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Possible Vaporstat Replacement

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EBEBRATT-Ed
EBEBRATT-Ed Member Posts: 15,616
Check out Mercoid (their part of Dwyer instrument) they have pressure controls suitable for steam (if you use a pigtail)
they have 1 model, range is 1/8lb (2oz) to 15 psi, minimum differential is 1 psi.

Maybe this could be used in place of the failing Vaporstats.

I have seen Mercoids on commercial boilers in the past, don't see them often $$$ They are high quality and high$$$$. They have 2 adjustment knobs you turn with your fingers 1 sets the cut out, one sets the diff...that's it your done



Model, .DA-31-153-1


Pressure switch, brass Bourdon tube, range 1/8-15 psig, 1 psig min. deadband.

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  • the_donut
    the_donut Member Posts: 374
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    Too bad minimum diff is 1 psi. Would prefer diff in ounces.
  • Jamie Hall
    Jamie Hall Member Posts: 23,433
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    the_donut said:

    Too bad minimum diff is 1 psi. Would prefer diff in ounces.

    True. But part -- not all -- of the problem in the microswitch style vapourstats which we have been seeing has to do with unpredictable nature of the actuating forces of the microswitch itself -- which makes calibration and setting the dead band to a small value very difficult. Compromises, compromises!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • the_donut
    the_donut Member Posts: 374
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    I’m just thinking in terms of high low high. Ideally i’d Like go to low fire after normal system cut in ~8 ounces in the little apartment complex I am thinking of and return to high fire at 4 ounces. With this I could set 2 ounces / 18 ounces, which is little different than the 8 ounces / 24 ounces with regular pressuretrol. Cost vs reward is worth it in my situation.

    It’s honestly too bad modern vaporstat production quality has tanked.

    I hear the argument that a input matched, well vented, and well balanced system will not need pressure controls for even heat, but I my case, the property owners will not upgrade the system and the system is oversized by quite a bit over pickup factor. Low fire allows better heat loss matching, but I have to wait until 24 ounces with a pressuretrol to send the boiler into low fire. That’s a lot of wasted pressure and fuel.

    I suppose a heating curve could made based on outdoor temperature and contacts feed into some sort of control device, but if they won’t spring for venting, doubt they’d spring for better controls (we run off a Honeywell RTH111B1016A).