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*General questions re. undersized steam boiler

Eli Member Posts: 42
They are both pretty far from the boiler but I wouldn't say the furthest. One is one the first floor, farthest from the boiler and the pipes run through a slab (they are the only pipes to do so as far as I can tell). This rad steams when I open it from the rad but I can hear gurgling. Is this normal? It's a slim possibility that the slab has settled, changing the fall of the pipe.
The other dead rad was working and stopped. It is far from the boiler in the other direction and on the 2nd floor (out of three).
I've never seen the boiler go off on pressure. It seems like it just steams until the t-stat is happy. The t-stat is located on the third floor north side (my initial guess at hardest to heat spot). It's a remote sensor with the t-stat in the boiler room where I can watch it.


  • Eli
    Eli Member Posts: 42
    *General quesition - undersized steam boiler

    Now that I've got my head back in the steam system, I'm seeing a few things fall into place that I missed before. If you saw my earlier post about the VECO system, excuse me while I repeat some data:
    Total load of 43 radiators is 1469 sq. ft. The basement pipes are insulated and the window all have good triple tracks. The building is stone and has passed it's 100th birthday. If I use a pickup factor of 1.33, then the boiler should be 1950 sq. ft. In fact, the boiler (a gas-fired Weil McLain, approx. 7 years old) has an output rating of 1375 (30% under). I had one (now two) radiators that don't get heat. I'm starting to think that the problem might be not enough steam (as opposed to venting, clogs, valves, etc). I'm also realizing that maybe the undersize is the reason I've never seen the gauge show any pressure. It is a vapor system (vaporstat set for 4-10oz), but my gauge goes up to 1.5 psi, so the range is good enough to read ounces.

    1) Can any of the experienced minds on the wall draw any conclusions from the data?

    2) In general terms, what are the results of an undersized boiler? The building (8 apartments) is really mostly comfortable with the exception of two rooms. It heats quickly and seems to have a sensible cycle time.

    3) Any recommendations on what to do? This is obviously the most important question. What would you (as a pro) suggest to your good, long-term-thinking client in this situation? I hate the thought of replacing a boiler with so much life left in it. And the cost of doing so. But I can't have uncomfortable tenants either. I run a tight ship.

    Thanks for any and all input, I'm SO glad for the mind-meld that is the wall.
    Eli - Philly
  • Steamhead
    Steamhead Member Posts: 16,719
    The boiler's square foot/net BTU ratings

    ALREADY include the 1.33 pick-up factor. No need to add that percentage to the existing radiation. That Weil isn't as undersized as you think.

    If your pipes are well insulated, the pick-up factor is probably well within 1.33.

    If it seems like it's not making enough steam, have a pro check to see that the burners are firing at their rated capacity. This would also be a good time to have the boiler and any other fuel-burning appliances in the building tested for carbon monoxide.

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    All Steamed Up, Inc.
    Towson, MD, USA
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    Oil & Gas Burner Service
  • Big Ed
    Big Ed Member Posts: 1,117

    Can you shut down any of the radiators ? Other then installing a proper size boiler .... You can also install smaller radiators . Most likely the radiation is over sized for the heat loss of the building. They were designed to heat with the window open...
  • Eli
    Eli Member Posts: 42
    7% is better than 30%!

    That's great news. Thanks for that. So what are the possible reasons that I don't see any pressure? (I WILL check the the gauge first!)
  • flange
    flange Member Posts: 153

    eli, one big question.......the gage never shows any pressure, who cares, does the boiler ever shut off on the pressuretrol???? if it does then you probably have other issues. if not i would still look elsewhere first unless those two are the two furthest from the boiler. its getting kinda warm relatively around here lately, are you getting anything now i think it might have hit thirty today! did anyone possibly edit the piping going to those rads? is it sized correctly to carry steam over there at that low pressure?
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