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Coil in boiler vs hot water tanks

Silvion
Silvion Member Posts: 26
Hello,
I have a weil mclain oil boiler that had a heating coil. I was having problems with the burner so I had the coil removed and replaced with two hot water tanks for tenants. The tanks use gas. I find that the coil was cheaper to use with oil. I fixed the burner and was wondering if you felt it was feasible to reinstall coils for hot water?

Thanks
sil

Comments

  • icesailor
    icesailor Member Posts: 7,265
    edited March 2015
    Silvion said:

    Hello,
    I have a weil mclain oil boiler that had a heating coil. I was having problems with the burner so I had the coil removed and replaced with two hot water tanks for tenants. The tanks use gas. I find that the coil was cheaper to use with oil. I fixed the burner and was wondering if you felt it was feasible to reinstall coils for hot water?

    Thanks
    sil

    You noticed that?

    I've said it for years and years of experience shows it to be true.

    Now that you have the two gas water heaters, convert them to storage tanks, fed off the boiler hot water coil.

    What breed of boiler, how many BTU input and what is the current firing rate of the boiler?

    You said "Coils", Plural, more than one. What happened to the old coils?

  • njtommy
    njtommy Member Posts: 1,105
    I think coil in the boiler is ok. But I find doing indirect tanks off the boiler is the better way to go and having plenty of hot water when size correctly.
  • SWEI
    SWEI Member Posts: 7,356
    Either will work when properly sized, installed, and controlled. You have your BTU delivery rate and you have your storage. The math is not all that complex.
  • icesailor
    icesailor Member Posts: 7,265
    Most indirect's are way oversized for the boiler input that they are connected to. Internal tankless coils in oil boilers are rated in the I/O to match the input of the boiler to which they are connected to.
  • Silvion
    Silvion Member Posts: 26
    I have a 578 weil mclain boiler
  • icesailor
    icesailor Member Posts: 7,265
    edited March 2015
    Silvion said:

    I have a 578 weil mclain boiler

    THAT is a big boiler. When you said "coils", I thought it was a misprint. Did you have two coils in the boiler?

    That boiler is Taylor made for storage tanks.

    That boiler was replaced by the 80 series. Both make 6.5 GPM @ 100 degree rise. That's around 390 gallons per hour. You need some serious BAG heaters to equal that. If you have two coils, they are usually mounted side by side and NOT connected in Series, but in a Parallel reverse return or whatever you want to call it. Both coils are fed with cold separately, hot out separately.

    521,000 Net IBR input. That will leave that place smoking.

    http://www.weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/products/discontinued/discontinued-boilers/78-boiler/78manual.pdf

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