Unvented cylinder discharge pipe location

purpleparrotuk

I posted a year or so back about the total messed up install I had of an unvented system. I can finally get this resolved. I’m having the cylinder moved from the loft into the airing cupboard. At present the discharge pipe runs down the outside side of the house from the loft.

Due to the move the discharge pipe would need to be run down the front of the house which I’m not happy with. So the installers say the pipe can be fed into the waste pipe under the bath.

Is this ok to do? I don’t want to replace one major problem with another. Does all the waste pipe need changing to heatproof? Also I see online it keeps mentioning the soil stack when doing this. Some bright spark before I moved in cut off the soil stack in the loft. There are valves on each toilet but the en-suite smells with shower badly now an again. I have read the correct tundish needs to be fitted to stop smells also from the waste.

Does the soil stack also need sorting out?

Jeepers_Creepers

I'm not sure about running the discharge pipe in to a normal waste - I just don't know. I'd have thought it would be ok, tho', since surely waste pipes would have to cope with potentially boiling water themselves anyway?

A tundish would be required here, tho' - that makes any sign of discharge visible. 

The soil pipe was cut in the loft? What do you mean - that it used to go through the roof but now doesn't? Is the soil pipe otherwise still 'active', or is it no longer used? If it's still connected to the sewer, can the cylinder discharge pipe be sent to it?

There are valves on each toilet - I presume you mean AAVs? A 'Durgo'? Does the shower waste gurgle in use, or after flushing the loo? I wonder if the AAV isn't allowing enough air in, so your shower trap is being emptied by 'suction' instead? That's a completely different issue to the new cylinder, of course. 

(Why were AAVs fitted anyway? I mean, why not fit a single AAV to the top of the soil vent in the loft?)

Can you trace where the en-suite smell is coming from? When the smell is there, can you stick yer nose over the shower drain, and then around the AAV. Is there enough water in the toilet bowl to fully cover the U-bend? 

purpleparrotuk

Jeepers_Creepers said:

I'm not sure about running the discharge pipe in to a normal waste - I just don't know. I'd have thought it would be ok, tho', since surely waste pipes would have to cope with potentially boiling water themselves anyway?

A tundish would be required here, tho' - that makes any sign of discharge visible. 

The soil pipe was cut in the loft? What do you mean - that it used to go through the roof but now doesn't? Is the soil pipe otherwise still 'active', or is it no longer used? If it's still connected to the sewer, can the cylinder discharge pipe be sent to it?

There are valves on each toilet - I presume you mean AAVs? A 'Durgo'? Does the shower waste gurgle in use, or after flushing the loo? I wonder if the AAV isn't allowing enough air in, so your shower trap is being emptied by 'suction' instead? That's a completely different issue to the new cylinder, of course. 

(Why were AAVs fitted anyway? I mean, why not fit a single AAV to the top of the soil vent in the loft?)

Can you trace where the en-suite smell is coming from? When the smell is there, can you stick yer nose over the shower drain, and then around the AAV. Is there enough water in the toilet bowl to fully cover the U-bend? 

Thanks for the reply. The sinks and shower trap do gurgle now and again. Sometimes when I lift the drain cover off the plug hole in the shower it stinks of poo very bad and gets very dirty. 

I will have a look at the soil stack in the loft and see if it’s capped off. I haven’t a clue why that was done. The cut off part still sticks through the roof. 

purpleparrotuk

So the soil stack that was cut off must have gone straight behind the main toilet. This has been capped off with a Durgo valve. Similar to the one in the pic I posted. 

Alter_ego

 Similar to the one in the pic I posted. 

I can't see the pic

purpleparrotuk

Alter_ego said:

 Similar to the one in the pic I posted. 

I can't see the pic

This is one on the downstairs loo. It normally has a cover on it. 

Jeepers_Creepers

It's hard to diagnose from this side of the screen, but are you saying that that cut-off pipe with the Durgo on it used to continue through the ceiling and meet up with the 'cut' one in the loft? If so, I can't understand why this would have been done - a properly venting soil pipe is far better than relying on a delicate flap valve like a Durgo. 

The drain cover in the shower - when you lift that off, can you see the water level inside. If you were to gently pour some water in there to 'fill it up' (ie, get it to normal U-bend level) would the poo smell stop? Ie, is the 'poo' smell coming up through that drain from further down the waste pipe, or is it just emanating from the 'dirt' that naturally builds up in the shower drain? (I suspect the former, since when I clean our shower drain - and pull out a huge rat's-nest of tangled hair... - it might have a whiff of general 'soilness' about it, but not of 'poo'. So I suspect that the poo smell is coming up from your sewer and isn't being sealed properly by the shower's 'trap'. 

As I say, tho', this is all guesswork. 

IF the shower/basin gurgles when you flush the toilet, then you definitely do have a problem of lack of soil 'venting'. In which case I suspect your Durgo isn't working as well as it should. But who knows what's been going on with your plumbing - why the vent pipe has been cut, why Durgos have been used instead, what sorts of issues have been going on for some time. Only a decent plumber on hand will likely work this out, I'm afraid. 

southcoastrgi

The discharge pipework requires a tundish, a "fanny trap" (the installer/merchants will know exactly what it is), this is connected to push fit waste pipe (not solvent weld pipe) then it can be run into the house drainage