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Hot water loop to heat exchanger loop

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JaymeHart
JaymeHart Member Posts: 30
in Strictly Steam

I recently had a new boiler installed, for a mainly single-pipe steam heated house, with a single hot water zone and circulator to heat the kitchen (added from a remodel). Boiler is in the basement, hot water radiator is upstairs one floor.

1000010477.jpg

The hot water loop was installed without a proper mixing loop, so I am getting flash steam in the hot water line. I am worried about it bursting the copper pipe.

I need to either 1) add a mixing loop, or 2) do what I wanted to do first and put in a proper heat exchanger system.

I am following this writeup: https://heatinghelp.com/systems-help-center/how-to-run-a-hot-water-zone-off-a-steam-boiler/

1000010482.jpg

For the heat exchanger, am I correct that this tank is the heat exchanger, vent, and expansion tank all in one?

1000010480.jpg

Comments

  • ethicalpaul
    ethicalpaul Member Posts: 8,177

    I recommend a bypass loop and for sure put the circulator pump on the floor and give it a good size supply pipe like 1”.

    You want as much head as possible from the boiler to the pump. Peerless boilers have a tapping higher than the one you are using exactly for that purpose

    It’s a lot less complexity and cost than a heat exchanger setup.

    Fair warning, I have only set up one of these, but it works!

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 11,588

    I wonder why you (or your installer) didn't select a tankless coil in the boiler for the hot water loop. Is that still an option? you may be able to purchase the proper tankless coil for that boiler if the tankless coil opening is there. Some boilers must be ordered with the tankless coil or the end section is different. Here is an illustration of Weil McLain's EG boiler with optional tankless coil section in the circle. So you would not have a place to install the coil in this case.

    Screenshot 2025-12-23 at 10.16.19 AM.png

    I would prefer the heat exchanger method for several reasons and the most important is the fact that you can pressurize the water loop to avoid flashing at the pump inlet. That loop would need to have a relief valve and expansion tank since it will be its own closed system.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • JaymeHart
    JaymeHart Member Posts: 30

    the boiler is a Utica UH1606HSID. It is alread a tight fit for the space....I dont think that tankless coil option on the boiler would have fit.

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