Search the forum,

Discuss DIYer - need help with toilet pipe air-valve install in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Messages
13
Hi,

New to the forum - hoping to get some help here.

I am rerouting my toilet to have the pipe work hidden in the eaves.

IMG_0337.jpg


Bath/shower/basin waste connects to the toilet drain via Barco Bos.

I need help with the air vent.
- Do I need one for toilet, and another for shower/bath/basin waste?
- Do I need one for each bath, basin and shower?

Where is the best location for the air valve (or valves)?

Many thanks for your help.
 
Is the stack vented to outside air or is there another stack on your system that vents?
What is a Barco Bos?
What size is the waste float picking up the bath & shower & how long is the run to the bath?
 
I fink op means a strap on or glue boss to put the 1 1/2 inch waste into the 4 inch. If its inch and quarter ..uck. chking
 
Boxing and run to the right off the toilet
 
Gents, thanks for your replies.

Yes, perhaps not the most logical approach but I'd like to try before giving up. This will make space available that was previously unavailable.

The bos (or boss) connects the 40mm on to the 4 in pipe.

It is not going uphill - there is a drop of about 450mm from toilet outlet to outside stack. Is this sufficient?

The stack can be vented outside, but will it take care of the basin/bath/shower pipe venting?

Adding rodding point to the planning.
 
Last edited:
I would say it will block in no time at all have you contemplated 45° bends
 
I have contemplated 45° bends, but they really complicate things. Pipe going in between joists, etc.

For what it's worth, i'm using wide 90° bends (don't know the actual name). Still bad?

IMG_0338.jpg
 
It’s more the proximity of the bends. Every turn causes resistance and friction to the nasties trying to run away. Sometimes the easy option isn’t the right one
 
Swept bends (what there called)
 
I wouldn’t were it me and based on the angle there you are eating up more and more space
 
I’m also not being pedantic but I suspect your run from the shower to the drain is too long for 1.5”
 
The bath on emptying will pull the seal out of the shower. Each appliance should each have its own waste ideally to the stack and not all joined up.
 
Last edited by a moderator:
See if you can substitute the 3 x middle 90° for 2 x 45°'s

If its already an internal stack take it high and fit a durgo if it's external take it past the highest outlet inside

Not all outlets / sanitaryware need a vent, unless it's pulling a trap ect..

If you want to play it safe fit anti-syphon trap under bath and basin there not that much dearer than a normal trap
 
The 40mm waste pipe will pull any water filled traps on the all the fittings when the bath is drained Part H of the building regs sets out the maximum runs for single runs to single fittings once you start combining them then you need to increase the waste pipe size or add an anti-siphon pipe or mini AAAV or replace the water filled traps with waterless traps.
The stack should be ventilated, the branch to the WC doesn't have to be but I would be tempted to run a 50mm anti picking up the WC & the bath (40 or even 32mm) if at all possible, run above overspill level of the pan & connected back into the dry part of the stack (vent pipe). In that way no mechanical devices would be required.
Medium radius bends are fine so long as the float is installed with the correct falls (18 - 90mm per M) de-bur the pipes & you will not have any problems.
https://assets.publishing.service.g...achment_data/file/442889/BR_PDF_AD_H_2015.pdf
 
Thank you all for your replies - very helpful stuff.

Ok, so install anti-syphon traps on shower/bath/basins.

AAV or Durgo on 40mm pipe. Inside eaves ok? see diagram.

AAV/Durgo not required for toilet, but better if it has it? Or definitely required? Or not needed at all?

I'll attempt to use 2 x 45° bends instead of the first 90.

IMG_0343.jpg

Did I capture everything? Thanks again everyone.
 
The 40mm waste pipe will pull any water filled traps on the all the fittings when the bath is drained Part H of the building regs sets out the maximum runs for single runs to single fittings once you start combining them then you need to increase the waste pipe size or add an anti-siphon pipe or mini AAAV or replace the water filled traps with waterless traps.
The stack should be ventilated, the branch to the WC doesn't have to be but I would be tempted to run a 50mm anti picking up the WC & the bath (40 or even 32mm) if at all possible, run above overspill level of the pan & connected back into the dry part of the stack (vent pipe). In that way no mechanical devices would be required.
Medium radius bends are fine so long as the float is installed with the correct falls (18 - 90mm per M) de-bur the pipes & you will not have any problems.
https://assets.publishing.service.g...achment_data/file/442889/BR_PDF_AD_H_2015.pdf


@ChrisWatkins - many thanks, very helpful.

Is this what you mean?

IMG_0347.jpg
 
@ChrisWatkins - many thanks, very helpful.

Is this what you mean?

View attachment 38193
No, you don't need & probably shouldn't have a "Durgo" on the main stack, can't terminate to atmosphere ? if it can then the loop is find but not essential it is more to try to anti the bath run so it will not self-syphon when discharged. Otherwise couldn't you run it separately along the eaves to connect directly to the stack?
Remember this work is covered by Building Control & you should be talking to them.
Please don't use anti-vac traps you may well live to regret it.
Try this type of trap = Sanitary waste valve in bathroom applications
 
Thanks Chris,

With a waterless trap I can now reroute the bath and connect directly to the toilet's 4 in. (See diagram) because it can go above joists.

View attachment 38194

This ok?
https://www.screwfix.com/p/osma-was...qAosAERuxAzb8d-yeEAaAmbpEALw_wcB&gclsrc=aw.ds


About the AAV - should it go on the 4 in behind the toilet, or the shower/basin 1.5 in?


You've got the right idea now,

Waterless traps are great but put them where they're accessible, anything compression should have access.

The 'outside pipe' should tee up above the roof if you're unable to do this and have a boxing or void behind the pan / toilet, take it up as far as you can go or same height as the Cistern and put a durgo on it
 
The bath connection is the main problem one for siphonage because of both the volume of water & how quickly it discharges. Not so with the shower because the water flow is much slower & there is normally water draining away slowly after the shower is off, this will refill a water trap even if the seal is lost.
All waste connections to 110mm soil pipes should ideally be made either in a vertical section or on top of a horizontal (it is normally taken that only the bottom 2/3rd of the pipe will be wet) but you will need to take care if you are close to the back of the pan because the solids may not be fully broken up & there could be splashing as the water leaves the Pan.
You may wish to put a small (40mm) AAAV (Durgo) on the basin run, put it up as high as you can under the counter on the 40mm tee & run 40mm float only reducing to 32mm as you come across to each basin trap.
 
I am still concerned that you may not be venting the stack, can you get the vertical stack outside to vent correctly to atmosphere?
Will this be the only vent on your drainage system?
By Law the head of the run must be vented !!!
 
Chris, thanks so much for all this.

This is not the main drainage system of the house. This is literally just this one bathroom, which was added by the previous owners.

IMG_0349.jpg IMG_6A9DE11B843D-1.jpeg
Latest:
1) AAV added to 4 in pipe behind wall.
2) Bath (with waterless trap) connects to toilet's 4 in behind wall with boss connector (see link below). May connect at exactly half line due to slope. Problem?
3) Waterless trap on bath and one on each basin (or one shared)
4) Normal trap under shower (no access)
5) 40mm AAV on the way out of both basins (confirm location-diagram)

Questions :
1) For two basins, should I install one waterless trap on each, or can they share one after a tee? (the tee can be the AAV?)
2) If using waterless traps, the syphoning may not be a problem any more. If joining bath waste to 4 in pipe too close to toilet is a concern, can the bath waste return to the original path and join the shower pipe?
3) Don't know what a 40mm float is.

Here's the shopping list so far : Please recommend alternatives if these are bad for any reason.

110mm AAV (Durgo) : https://www.screwfix.com/p/floplast-ax110g-air-admittance-valve-grey/47962

40mm AAV for basin: https://www.screwfix.com/p/floplast-af32w-air-admittance-valve/42968

Boss Connector : Water Waste BIG BOSS Pipe Adaptor - 40mm - 1.1/2"- Black - Pipe & Fittings | BES.co.uk-19871 | BES.co.uk

Waterless trap: https://www.screwfix.com/p/osma-waste-valve-white-x/1819K
 
There are so many variations & options without being on site I can't go any further than the comments below against yours in red.
View attachment 38226 View attachment 38227
Latest:
1) AAV added to 4 in pipe behind wall. Building Control may allow a AAAV valve to be installed behind the WC in the void so long as it is above the overspill level of the pan & accessible.
2) Bath (with waterless trap) connects to toilet's 4 in behind wall with boss connector (see link below). May connect at exactly half line due to slope. Problem? May be OK but would need to see in relation to pan outlet. Can't you run it further along the void before connecting?
3) Waterless trap on bath and one on each basin (or one shared) I would definitely fit one to the bath, as this is the problem appliance.
4) Normal trap under shower (no access) If this is to remain a water filled trap don't connect the bath waste to it as it will pull the shower trap when it is discharged.
5) 40mm AAV on the way out of both basins (confirm location-diagram)

Questions :
1) For two basins, should I install one waterless trap on each, or can they share one after a tee? (the tee can be the AAV?) A cross tee is not a common fitting so I would have a vertical pipe in either of the corners of the vanity unit with a 40mm tee & an access on the vertical end with a 40mm float (see below) running across with 40mm tees with a 40x32mm reducer picking up each basin. You could either have normal P traps on each & off the end of the float have a vertical rise to get you up as high as you can within the unit & put a mini AAAV to allow air in & break any siphonage that may occur. The other option is just fit a 40mm waterless trap on the vertical drop in the corner.
2) If using waterless traps, the syphoning may not be a problem any more. If joining bath waste to 4 in pipe too close to toilet is a concern, can the bath waste return to the original path and join the shower pipe? Not recommended see above
3) Don't know what a 40mm float is. Horizontal run of pipe connecting appliances in a line, as in your basins.

Here's the shopping list so far : Please recommend alternatives if these are bad for any reason.

110mm AAV (Durgo) : https://www.screwfix.com/p/floplast-ax110g-air-admittance-valve-grey/47962
40mm AAV for basin: https://www.screwfix.com/p/floplast-af32w-air-admittance-valve/42968
Boss Connector : Water Waste BIG BOSS Pipe Adaptor - 40mm - 1.1/2"- Black - Pipe & Fittings | BES.co.uk-19871 | BES.co.uk
I don't like these & would always try to use a 110mm boss pipe to connect waste to soil pipe, if not possible then a strap-on but these (IMHO) are fine for connecting a condensate waste to an existing stack externally but lack the strength effect the bore.
Waterless trap: https://www.screwfix.com/p/osma-waste-valve-white-x/1819K
Don't forget you will need the adapters for one end if you are not going straight onto an appliance.
Best of luck pc_upf
 
Wouldn't be happy with this. How about a corner toilet, or move onto side wall and straight out? With the low water content toilets even ours doesn't clear every time and that is straight out.
 
Some professionals show up and some don't. Some of those who show up never come back. And some who promise to come back and provide a quote for the work, never end up providing a quote because they're taking the girlfriends to New York (true story). The best help I've received so far has been on this forum.
 

Reply to DIYer - need help with toilet pipe air-valve install in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Creating content since 2001. Untold Media.

OFFICIAL SPONSORS

OFFICIAL SPONSORS

Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock