I'm trying to clean out our kitchen sink. While it has a fairly normal-looking drain from the top:



The bottom of the drain assembly (that abuts the sink) attaches to this bizarre contraption that I've never seen before:






A little further down on the pipe is a kind of normal looking P-Trap that should be easy to clean out.

Does anyone know what kind of drain assembly this is -- maybe a brand, or what it is called -- so I can google it or try to find a video on how it's taken apart and, most importantly, reassembled?

While I am tempted to just start taking things apart kuz it can't be that complicated, I was told that someone once did exactly this and then had a "hell of a time" trying to get it back together.

The "Bizzare contraption" is the mechanism to open and close the bung hole in the sink, i think

Yeah, but I still need to get inside of it 90 to dig out the gunk that has accumulated. I don’t see any brand or model information on it. I was hoping it was a common fixture in CH and that I could find a schematic or something, before I started removing screws and whatnot.

If it difficult to physically clean, you can try a bit of chemistry. You need Waschsoda (Sodium carbonate) available from the drogerie. Make a fairly concentrated solution and pour it into the sink. Leave overnight and then rinse out. Wasch soda solution is also available from amazon.de

Have you looked on Youtube? You must look for a "Franke" or a "Eisinger" Spülbecken Ablaüf. Youtube have very good videos of both models.

I use a steam cleaner. I have one with a fine nozzle which does a great job. Although I love taking things apart, the kitchen sink drain is not one I will attempt.

Which one are you using? Also does it only clean the first stage or can you get further in (around the bend)?

Try a plunger. Availabe at supermarket etc.

This is an informed guess:

The middle of the drain hole, marked with 'Eisinger' probably unscrews or can be prised off with a screw driver, or without. You'll need to experiment to work out which way to take it off.

Under that should be a rod with a slotted end which you can unscrew and that should allow the section under the sink to drop down so you can clean it.

Make sure any rubber seals are in place correctly when you re-assemble.

Does that middle, circular piece come out so that you can get something larger down the drain hole, to try to clear it out?

They do sell "snake things" which are basically long, flexible wire-like things meant to be "snaked" down drain holes, to clear them. Like this:

https://www.gonser.ch/abflussreinige...E&gclsrc=aw.ds

There's also this thing, which is similar but different, and looks like it's received good reviews:

(90cm) Abflussspirale Ablauf Rohrreiniger Reinigungswerkzeug Dusche Küche Waschbecken mit Greifzange
https://www.apfelkiste.ch/abflussspi...xoCChgQAvD_BwE

Thanks so much for the help so far! I have had some luck searching on youtube for "Spülbecken Ablaüf". I am still trying to find a schematic from Eisinger / Franke for the specific model I have, just to understand exactly what is going on inside the drain when the button is pushed to close/open the drain from above. But from what I have seen on the internet, it's just a matter of unscrewing some stuff and it doesn't look all that complicated to me. (that's what the last guy said, but then, maybe he was an oaf and just cross-threaded something or forgot an O-Ring).

But perhaps all that is not necessary and let me not lose sight of my objective -- to clean the thing out, so it flows better. From the videos I have seen, this assembly looks pretty straight-forward and so cleaning it out might just be a matter of probing it with a wire hanger from above, and then (after disconnecting the drain piping) from below, to get all the goop out. I have had a hard time finding a drain snake at OBI.

When I get around to the task, I will certainly post follow-up, in case anybody else stumbles across this in the future.

It is an old Kärcher with a nozzle. I've had it for years and it is great for small areas. I don't know how far down the steam goes and clearly if the drain is blocked then steam is not the answer. But it cleans where I can see into the drain, under the stopper. No brush will reach in there, not even an old toothbrush.

The model number of the sink can sometimes be found on a label on the underside of the sink. Mine is an Eisinger but there is no screw under the stopper, which is a Franke. I can lift the stopper out although it works with a button you turn.

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We had this problem recently and I (unwisely) tried to fix it myself.

First I tried the chemical solution but when that failed I dismantled all the drain pipes from our double kitchen sink and cleaned them. I also tried to clean the main drain entry using a tool specially made for this but it was full of what looked like a giant brown fungus that was growing in the drain and from there up into the sink pipes - putrid and disgusting! I put it all back together but the problem didn't go away. I think I spent the best part of a day to do this, say 5 or 6 hours.

In the end I got my local plumber to come and thoroughly clean the pipes. He used a specialised scouring machine and a camera to ensure he had cleaned everything. Total cost: Fr 150

The tell-tale sign you have problems in the main drain is when the sink has emptied you hear a "glug-glug-glug" sound for a few seconds after

When I consider what I spent on chemicals, the useless tool and my time, it was all wasted effort and a hell of a job to clean up afterwards - get a pro to do the job for you.

Has anyone ever tried one of these gadgets or similar?

https://www.youtube.com/watch?v=XD1qg06xWao

There are several versions on the market, which all work in a similar fashion, i.e. charge/pump to build up some pressure in the device and then press-a-button/pull-a-trigger to release the air in a short blast.

What I have noticed with all the demo videos they show, are that there is no trap under the sink, but instead just a u-bend.

Are you trying to clean the sink or unblock the drainage ???

Us mere mortals use something like CIF of whatever for the first, and a normal, supermarket anti-blocking agent for the second. Such as

https://www.coop.ch/de/haushalt-tier...iger/p/3513874

If you are renting be careful with fooling around with the kitchen infrastructure when bored, or just trying to impress your partner. It might backfire badly.

If it’s a real blockage, then you need to inform your Vermieter, and it needs to be done professionally. At their costs. They will be happy that you reported it if you live in an apartment, because it can affect all other apartments below you.

If you don’t report it, or try to fix it yourself, then you might be liable for any structural damage that results. It’s an indication that the system needs to be checked, especially in older buildings.

I have one and use it each time a sink is slow to drain. We once had a blockage and this is what the plumber used to clear it. I ordered one for our household right away. Works like a charm each time
.

That video is very misleading because it shows only sinks/basins with out an overflow. We have only one such sink in wash room and there the stopper, being a long plastic tube, acts also as an overflow.

If you use any type of device which uses air pressure to force out a blockage (say a plunger or that pressure gun in the video) you have to attempt to cover the overflow aperture, otherwise the air pressure from the cleaning device is wasted through the overflow. That introduces the risk that the pressure build up damages or dislodges some seals or the overflow pipe. This has to be done carefully or could mean an expensive repair.

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