Boiler zones

[hayseedd]

I recently had an old cast radiator freeze crack and leak. It was in the sun room, we do not use and was turned off. The window was left open, this was the main reason for it freezing, never left the valve on before and never froze. Instead of getting another radiator. I just took the radiator out of the system and looped the copper lines back excluding the radiator.

Now it is that one part of our radiators are not working. The section with the radiator that froze, is still funtioning with warm, baseboard heat. The other zone of which i think there our only two, is ice cold. I do not think it froze but how would I know. All the pipes in the boiler rooms are warm. if one zone was not circlating, would there not be some pipes there that wod be cold. Please respond to what and how i canget this remidied, can i open valves to help find the problem?

 

[Jadnashua]

When you open up the pipes to do maintenance on the boiler, at least part of it ends up getting drained. A little bit of air trapped in the pipes is all it takes to block the flow. The most likely problem is you need to bleed the system to get the air out. Now, sometimes, that can be a real pain. THe air will tend to accumulate at the highest point. FWIW, the circulator pumps used on most systems are NOT big enough to push water up very high...they work fine if there's no air since the water falling down on the return helps, and the pump only really needs to overcome friction, but it will not work if there's air.

Time to bleed the lines...how best to do that, depends on what's available, and we cannot see that.

 

[Sponsor]

 

[hayseedd]

I have had this system opened up before, totally open and this did not effect the flow, what is the difference this time, do you think.

 

[Dana]

Any time you open the system there is a chance of getting a large enough bubble to get a vapor-lock stopping flow. Just because it didn't happen the last five times you worked doesn't mean the sixth time wasn't the charm. Where you break it open, where the system vents & pumps are and how much water was taken out all play a part.

Bleeding the system to purge the at least MOST of the air out after opening it up is standard operating procedure to avoid having to come back and deal with it later. Hopefully you have at least one system vent, and somewhere to bleed it somewhere close to the high point of the system?