all three then the problem is lower down the pipes imo

Eldi_Dos

@SarahB1 try filling bath and sink in ensuite with cold water and go to kitchen sink area and get someone to pull plug in bath and sink then flush toilet at same time. While you are in kitchen listen and look under sink, can you tell if water is being syphoned from u bend under sink or adversely backing up and putting foul water into dishwasher outlet hose.
If you could post photo of pipework under kitchen sink it would help.

MikeJXE

Have you checked the sink trap as in running water into it after flushing the upstairs toilet ? Also if someone stands with their ear to the sink they might hear the water in the trap being sucked out. Plus remember there are plumbers and there are plumbers 

SarahB1

Eldi_Dos said:

@SarahB1 try filling bath and sink in ensuite with cold water and go to kitchen sink area and get someone to pull plug in bath and sink then flush toilet at same time. While you are in kitchen listen and look under sink, can you tell if water is being syphoned from u bend under sink or adversely backing up and putting foul water into dishwasher outlet hose.
If you could post photo of pipework under kitchen sink it would help.

@sarahB1

Thanks, I will give it a go.

These are photos of under the kitchen sink

SarahB1

Lorian said:

MikeJXE said:

Looking back at your query, in my opinion Dyno Rod back up my theory that the upstairs bathroom is sucking out the sink trap due to a faulty air admittance valve

I'm thinking when the on-suite was updated they maybe bypassed it - and when it got replaced recently it was still bypassed

The main bathroom was updated, the en-suite hasn't changed (I am just trying to think of what has changed that may have caused the issue).

The air admittance valve has been replaced although it is worth checking that it is working OK.

Jonboy_1984

Does the main soil stack pass through the roof and open to the sky? Have you considered if it has a blockage and not breathing properly?

(Should be able to look down it with a torch, and wash it out with a hose if leaves etc stuck in it).

SarahB1

Jonboy_1984 said:

Does the main soil stack pass through the roof and open to the sky? Have you considered if it has a blockage and not breathing properly?

(Should be able to look down it with a torch, and wash it out with a hose if leaves etc stuck in 

Thanks - no, the soil stack goes onto the loft

Apodemus

SarahB1 said:

Lorian said:

MikeJXE said:

Looking back at your query, in my opinion Dyno Rod back up my theory that the upstairs bathroom is sucking out the sink trap due to a faulty air admittance valve

I'm thinking when the on-suite was updated they maybe bypassed it - and when it got replaced recently it was still bypassed

The main bathroom was updated, the en-suite hasn't changed (I am just trying to think of what has changed that may have caused the issue).

The air admittance valve has been replaced although it is worth checking that it is working OK.

As mentioned above, if the plumbers installing the new bathroom somehow managed to re-run the pipes so that only the new bathroom (and not the en-suite and kitchen) were connected to the air-admittance valve, that could cause the problem, but it seems unlikely. 

I wonder if your initial presumption was correct and that the en-suite's air admittance valve is indeed behind the tiling and that the bathroom is on a separate system? The bathroom may be a red herring here.  It is entirely possible that the easiest way to install the en-suite was by extending the kitchen drainage up rather than the bathroom drainage across.   Are you able to trace the drainage pipe work to see?  

grumbler

The easiest way to check if the air admittance valve is at fault is to remove it temporarily and to see whether the problem persists.