Regulations on Cistern Overflows in Bathrooms

[FozzieBear]

Can anyone advise on the correct way to connect a toilet cistern overflow in a bathroom served by a 100mm PVC soil stack and no external wall. The toilet is close coupled so I cannot connect to the flush pipe but I am not sure if it is permissable to connect to the soil stack above the boss accepting the toilet outlet.
Can I attach an adhesive boss to the soil stack and with appropriate reducers connect the 20mm overflow pipe or do I have to use/make a trap to prevent smells feeding back up the overflow into the cistern?

Fozzie

 

[TicklyT]

The easiest way is to replace the syphon or flush valve with one incorporating an internal overflow.

 

[JohnD]

like this fluidmaster. you can just make out the white overflow pipe which rises up inside the cistern

http://www.screwfix.com/prods/50692...ngs/Fluidmaster-Toilet-Flush-Valve-Handle-Kit

It is also called a Flapper Valve. It gives a forceful and quiet flush.

 

[kirkgas]

Can anyone advise on the correct way to connect a toilet cistern overflow in a bathroom served by a 100mm PVC soil stack and no external wall. The toilet is close coupled so I cannot connect to the flush pipe but I am not sure if it is permissable to connect to the soil stack above the boss accepting the toilet outlet.
Can I attach an adhesive boss to the soil stack and with appropriate reducers connect the 20mm overflow pipe or do I have to use/make a trap to prevent smells feeding back up the overflow into the cistern?

Fozzie

you cannot connect an overflow to a stack as you have to know it is running, the only option is to change the syphon so it runs into the pan

 

[FozzieBear]

Thanks for the replies guys and for the link.
The previous tenant had tried to reseal the cistern with silicon so I have already had to change the donut so a change of the flush system seems a much easier option than faffing around with the overflow.
Fozzie