Drainage Pipe Fitting For A 380L Boiler

edited March 2022 in General


The stainless threaded end on the drainage pipe, after the lever valve (photo attached), what screw fitting is this? I've been told by my plumber that it's a 28mm imperial fitting that's not stocked anymore, is this correct? If not can you tell me the actual size.

I'm based in the UK.



800 x 575 - 46K


  • edited March 2022

    Is there any connection advised to connect to this stainless threaded end, so we can tie it directly to the drain.

  • Can you zoom into the thread and take the picture

  • Sorry picture is bad and can't see properly, but it looks like you have a tri-clover fitting on the one side and then the internal thread on the other side of such fitting. If you are struggling, swap it out with another fitting that best suits you. You can also cut the thread portion off and weld on such suitable piece. You will have lots of piping suppliers in the UK that can help you here and potentially is a standard item supply.

  • edited March 2022

    That threaded triclamp adapter looks like it's reducing the larger drain pipe. Don't use this, as you'll never be able to drain the bottom tubing entirely.

    The kettle drain should not plumb directly to any building sewer or drain pipe, this connection should be made with a hose on an as-needed basis. Even hard plumbed systems (you don't have this) need to use an air-gap on the kettle drain for sanitary purposes, meaning it should not be directly plumbed into any kind of building drain system.

    You will need to use the bottom drain for any kind of clean-in-place operation, meaning you'll need to hook it up to a pump to recirculate cleaning chemicals.

    Unscrew the closest clamp, remove the clamp, gasket, and threaded adapter. Throw the threaded adapter in a drawer somewhere, now you are done. Your plumber has nothing to do with this fitting at all.

  • Cheers for that guys.

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