Bath P-trap Inlet Lower than Outlet

[Billy Whizz]

Hi all,

Just fitted a new bath (height fixed due to bath panel). Plughole mechanism now means the bath waste connection is an inch lower than the original and hence there is no fall on the wastepipe. Soil pipe connection cannot be lowered to compensate.

How can I raise the P-trap outlet higher than the waste inlet to reproduce the fall on the waste pipe again?

Many thanks & best regards,

BW

 

[PAUL JA]

would this work ?

McAlpine T12A-2 BSP Straight Coupling White 40mm x 50mm

 

[Billy Whizz]

Thanks Paul JA. A little too long unfortunately. :-(

 

[JCplumb]

How long is the level run of pipe?
If it's only a foot or two you should be OK, I've seen much worse perform well, much longer than a couple of feet and you will need to adjust it. If the fitting posted above fits then that will do fine as long as it doesn't increase the water level in the trap too much. If it does raise the water level too much, you could use an adjustable trap to get the level right. You only need approx 1cm per meter drop on the pipe.

 

[Best]

Is the waste pipe level and how far does it travel at level (or wrong fall) ?

 

[JCplumb]

Here's a link for an adjustable bath trap.
McAlpine Adjustable Inlet Tubular P Trap White 40mm

 

[Best]

Adjustable trap will probably not be any use as it only normally allows trap to lower, but not go higher than standard traps. But some do vary.

 

[JCplumb]

Adjustable trap will probably not be any use as it only normally allows trap to lower, but not go higher than standard traps. But some do vary.

In conjunction with the item linked in the first reply.

 

[oz-plumber]

Might be a case of making a trap out of solvent welded fittings.
We do this on occasions when in a similar situation.

 

[PAUL JA]

Thanks Paul JA. A little too long unfortunately. :-(

looks like you can get shorter ones

McAlpine BSP Coupling 1" Long 1 1/2" - Toolstation

 

[Stigster]

I'll stick my oar in. I reckon this will do the trick because the outlet is much higher than on any other trap I know. I bring you the McAlpine Bath Trap!

McAlpine SM10E Bath Trap 40mm - Toolstation

 

[Billy Whizz]

JCPlumb/Best,

The pipe run is 1.2m and is currently falling 3cm towards the bath (the wrong way). If I can raise the outlet until the pipe run touches the first bath support rail (adjacent to the trap in the first image) it will at least bring it level.

Will have a go at some of the shorter McAlpine couplings.

Oz-plumber,

I had considered the welded fittings but would rather something that can be unscrewed if needed.

Sigster,

Tried one of those. Looked good but not enough clearance due to adjacent floor-level bath support.

Thanks for your input guys, plenty of food for thought....

Best regards,

BW

 

[JCplumb]

With an adjustable trap and the extension piece in the right place you can control the height of the trap exit to get the waste pipe exactly where you need it.
Here's a hi-def photo of one I did earlier. I used the same camera I used to photograph my wedding so the quality is awesome.
The arrow on the left is where you adjust the trap which will raise lower everything else to where you want it.
The pink bit is the extender that Paul JA linked on the second post.
The waste pipe is green because it's now in the right place 😀

But the McAlpine trap that Stigster linked above may also work 😉

 

[Michael1960]

Use a dry trap inline, come off of waste with a 90 and put a dry trap in.

 

[Billy Whizz]

Thanks everyone for your suggestions.

In the end, Paul JA was right with the 1" coupling fitting. Initially it didn't fit but that later turned out to be due to a minor manufacturing difference between the new McAlpine coupling and the old original trap. Having purchased a McAlpine P-trap to match the 1" coupling, it all fits sweet as a nut, I have a level waste and the bath empties nicely. The best I could hope for under the circumstances. 🙂

Many thanks once again y'all.

Best regards,

BW

 

[kris]

I'll stick my oar in. I reckon this will do the trick because the outlet is much higher than on any other trap I know. I bring you the McAlpine Bath Trap!

McAlpine SM10E Bath Trap 40mm - Toolstation

Second this , this is exactly wot needed

 

[kris]

Was there always a hole in the floor or was it made for new nbath

 

[Billy Whizz]

No Kris, it was already there from the previous bath. And as I mentioned previously, that trap with the rodding point would not fit under my bath due to adjacent fittings. 🙂

 

[Harvest Fields]

Can you not use this??

 

[Billy Whizz]

Thanks Harvest Fields, but no. This trap has been suggested previously but the outlet was still the same level as the inlet. 🙂🙂

 

[Harvest Fields]

Thanks Harvest Fields, but no. This trap has been suggested previously but the outlet was still the same level as the inlet. 🙂🙂

But surely the same is better than worse then. However maybe one of the other ones mentioned above will work?

 

[ShaunCorbs]

But surely the same is better than worse then. However maybe one of the other ones mentioned above will work?

It's all sorted now i believe

 

[JCplumb]

If there's any length to that horizontal run make sure it's supported.
Would be wise to dose with something like soda crystals once a month too to stop any build up in that horizontal length. Don't buy one shot or any other chemicals, an 80p bag of soda crystals will keep it clear for a couple of years. Couple of teaspoons dissolved in a pint of hot water, bung it down the plug hole, flush it away 30 mins later.
*edit*
Health and safety disclaimer:
Follow the instructions on the bag. 🙂

 

[Harvest Fields]

It's all sorted now i believe

What did he use in the end?

 

[ShaunCorbs]

What did he use in the end?

1" high male to female adapter (mcalpine)