Kinky stack

[i_am_fubar]

We're replacing an old cast iron stack, but the ol' hole in the ground doesn't quite line up with the new plastic (plastic pipe mounts have different dims to the old CI ones and the invert is at an angle).

I've got a manifold aprox 400 above floor level servicing the utility.

What options are there to correct aprox. 50mm misalignment between plastic soil and the old concrete pipe in the floor?

Also, what are acceptable ways of sealing the plastic to concrete apart from using a rubber adapter? (Plumbers mate, mortar... etc)

Cheers,
Fubar.

 

[Hugh Jaleak]

Without seeing it I can only suggest an adjustable bend to get it to align, and use a McAlpine DC-1 or similar to join to old drain. Fear use of anything else will cause it to leak before long, if not straight away!

 

[i_am_fubar]

I assume you mean gas leak rather than fluid leak (unless in the event of blockage) as the plastic would be inside the concrete regardless.

I looked at the adjustable bends, but would need two to get a slightly offset (but still parallel). Would be quite long as far as fixings go.

What sort of flexibility is there in those push fit joints? I know they're designed to be straight, but there must be some give.

Cheers,
Fubar.

 

[Charnwood]

Fundamental question that I don't think has been asked;
why was the CI alligned but the plastic not?

Hunter do an adjustable bend, range 0 to 90° (90 to 180° if you like) and a 5 to 30°. Other brands available.
Similar to Brett Martins 0 to 30°:

 

[i_am_fubar]

CI had one bracket (that was actually attached to the wall) and was installed far from vertical

Those look like they could do the trick.

Will try and get some pics.

Fubar.

 

[Hugh Jaleak]

Unsure whether this would allow sufficient movement on the 2 joints to be of use? http://www.screwfix.com/p/adjustable-bend-grey-sp560/50087#

 

[Charnwood]

Unsure whether this would allow sufficient movement on the 2 joints to be of use?

Fugly, but looks to be more than adequate to compensate for a 50mm centre-to-centre deviation by making a swan-neck.
Good find, Hugh.

 

[i_am_fubar]

Thanks for all the help. Think I've gotten it all sorted.

Picked up an adjustable bend, but wasn't suitable.

Turns out it was slightly under 50mm and I managed 'persuade' it to fit. The manifold flexed slightly, and with the movement between the output of the manifold, dual socket coupler, length of pipe and DC-1, got it to fit. Will try and get some pics.

Just one question. Part H, Section 1.28, states that [the diameter] "should
not reduce in the direction of flow"

Those DC-1's do, in fact, reduce in diameter by virtue of their design. How does that play out with regards to the apparent regs conflict?

Cheers,
Fubar.

 

[sooey]

Off topic and irrelevant but I've just noticed there's a great spoonerism for this thread title, appropriate too.