Toilet not flushing unless AAV pulled off

[burts]

I went to a toilet filling to the rim and going down slowly. Everything seems clear.

It's downstairs and has a small stack with an AAV. When the AAV is removed, it flushes properly, when re fitted it fills to the brim. Tried changing the AAV and it makes no difference.

 

[HERTS P&D]

Check your manhole for a blockage.

Andy

 

[burts]

I would have but I couldn't find one on the run. Its almost like an extension has been built over all drains.

 

[Newboy]

That's not good!

It's a blockage causing back pressure within the pipework - as soon as you remove the AAV the pressure is released and the pan empties.

It's time to start looking at the property boundary and working your way back towards the building until you find a route in

 

[burts]

Tell me about it, These days I am more of a heating installer and don't get involved with drainage but they are customers of mine. The main bathroom upstairs runs away fine as does every other appliance. I tried rodding down through the stack but the rod goes past the first bend and then it wont go no more and there is no drain in line where it leads out. There is about 3 different extensions.

 

[Newboy]

time to refer to drainage company?

 

[burts]

I will do if I can not locate a drain but I do not like being beaten. I will have another hour at it and see what happen.

 

[Newboy]

I know the feeling well!

 

[Hugh Jaleak]

Upstairs will work ok, its got a lot of pipework to fill and is probably vented so there isn't the issue with air displacement as there is on the downstairs when the AAV plugs the pipe! Manhole could be under the extension, its not unknown for a sealed cover to have been carpeted over....

Worth checking if the neighbours have problems, if its a shared drain then it's the Water Company's remit anyway.

 

[Mikefromlondon]

A similar problem occurred regularly where one of the adjoining properties g/f toilet wouldn't flush out speedily and the water would rise up to the rim and drain away slowly, on opening the MH cover located in the rear garden, water logging could be seen 3/4 way up, this common drain carries waste water for 2 properties on either side of it, so altogether 5 properties connected to it, and runs under the middle property from the rear to the front sewer MH that is then connected to the main sewer under the road. The blockage occurred in the pavement MH, and each time we had to call our water company (Thames Water) or at one time the local council became responsible and their lads would come and clear off the offending blockage until it blocked again in about 6 months, this kept happening until the TW relaid new drains and sewer pipes, the problem has since gone.

(Just thought this might help as the blockage may be not within the property but where the commoned house drain join the main sewer pipe on the street.)

 

[it's not that hard]

I had this problem in a downstairs wc in a new build,drains weren't blocked, left a hosepipe running down there for an hour,told them to refer back to the builders,there was no way either to redirect the pipe outside as there was no outside wall by the wc,

 

[HERTS P&D]

You could always get it jetted via the AAV section of pipe work.

Andy