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water feeder

I'm so pleased to find this site again. My old link stopped working and I've just discovered it via Google again. Of course I have a question.

I went down to check my furnace before firing up and discovered that the water had risen well over the top of the glass. I did Dan's troubleshooting procedure in "Lost Art" (p. 210) and discovered that the water feeder was leaking and I can't stop the leak by jiggling the valve stem. Is it part #341600 (Mcdonnell 47-2) that my heating guy has to replace ("valve, cartridge and stainer") or do I have to replace the whole unit that sits beside the big float unit?

Further to this, while reading about the low water cutoff Dan says there are two types- Mcdonnell 47-2 and also No. 67. I discover I have both! Is this normal?(see photo)

Thanks for your help


  • TimcoTimco Member Posts: 3,010

    Yes, having both is fine. Code here says you need two lwco devises. One is feeding your water and protecting, and the other is just protecting. You can just replace the feeder.
    Just a guy running some pipes.
  • Dave in QCADave in QCA Member Posts: 1,759
    edited September 2010
    Assembly kit includes housing

    341600 SA47-101-102 Valve, cartridge & strainer assembly kit includes the cast iron housing.  This is the entire assembly that is attached to the side of the large float chamber.  This should be all that you need and should get your boiler back in tip top condition.

    As Timco said, 2 lwco devices with one of them being the feeder & lwco and one as a lwco only, is the normal setup.  Notice that your type 67 is also installed at a lower level.  It is the backup to the main device.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
  • ottawanottawan Member Posts: 14
    Thank You

    I feel much more confident now about what I need. Thanks.
  • BobCBobC Member Posts: 5,112
    Auto water feeders

    I can understand why having two automatic feeders would be a good idea but it also doubles the failure rate.

    I've lived with steam heating systems for over 60 years and never had automatic feeders on the boiler. This means you have to look at the boiler a couple of times a week and if you go away for any extended period, you have to have somebody keep an eye on the boiler.

    The good news is that it forces you to look at the boiler a few times a week so any problems are usually caught early. Also replacing a manual valve costs less than $10 while the auto-feeders cost $150, assuming you do the work yourself in both cases.

    i think I'll stick with the manual valve and I'll be sure to test the LWCO monthly to be sure it works.
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Jamie HallJamie Hall Member Posts: 12,947
    Two LWCO's

    Timco was referring to two LWCOs, not two automatic feeders, as being required by code, and he's right -- at least where I am.  Furthermore, the lower one of the two must be a manual reset around here; that is, if it trips, it stays tripped until someone resets it by hand.  Who, hopefully, is not a doofus and checks around to figure out why it tripped...

    The upper one, around here at least, is commonly tied into an automatic feeder as well as an LWCO, with the LWCO having a bit of a delay (so does the feeder, but less of a one, usually).
    Br. Jamie, osb

    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
  • BobCBobC Member Posts: 5,112
    re: two LWCO


    I fat fingered that one pretty bad. i was trying to make the point that the boiler might be better off if homeowners had to visit it a few times a week and not ignore the beast in the basement.

    Again I can see why redundant LWCO's are a good idea but as others have pointed out they should be teamed up with a meter so one can see how much water is being fed. Even the meter won't be much good if nobody goes near the boiler on a regular basis and keeps a log to track water usage.
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
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