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HB Smith oil furnace

Rtraveler1 Member Posts: 8
I have a 40-50 year old (maybe more) H.B. Smith oil boiler in my warehouse. The access doors were left open, which triggered the sprinkler system and now all the electrical components are damaged. the tenant claims that he heard an explosion which caused the access doors to open. During the 30 years that I occupied the building, this has never happened.

Has anyone ever heard or experienced the access door opening due to an explosion? Thank you.


  • JStar
    JStar Member Posts: 2,752

    Yes. It can happen if the combustion chamber fills with unburned oil. Then, with eventual successful ignition, the excess oil in the boiler can cause an explosion. The force has been known to blow very heavy doors off of their hinges.

    I would have the boiler inspected immediately. It is 100% certain that anything touched by water will need to be replaced. Even if the controls are working, they are a huge fire hazard at this point. Do not even attempt to operate the boiler.

    Chances are that the boiler sections may have suffered some damage as well. The entire boiler needs to be looked at, inside and out.
  • Rtraveler1
    Rtraveler1 Member Posts: 8
    HB Smith

    The reason i dont believe the tenant is because the access doors are fine and I don't see any evidence of an explosion.
  • Jamie Hall
    Jamie Hall Member Posts: 23,426
    Whether you believe the tenant

    or not is quite irrelevant; that's  matter for you and the tenant and, most likely, a few lawyers, if it comes to that.

    None of which is relevant to the boiler.

    If that boiler has gotten wet from sprinklers, as Joe said -- all the electrics -- all of them -- are suspect, and must be replaced.  While that is being done, there is much to be said for inspecting the boiler to make sure that all is well in there.  A good steam man can do all that, and it will be very much less expensive than the possible consequences if the inspection is not done and there is something amiss.

    I might add that if that HB Smith is anything like some others I've known, those doors could be blown open by an ignition misfire -- "explosion", if you like -- and show little or no trace of it.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • icesailor
    icesailor Member Posts: 7,265
    Explosions and doors:

    Those older industrial sized Smith Boilers were originally designed back in the coal was king day. Then fired with oil and gas. The doors were and are hinged so that if you had a coal gas explosion, they would blow open and relieve the expanding gas pressure. Later Smith boilers had plates that replaced the explosion/clean out doors. The upper doors were cleanout doors. The one that lets you clean and look in to the fire box is usually the only one that would blow open. The main function in later years was to give access to the flue ways. Sometimes, the ramp that the latch rides on is worn and it lets the door open easier. A good service person would have realized that and ground it down to make it stay closed easier.  It sounds to me like the burner needed service, it had delayed ignition on start and blew the doors open upon ignition. With the doors open, the room overheated and set off the sprinklers.

    Sounds like you had a control failure because if it is a really big oil boiler, it should have had low-high-low fire with a 15 second trial fire on low. If you or someone had been standing there when that happened, you would have experienced "The Kiss of the Dragon". Always an attention getter.

    With the controls operating properly, that shouldn't ever happen.

    There are other "issues" to be resolved.