Sink trap slightly wrong size

28 May 2022
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United Kingdom
I have a standard sink trap (not sure on brand) below sink which only the sink and washing machine use. I would like to fit a sink trap with an air admittance valve. I have bought a mcalpine one that I was hoping would have been a like for like replacement (it looks exactly the same) but where it joins to the external black waste pipe in the wall it is slightly too low, maybe by 2CM or so, so the size is obviously slightly different. What options do I have in making it fit? I had a look at solvent welding but I don’t have much space on the straight sections of pipe to fit the connector required for the weld. The part I have bought is called ‘Mcalpine WM2V 1½" Anti -Syphon Sink Trap with Horizontal Nozzle’. Thanks in advance!
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Sorry everyone, I couldn't figure out how to upload a picture on my phone, please find photo here of my attempted explanation of the problem. The red lines show what the new traps height is, so it isn't inline with the external waste coming out of the wall. I was hoping for some way (or any other alternative!) to make the right hand side section 2cm or so longer to match up with the existing external waste. The size on the left matches up fine.


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You need an adjustable trap. Unfortunately you don't get an adjustable anti vac trap that has an appliance spigot.

You'd need to get creative and re-route the outflow somewhat.

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