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filling the system

My very old three-family home has three furnaces, two water, one steam. The semi-finished attic is on the same water furnace as the basement apartment. The basement heats great; the attic does not heat at all. Two different circulators, two different circuits.

I'm pretty sure the problem is that there is no water in the pipes in the attic. Playing around with the valves, I can't drain very much water from the attic pipes. In fact, it seems that it only fills to the same height as the basement -- the basement pipes go up to the basement ceiling, and that's about how much water comes out of the attic circuit.

The water refills automatically -- but when I close the valve below the attic drain, and then drain that attic pipe, the water doesn't run until I reopen the valve -- from which I deduce that there is not a circuit of water: whatever tells my water to stop filling sees that the out going to the attic is still at its appropriate height -- basement ceiling height -- even though I'm draining the return, and it does not fill further than that.

The attic has baseboard radiators. I don't see any way to fill up there.

How do I get these pipes to fill?



  • JStar
    JStar Member Posts: 2,752

    The system cold fill needs to be high enough to raise the water up to the third floor, plus a little for safety. You'll also have to verify that the compression tank and relief valve and sized accordingly.
  • EricOfNewark
    EricOfNewark Member Posts: 2
    response to Joe

    Joe in Metuchen: thanks, but that doesn't answer my question: how?!

    The system has worked in the past -- the previous owner says ten years ago there was fine heat in the attic. So there must be a way to fill it. But how?!
  • Paul48
    Paul48 Member Posts: 4,469
    edited April 2013

          You need valves on either end of the attic loop to isolate it from the system.Then you fill it with a garden hose, two actually...one filling and the other out to the lawn or drain. Make sense? Static system pressure of around 15-18 should keep it full, and a means of removing air automatically would be a good idea.

         Your test by opening the valve is flawed. Put a straw vertically in a glass of water, then put your thumb over the top of the straw and lift it out of the water. The water will stay in the straw until you remove your thumb.
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