Help with reducing/feed valve for boiler heating system?

Question

Here’s a puzzle for you: My downstairs radiators work fine, and kick a lot of heat. My upstairs ones, however, are only warm at the bottom, and are cold on top. I’ve tried all the various fixes I’ve found on the internet: Bleeding the radiators, bleeding them in a certain order, etc., but I still can’t seem to fix the problem. When I bleed the downstairs ones, water comes out immediately. Upstairs, I can bleed a bit of air every day, but no water ever comes out (and recently, I can only bleed air from the first radiator I attempt to bleed upstairs, nothing happens with the other two). What’s going on?

I’ve read that I might need to add water or pressure to my system, but I’m not sure how. The pressure gauge on my boiler usually reads around 10 PSI or so. I found a reducing valve (or feed valve, a Bell Gossett one with a lever), but I’m not fully sure how it works, since I don’t know which position is on and which is off; and I’ve tried running the system both ways and it doesn’t seem to make much of a difference.

Does anyone have any insight or suggestions? Is there anything easy/obvious I might be missing? I just bought the house this year, and the system is pretty old, but otherwise seems to be working alright (I just had a furnace guy inspect it a few months ago).

Answer 1

When you bleed the radiators water should rush in and purge the air out and eventually spray out the bleeder valve, If it is not doing this, it is because something is preventing the water from entering the system. I'm guessing there is either a valve ahead of your regulator that is shut off, or the regulator is busted or clogged with mineral buildup. There are several versions of these regulators; the one at our house has a little lever that lets you manually over-ride the regulator and manually fill to desired pressure. If yours has this lever, try pulling up (away from the unit) and listen for the sound of water rushing down the pipe. If this works, you can temporarily bleed the air and refill this way but once the radiators are full and at ~15psi leave the lever in the closed position so it won't pressureze to the full city water pressure. Ultimately, you might have to replace or rebuild the regulator.

Some further explanation:

I just noted your part about running it with the lever up; Your system is at about 10 psi (partly filled with water and partly filled with air); when you bleed the lower radiators, the pressure of the air above forces out some of the water, so it makes it appear that the regulator is letting water into the system, when you bleed the upper ones you just get air. If you've run it for a considerable time with the lever up and you still didn't get any water entering there is definately something preventing the water from re-filling the system; it should re-fill in a few minutes (of course the bleeders need to be opened to get the last of the air out). The possible problems are the same as what I mentioned before.

Answer 2

It has an auto feed on it therefore you should not try to raise the pressure or add water. There is probably air still in the system. It will happen in the upstairs radiators and will have to be eliminated.