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Hot water from a Steam Boiler?

DaveGateway Member Posts: 568
Ask two people the same question and get two different answers.
But is there anything really wrong with either of the answers?

One of two experts I asked for recommendations and a proposal recommended using my existing steam boiler to heat a new indirect fired hot water heater. He also recommended picking up my radiant heat loads (approx 30mbh) with a heat exchanger, strainer, pump etc from the steam boiler. This expert #1 considered the “best” way of handling the radiant load and giving me efficient hot water. Call this Option 1.

Being a careful consumer, I ask for a second opinion from expert #2.
Expert #2 starts off by telling me that I can’t use the steam boiler to do what was proposed above. When I asked why, he told me that it could be done, but if it was the option which I wanted to go with, he would not do the work, period. His reason being that the dirt and muck of the steam system will cause the pumps to fail or heat exchanger to clog within a year, and I will end up cursing him.

Expert #2 insists that the right solution and what he will be quoting is a new boiler by Buderus stacked on top of a Buderus indirect fired water heater. Call this Option 2.

I understand what Option 2 entails, but it seems like overkill to me, not to mention, the fact it will probably be thousands more than the Option 1.
But am I being taken for a ride by Expert #2 or is Expert #1 really selling me a maintenance nightmare?
If Option 1 can be made to work, what special precautions should I insist on?

Thanks for taking the time to read this and respond.


  • I myself like option 1

    but it would depend on the size of the radiant load, and what you choose for a heat exchanger.

    If the radiant load is more than 25% of the DOE Output under the steam column on the rating plate, and the boiler is the right size for the steam load, I wouldn't do it. Not enough boiler for the job.

  • chuck shaw
    chuck shaw Member Posts: 584
    One more thing

    Buderus doesnt make a steam boiler, so he would be converting your whole system to hot water. Just one more thing to think about


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  • Al Letellier
    Al Letellier Member Posts: 781

    As many of these going around as kinds of cars these days. There is some merit to both options but the key factors that I would look at are: as mentioned in previous post, can the boiler handle it; how old is the boiler and what condition iS THE WHOLE SYSTEM in, and what kind of equipment will be used.
    If the boiler is reasonably new, I'd go with option one. Option two means a completely new system as Buderus doesn't make a steam boiler, so the expense will be much higher. If the boiler has some age to it, but the system is in good condition, maybe a new steam boiler and option 1.
    As you can tell, the options are varied and so is the cost. But, based on the info you gave, I'd go Option 1

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  • DaveGateway
    DaveGateway Member Posts: 568

    Thanks for the advice.
    A bit more info on the situation - The existing Boiler is a Weil Mclain EG55 installed 6 years ago. Regardless of Option, the steam system would stay in place. Option 2 was actually adding an ADDITIONAL Boiler next to my steam boiler. The original system is 1940's one pipe and it appears that only the boiler and near boiler piping was replaced. I also replaced the condensate return lines last year.

    As for Option 1. Are there certain types of pumps which should be used and how often might they need to be replaced.
  • bob young
    bob young Member Posts: 2,177
    combination systems

    check and see if boiler is sized correctly to existing house steam radiation load. if it is slightly oversized the radiant can probably be added by use of a mixing valve { holby or equal } and pertinent piping and controls. i would then install a gas fired water heater for domestic hot water. then in the summer you can shut down the boiler. you could even get more creative and add a coil and use it as a pre-heater for the supply to the storage tank. the eg 55 is a decent boiler and at 6 years is considered new.
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