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H.B. Smith Boiler circa 1954

We have an H.B. Smith Co. boiler in our basement that was installed in 1954.

The metal plaque on the inside of the unit says: #15-150-1500-100-1100.

Cast into the iron on the side of the boiler it says: 7500 Mills Boiler - Smith - Taco - Tankless No SS 11-15.

How can I find a manual or information about this boiler?

Thanks so much in advance,


  • Steamhead
    Steamhead Member Posts: 16,719
    How about taking some pictures and posting them here? Also, is this a steam or a hot-water system?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    EBEBRATT-Ed Member Posts: 15,307
    I probably have some info on those I will look tomorrow. A pic will help. Made by HB Smith in Westfield, MA.

    They made many different models with a few different ratings but are all basically the same. The manual wont help much I am sure the 1954 burner you have has been replaced??

    That same boiler was made for at least 40 years
    EBEBRATT-Ed Member Posts: 15,307
    Unfortunately I must have thrown all my old HB Smith catalog away.

    If you have any specific questions repost and we will try and help.
  • Jamie Hall
    Jamie Hall Member Posts: 22,908
    Couple thoughts on that boiler. The boiler two generations before Cedric in the place I care for was an HB Smith, and much to @Charlie from wmass dismay the old steam drum is still in use (my idea, not his!). End result between his beautiful drop header and that steam drum is insanely dry steam.

    However. That is beside the point.

    The main point is that HB Smith -- which had been installed in 1930 -- didn't heat the place any better than Cedric does, and used almost twice as much oil to do it (it had a 5 gallon per hour Quiet May -- which wasn't quiet in the least -- vs. Cedric's now 3.0 gph...).

    Improvements have been made over the years...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • AnnKatz
    AnnKatz Member Posts: 4
    This is a one-pipe steam system, converted from original 1912 coal.

    We're trying to determine if our plumber is a knucklehead, because he's given us conflicting information, but we're in a very small rural town, and he's the best we've found.

    Please see attached photos.

  • KC_Jones
    KC_Jones Member Posts: 5,692
    We might also be able to help with the conflicting information if you let us know what is going on.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Jamie Hall
    Jamie Hall Member Posts: 22,908
    What, if anything, is wrong with it? It looks to be in OK shape, and the piping is reasonable... Or with the system as a whole?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • AnnKatz
    AnnKatz Member Posts: 4
    Well, we're trying to improve things. Some of the radiators bang, some gurgle, some spit, some hiss and some don't heat evenly.

    We have insulated the bare pipes in the basement and replaced air vents on the mains.

    The boiler water level in the glass is dirty and bounces quite a bit, and goes too high unless we drain it every few days.

    The main concerns are:
    a) why does the boiler water level keep rising?
    b) can the dirt in the boiler be cleaned or flushed?

    Thanks again for all your help!
  • Jamie Hall
    Jamie Hall Member Posts: 22,908
    The rising boiler water level could be one of two things. If there is a domestic hot water coil, it could have a pinhole leak and be adding water. Or it could simply be that the valve for the water feed to the boiler is leaking slightly.

    The boiler can be cleaned and flushed, and it is quite possible that it should be. If there are oils on the surface, they can make the water level bouncy (though if the bounce is less than an inch to an inch and a half, I'd not worry about it) and they can be removed by skimming. I'll have to look at the pictures again -- later! -- to see if that would be easy. Otherwise, the system can be drained and flushed out and refilled -- but that is better done in warmer weather!

    The banging you mention should be looked into and corrected. It is most likely to be water hammer, which usually comes from pipes which have lost their proper slope or sagged, or sometimes from radiators which have sagged so they don't drain properly (particularly the ones which gurgle!). Check the piping for proper slope, and likewise the radiators. Think like water: you want all the water formed by the condensing steam to flow easily back to the boiler.

    The spitting vents make we wonder a bit what pressure the system gets to; the pressure control on the boiler should be set to cut the burner off at about 1.5 psi to 1.8 psi.

    And last -- none of the things you are trying to correct are related to the boiler itself, so replacing the boiler wouldn't change them!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • BobC
    BobC Member Posts: 5,471
    edited November 2016
    If the water level rises on a regular basis you have a leak in the fill valve or if you use the boiler to make hot water with and internal coil a leak in that coil. Try valving off any outomatic feeder, the seats on those may not be sealing properly.

    If the boiler water is filthy you should get the boiler skimmed and then drain and flush the boiler out. If it's really filthy somebody may have to use a cleaning wand on it. Make sure the boiler is brought up to steam after refilling to drive off any oxygen in the water.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • There are some excellent books on steam heating in the shop here, which you should read, and therefore be more knowledgeable about steam in general. Your plumber will benefit as well!
    The most important things for the pro to check and rectify are:

    1.Pressure should be set below 1.5 psi, (basic functionality), or below 8 ounces, (comfort and economy). These pressures should be verified by a low pressure 0-3 psi gauge, and controlled ideally by a vaporstat. This overpressure may be the cause of overfilling because of the water being forced up into the returns, lowering the boiler water level.

    2. Main vents, which are larger than radiator vents should be sized properly to allow the air to escape from all the supply pipes in a couple of minutes.

    3. The pure water in the boiler should be clean, (see skimming).
    Many of these things you will be able to do yourself.--NBC
    EBEBRATT-Ed Member Posts: 15,307
    The picture shows a McDonnell Miller #47 feeder/cutoff. That is the most likely culprit that would be leaking by and overfilling the boiler. Most likely it needs a replacement "valve and strainer assembly" and the rest of the control should have a good cleaning.

    Also what is the pipe with the yellow handle ball valve? I hope that ball valve is not on the safety valve blowoff pipe or is that a steam vent on top of that tee???
  • AnnKatz
    AnnKatz Member Posts: 4
    Dear Jamie, Bob, Nicholas and Ed,
    Thank you so much for your replies. You steam-heads are very articulate, helpful and generous with your time and experience!

    The hot water coil has been long disconnected.

    It’s nice to know that we’re on the correct trail on the overfilling.

    We turned off the automatic feeder to test it for a few days and it does seem that the resting water level remains pretty consistent, so as you suggest, something to do with a seat not sealing. Our plumber has ordered the seat and filter kit for the unit.

    It’s comforting news that we don’t have to replace the boiler, as we’re in rural southern Vermont and candidly, our choices of skilled HVAC folk is limited. A new boiler would probably mean a new main which we believe is from 1912 when the system was coal-fired. The main is a loop running around the basement perimeter with pipes running to radiators off that loop. Of course, the main air vent was replaced with a plug and we’re putting in vents.It would have been nice if the main air vents still were in place but the only single tap in the main (1/4 inch) had been replaced with a plug. We removed and replaced the plug with an antler of 2 valves (which we raised about 10” above the main). We saw some decrease in the water hammer but it still takes a long time (45 minutes at least from cold start) so we’re adding a larger third air vent to the antler.

    The water is not clean. Our plumber says that there is no skimming access at the waterline on our boiler. Unfortunately, the only access to the bottom of the unit is through a hose valve so I don’t know how we could get access into the heart of the boiler.

    Our plumber says that there is no way to skim the unit as there are no taps at the water level. As to draining and flushing, there is a standard size spigot at the bottom of the boiler but when our plumber ran it for a moment or two, the water ran clean. We’re suspicious that it really isn’t clean, though, considering the amount of muck that comes weekly from the low-water shut off ball float mechanism. We cannot imagine that this unit has been cleaned in the last forty years.

    We have a pressuretrol which is set to .5 low and 1.5 high. Our plumber did not use a low pressure gauge to confirm that the pressuretrol is behaving, though. We will have him do this when he returns to put in the valve/strainer replacement kit. If our pressuretrol turns out to be working adequately, would we still benefit from replacement with a vaporstat to get the pressure down below .5?

    We purchased and have been reading through a bunch of Holohan’s book; they have been very instructive. Still, we often do not know how to evaluate what we’re looking at.

    The pipe with the yellow handle splits off from the tee below the high pressure steam vent so that the steam vent can never be shut off. Of course, our system doesn’t even have a Hartford Loop (perhaps it should have been added when the furnace was replaced in 1954 but…).

    Thanks again for all your expertise,

    Annie (and her husband Richard)
    EBEBRATT-Ed Member Posts: 15,307
    You could probably skim from the yellow handle ball valve. I prefer Dan's method of skimming add chemicals TSP & lye (if needed be careful with that stuff) get the water hot shut the burner off and skim for several hours just trickle the make up water in. Drain, fill and flush with the boiler cool. as described in Dan's book LAOSH.

    adding more vents will help the steam distribution. If you can measure the length of the main and the pipe size the vents can be properly sized. Radiator vents as well.

    A lot of old jobs don't have the Hartford loop.

    A vaporstat and a low pressure gage is nice to have but not mandatory in my opinion. If the boiler can heat the radiation quickly without building pressure above 2 psi is the goal. many residential jobs can do this without showing any pressure on the gage
  • Jamie Hall
    Jamie Hall Member Posts: 22,908
    This is probably heresy, @EBEBRATT-Ed -- I agree completely. One does need a vapourstat on some vapour systems, if only to keep odd things from happening (like Hoffman loops tripping!) but otherwise... probably overkill.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England