Bath and basin using same waste

[Adam535]

https://photos.app.goo.gl/oyLc6pV4EzNcRUeT9

https://photos.app.goo.gl/4jKFYV7JEcajgnneA

https://photos.app.goo.gl/1LG5ibacxNEor3kp8

https://photos.app.goo.gl/4cFLuKtq7aydGVyT7


https://photos.app.goo.gl/yH2EMRGKcGrryfdp8


I have a problem. Both bath and basin using same waste.

The bath waste pipe is 40mm going into 32mm basin waste. Can’t change all to 40mm because they have ran the pipes the roof etc too bigger job

Water is draining but very very slow on bath. But when I put on basin tap and the turn on bath taps it drains perfect.

 

[Madrab]

You do have a problem, yes. That should never have been done. Absolutely ridiculous and in push fit so it's doubly dodgy. Nothing to do with the baths taps but putting on the basin taps and running the water down the basin waste is probably removing a vacuum that is created in the basin waste pipe when draining the bath. Disconnect the basin waste pipe from the basin trap and then drain the bath and see if it runs ok, if so then you need an anti vac trap on the basin

 

[Adam535]

Thanks Madrab let me try that

 

[Newboy]

because they have ran the pipes the roof

Whoever 'they' are, get them back and instruct them to:

a) Run the correct sized waste pipework for the appliances and the length of run.

b) To use appropriate fittings - not push fit.

c) Run separate wastes for the basin and bath.

d) Make two connections to the stack - the 32mm (existing) connection can possibly be re-used.

 

[Adam535]

I just bought the house 1 month ago. This must have been done a long time ago, just trying to put it right.

 

[Nige F]

The bath trap should be a deep seal - not that shallow seal one. You could take the push fit apart where bath waste meets basin - then use a sani snake to clean the pipe. Do Not use any acid/ alkaline cleaner down those pipes !

 

[Adam535]

Just disconnected sink from the waste. Water flows perfect from bath

Now I’ve connected a anti vac to sink. Back to same problem, but little better flow.

Do you I need to add something more? To the pipework

 

[Adam535]

https://photos.app.goo.gl/2JLHKWp95bBMf85v9

Video might give better idea

 

[Madrab]

OK, so it's the basins 32mm pipework that causing the vacuum with the bath @ 40mm trying to drain into that, the Anti vac trap is letting enough air to ease the issue but not enough to remove it.
You can Tee off the basin waste pipe under the basin and then put a 32mm AAV in to fully vent the basin waste or do it the correct way, re-do the pipework to make it all 40mm behind the unit and then the basin waste tee's into that. It's the 32mm waste pipe where the bath reduces down that's ultimately causing your problem.

 

[Hugh Jaleak]

As Madrab has said, only long term solution is to replace the pipework with 40mm. Where does it run from there, how far and what would be involved in getting to it? If a straight run you may be able to feed a length of pipe in from one end, provided it is supported adequately in the void, and just reconnect the other end.

 

[Adam535]

i thought i would update. thank you for everyone who replied.

another air inlet valve was needed on the 40mm waste pipe from bath.

ideally use a air inlet valve or quick temporary measure is put T-Fitting with a big pipe in the top the pipe needs to be higher that basin waste. this lets enough air in.

i will take photo next time i'm there. in the future i will change all the pipes and plumb correctly.

 

[Newboy]

Even as a quick temporary measure you need to put an AAV on the top of your 'T' otherwise you will potentially have an open pipe venting from the stack - sewer gases venting into the room isn't a great idea

 

[Adam535]

i thought i would update. thank you for everyone who replied.

another air inlet valve was needed on the 40mm waste pipe from bath.

ideally use a air inlet valve or quick temporary measure is put T-Fitting with a big pipe in the top the pipe needs to be higher that basin waste. this lets enough air in.

i will take photo next time i'm there. in the future i will change all the pipes and plumb correctly.