What is this loop for?


Can someone please explain to me what the pipe loop in the hot-water Rad system is for?

Thanks so much,


Looks to me like some one put it in to trap air and use it to stop water hammer .
I think the water could eventually absorb the air stopping it from working

Looks like another unit was in place and taken out no other purpose except to by pass the shut off valve

Try turning off the shutoff valve and see how effective it is! Probably done by the same guy that put in the floor.

Yes, that’s what I was thinking…lol…thanks for all your help.