U-Bend question

[Skoot]

My bath backs up when I shower as the water doesn't go down the plug fast enough. The problem seems to be the U-bend under the bath causing a bottle-neck. Can I just remove the U-bend and fit a 90° bend?

 

[Jeff Handy]

No, the u bend holds water, which is blocking sewer gas from coming up out of the drain.
You need to clean out the trap or the drain line.
It is probably full of hair and soap.
The clog might be right nearby, or could be twenty feet away.
You can try snaking down the tub drain, and also down the overflow opening.
Or try an enzyme cleaner like Zep Drain Defense.
A little plastic snake like a ZipIt will pull out hair up to about two feet away.

 

[Skoot]

No, the u bend holds water, which is blocking sewer gas from coming up out of the drain.
You need to clean out the trap or the drain line.
It is probably full of hair and soap.
The clog might be right nearby, or could be twenty feet away.
You can try snaking down the tub drain, and also down the overflow opening.
Or try an enzyme cleaner like Zep Drain Defense.
A little plastic snake like a ZipIt will pull out hair up to about two feet away.

Thanks for the reply.
I have poured drain cleaner down a coiple of times and it didn't make any difference. So I took the U-bend and a bit of pipe off and had a look. Everything looks clear. I tried pouring water straight into the drain pipe and it showed no signns of backing up. I poured water straight into the U-bend and it backs up immediately. Could it be that the U-bend is the wrong type? (Sorry, I don't really know what I'm doing so apologies if I'm using the wrong terminology) There doesn't seem tto bee much space between the bath and the floor underneath. I've included a pic.

 

[Twowaxhack]

If you can pour water down the pipe and it flows good but not into the p-trap then you have a clog in the Ptrap.

 

[Jeff Handy]

Your description of pouring water is confusing.

Meanwhile, just pouring in some water is nowhere near the volume of water that would flow down there during a shower.

Try a cheapo ZipIt snake down the tub drain, into the trap bend.

You will find info on ZipIt or other similar hair pullers on Google.

 

[Skoot]

Your description of pouring water is confusing.

Meanwhile, just pouring in some water is nowhere near the volume of water that would flow down there during a shower.

Try a cheapo ZipIt snake down the tub drain, into the trap bend.

You will find info on ZipIt or other similar hair pullers on Google.

Sorry if I was confusing. I squirted the shower straight into the drain. The shower reached. So the volume should be the same. It didn't back up. Didn't look like it was even close to backing up. I then held the U-bend under a tap and poured water into it. It backed up immediately. There is no debris inside the U-bend. It just seems that it can't deal with the amount of water coming through.

 

[Jeff Handy]

Still making no sense!
The bend is open, clean, and still backs up.
Not possible.
Unless you hold it level, and pour water in.
Then of course it will fill up.
Water does not run uphill or defy gravity.

What does “the shower reached” mean?

 

[Skoot]

Still making no sense!
The bend is open, clean, and still backs up.
Not possible.
Unless you hold it level, and pour water in.
Then of course it will fill up.
Water does not run uphill or defy gravity.

What does “the shower reached” mean?

I meant that the shower hose was long enough for me to squirt water straight into the drain pipe after the U-bend.
I held the bend level, in the same position as it is when fited and the water doesn't seem to be able to get through the bend quick enough. That's why I was considering replacing the bend with a 90.

 

[Twowaxhack]

You may be flowing too many GPM for your tubs waste and overflow arrangement. Like a restrictive strainer.

 

[Skoot]

You may be flowing too many GPM for your tubs waste and overflow arrangement. Like a restrictive strainer.

Is there anything I can do about that? Even with the shower flow fairly low it still backs up.

 

[Twowaxhack]

Is there anything I can do about that? Even with the shower flow fairly low it still backs up.

I see you’re in the UK. I’m not familiar with any of the plumbing there. Sorry, I’m out.

 

[Skoot]

I see you’re in the UK. I’m not familiar with any of the plumbing there. Sorry, I’m out.

OK, thanks for your input.

 

[sarg]

But I'll say I appreciate the picture of your tub support .............. that's a solution I've been looking for !

 

[Jeff Handy]

The bend of your trap has a fitting molded into it.
It looks like maybe a cleanout plug, to remove hair etc.
Maybe that is causing a restriction.
Look for a new trap without that goofy thing stuck on there.

Take the trap bend off again, and post some pictures of it, from different angles.
Especially of that weird fitting sticking out of it.

Also, your drain pipe is a bigger diameter than the diameter of the trap, so yes it can handle more flow rate.

Post a pic of the screen or grate that is in the tub drain, maybe it needs replacing for one with bigger holes.

Maybe you just have massive flow rate from the shower head.
In the US, the government has required shower heads to be choked way down, to conserve water.

 

[Skoot]

The bend of your trap has a fitting molded into it.
It looks like maybe a cleanout plug, to remove hair etc.
Maybe that is causing a restriction.
Look for a new trap without that goofy thing stuck on there.

Take the trap bend off again, and post some pictures of it, from different angles.
Especially of that weird fitting sticking out of it.

Also, your drain pipe is a bigger diameter than the diameter of the trap, so yes it can handle more flow rate.

Post a pic of the screen or grate that is in the tub drain, maybe it needs replacing for one with bigger holes.

Maybe you just have massive flow rate from the shower head.
In the US, the government has required shower heads to be choked way down, to conserve water.

I checked in the local plumbing supply shop and all the shallow U-bends have got those fittings on them. It has to be a shallow bend as there isn't enough space for anything bigger. Here's some more pics.

 

[SHEPLMBR]

oh my. That is so tiny for a tub drain. I have never seen one so small.

 

[Jeff Handy]

If you change to just a 90 elbow, you will get sewer gas coming out of the drain.

The lack of depth under your trap is causing you to need that skinny and stubby trap bend.
If you could cut out more plywood underneath, you could fit a thicker, longer, and more gradual bend, but you would also have to slightly shorten the drain pipe it attaches to.

And I can’t tell if it would jeopardize the stability of that metal
support shown right next to it.

Get a pro plumber in to look at it, and also from below, if there is access there.

 

[Jeff Handy]

A plumber might be able to create a custom trap out of two long sweep 90’s.

Or put a drain/waste/vent 90 under the tub drain, then install a running trap a little further away, farther from that metal support.

Your codes and customs are so different from north America, you need a local pro to advise you.