CONNECT TO BASKET STRAINER

[RONCHAM]

Hi - I want to replace my sink basket strainer. Can someone advise me what fitting I use at the lower threaded section of the strainer so I can continue off in 40mm plastic pipe and fittings to my existing trap. I've seen the fitting used but I don't know what it's called - basically a plastic nut (or sometimes a brass nut) and a (top hat?) washer. Would a McAlpine T29 fitting be suitable?? - or I've seen trap height adjusters which may possibly be suitable. All advice appreciated.

 

[oldbuffer]

The strainer is connected to a trap. The top of the trap has a white plastic nut on it, and a flange just before the top. The top fits inside the waste, a rubber washer seals between the base of the waste and the flange, and the nut tightens onto the threaded shank of the waste. The white plastic nut is generally part of the trap and cannot be removed. The pipe which leads from the waste to the trap (U trap, S trap or bottle trap) is part of the trap, and not necessarily 40mm in diameter, although it may be.

If the new waste fitting (basket strainer) won't reach the existing white nut connecting to the trap, you'd need to replace the trap. I'd suggest a McAlpine trap as I find them of good quality. If you have washing machine and or dishwasher draining through the trap, look at McAlpine WM11. If no appliance drains, look at ASC10. They do lots of other traps, so you should be able to find one to suit on their web site.

 

[RONCHAM]

Thank you for your advice.
I've seen McAlpine P traps with adjustable inlets which would presumably be suitable? But in my case I wanted to use the existing trap which is some distance away so I'd need a short length of vertical pipe and a bend or two to reach it.
I thought a tailpiece was available with a BSP female thread, flange (and nut?) at one end as you describe and a plain pipe (or compression fiting?) at the other end to continue? Isn't the McApline T29 this arrangement although there is not a nut at the flanged end, or is it for another purpose??
Or alternatively a McAlpine T12 BSP coupling? - I assume the threaded end accepts a 40mm compression fitting?
Thanks again.

 

[Madrab]

A pic would help but most new basket strainer waste and roughly the same depth and are the same 40mm size or at least you should be able to find one with the same throat length/shape. So replacing the whole sink waste for a new one shouldn't really effect how the trap will fit.

 

[RONCHAM]

Thanks for your quick response, you would probably be right normally BUT I have a waste disposal unit at the moment which I intend to abandon.
And I'd still like to know the various fittings that can connect to a strainer basket and allow me to continue with 40mm compression fittings ie T29, T12 etc. (Actually I get a bit confused by mention of 38, 40 and 11/2" sized fittings? I assume the strainer basket outlet is 11/2" male BSP?).

 

[Madrab]

The size of the waste in the sink, once the waste disposal (WD) is removed will be key. Most are 90mm dia which means a normal strainer waste will fit. Some WD's have their own internal traps, has yours? If not then you will have to extend the pipework from where the trap is currently to where the waste outflow's new position will be, what type of trap is there currently? Then it would just be a case of a piece of 40mm pipe and some couplers to fit to the existing waste pipe run.

I would adjust the waste pipe and move the trap, if a standard P trap, up to where the waste outflow will be, leaving everything the way it is and trying to use various couplers and bits to fudge a connection from the trap to the sink waste is a recipe for potential problems in the future

Again pics of the current setup and waste run etc would be a big help

 

[RONCHAM]

Thanks for your advice.

I’m fairly sure it’s a 90mm dia. sink waste. The WD is an Insinkerator and I’m fairly sure there’s no internal trap – not least because there’s an external P trap! In any event I intend to dispense with the WD.

But my fundamental question is the connection to a new basket strainer which will allow me to continue with 40mm dia. plastic pipe ie is it a McAlpine T29, T12 or some sort of tailpiece (if I reuse the existing trap)? And is the basket strainer 11/2” (40mm?) male BSP at its lower end? As I said I'm a little confused by mention of 38, 40 and 11/2" sized fittings.

As you suggest a photo is better than a thousand words (I think I should've shrunk it somehow!).

 

[flameport]

But my fundamental question is the connection to a new basket strainer which will allow me to continue with 40mm dia. plastic pipe ie is it a McAlpine T29, T12 or some sort of tailpiece

The trap connects to the basket strainer.
While there may be other parts that could be cobbled together to do that, it's entirely the wrong solution, will cause problems and is just making a pile of work for nothing.

Trap: https://www.screwfix.com/p/mcalpine-adjustable-inlet-tubular-p-trap-white-40mm/46577
You will also need two of these: https://www.screwfix.com/p/mcalpine-mt4-bend-90-40mm/45446
and a length of pipe: https://www.screwfix.com/p/floplast-push-fit-pipe-white-40mm-x-3m/65426

New trap onto the basket strainer.
Pipe horizontally from trap outlet to one of the elbows, with the other opening downwards
Other elbow goes on the existing waste pipe with the other opening upwards
Piece of pipe vertically between the two elbows.
Lengths of pipe cut as required so that the elbows line up vertically.

The existing trap and the other bits attached are removed.
Theoretically possible to clean and reuse but it will inevitably need new seals and what's gunged up inside it will be vile.

38, 40 and 11/2" sized fittings.

All essentially the same thing.
There are minor size differences which are important if using solvent weld or push fit. That's why using the universal compression items above is suggested as they avoid sizing problems.

 

[RONCHAM]

Thank you flameport for your comprehensive reply. I'm sure you're absolutely right about using new fittings and pipe - start with a clean sheet so to speak. By the way the Insinkerator is at least 20 years old! - I believe this is past its normal life but it still works well and doesn't leak at present.
Thanks again.