Find a suitable connection from metal rainwater pipe to KG pipe

Hello everyone,

I am looking for a proper solution to connect my downpipe to the existing wastewater pipes.

The downpipe is made of a dark sheet metal and has an inner diameter of 77mm, outer diameter 78mm. No idea what material it is, it could be copper.
A suitable connector must be found so that it fits into the existing KG pipe DN110 ("10er Rohr").

Picture attached.

What I find somehow doesn’t really fit. Most of the time it is way too big.

That is a 76mm downpipe diameter if you haven't measured incorrectly, it looks bigger in your photo. A 76mm downpipe fits into a 70mm HT socket, then you only need a 70/100 transition piece.

What is that anyway? Looks like a repurposed rainwater pipe flap. Does it come out of the wall or from above?

Thank you for your response. This is simply a downpipe coming from the gutter above. It originally led all the way down into the stoneware pipes. The orange KG pipe is now inserted into the stoneware pipe. It was planned to connect additional drains there (second downpipe, light well, possibly even a cistern in the future, but not for now), so it was replaced with the KG pipe. The flap is still attached, which can be seen in the picture. Originally, it led into a rain barrel. Maybe in the future as well, we'll see. Yes, it could also be 76, but I don't think the millimeter matters as long as it is inserted into a rubber seal. As far as I know, HT pipe is not suitable for outdoor use, or am I mistaken?

yes, true HT not for outside, that just slipped out of me

70s with coupling remains the same

I have just measured again, this time I am pretty sure that it is 79mm. I have verified it multiple times. So I need a transition piece from 80mm to 100mm. I have seen that it is available in zinc or copper. Then the [KG Rohr] can connect directly below. In theory...

First of all, the dark downpipe with the beautiful rainwater flap is a copper pipe. It never breaks, but you can only connect to it with a copper pipe. At least you should do that.

I would shorten the KG pipe and insert an appropriate piece of copper downpipe. Of course, there are also adapters from copper pipe to KG pipe. Also the clamps for the wall.