Belfast sink - joining old waste to new 40mm trap and pipe

[Plumb Line]

Hi all

We're having an old belfast sink fitted in our WC/utility room. We'd like to use the existing old waste; and by all accounts it'd be a pig's jacksie to remove even if we wanted to!

The threaded section in the photo measures approx. 1.88" / 47.8mm outside diameter and 1.24" / 31.5mm internal diameter.

The only thing I can think to use is something like this:

Swell Rubber Reducer

Rubber reducers for many pipe grades like PVC, waste and pressure pipes Made from a high grade EPDM rubber Various sizes available

www.swelluk.com

But whilst the sink out will be inside the reducer, which is good from a gravity point of view, the 40mm trap and pipe will also be inside the reducer which ain't so great.

So I wondered if there are any other options? Anything entirely different? Or something along the lines of the rubber reducer, but with a threaded connection on the smaller end to it connects to the 40mm trap and pipe properly?

I'll keep looking in the meantime.

Thanks a million

 

[rpm]

Cut it out before the sink is fitted and replace with the McAlpine Belfast sink waste.

 

[Basher]

That waste o/d is surely 1.5" bsp?
So a 1.5" trap would fit directly.
But it sounds like you already have a 40mm trap.

There are reducers of various sorts, eg

1.1/2 inch BSP to 1.1/4 inch BSP Thread Reducer - 39004012

1.1/2 inch BSP to 1.1/4 inch BSP Thread Reducer This plastic threaded reducer will reduce male 1.1/2 inch BSP threads to a 1.1/4 inch BSP male

www.plumbers-mate-sales.co.uk

 

[Plumb Line]

Cut it out before the sink is fitted and replace with the McAlpine Belfast sink waste.

Perhaps. And if we have to do that then so be it, but I'd like to see what options I have first as it's definitely our preference to keep the old waste.

That waste o/d is surely 1.5" bsp?
So a 1.5" trap would fit directly.
But it sounds like you already have a 40mm trap.

There are reducers of various sorts, eg

You'll have to forgive me, I'm not familiar with the different types of plumbing fittings, BSP, etc. Turns out that the "nut" from a standard trap (the bit that you tighten) does indeed screw on fine, so yes, I guess the thread is standard 1 1/2" BSP.

The problem is with the pipe section and rubber seal of the trap. Because the sink waste's inner diameter is smaller than normal, the trap pipe won't slot into the waste to form a seal with the O ring. So whereas it should be like this:




On my sink it doesn't and it looks like this:




With all that in mind, do you still think I should be able to get something to work?

Many thanks

 

[exedon2]

Look for Mcalpine 1 1/2 waste adaptor used on commercial sinks which have flat bottomed wastes can then use standard trap.

 

[ShaunCorbs]

https://www.NoLinkingToThis/p/mcalpine-t12a-f-1-bsp-eu-uk-coupler-white-40mm-x-40mm/1358v

That’s what you need

 

[Basher]

https://www.NoLinkingToThis/p/mcalpine-t12a-f-1-bsp-eu-uk-coupler-white-40mm-x-40mm/1358v

That’s what you need

On that part the female thread is 40mm metric, not 1.5" bsp, so I thought it wouldn't fit?

 

[ShaunCorbs]

On that part the female thread is 40mm metric, not 1.5" bsp, so I thought it wouldn't fit?

Trap nut fits so that will aswell

 

[Plumb Line]

Looks like the McAlpine could be just the job, judging by the pictures. I've got one on order and will report back as to whether it works.

Many thanks for the help and recommendation.

 

[Plumb Line]

I'm unable to leave the house at the moment, so haven't picked up a McAlpine T12A-F as of yet.

But I was mulling it over just now and took the waste pipes off my kitchen sink to see what they have. Turns out that what I have on the 1/2 side of my one and a half sink is just the ticket... Or at least I think it is, but I'm no expert. It has a moulded "nut"/end and flat washer. I've put a couple of pics below.

Is there any reason why something like that wouldn't work? If it is ok to use, then:

• What's it called / how do I find one the same?
• How does it then connect to the P-trap?

Sorry that these are such basic questions, and also if I'm missing the glaringly obvious. It's all new to me!

Cheers