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Ruptured water heater

Discussion in 'Technical Discussion' started by Seasmaster, Feb 2, 2020.

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  1. Seasmaster

    Seasmaster Senior Member

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    As the "Chiller" issues are resolved [thanks for all the constructive inputs], a new problem was discovered. The original water heater for the boat, 2011 manufacture, decided to bulge. A new one from the same mfr has been installed.

    What boggled my mind was the fact the old one went "over-pressure" and started leaking. It appears from the original name-plate data that it was a 600w/110V unit. However, the heating element that was in it was a 1500w/220V unit. The boat is European built, has 220 & 110. I don't know if owner #1 or 2 did some redneck engineering, or if the Elling boatyard got a deal on 110v units, and put in a 220.

    I don't really know if the water heater vessel is the same for both voltages or not, but obviously the water got too hot & tried to become a steam plant. . .

    Name plate Data

    01IMG_3327.jpeg

    Heating element in the unit:

    02IMG_3330.jpeg


    Bulging of the casing:

    03IMG_3322.jpeg

    Another view:

    04IMG_3324.jpeg

    The distortion was bad enough to warp the alignment of the pipe fittings

    05IMG_3326.jpeg
  2. Seasmaster

    Seasmaster Senior Member

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    A view of the overpressure on the water tank itself:

    06IMG_3329.jpeg

    Another view of the pipe fitting misalignment:

    07IMG_3353.jpeg

    And the actual leak: Around the heating element.

    08IMG_3332.jpeg

    The new boiler: 1200w/220V


    01IMG_3360.jpeg


    New nameplate data:

    02IMG_3361.jpeg

    That's the story. My eyes brow's still reach up to my receding hairline on the old unit's heating element - 1500W/220V in a 600W/110V box!!!
  3. Capt Ralph

    Capt Ralph Senior Member

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    Your pressure safety valve should of popped. Was there an original safety valve?
  4. Pascal

    Pascal Senior Member

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    If i had a water heater burst after only a few years I certainly wouldn’t replace it with the same model...

    keep in mind that European 220 is incompatible with US 220. Euro is 220v hot and neutral... US uses two 110v hots on opposite phases.
  5. Seasmaster

    Seasmaster Senior Member

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    m

    I was aware that hertz mattered, 50 vs 60. Didn’t know voltage mattered.
  6. Oscarvan

    Oscarvan Senior Member

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    Hertz matters for motors, processors. A heating element wouldn't care. And it's not the voltages per se, it's how it's wired. I THINK a heating element wouldn't know the difference. Hence the ability of PO/yard to be creative in the engineering.

    That said, a thermostatic control would have controlled heat in the thing regardless and if it didn't, Capt Ralph is on the money, the blow off should have done its thing. This sounds like a compound failure. You're lucky it didn't blow. I've blown up water systems, not pretty.:D
    Last edited: Feb 2, 2020
  7. Capt Ralph

    Capt Ralph Senior Member

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  8. Oscarvan

    Oscarvan Senior Member

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  9. mapism

    mapism Senior Member

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    100% agreed.
    And even if I can't be positive about this, I believe that the above type of heater is designed to be equipped with an external expansion vase, and THAT should incorporate a pressure safety valve, which I don't think exists at all in the heater itself.
    Besides, in the second photo of the OP there is one part missing, i.e. the stem thermostat that goes inside the hole, and that allows to regulate the working temperature.
    This is the producer webpage of the missing component, for your reference.

    FWIW, I like to keep that as low as 50°C (around 120F) on my boat, which doesn't stress the expansion vase at all, but that depends to some extent also on the heater capacity vs. the onboard needs.
    In fact, another pet peeve of mine is the heating through engines, which I hate.
    My previous boat was equipped with a very basic heater, actually meant for home usage, and it's still working just fine after a quarter of a century.
    My current boat came instead with a nautical heater similar to the one which is being discussed, engines circulation included, and the first thing I did when I bought her was to close the circulation valves on the engine side.
    Aside from the fact that also while cruising I never stay without AC onboard for long periods of time, the engines cooling liquid flows at around 85°C (185F), so it gets also the fresh water equally hot inside the heater tank, regardless of any regulation of the electrical element.
    And I neither need nor want it to get so hot.

    But of course, in principle the heater is designed to handle such high temperature, so I'm not excusing at all the fact that it didn't withstand it - aside from being maybe not installed properly, with no safety valve.
  10. wdrzal

    wdrzal Senior Member

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    This was not caused by electrical voltage ,watts or frequency. Steam is compressible, water is not. For this to happen , 1: There is not a properly working expansion tank on the hot side of domestic water. 2: There is not a properly working pressure relief valve.... (many times a relief valve is Dripping or blowing off and someone decides to fix it with a plug. ) By doing that someone created a bomb. That was very close to a catastrophic failure.
  11. v10builder1

    v10builder1 Senior Member

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    As Mapism pointed out, there was no thermostat control of the water temperature. Previous owner/paid hacker removed it from the circuit? Without a thermostat, the pressure relief would weep/vent with some regularity because the element was on continuously. Same hacker plugged that "leak" by disabling the relief valve?

    A 1500W @220V element would only provide 375W @110V (power varies with the square of the voltage), so maybe the tank construction could live with that heating energy until it couldn't anymore.

    A hot side expansion tank is a great idea and will keep the heater relief valve from weeping, but, IMHO, most boats don't have them (mine does now).

    I don't think the problem(s) was the fault of the manufacturer - good news is - you are back in business, anyway.
  12. Seasmaster

    Seasmaster Senior Member

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    Sorry for the delay, had my head wrapped around the water maker. . . Yes, there was a relief valve. . . as does the new one. The new one is a better product.
  13. Seasmaster

    Seasmaster Senior Member

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    Thanks for the info . .I saw the old stem thermostat on the old unit. It was unremarkable though.