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Are Boilers Dangerous?

If you search the internet for boiler explosions, you will see some pictures which will make you gasp. It is often thought boilers are a dangerous way to heat. In reality, they are really quite safe. I will be speaking next month about boilers and my research for the talk showed me some amazing statistics. The following are the odds of dying in something else other than a boiler explosion:
3,746 times more likely in vehicle accident
50 times more likely by a hippo in Africa
15 times more likely to have a coconut fall on your head
10 times more likely from a falling icicle in Russia
1.3 times more likely to have a vending machine fall on you after shaking it.

If you simply have the boiler checked on regular basis, it will provide an efficient comfortable heat for many years.
Respectfully submitted,
Ray
Ray Wohlfarth
Boiler Lessons
DZoroSolid_Fuel_Man
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Comments

  • Jellis
    Jellis Member Posts: 224
    I agree Ray! As i sat in classrooms learning about controls for heating equipment i often thought there is no way these things can be dangerous!! There is a safety for everything! Then i went to work, and met customers like the guy who found he could make his boiler work by jamming a stick between the wall and his low water cutoff. (It was low on water and the stick was causing the control to short out and power the burner!)

    All of the systems installed these days are extremely safe if installed correctly and inspected and maintained by a professional!

    Although you cant fix stupid
    SuperTech
  • STEVEusaPA
    STEVEusaPA Member Posts: 4,810
    Most of the explosions on the news seem to be natural gas related.
    Boilers, especially steam (to me) require more care than FHA.
    With FHA, maybe the h/o changes the filter as they are required.
    With boilers, they need more attention.
    For Hot Water, check the pressure, every day, or at least every time you walk by it. Look for drips, listen for noises. Test the relief valve annually (or have your service provider do it with you watching).
    Same with steam, but blow down weekly, check the gauge, monitor the feed display, etc.
    People will stare at their Nest or Wifi thermostat all day, but wont take a walk down to the boiler.
    steve
  • I will never shake the vending machine again!—NBC
    Solid_Fuel_Man
  • RayWohlfarth
    RayWohlfarth Member Posts: 867
    @Jellis I like to show those pics to my customers to get them from doing what your customer did.
    @STEVEusaPA You are correct about the maintenance of a furnace compared to a boiler but there are two advantages of the boiler versus a furnace. The boiler should last twice as long as the furnace and a leaking heat exchager is much easier to diagnose on a boiler than a furnace.
    @nicholas bonham-carter I did the same thing LOL

    Ray Wohlfarth
    Boiler Lessons
  • kevinj_4
    kevinj_4 Member Posts: 90
    No, Ray

    Boilers are fine, the problems are people.
    SuperTech
  • John Mills_5
    John Mills_5 Member Posts: 935


    Huge high school around the corner from our office. It goed boom 2 nights ago. Workers were running new gas pipe to a boiler room. Boilers weren't at fault, something in the piping was they say. Boilers badly damaged. Apparently inspection ran out in September on the boilers.
  • RayWohlfarth
    RayWohlfarth Member Posts: 867
    @kevinj_4 Its funny you say that. Boiler accidents causes used to be categorized differently and the leading cause was always poor or improper maintenance. Several years ago, OSHA started tracing the causes and now they do not blame people they blame components. LOL
    @John Mills_5 wow thats scary Its never the boiler
    Ray Wohlfarth
    Boiler Lessons
  • kevinj_4
    kevinj_4 Member Posts: 90

    @kevinj_4 Its funny you say that. Boiler accidents causes used to be categorized differently and the leading cause was always poor or improper maintenance. Several years ago, OSHA started tracing the causes and now they do not blame people they blame components. LOL

    The last report in National Board still showed people issues.

    Even on the recent dry fire here you could say it was the control but it was wired wrong (people)
  • Voyager
    Voyager Member Posts: 248
    I think all modern heating systems are amazingly safe, boilers included. My experience is that FA furnaces last at least as long as boilers, assuming proper installation and maintenance for both. The furnace in my last house was 38 years old when I sold the house and last I knew the owner had not replaced it. That makes it 57 years old now. I finally got tired of replacing the thermopile so I converted the gas valve to 24V. Other than that and a blower fan belt replacement, it just ran and ran.

    My current three Lennox furnaces are only 19 years old, but still going strong. Had one early board failure on one of the attic units (just out of warranty of course) and replaced the inducer on the main furnace this year, but otherwise all three are original and running well. I doubt they will last 58 years though.
    🙂
  • Jamie Hall
    Jamie Hall Member Posts: 15,325
    Realistically, components do fail from time to time. More often than not, however, even when it is a component failure it should have been caught before failure by proper inspection and maintenance. Further, in almost all cases (there are exceptions) if a single point failure can cause catastrophic results, it can -- and arguably should -- be engineered away through true redundancy.

    One of the problems, though, is in clearly determining the actual chain of events which led to the failure, so that it can be prevented. In some areas (aviation, rail, marine) some countries, notably the US, Canada, and the UK, this has been taken to a high art. In some other countries (France, for example) and in almost all other areas (notably the US for highway, never mind such things as boiler explosions) the emphasis is not on finding the causal chain, so that it can be fixed, but on finding some individual or company who can be sued or jailed or both. This is not helpful (the US in several recent accidents has moved away from finding and fixing the causal chain to finding and taking vengeance on a plausible villain, unfortunately).
    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
    Canucker
  • hot_rod
    hot_rod Member Posts: 14,552
    I'd add improper installation to the list of potential causes of failures or explosions. Not everyone knows how to, or should be allowed to blend fire, water and electricity :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    SuperTech
  • RayWohlfarth
    RayWohlfarth Member Posts: 867
    @kevinj_4 Didnt know if the National Board still published those. I have been looking on Osha site
    @Voyager I do not believe anything is designed to last that long anymore.
    @Jamie Hall Lawyers need work as well LOL
    Ray Wohlfarth
    Boiler Lessons
  • RayWohlfarth
    RayWohlfarth Member Posts: 867
    @hot rod_7 You are right there Some people cannot combine all those
    Ray Wohlfarth
    Boiler Lessons
  • Voyager
    Voyager Member Posts: 248
    hot rod_7 said:

    I'd add improper installation to the list of potential causes of failures or explosions. Not everyone knows how to, or should be allowed to blend fire, water and electricity :)

    I think the idea is to keep them from a blending. That is when the problems begin. LOL.
  • kevinj_4
    kevinj_4 Member Posts: 90
    Ray,

    Go to the national board website and sign up for the bulletin. It is a very nice magazine that comes out quarterly.

    About once a year they have incident reports.

    Best part is it is free.
  • RayWohlfarth
    RayWohlfarth Member Posts: 867
    @kevinj_4 Thanks I will do so. I wrote an article for their magazine a while back
    Ray Wohlfarth
    Boiler Lessons
  • SuperTech
    SuperTech Member Posts: 1,574
    edited December 2018
    Boilers and furnaces aren't dangerous at all. Untrained and poorly trained technicians and installers are the most dangerous threat to a safely operating heating system.

    I do believe that boilers are slightly safer than furnaces due to the fact that they heat water rather than air. But both are perfectly safe if installed and maintained properly.
  • RayWohlfarth
    RayWohlfarth Member Posts: 867
    @SuperTech I think untrained maintenance people should also be included in the list. I reference a maintenance person in a nursing home who kept pushing the reset button on the boiler. When it ignited, it sent him flying thirty feet across the boiler room
    Ray Wohlfarth
    Boiler Lessons
    VoyagerSuperTech
  • ChrisJ
    ChrisJ Member Posts: 11,491
    Voyager said:

    I think all modern heating systems are amazingly safe, boilers included. My experience is that FA furnaces last at least as long as boilers, assuming proper installation and maintenance for both. The furnace in my last house was 38 years old when I sold the house and last I knew the owner had not replaced it. That makes it 57 years old now. I finally got tired of replacing the thermopile so I converted the gas valve to 24V. Other than that and a blower fan belt replacement, it just ran and ran.

    My current three Lennox furnaces are only 19 years old, but still going strong. Had one early board failure on one of the attic units (just out of warranty of course) and replaced the inducer on the main furnace this year, but otherwise all three are original and running well. I doubt they will last 58 years though.
    🙂

    The house I grew up in still had it's original 1958 furnace when we moved out in 2007. It had a cast iron heat exchanger and a simple cast iron burner setup. No thermalcouple on the pilot light.

    No, a modern furnace isn't going to last that long, so you cannot compare them.


    I would bet your Lennox furnaces are about done.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Voyager
    Voyager Member Posts: 248
    ChrisJ said:



    The house I grew up in still had it's original 1958 furnace when we moved out in 2007. It had a cast iron heat exchanger and a simple cast iron burner setup. No thermalcouple on the pilot light.

    No, a modern furnace isn't going to last that long, so you cannot compare them.


    I would bet your Lennox furnaces are about done.

    You may be right, but they still look and run like new. I can’t see the inside of the heat exchangers so maybe they are getting ready to rust through, but I keep several CO detectors in operation and so far so good.

    I am surprised that I haven’t had to replace parts such as igniters, flame sensors, pressure switches, etc., but all original thus far. I do maintain the furnaces reasonably well and keep filters cleaned, etc. We shall see how long they run.
  • Voyager
    Voyager Member Posts: 248
    SuperTech said:

    Boilers and furnaces aren't dangerous at all. Untrained and poorly trained technicians and installers are the most dangerous threat to a safely operating heating system.



    I do believe that boilers are slightly safer than furnaces due to the fact that they heat water rather than air. But both are perfectly safe if installed and maintained properly.


    I consider them about equally dangerous. Furnaces have the issue of CO if the heat exchanger fails. Boilers are pressure vessels and if the safety features fail can build enough pressure to rupture something. Both of the above are rare occurrences in well-maintained systems, but the possibility always exists.
  • SuperTech
    SuperTech Member Posts: 1,574
    > @Voyager said:
    > Boilers and furnaces aren't dangerous at all. Untrained and poorly trained technicians and installers are the most dangerous threat to a safely operating heating system.
    >
    >
    >
    > I do believe that boilers are slightly safer than furnaces due to the fact that they heat water rather than air. But both are perfectly safe if installed and maintained properly.
    >
    >
    > I consider them about equally dangerous. Furnaces have the issue of CO if the heat exchanger fails. Boilers are pressure vessels and if the safety features fail can build enough pressure to rupture something. Both of the above are rare occurrences in well-maintained systems, but the possibility always exists.


    I've seen dozens of furnace heat exchangers fail to the point of letting CO into the home, I've only seen one boiler rupture and leak out it's water. The cast iron boilers are much more stout and robust than modern forced air furnaces.
  • ch4man
    ch4man Member Posts: 239
    edited December 2018
    well ive seen dozens of boiler with failed retort leaking CO laden flue products into the home as well.

    no, a FA takes an every so slight edge in safety. consider this
    both suffer many of the same safety issues.
    venting
    delayed ignition
    freezing up a house
    burning down a house (stuck on, run away)
    CO
    fire
    ect...

    what a FA wont do is have a failure that results in a steam related pressure vessel explosion.
  • Voyager
    Voyager Member Posts: 248
    SuperTech said:


    I've seen dozens of furnace heat exchangers fail to the point of letting CO into the home, I've only seen one boiler rupture and leak out it's water. The cast iron boilers are much more stout and robust than modern forced air furnaces.

    Apples to oranges. Old cast iron furnaces were more stout and robust also. A modern furnace needs to be compared to a modern boiler and most mod cons aren’t nearly as stout and robust as the old cast iron boilers.

    Modern furnaces and boilers are both very safe, but either can fail. It is hard to compare failure numbers without knowing the installed base of each system type. I don’t have a good idea for that. In my area, I would estimate that furnaces outnumber boilers probably 5 to 1, but I suspect this varies heavily by what part of the country you are in.
  • SeanBeans
    SeanBeans Member Posts: 483
    I’d say boilers are more dangerous than furnaces for the tech to work on.


    I mean I don’t know if I haven’t learned the tricks of the trade yet but I’ve burnt myself numerous times trying to get a big bearing assembly off.. finally comes off but so does a handful of 180 degree water.
    SuperTech
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,249
    It's kind of the same argument as oil is safer than gas. Oil won't make my house explode, but the tank in inside and can rust through and leak a potential of 250 gallons especially while its being filled and the delivery driver has no visual on the tank and no one is home...

    Gas, I'll speak to LP (NG is 150 miles away) tank and regulator is outside and low pressure inside. But a leak can fill a space and cause an explosion. There are gas detectors which can slightly mitigate that danger but are not required on any but the largest equipment.

    FA has sheetmetal HX which gets really hot and can warp and/or leak exacerbated by the heat of oil FA. Furnaces also can blow smoke throughout a space and feed an unrelated fire. Clogged filter and undersized ductwork makes early failure more likely, if te burner bounces off the high limit often.

    Boilers are pressure vessels and have the potential to explode if dry fired and water hits them. Pressure relief valves and low water cutoffs are really the most important safeties. High limits and operating limits are secondary. Manual reset high limits should be required on everything, but again you cant fix stupid when someone can bypass them, but that arguement can be made for anything!

    Well a furnace can poison you with CO when (not if) the HX fails. A boiler likely won't explode unless lots of safeties fail or are bypassed/wired incorrectly. I'd rather sleep in a room with a piece of fin-tube/radiator/heated slab, then with a register which connects me to all the air in the rest of the building and its potential hazards.

    There is my completely subjective opinion😎
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
    VoyagerSuperTech
  • Voyager
    Voyager Member Posts: 248

    It's kind of the same argument as oil is safer than gas. Oil won't make my house explode, but the tank in inside and can rust through and leak a potential of 250 gallons especially while its being filled and the delivery driver has no visual on the tank and no one is home...



    Gas, I'll speak to LP (NG is 150 miles away) tank and regulator is outside and low pressure inside. But a leak can fill a space and cause an explosion. There are gas detectors which can slightly mitigate that danger but are not required on any but the largest equipment.



    FA has sheetmetal HX which gets really hot and can warp and/or leak exacerbated by the heat of oil FA. Furnaces also can blow smoke throughout a space and feed an unrelated fire. Clogged filter and undersized ductwork makes early failure more likely, if te burner bounces off the high limit often.



    Boilers are pressure vessels and have the potential to explode if dry fired and water hits them. Pressure relief valves and low water cutoffs are really the most important safeties. High limits and operating limits are secondary. Manual reset high limits should be required on everything, but again you cant fix stupid when someone can bypass them, but that arguement can be made for anything!



    Well a furnace can poison you with CO when (not if) the HX fails. A boiler likely won't explode unless lots of safeties fail or are bypassed/wired incorrectly. I'd rather sleep in a room with a piece of fin-tube/radiator/heated slab, then with a register which connects me to all the air in the rest of the building and its potential hazards.



    There is my completely subjective opinion😎

    I almost completely agree with you, other than the part about which I’d rather sleep with. I prefer FA as I like a deep setback at night to sleep. I don’t sleep well in a room above 65 and prefer 60 if adequate blankets are available.

    I have yet to experience a hydronic system that can handle the recovery from this in any reasonable time. My FA system comes on 10 minutes before my alarm and by the time I get out of the shower about 20 minutes after the heat came back on, I am warm enough to be comfortable. Full setback recovery takes 20-60 minutes depending on outside temps, but it has to be below 0 for the recovery to take more than 40 minutes and 20 minute recovery is typical in the winter for a 15-20 degree night.

    I definitely would not have FA without multiple CO detectors though. I lived for years without them, but that was taking unnecessary risk. Then again, I have lived in forced air heated homes my entire life and have never had an FA heat exchanger fail and that includes everything from the ultra cheap Miller mobile home furnaces up to my current Lennox Elites.

    I think asking whether boilers are more or less safe than furnaces is a useless question as the safety issue of proper installation and maintenance is by far the dominant factor in overall system safety.
    Solid_Fuel_Man
  • SuperTech
    SuperTech Member Posts: 1,574
    > @ChrisJ said:
    > How did we end up with someone that doesn't hate forced air heat on here!?!?! :D Not only does @Voyager not hate it, he likes it!
    >
    > @Erin Holohan Haskell What have you done!!!!!!!!

    This made me laugh.

    I suppose any system can be dangerous given the right situation, even a heat pump.
    Voyager
  • RayWohlfarth
    RayWohlfarth Member Posts: 867
    I realize everyone has different opinions on which system is safer. Its kinda like comparing Dodge and Chevy trucks. My point was that boilers are safe if they are checked on a regular basis. I like to use an analogy of a vehicle. In my neck of the woods, there are about 4,000 heating hours per season. If you drive an auto for 4,000 hours at an average speed of 25 miles per hour. The vehicle would have 100,000 miles per year. You would never drive a car that long without doing some mainteance.
    Ray Wohlfarth
    Boiler Lessons
    STEVEusaPASuperTechSolid_Fuel_Manratio
  • Fred
    Fred Member Posts: 8,513
    At the end of the day, they are all safe, until they're not. Everything is going to fail at some point. The question is how dangerous are the most common failures/failed parts? I don't think any of us can speak to safety, with any degree of certainty given the varying ages of the equipment in the field, the level of (or lack of) maintenance they have received, the number of unaddressed recalls that have occurred, the environments those units have been installed in, the quality of the original installation, the modifications/adaptations that may have occurred over the years, so many variables. I would say they all start out reasonably equally safe, within the standards of the time of production/installation, and they lose a level of safety over time, maybe even directly relative to their life expectancy. JMHO
    Solid_Fuel_Man
  • SuperTech
    SuperTech Member Posts: 1,574
    Are we sacrificing some reliability and safety with the new high efficiency equipment that will never last as long as the old, stout lower efficiency equipment of the past? I'm just thinking about some of the extremely old furnaces that I've seen running safely but inefficiently and neglected as far as routine maintenance. It's amazing how some of the old equipment could withstand abuse and poor installation. Mod cons and condensing furnaces are nowhere near as forgiving and no one expects them to last that long.
    VoyagerNY_Rob
  • Jamie Hall
    Jamie Hall Member Posts: 15,325
    I think that it's a very complicated tradeoff between simplicity and maintainability, reliability, safety, and efficiency -- and cost. Seems to me that the safety and efficiency of the newer equipment is superior, but only if the maintenance is much better than what older equipment could, and did, tolerate. Maintainability is worse; more and more we are going to see parts changing becoming common and required -- a printed circuit board/PLC controlled boiler or furnace, in many cases, simply cannot be repaired or adjusted -- swap out the board (we see this even more dramatically in cars and trucks!). To a certain extent, this has a negative impact on reliability -- the magic stops, and there's nothing to be done but replace it, while before you could tweak this or fiddle that and at least limp home (or have heat). This can be mitigated to a great extent by providing dual or triple control systems (consider modern aircraft) - but that comes at a price.

    Where the heating trade may really have a problem on the simplicity and reliability fronts, though, is in the cost and efficiency equation: while trying to wring the last percentage point of efficiency out of the equipment, but at the same time controlling costs, something is going to lose - and it tends to be reliability.

    Interesting problem...
    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
    SuperTech
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,249
    It's like a heat pump, how long will it last? 10-15 years I'm guessing. I service A LOT of them, and I dont own one. But even if they last 10 years they have saved vastly more money then their installation and operation costs. I just dont like the idea of r410a in my living space.

    I also like efficient equipment, and there is the potential for a lot of it to make it 15 or 20 years. Honestly, I'd rather replace a mod/con twice than an iron horse once. And if setup correctly it will still be cheaper all around.

    As far as reliability, backup should be incorporated into all critical equipment. Redundancy is the name of the game. We always have redundant pumps and boilers in commercial jobs. Keep the iron horse for backup if you want.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • SuperTech
    SuperTech Member Posts: 1,574
    edited December 2018
    I would certainly prefer to have a backup if I had a mod con, but my customers expect the system's we put in to be 100% reliable. And with the complexity of the high efficient equipment I can't guarantee that every single component will make it to next year the way I can with the old stuff. As a service technician I can appreciate the fact that the new equipment is so maintenance sensitive but we all hate emergency service calls, especially when the problem is some model specific part I don't have.

    Sorry to hijack the thread, I realise this is supposed to be about safety, not reliability and efficiency but all three factors need to be considered. I think the manufacturers found the best combination of the three with the 80% efficiency systems.
  • Voyager
    Voyager Member Posts: 248
    ChrisJ said:

    How did we end up with someone that doesn't hate forced air heat on here!?!?! :D Not only does @Voyager not hate it, he likes it!

    @Erin Holohan Haskell What have you done!!!!!!!!

    :p

    I am sure she will be booting me off the Wall any day now!

    Even though it says “heatinghelp” I learned quickly when I was mainly in lurk mode that it really is “hydronicheatinghelp.” 😂

    However, I found the forum while doing my research for my workshop boiler and have found it super helpful. And reading some of Dan’s stories is always a treat.

    However, as an engineer, I try hard to remain objective and look at the facts of each situation. And, as I said, I work with both FA and two forms of hydronic: fin tube and in-slab. I like both system types and see pros and cons in both. I am pretty much technology agnostic and will recommend whatever system type I think fits the users needs.

    If someone wants uniform heat and does not have any interest in doing nightly setbacks and doesn’t care about AC, then high mass hydronic is hard to beat. If someone wants AC and also wants fast response to do nightly setbacks, then a good FA system is hard to beat, particularly if you don’t have concrete floors. I live in the northeast where almost every house has a basement. This generally means wood floors and underfloor temps that are moderate even in the winter. Add carpet and the cold floor issue is not a big deal. However, in a house with a cold crawl space under an uninsulated floor or a slab on grade in a cold climate, cold floors will be an issue with FA heat and, by the way, with fin tube hydronic. In that case, pex in the concrete is the ideal solution.

    So, yes, I like FA, but I also like hydronic. I’m ambidextrous. 😁
    Erin Holohan Haskell
  • Fred
    Fred Member Posts: 8,513
    @Voyager , I call that hedging your bet. Maybe she'll kick you off, Maybe she won't. >:)
    Erin Holohan HaskellVoyager
  • ChrisJ
    ChrisJ Member Posts: 11,491
    @Voyager You are of course entitled to your opinion. Even if you're wrong. :)
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    CanuckerVoyagerSolid_Fuel_Man
  • Erin Holohan Haskell
    Erin Holohan Haskell Member, Moderator, Administrator Posts: 1,554
    Haha! @Voyager, glad you're out of lurk mode.
    President
    HeatingHelp.com
  • RayWohlfarth
    RayWohlfarth Member Posts: 867
    @Voyager You sound more like a politician LOL I guess its whatever makes you comfortable and is in your budget
    Ray Wohlfarth
    Boiler Lessons
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