Plumbing a baseboard heater

eurban

I recently had a new combi boiler installed and at the same time I had my contractor plumb in a salvaged baseboard radiator that I had mounted to the wall in my garage. It's a cast iron Slant Fin unit with three sections. Its currently connected with the supply and return on one end only. When the heat goes on only the section with the piping connected to it and the middle section heat up. The third section does not (but will eventually get hot, probably just by conduction) I am trying to figure out if there is some sort of blockage in the third section or is the problem that the supply and return are on the upper and lower fittings of the same side? Here's a picture and yes the baseboard unit is mounted on the wall just below the ceiling. It is the only out of the way space I have in the garage and even if it helps just a little I will be happy! Thanks!

bburd

Due to the way those radiators are constructed, I don’t believe that will work correctly unless one pipe is moved to the other end. The hot water is short-circuiting through the end near the pipes.

There is one more possibility: does the radiator have a vent to remove air, and is it pitched upward in the direction of the vent? It might be air-bound.

hot_rod

you could run copper to the other end, either above or below the sections. For supply and return at opposite ends

mattmia2

It might help if you can slow the flow down but the textbook way would be to pipe supply and return to opposite ends.

bburd

Also, if they are plumbed on the same end the supply should be above the return. Putting the supply below the return almost guarantees short-circuiting.

eurban

Thanks for the thoughts so far. There is a bleeder on the upper left. I didn't pitch the radiator, I installed it level. Since I discovered the non heating issue, my plan has been to plumb the upper right connection over to the upper left and switch the bleeder over to the right. I figured I would check here first in case the plumbing was OK and a clog was likely. Sounds like the piping is the issue. So, switching the top right connection over to the top left should do it? Thanks!

bburd

Opposite ends should work, provided that the return connection is on the bottom.

eurban

Thanks. I will have to check to see how it is plumbed now and hopefully won't have to reroute both fittings.