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can you add on demand to an older gas boiler for radiant baseboard heat?

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beoutside
beoutside Member Posts: 9
in Radiant Heating
We have an older system in a small house. It is a Valliant boiler closed-loop radiant floor baseboard with the individual on/off valves at each heater. Is there a way to add on-demand hot water?
Thank You
Donny McClure
Carpenter/ home Plummer and mechanic

Comments

  • Zman
    Zman Member Posts: 7,569
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    Does the boiler have a plate where a tankless coil could be installed? Pictures?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • beoutside
    beoutside Member Posts: 9
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    No, just the gas and water in on the back, flush on the front bottom. We are demoing the pantry and looking to save space and thinking of replacing the electric water heater that is as old as I am.
    Thank You




  • HVACNUT
    HVACNUT Member Posts: 5,841
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    Add an indirect water heater with priority.
  • GroundUp
    GroundUp Member Posts: 1,909
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    "On demand" is going to cause a lot of short cycling for the poor boiler on short bursts of hot water just for hand washing or whatever. It can be done but I would go the indirect route like has been mentioned above so you have some storage
  • Zman
    Zman Member Posts: 7,569
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    As mentioned, a small indirect (30 or 40 gallon) would be a good option.
    I think we need to talk about your flue pipe. Is that what I think it is? A closer picture would help.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    beoutside
  • HVACNUT
    HVACNUT Member Posts: 5,841
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    > @Zman said:
    > I think we need to talk about your flue pipe. Is that what I think it is? A closer picture would help.

    Looks like Z-Flex, Zman. Would've been a straight shot up and in with 26 gauge gal pipe. Lazy.
    beoutside
  • beoutside
    beoutside Member Posts: 9
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    Yes , that is the way it was vented when we bought the house. Flex pipe to an old chimney.
  • beoutside
    beoutside Member Posts: 9
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    Appreciate all the input, this old house did a video on adding an indirect with all the correct valves and safety measures..... I guess we can bypass saving space and just put the indirect were the old water heater is. On the video, the broiler used was larger than ours and had a side plate accessing the water they used to heat the house. With our baseboard radiant system, it is much smaller heating baseboard heaters, approx 40 feet total on one floor. We also heat with an efficient airtight wood stove.
  • beoutside
    beoutside Member Posts: 9
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    Ill double check but think our boilers BTU's is only 50000. Someone online recommended a minimum of 100000 for it to pump out hot water at an acceptable and predictable rate. Is that the case? Maybe we should just ad a tankless hot water system?
  • beoutside
    beoutside Member Posts: 9
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    Do you need 100000 Btus an indirect system to work well?
  • Zman
    Zman Member Posts: 7,569
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    Your existing electric heater is probably 16,000 btu. Your 100,000 is probably derated to 80,000 btu. An indirect should do the trick
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • beoutside
    beoutside Member Posts: 9
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    Does your broiler need to pump out a minimum of 100000 Btus, I meant!
  • beoutside
    beoutside Member Posts: 9
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    I’ll check but I think our broiler is 60000 BtU and I hear you need 100000 btu broiler as a minimum ? To work with an indirect
  • GroundUp
    GroundUp Member Posts: 1,909
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    Aren't broilers used in the kitchen? According to the ID tag photo above, your boiler's output is 50k which is plenty for your DHW needs when on priority. You won't get any space heating while on a DHW call, but that's not typically an issue unless you plan on using a million gallons of hot water
  • beoutside
    beoutside Member Posts: 9
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    Thank you ! I’ll broil you up some rib eyes :)
  • GroundUp
    GroundUp Member Posts: 1,909
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    beoutside said:

    Thank you ! I’ll broil you up some rib eyes :)

    Medium rare please :#
    beoutside

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