Can you use a soil manifold without a WC?

[timbeam]

I'm in the process of planning a kitchen install and I have access to a soil pipe where an old toilet was.

I'm hoping to use a soil manifold to connect the kitchen sink, washing machine, dishwasher etc but won't be connecting a toilet to it.

Is it ok just to cap the top of the soil manifold off so the waste connections can still be used? Or would it require an air admittance valve?

Thanks for the advice.

 

[Madrab]

Is the current setup for the old toilet a stub stack with an AAV or is the pipe vented? If it is a stub then you would probably get away with anti vac traps on the outlets and cap the stub. If it's vented then you need to check your soil/drain system will still be properly vented.

 

[timbeam]

Thanks for the reply Madrab.

To expand a little on what I said above, the toilet that is going to be removed joins the foul drain through the floor. The drainage system is quite extensive with multiple foul and rain water drains going into it - it's a combined system since the house was built in 1920s.

There is a vented soil stack that enters the system but it only services one toilet directly (not the toilet that is getting removed) and then enters the drain also. I hope that makes sense?

 

[Madrab]

There is a vented soil stack that enters the system

Yep, that's exactly what was needed. Your soil/drain system needs to be vented both for positive and negative pressure, an AAV will only vent negative pressure. Therefore if that stub was the only vent then it's would be a problem to cap/aav it, given the soil/drain run has a full vent to atmosphere then the small stack you are looking at could be sealed and then just use antivac traps to remove the chance of any waste water runs pulling on the traps and causing gurgling/self syphoning.