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Slow and cold returns on a two pipe.

John PJohn P Posts: 16Member
Old house with returns buried in plaster walls that have been slowing down. Last year. returns in basement always cold but watching auto feed with water needed only 2-3 times per week during peak north east winter. After system is off, water eventually floods back. What are my options here. I do not trust the local help.


  • JStarJStar Posts: 2,668Member

    You should not need to add any water (assuming you never drained any). Do all of the radiators heat evenly? Are the returns high or low near the boiler? What pressure are you operating at?
  • nicholas bonham-carternicholas bonham-carter Posts: 7,770Member
    Cold, and slow returns

    When you say the auto/over-feed adds water twice a week, how much does it add? I would valve off the feed, and see how long you can run before the water line drops to the lwco cutoff point. Check your pressure, and keep it as low as possible to avoid forcing water out of the boiler and up into the returns. Any horizontal elements in the returns which are close to the height of the boiler waterline could hide a great deal of water as pressure rises, only to return later when firing has finished.

    If you run out of water quickly, and therefore suspect a leak, then over fill the boiler well above the top (put a longer nipple in the prv tapping), and look for the water level falling.

    Your boiler should not loose much water to evaporation, if it is in good repair.--NBC
  • John PJohn P Posts: 16Member
    Slow and cold returns on a two pipe.

    Yes I have a valve on the feed and nervously have had it off watching twice a day. During the peak season in the Buffalo NY area, Im feeding 2-3 times per week. I get pretty even heat with a vaporstat under a pound. Adding the low pressure gauge come fall to get a better handle on it. Cant seem to find any steam heads locally that really understand it. When I bought the house, I bought Dans book and showed the local steam experts that I needed vents as opposed to the stopcocks that served as traps on several of the rads. Appreciate any and all advice.
  • Jamie HallJamie Hall Posts: 10,011Member
    When you say...

    that the water eventually floods back in, does that mean that either you or the auto feeder feed two or three times a week, but that the water level rises later (which would seem to me to produce an over filled boiler eventually)?

    Or are you simply saying that the water level drops considerably while the boiler is firing, but that after a period of time it rises back close to where it was when the cycle started?  Two very different things.

    If you are actually adding water two or three times a week with the water level holding reasonably steady -- no overfilling -- that seems to me to be excessive, and suggests rather strongly that you may have a leak somewhere.  NBC gave you some suggestions on looking for it; the only thing I might add is making sure that the various valves and vents aren't losing steam; this can be very hard to see.

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • John PJohn P Posts: 16Member
    slow and cold returns on a two pipe.

    Early in the season, when the call is intermittent, the water level seems to drop quicker (not as the boiler fires) more over a few days. Then if we go a few days without the boiler firing, I tend to find the boiler overfilled. During peak season, the water level seems to stay fairly consistent, without overfilling, but over the course of a week will drop to a point where it needs water. As spring approaches and the system is slowing down, the boiler eventually overfills. Im going to measure what I drain here in a few days and post a few more pictures of my returns. Thanks for your help
  • nicholas bonham-carternicholas bonham-carter Posts: 7,770Member
    Dropping waterline

    If you have a problem of just clogged returns with no leak, the waterline will stay at a constant level between firings. In cold weather, the rate of steam production will exceed the rate at which the returns are able to return water to the boiler, and the lwco will be interrupting the operation, until the water has slowly trickled back to the boiler, and restored the water level.

    In your situation, there seems to be more going on than that, so do the leak test, and if it is negative ( no water loss), then check the main vents for being stuck open.--NBC
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