Shower trap 45 elbow

[mike42]

Hi

I just bought a shower trap and it came with a 40mm 45 elbow. It would be difficult to fit either pointing 45 degrees down or sideways and ideally I'd like to connect from the shower trap directly with 40mm pipe for a gradual fall (45mm ish per metre) for just about 350mm-450mm.

So the my questions are:

1/ Is that permissible and/or a really bad idea or do I need a run 45 degrees heading down from the trap?
2/ If allowed, how can I connect 40mm waste pipe onto the fitting? It looks a smaller thread than a standard 40mm compression fitting.
3/ And how can I achieve that gradual fall if the outlet is dead horizontal? Is it ok to allow it almost horizantal for that short distance before it falls a lot more?

The trap is a McAlpine ST90CP-70 .

Thanks a lot for any advice - I hope this one is reasonably straightforward (to those that know!)

 

[Bonni]

I always use 45 degree fittings on all sizes of waste pipe for better flow.

I've even replaced/re-routed waste pipes to achieve this or raised a shower tray slightly.

 

[mike42]

I always use 45 degree fittings on all sizes of waste pipe for better flow.

I've even replaced/re-routed waste pipes to achieve this or raised a shower tray slightly.

Thanks but is that 45 straight down or angled to achieve a gradual fall?

 

[Nige F]

Hi

I just bought a shower trap and it came with a 40mm 45 elbow. It would be difficult to fit either pointing 45 degrees down or sideways and ideally I'd like to connect from the shower trap directly with 40mm pipe for a gradual fall (45mm ish per metre) for just about 350mm-450mm.

To connect direct to the shower trap you'll need another trap (possibly McAlpine) with a straight connection

 

[mike42]

That makes sense. Is the idea with this one that you'd rotate the 45 to get a gradual fall or would most people put a 45 degree drop straight out of the trap? That's the bit my non common-sense brain can't get its head around !

 

[Madrab]

Is the idea with this one that you'd rotate the 45 to get a gradual fall or would most people put a 45 degree drop straight out of the trap

If the waste pipe/shower drain cannot be changed/installed to allow the waste pipe to be plumbed straight into the trap with a straight connector with correct fall then the 45 degree trap can be used to allow connection to aide with mis-aligned pipework. It's not usually possible to run the waste downwards at 45 deg, unless there's a pretty deep void underneath.

 

[mike42]

So after more research into what traps are out there I couldn't find a single one that is 92degrees straight out of the trap except one no name one which was wider than the mcalpine above.
It seems most of the traps do come with 45 elbows so I guess I'll have to live with it somehow.
I guess flexi is frowned upon? Is it even building regs compliant I wonder.

Other option is to go down 45 degrees and then immediately level with another 45 degree elbow but that means I'd need to then run dead level through a single skin brick wall before going down again - would that be ok?

 

[MeldrewsMate]

Have you tried a short piece of pipe directly into the trap, using the nut and seal from the male end of the 45° bend supplied? Unless it's one of those crazy foreign traps (and it's not, it's a McAlpine) then the 45° bend has a 40mm (nominal) spigot. As for the pipe you intend to fit to it, polypropylene pushfit pipe is about 40mm diameter, but 40mm solvent weld pipe (ABS or muPVC) is about 43mm diameter. the compression outlet on the trap will allow minor misalignment, so the 2.5° you seek should be achieveable.

Given the option I prefer to dispense with the 45° bend, installing as few bends as possible to both aid drainage, and to aid rodding/cleaning in the event of a blockage.

 

[mike42]

I just tried some solvent weld pipe and it doesn't fit but only by (I reckon) a mill or three. So maybe some pushfit pipe will go in. However the supplied 45 bend has two male ends (two nuts) of different sizes. One is I think a regular 40ml compression and the other is the smaller fitting.
McAlpine describe is like this: BSP coupling nut x 1½" Multifit

Maybe I should try with some pushfit pipe but not sure where to get the bsp coupling nut from?

Thanks for the other tips by the way.