How to dock the pipe and the riser in the toilet, if their diameters do not match?
Hello. We make repairs in the bathroom and decided to change the sewer pipes, since we have the entire system since Soviet times. Bought from polypropylene with a diameter of 11 cm. And then the problem turned out: they do not fit the diameter of the hole to the outlet of the riser. The difference is somewhere in the millimeter 2. We looked in stores with a smaller diameter, but there were none. It turns out that we cannot dock the riser and new pipes. We checked the old pipe - its diameter is smaller than that of those that are purchased now (approximately 10.7-10.8 cm). What to do? Change the entire riser or somewhere you can find pipes with the diameter we need? Or maybe we are installing it incorrectly, and we need to properly push it so that this pipe fits into place?
Methods of connecting pipes of different diameters
Plastic pipes were rarely installed in apartments under Soviet life, because they were purchased abroad: in Yugoslavia or the Czech Republic. Apparently, in your house the sewerage was made with exactly this material. The pipes were indeed smaller in diameter than the plastic of which they are made today. Old - 108 mm, new - 110 mm. Do not insert the pipe with force into the old riser, because over time, the socket will begin to become cracked from the strain.
Of course, it is most convenient to change the entire system, including the riser with the cross. You take into account that the old Soviet sewage system was designed for a service life of no more than 25 years, and it seems that this time long ago ended. In addition, the material in those years was different from modern polypropylene. It was called PND and was used for water with a temperature of up to 60 degrees. Today, a large maximum temperature of up to 90 degrees has been introduced in the building codes. And the old sewage system may not pull this degree, it will begin to deform and become covered with cracks. Well, if you still decide to leave the old riser, then you can try to dock pipes of different diameters using an adapter.
To connect pipes from one or different materials that do not have the same diameter, special adapters with different inlet openings are produced
Ask in stores adapters for joining pipes of different diameters. In your case, an adapter connecting an old-style plastic or cast-iron pipe (with a diameter of 108-109 mm) with modern polypropylene (110 mm). They can be joined by a special large cuff, which will have to be bought separately, or by two elements - a cuff and a ring.
The second way is to dock without a cuff. To do this, the purchased adapter and the old riser are gently heated with a construction hairdryer and very carefully insert them into each other.
