Bath drains very slowly

[Shoeshineman]

I've just renovated a flat that had an internal cast iron soil stack along with a separate smaller diameter stack for venting. This was all plumbed in using lead pipe. I removed all the lead pipework and replaced with plastic.

The old lead vent pipe was originally sweated onto the bath overflow but I didn't reuse this as it was impractical and I used a 40mm inline vent instead. After fitting this I noticed that the bath drained very slowly. I then removed the inline vent all together but there is no difference to the flow and I'm still having problems draining the bath.

The kitchen and bathroom sinks don't have the same problems and the u-bend is clear. Can anyone recommend a way to fix this issue?

Thanks

John

 

[petej]

I would be looking at the waste from the bath to the stack, is it falling in the right direction ? the vent pipe is there to prevent the water in the trap being sucked out (and leaving the trap almost empty) caused by the fast flow of water down the stack. When the bath plug is removed the drain can vent through the plug hole.

 

[SMR Bathrooms]

Hi Shoeshineman,

Did you manage to work out what was wrong? I can't add any more than petej but I'd be interested to know what it was.