Discuss Basin Waste and Piping and Not Aligned - Causing Weeping of Connectors in the UK Plumbing Forum | Plumbing Advice area at PlumbersForums.net

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In my last posting, I requested assistance in exchanging a waste that had been fitted using silicone, without actually removing the basin. Mission accomplished. However, I now have a further issue for which I would welcome any suggestions or advice.

I decided to replace the McAlpine Pedestal Trap 1 1/4" Anti-Syphon trap. However, despite various micro adjustments of the top Spigot nut and the bottom universal connector, I am not confident of the water tight integrity of the fitting. I fear this is due to the lack of alinement between the bottom of the waste and the connector to which the pedestal trap is fixed. Although the trap fits to gap perfectly, it is not seated correctly, despite whatever steps I take in an attempt to remedy the issue.

My idea was to cut the pipe above the bottom elbow and use an appropriate flexible connector, which hopefully would allow water tight connections to be accomplished at both ends. by implication, the alignment issues will hopefully be rectified. Advice as to whether this idea would work in practice and suggestions as the the specific component I should use.

I attach an image of the pipe and another to illustrate how much space I have available

All suggestions gratefully received.
 
I have managed to make both ends watertight, but typically not at the same time, hence my theory that the waste and pipe are not aligned. it could also be the the faces of the components are not fully seated.

Specifically, leaking has occurred below the nut that connects the top of the trap to the bottom of the waste. Similarly, leaking has occurred at the universal connector at the bottom of the trap.

Currently, the leakage is small and intermittent, hence my lack of confidence longer term and thus search for a more permanent remedy.
 
A compression waste joint allows for a considerable misalignment and as this is a replacement I think it should be possible to make it watertight both ends simultaneously- as presumably the previous one was?
Make the spigot joint first, with the compression joint not tightened at all- just with the nut, slip ring and cone washer on the pipe but below the trap.
Then slide the cone washer up the pipe to level with the bottom of the trap. Now slide the nut up, using it to push the slip ring and cone washer into place and tighten the nut hand tight but don’t graunch it up. This allows the pipe to be slightly misaligned if that is how it needs to be.
Honestly this will make if work, presuming you have the cone washer the correct way around .
 
A compression waste joint allows for a considerable misalignment and as this is a replacement I think it should be possible to make it watertight both ends simultaneously- as presumably the previous one was?
Make the spigot joint first, with the compression joint not tightened at all- just with the nut, slip ring and cone washer on the pipe but below the trap.
Then slide the cone washer up the pipe to level with the bottom of the trap. Now slide the nut up, using it to push the slip ring and cone washer into place and tighten the nut hand tight but don’t graunch it up. This allows the pipe to be slightly misaligned if that is how it needs to be.
Honestly this will make if work, presuming you have the cone washer the correct way around .
To be honest, this is virtually the same process I adopted when I fitted the trap initially (and since) I did assume that it was imperative to achieve a good seal between the waste and spigot recess top of the trap, so focussed on that first. I then ensured that the rubber cone washer was in place before slowly tightening the compression nut at the bottom of the trap.

Whilst the compression joint is now watertight, the spigot connection area is weeping intermittently. The waste I have fitted is a Bristan round push button style and appears to making a good connection, but something is clearly not right. Also, I am as certain as I can be that water is not leaking from above, having used Plumbers Mate, a poly basin washer and the brass back nut in fitting the waste itself.

I have not resorted to using PTFE tape around the bottom of the waste, nor indeed smeared any plumbers mate on the threads of the spigot nut. Its really frustrating.
 
Is there a rubber washer on the top of the trap where it fits to the chrome waste?
Is the bottom face of the waste flat and not corroded and if it's plastic not split?
Is the leak from the trap to waste connection from below the spigot nut or above, if above it can sometimes be the chrome waste (if it's not new) has corroded within the thinnest part of the thread and is leaking down and over the nut?

If after a couple of attempts the trap to waste still leaks, get some PTFE, roll it up like string and wrap a few turns just above the top edge of the washer, it'll push up into the bottom of the waste and provide a larger sealing surface.
In the past where the bottom of the chrome waste has corroded I've removed the washer and wrapped many turns of ptfe to create a large soft seal.

As BEN has said, the lower compression joint will normally seal with quite a noticeable misalignment.
 
Something is very wrong if you can't make that water tight.
That's not misalignment by any figment of imagination.

Get some new rubber seals. Make sure they are the correct ones
 

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