Kitchen sink waste replacement

[pauldavidson]

Hi. I just pulled out an Insinkerator that was leaking and replaced it with a plain waste. (This was in the smaller sink of two in our kitchen). The waste in the larger sink was looking pretty grubby so I pulled it out and replaced as well (it was stinking). The problem is I bought replacement wastes from Bunnings - these only had one rubber sealing washer each - I fitted the rubber washer on the inside of the sink and all seems to be good. I'm just curious as to why there's only one rubber seal - not two? I noticed today that Bunnings are now stocking a new brank (other than Kinetic) which has two seals supplied. The Kinetic wastes I bought didn't have any sort or instructions and I can't find any clear info on line.

[Jason]

Hi @pauldavidson,

Welcome to the Workshop community, we're pleased to have you join us. 

Let me tag @MitchellMc who will be back on the site first thing tomorrow. In the meantime, hopefully one of our other community members with plumbing experience might be able to answer your question. 

Please don't hesitate to post anytime you have something to share with the community or need a hand with a project around the house and garden. We're looking forward to reading more about your projects and plans.

Jason

[MitchellMc · Accepted solution]

Welcome to the Workshop community @pauldavidson. Thanks for your question I'd be happy to assist with it.

Rest assured there is only one rubber washer required in a sink drain and you have indeed fitted it correctly. The rubber washer goes inside the top flange and seals water from getting under the waste leaking down beneath the sink. A second washer underneath would be redundant as the first seals the water from getting underneath from the bowl. The nut pulls the waste down against the rubber washer and seals it against the internal wall of the sink.

To qualify this, if you were to take the single washer and fit it underneath the sink it would leak. This is because the water would migrate through the threaded section of the waste for the nut.

If you have further questions or need assistance, please let me know.

Mitchell

[pauldavidson]

Awesome. Instructions with the product might be good? Also wonder why other (newer) products on the shelf have two washers. Thanks for the advice though.

[MitchellMc]

Hi @pauldavidson.

Instructions definitely would be helpful. If you could let me know the details of the waste you are using, I can certainly pass this feedback onto the merchandise team.

Thanks,

Mitchell

[pauldavidson]

Mitchell,

I used two wastes - pretty sure they were both Kinetic brand - both were straight drains (no basket) - both 50mm - one had a 3.1/2" flange (90mm) the other was a 4.3/8" flange (110mm) to replace the Insinkerator. Don't have specific details alas.

Regards.

[MitchellMc]

Hi @pauldavidson.

Many thanks for the additional information, I'll pass it on.

Mitchell