This past summer, roofers put a nail through one of the pipes of our hydronic heating system that runs in the attic to the baseboard across the room. This was repaired, and the system seems to be working fine, except for that set of baseboards now. Every other baseboard that is fed from under the house in the other rooms is working fine, but this one that is fed by the pipe that goes up into the attic is ice cold. My suspicion is that when the pipe was repaired, the water was never able to be drawn back up and to the baseboards again because it was fighting against gravity (although it with a pump running things, that doesn't make perfect sense). I thought maybe bleeding that particular baseboard could get the hot water flowing to it again, and release any air in that part of the system, but using the bleeder screw, I filled an 8 oz glass with water that seemed to be under pretty good pressure, without evidence of air escaping, so I stopped, not being exactly sure if the water I bleed out is automatically replaced from the city feed, and not sure anymore if that was the correct solution. So I guess, I'm wondering what the exact problem may be, and wondering if I was on the right track, but just need to bleed for longer to get it to work. And if I do, should I be doing that with the system running, or leave it off? Thanks for your help!

It looks like you have air lock in the line. Do this: Go to the most distant radiator - or to the pump's bleed screw - and open it. Let water run until you feel hot water in all radiators. That should do... Also, you could install Watts air release valve. It does bleeding automatically.

Hi all...

Sillywabbiit... continue bleeding that baseboard using its own vent... try to get about a gallon of water out of that basebaord vent... shake the pipe abit while doing it. You might be surprised to find that with some pipe systems that are looped it can be problematic to get that one air pocket out that stops the pump from engaging and pumping the water up.

The weather hasn't gotten cold enough to freeze the pipe in the attic, by chance, has it? Just another thought.

MARK

Okay, so basically keep bleeding until I get the hot water back into that baseboard? Should the system be running while I am doing this, or do I need to leave it off?

And in terms of the pipes freezing, we did have a pretty nice cold snap into the low 20's for a couple days, but I don't think the pipe froze, and the temps have since evened out above freezing again.

Thanks for your help guys, it's much appreciated.

Keep bleeding the pipe and then after you have collected tons of water and FINALLY find that air pocket holding you up (it will show up in a big spurt or multiple spurts if air is the issue), you turn the furnace back on and see if it worked... ;)