On Tuesday, December 18, 2018 at 11:30:04 PM UTC-5, micky wrote:
In alt.home.repair, on Tue, 18 Dec 2018 18:01:09 -0600, Vic Smith
wrote:

On Tue, 18 Dec 2018 17:20:28 -0600, wrote:

A friend has an outdoor wood furnace going to a building. He put two
radiators (the old cast iron type) in the lower level and they heat
well. He put another radiator in the upper floor and that one will not
fill up. It's only heating the bottom of that radiator. I opened the
bleeder while it was running, and no air or water comes out. I then
removed the entire bleeder and still nothing comes out. There does not
appear to be a clog behind that bleeder.

I am thinking one of two possibilities. Either the pump on the furnace
does not have enough pressure to lift the water to that second level, or
else that radistor needs some sort of restriction on it's OUTPUT side to
force the water to the top of the radiator. Currently he just has both
pipes going to the radiator, one to the bottom left, the other to the
bottom right.

(This is a HOT WATER, -NOT- a Steam heat setup).

Anyone have any suggestions?

Hot water radiators get filled with house water pressure. You bleed it when there is
pressure to it. Make sure the fill valve is open before you bleed it.

Make sure the fill valve is open.

If the bottom half warms up, doesn't that mean the fill valve is open?

Maybe. If they are just starting it up, a new system, and they have
this problem, then yes, it would be. But if it's an existing system,
been sitting there for who knows how long, maybe has a leak, etc,
then the valve could be shut. I think modern ones have autofill with
the valve on all the time, but this sounds like a homebrew.