Mount the siphon - that's how it works

Of course, the new kitchen sink also wants to be connected - and that includes the wastewater connection. How to properly assemble the siphon and connect the sink to the sewer pipe is described in detail in our step-by-step instructions.

Function of the siphon

The siphon sits between the dip tube and the pipe leading to the waste water connection. Its task is to prevent malodors from the sewer and the sewer system from escaping up into the room.

The structure may vary, not always you have a separate dip tube. In this case, you can attach the siphon directly to the drain valve and do not need to install a separate pipe.


In some cases, you need to get the right drain fitting for your sink yourself. You have to pay attention to the right sizes. In any case, be sure to measure the diameter of the drain valve connection and the diameter of your wastewater connection beforehand. For a simple inch rule is sufficient, since the diameters are standardized anyway zöllig.

Correct cutting to length

Immersion tube and sewage pipe you will have to cut to length in most cases. This is not a problem with plastic fittings. For metal pipes you should rather see, to get suitable pipe sections.

Otherwise, in both cases - with plastic and metal - you can easily use a metal saw to cut the pipes to length (as fine a toothing as possible). After cutting, remove the burr absolutely clean. Plastic pipes can also be sanded with the file a little at the edge, so that they slide easier during installation in the port.

Installing the siphon - step by step

  • siphon
  • Rohrgleitmittel
  • pipe wrench
  • possibly soft cloth (to protect the sleeve from the pipe wrench)

1. Determine the required lengths of the pipes

Temporarily plug the dip tube onto the drain port. Plug the sewer pipe into the drain connection in the wall. Now hold the siphon so high that the bottom connection is flush with the sewage pipe. Now you know what length you need on the dip tube. Add the length of the connector inside the siphon minus 10 mm. Cut the sewer pipe to the appropriate length (also 10 mm less than the inner length).

2. Cut the tubes to length

Cut both tubes off and deburr them carefully.

3. Assemble drain

Provide all pipes with the appropriate seals (seals are always pushed onto the pipe, not inserted!) And push the pipes as straight as possible into the two openings of the siphon. Coat pipe ends first with a little pipe lubricant. Temporarily secure the pipes by tightening the union nuts lightly.

4. Finish the drain

Align the siphon exactly and tighten the union nuts. Make sure that the pipes are in the correct position. Then test the drain for leaks.

Tips & Tricks

You can make life much easier when plugging in using a flexible drain hose instead of a rigid pipe. This eliminates many tricky measuring work, and they have a little leeway at the dip tube. But always work very carefully when it comes to the water installation. Even small leaks can permanently cause unpleasant water damage.

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