Bath plug gurgles and splutters when toilet flushes?

SHarrison · Post by **SHarrison** » Mon Sep 17, 2007 11:49 am

Hi all,

A weird problem's developed in the last 2 weeks in the upstairs bathroom.

When we flush the loo it causes the water in the bath u-bend to gurgle and splutter violently. In the last few days it's become worse and the toilet now fills up to a high level when flushed, before quickly returning to its proper level. Running the sink at full blast also now causes the gurgling in the bath (but to a lesser degree).

I thought there might be a blockage, but both sink and bath drain quickly, but I shoved chemical unblockers down bath and sink and I've plunged the toilet, these things seemed to help but only temporarily.

If it helps I'll describe the configuration of the pipes. This is the view from the garden looking at external pipes at the back of the house coming out from the bathroom:

external
air vent...................toilet waste........bath waste pipe
||
|| ================||--------------|
|| <extension>
||
to ground

So basically the toilet waste comes straight through the bathroom wall out into a wide waste pipe, which runs almost horizontal along the top of an extension and then straight down into the drain on the left. The smaller bath pipe comes out the wall and runs into the end of the bigger main waste pipe. I think the sink merges with the bath pipe at some point.

Any ideas what I can try?

Many thanks
Simon

Jaeger_S2k · Post by **Jaeger_S2k** » Mon Sep 17, 2007 12:44 pm

Hi Simon,
Welcome along.
Can you take a picture of the real thing?

It sounds like you need a AAV vent on the bath and possibly the basin traps but alternative is to replace them with a HepVO trap.

When the toilet is flushed it's causing a vaccum and is sucking in air through the basin and bath traps.

The basin is possibly pushing the water back up the bath trap.

Are you getting any foul smells from the basin trap/ plug hole? You might need to stick your nose inside the rim of the basin or near the over flow.

Fitting HepVO trap will solve this but you should remove the existing wet traps when you fit HepVO dry trap.

Details here

Technical Design Guide PDF Here

Hinton Heating · Post by **Hinton Heating** » Mon Sep 17, 2007 5:41 pm

what is the external air vent?

have you checked this is clear?

bathstyle · Post by **bathstyle** » Mon Sep 17, 2007 6:42 pm

It's called induced syphonage, if it's just started doing it after a few years then your Soil pipe has a blockage or your drain (check the manhole)

If it's aways happened or since work has been done then it's been piped up incorectly.

SHarrison · Post by **SHarrison** » Mon Sep 17, 2007 7:28 pm

Hi everyone, thanks for your replies,

Jeager - I defiinitely don't have these types of traps fitted at the moment. Thing is, since it's only just started happening in the last 2 weeks, after 4 years of no trouble, would it not be more likely to be a symptom of a blockage along the horizontal soil pipe? Since otherwise I can't think why else it would just start happening? I'll see if i can take a photo in daylight tomorrow to make that diagram a bit clearer...

Hinton Heating - don't know exactly what it is, as it's difficult to see from below, but from what I can make out, the vertical downpipe ends in a flat 'cap' type thing just above where the horizontal soil pipe joins the vertical downpipe that goes into the drain. I presume it's a vent, but ;?

bathstyle - you echoed my thoughts, after 4 years no trouble it's only last 2 weeks the bubbling started and has got worse since then.

Cheers,
Simon

SHarrison · Post by **SHarrison** » Mon Sep 17, 2007 7:38 pm

Forgot to say - no smells from any of the plug holes or overflow holes during the glugging.

cheers
S

Jaeger_S2k · Post by **Jaeger_S2k** » Mon Sep 17, 2007 10:47 pm

If you've not got smells then a blockage is the most likely.

More investigation required.

A picture will help to show the drop on the soil across the extension.

bathstyle · Post by **bathstyle** » Mon Sep 17, 2007 11:06 pm

I would have the manhole up first thing

Jaeger_S2k · Post by **Jaeger_S2k** » Mon Sep 17, 2007 11:09 pm

bathstyle wrote:I would have the manhole up first thing

... and if it's blocked, beyond the hole, you won't need to stick your head down it