Cold Radiators

[chillybmore]

Hi - Common Question, I know, but I'm puzzled.

I have hot water heat. Oil Boiler (also provides hot water to rest of house).

Main supply comes out of Boiler and branches three ways:
1- Back of house
2- Middle of house
3- Front of house

Each of those branches run vertically up to all three floors of the home.
The returns run in parallel, effectively.

The back branch is suspect at best, but not a concern at this point. The middle branch works great, all of the way to the top. The front branch is my concern.

I have three radiators on the front wall of my house. Each is married into the supply and return (respectively). None of them get cold.

I can feel the supply line that reaches the front of the house when I'm in the basement. It is Ice Cold. No circulation at all.

So... I've bled and bled and bled the radiators, hoping for an air lock or something. No dice.

When I'm bleeding the top two floors, I occasionally get lukewarm water, but it mostly is just backwash up through their return line, since there is no pressure from keeping the water backing in there.

The odd thing is the ground floor radiator. When I bleed it, the supply line that is usually cold heats right up. The radiator gets hot and the bleed water is hot, all coming through the supply. As soon as I stop bleeding though, the hot water stops flowing.

So... I turn the supply valve off at the radiator and bleed again. Predictably, the bleed is much slower, but I do get some pressure. I feel the return pipe for the radiator heat up because I'm bleeding out backwashed return from the rest of the system. Again, when I stop bleeding, no circulation.

So, my question is, if I can get pressure into the radiator when bleeding and I can get water flow through the return when bleeding, why won't the water circulate through the unit! I think this one radiator is causing the problem with the other two radiators on that same supply/return line as well. I'm guessing that its one problem gumming up all three of them.

Sorry for the long, detailed post. I'm just totally at a loss here and any help would be hugely appreciated.
- J

[KField]

One possibility is that one of the other loops is taking all the flow and not leaving any pressure differential to move water through the problem loop. It sounds so severe that I have to wonder if there is a valve somewhere that is closed. Either on the supply or return, or even on the radiators themselves. What do the valves look like on the radiators and how far do they turn from on to off? If you turn off one or two of the radiators in the section that now heats normally, do any of the others get hot? Is there a valve in each of the 3 loops in either supply or return to balance flow?

Ken

[chillybmore]

I'm a total newbie, so you'll have to bear with me. I greatly appreciate your response though.

I can access the main supply in the basement. I can't see any valves specific to the three loops, only valves on the main supply + return.

The main supply breaks into the three loops. Where the supply breaks into the middle loop is where it goes cold. The supply line is hot right up to the veritcal break for the middle loop. Three inches past that break, where the supply continues to the front of the house, it's ice cold. So there is no flow at all.

There is a broken valve (no turn) on the third floor radiator, front loop. Its possible that it is not open as I have not been able to get hot coming into the supply, even when bleeding (though I do get warm backing up through the return).

Could that valve, if its stuck in the closed position, prevent the flow to the radiators on the bottom two floors?

The ground and second floor radiators both have working valves. One full turn (360 degrees) to open and close. Both are in the open position.

I have tried to close the working loops and run the boiler - still no flow to the front loop.

Thanks again for your help - Very much appreciated.

- J

[KField]

Would you have a way to send a picture of the radiator valves?

I can give you my email address if needed.

Ken

[chillybmore]

Ken - absolutely yes. Send me an email to:

congruent AT gmail DOT com

And I'll reply with a couple of shots of the valves on my radiators, specifically the broken one.

Thanks again for your help.