I have a Tarm OT-50 that i'm installing. I just talked with the plumber and he had a question that i couldn't answer. We downloaded the info from the Tarm website and looked that over and still can't find the answer. I'm hoping someone on here that knows the boilers can answer the question.
On the back of the boiler there are three 4 bolt flange connections. As you can see in the picture i have uploaded, one is a supply and one is a return. Both of these are labeled in the Tarm documentation. The third one is not listed in the documentation. There is a picture of what the piping on the back should look like in the manual and it shows a pipe coming from this connection and disappearing out of the picture but it doesn't show it going to anything and it isn't labeled. The jacket on the boiler says that it is a return, but i already have a return so it doesn't make sense to me why i would have two returns. My supply and return are 1 1/4 inch. This extra return is 3/4 inch. Can anyone explain to me what this extra return is for?
![[Hearth.com] Tarm OT-50 plumbing](https://www.hearth.com/talk/data/attachments/141/141995-d080bf7ec9a68caa5a18fd1e35d4d82c.jpg?hash=8CXr7GUHeg "[Hearth.com] Tarm OT-50 plumbing")
On the back of the boiler there are three 4 bolt flange connections. As you can see in the picture i have uploaded, one is a supply and one is a return. Both of these are labeled in the Tarm documentation. The third one is not listed in the documentation. There is a picture of what the piping on the back should look like in the manual and it shows a pipe coming from this connection and disappearing out of the picture but it doesn't show it going to anything and it isn't labeled. The jacket on the boiler says that it is a return, but i already have a return so it doesn't make sense to me why i would have two returns. My supply and return are 1 1/4 inch. This extra return is 3/4 inch. Can anyone explain to me what this extra return is for?
