I am trying to connect a new shower tray to the existing waste pipe.

The existing waste is an 1 ¾” PVC pipe. I think that this standard has
now been abandoned – all the wastes in B&Q are now 40mm (1 ½”). Is it
likely that a plumbers merchant will stock 1 ¾” fittings – I need a
new P trap?

What are the prospects for connecting a 40mm P trap to a 1 ¾” waste
pipe? Do I just stuff a bit of 40mm pipe inside the 1 ¾”, whack some
silicone sealant round it and hope for the best or is it possible to
find an adaptor from 40mm to 1 ¾”?

Indeed will 40mm PVC pipe fit inside 1 ¾”?

"Eric" wrote in message
...

I am trying to connect a new shower tray to the existing waste pipe.

The existing waste is an 1 ¾” PVC pipe. I think that this standard has
now been abandoned – all the wastes in B&Q are now 40mm (1 ½”). Is it
likely that a plumbers merchant will stock 1 ¾” fittings – I need a
new P trap?

What are the prospects for connecting a 40mm P trap to a 1 ¾” waste
pipe? Do I just stuff a bit of 40mm pipe inside the 1 ¾”, whack some
silicone sealant round it and hope for the best or is it possible to
find an adaptor from 40mm to 1 ¾”?

Indeed will 40mm PVC pipe fit inside 1 ¾”?

Bear in mind that you don't just need watertight connections - you also need
the inside to be as smooth as possible - otherwise it will clog with all
manner of horrid stuff.

On 30 Nov, 08:51, Eric wrote:
I am trying to connect a new shower tray to the existing waste pipe.

The existing waste is an 1 ¾” PVC pipe. I think that this standard has
now been abandoned – all the wastes in B&Q are now 40mm (1 ½”). Is it
likely that a plumbers merchant will stock 1 ¾” fittings – I need a
new P trap?

What are the prospects for connecting a 40mm P trap to a 1 ¾” waste
pipe? Do I just stuff a bit of 40mm pipe inside the 1 ¾”, whack some
silicone sealant round it and hope for the best or is it possible to
find an adaptor from 40mm to 1 ¾”?

Indeed will 40mm PVC pipe fit inside 1 ¾”?

50mm waste is still very much in use, and a plumbers merchant will
stock a trap or an adaptor if you prefer. The leap from B&Q not
stocking something to the conclusion that it is no longer available
isn't really sustainable. All wood other than banana wood would have
been abolished for a start.

"Eric" wrote in message
...

I am trying to connect a new shower tray to the existing waste pipe.

The existing waste is an 1 ¾” PVC pipe. I think that this standard has
now been abandoned – all the wastes in B&Q are now 40mm (1 ½”). Is it
likely that a plumbers merchant will stock 1 ¾” fittings – I need a
new P trap?

What are the prospects for connecting a 40mm P trap to a 1 ¾” waste
pipe? Do I just stuff a bit of 40mm pipe inside the 1 ¾”, whack some
silicone sealant round it and hope for the best or is it possible to
find an adaptor from 40mm to 1 ¾”?

Indeed will 40mm PVC pipe fit inside 1 ¾”?


1 1/4" and 1 1/2" are very much still available ... in metric guise of 32
and 40mm

Some places will also stock 50mm

You can get reducers to connect between the sizes

On 30 Nov, 08:51, Eric wrote:
I am trying to connect a new shower tray to the existing waste pipe.

The existing waste is an 1 ¾” PVC pipe. I think that this standard has
now been abandoned – all the wastes in B&Q are now 40mm (1 ½”). Is it
likely that a plumbers merchant will stock 1 ¾” fittings – I need a
new P trap?

What are the prospects for connecting a 40mm P trap to a 1 ¾” waste
pipe? Do I just stuff a bit of 40mm pipe inside the 1 ¾”, whack some
silicone sealant round it and hope for the best or is it possible to
find an adaptor from 40mm to 1 ¾”?


How old is the installation? What is the make?

If it is a true imperial size then it must be at least 30 years old,
more likely older. If a true metric size it could be either a
'special' or perhaps a size peculiar to one (?minor) manufacturer.

If you can discern the manufacturer's name it might be worth ringing
up their technical help service (look on web for tel no) for
suggestions.

Otherwise (& especially if imperial) IMHO it would almost certainly be
best to strip out & renew using standard metric sizes. Domestic
plastic waste fittings aren't that expensive & biting the renewal
bullet now might suave you lots of aggro in the future.

If it is a true 1.75inch bore the changing to 50mm might be the best
option.

It is possible you might find a good plumbers merchant would recognize
your problem and be able to fish out an adapter from under the
counter. OTOH he might not :-(

Indeed will 40mm PVC pipe fit inside 1 ¾”?

no not if both are internal bore diameters. using mastic/sealant
might work for a time but in thene IMHO will fail.

HTH

On Sun, 30 Nov 2008 00:51:48 -0800, Eric wrote:

I am trying to connect a new shower tray to the existing waste pipe.

The existing waste is an 1 ¾€� PVC pipe. I think that this standard has
now been abandoned €“ all the wastes in B&Q are now 40mm (1 ½€�). Is it
likely that a plumbers merchant will stock 1 ¾€� fittings €“ I need a new
P trap?

What are the prospects for connecting a 40mm P trap to a 1 ¾€� waste
pipe? Do I just stuff a bit of 40mm pipe inside the 1 ¾€�, whack some
silicone sealant round it and hope for the best or is it possible to
find an adaptor from 40mm to 1 ¾€�?

Indeed will 40mm PVC pipe fit inside 1 ¾€�?

There are two standard of plastic waste pipe.

1) BS 5454 is the push fit type, this is compatible with the copper sizes.
The ODs are 35 and 42mm.
2) BS 5455 is the solvent weld size. The ODs are about 36 and 44mm.
The next size up has an OD of about 56mm.

Compression fittings fit both standards. Just to make matters more
confusing the basin/bidet size is called 32mm or 1¼" (based on its approx
ID). The Shower/Sink/Bath stuff is called 40mm or 1½" likewise.









--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
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