Anyone know what this pipe is?

[Redhotferrari]

Hi Guys,

Please have a look at the picture, does anyone know what the hell the pipe is coming out of the top the waste pipe to the basin?

Background - Its in my parents house which is about 35 years old, the whole estate they live on was plumbed in plastic pipework when they were built, not just under the floor, I mean the whole house!!

Anyway, as you can see by the picture, where the trap connects to the waste pipe, the waste pipe is open at the top, and the pipe entering the top of it a 15mm (approx) and in plastic, this pipe has to elbows on right up under the basin, down to the floorboards and follows the waste pipe under the bath and obviously joins the main soil on the other side of the bathroom.

My question is what is it for!!! Never seen anything like it before, was thinking it might be somekind of vent, but only guessing!

Do not ever get any smells coming out of the waste pipe either which seems a bit odd as its open at the top, cant see down into it to see how far down the smaller pipe goes without taking sink etc off.

Hopefully one of you knowledgeable poeple can enlighten me?

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[doitall]

Could be the waste pipe from a saniflow at one time.

 

[WDIK]

sink overflow?

 

[Redhotferrari]

Afraid not, parents have lived in the house since new and nothing like this has ever been fitted, this pipe and the waste is as old as the house.

Thanks for having a go though!!!!

 

[Redhotferrari]

Not the overflow either, it does not connect to the basin in anyway shape or form! The basin has been replaced a couple of times over the years and the overflow is part of the basin!

Previous plumber that changed the basin had no idea what is was either!

 

[mrgas]

Anti vacuum pipe?

 

[Redhotferrari]

Who knows!!! Do not really know where it goes, but it follows the waste back to the soil, so assume it enters it at some point, will not know for sure until I start ripping the bathroom out they want changing.

Ideally dont want to leave this in place as it looks awful, know its difficult to say as dont know what it is, but do you think it could cause problems removing it?

Current waste runs above the floorboard and want to re-route and run new under boards and into soil with a strap on boss, if the joists run the right way!!

 

[tonybhoy]

Probably a back vent.If it is it should connect to the soil somewhere above the basin but usually in the loft if the bathroom is upstairs.

Only place I've seen these (domestic) is in Wimpey houses with internal bathrooms.

Having said that the pipe looks like 22MM or 3/4 inch which is overflow pipe.

 

[Redhotferrari]

Thanks Tony, not an internal bathroom or Wimpey house, but thats not to say its not what it is.

Will have to find out where it goes, the soil is all boxed in so maybe it follows the waste until it gets to the soil, then up into the loft.

If its a back vent, what is it and how does this work? Can I remove it whe replacing the bathroom?

Def not overflow!

Really appreciate your thoughts

 

[tonybhoy]

It ensures that the basin trap doesn't lose it's water seal.

Usually fitted if the basin is about 2mtrs away from the soil so what you have is basically have a loop of pipework.

You can fit an anti-syphon trap which will do the same job or you may have to fit an air admittance valve (similar to a Durgo valve)somewhere close to the basin in a similar way to the existing back vent if that is what it is.

Or do what most other punters do and just fit the basin to the waste and to hell with the rest

 

[Redhotferrari]

Anti-syphon trap it is then!!!!!

Basin is about 3.5 mtrs away from soil and on opposite wall.

Thanks for clearing that up for me.

Cheers