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Control system options?

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bugaboo
bugaboo Member Posts: 14
in THE MAIN WALL
I have a small (850 sq.ft.) house that I am replacing the heating system in, and I need some suggestions on how to control the system.

There will be two zones, one baseboard, and one radiant, plus an indirect hot water maker. The baseboard zone is for a single room that has not been redone, while the radiant is for the rest of the house (600 sq.ft., living room, bedroom, kitchen, and bathroom). In the future I may be upgrading the baseboard-using bedroom to radiant as well, but not yet.

I have oil for the fuel source, and have been looking at the Burnham MPO-IQ, the Buderus 115, and the Biasi B10.

All three boilers are cold start, and I would like to be able to use that feature in order to conserve energy.

How would you recommend controling this setup?



Thanks!

Comments

  • furnacefigher15
    furnacefigher15 Member Posts: 514
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    You will

    Want to zone with pumps, not valves. The in floor zone will need a mix down control such as a 3 way thermostatic mixing valve.



    And Have the pumps controlled by a 3 place pump control, that has a priority setting for the dhw demand.



    Each zone will need a thermostat, or tank sensor to provide input to the pump controller.



    The pump controller will then provide demand to the boiler.



    If outdoor reset is wanted, then the best option will vary with your boiler selection.
  • bugaboo
    bugaboo Member Posts: 14
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    On the same page so far!

    Thank you.

    From what I have read, an outdoor reset on the boiler is not going to do much, if anything for me. The boiler is just going to be much too large for my heat loss.

    I am under the impression that using outdoor reset for the radiant (and I suppose one on the baseboard as well) is something that will work.



    As I understand it, the Burnham IQ control will run two circuits, but not the three I need. So, I would need a zone control anyway, right? The integrated LWCO is nice, but something like the Beckett Aquasmart could be used on one of the others and give about the same results, right?



    What products would you use?
  • Ironman
    Ironman Member Posts: 7,387
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    Radiant Zone

    Is the radiant in slab or "staple up"? If it's in slab, then you'll need to control the water temp to the slab based on outdoor reset, not a fixed temp device. The slab is high mass and will over-heat the zone if the water temp is not matched to the load. This is what known as the "flywheel effect".



    A smart valve or variable speed injection are your options. Buderus has a card that works with their 2107 Logamatic control to control a mixing valve for radiant floors.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • furnacefigher15
    furnacefigher15 Member Posts: 514
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    Why too large?

    Size the boiler to the heating load.
  • bugaboo
    bugaboo Member Posts: 14
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    Staple

    It is "staple up", though it is actually 'clip up', since it is in transfer plates.
  • bugaboo
    bugaboo Member Posts: 14
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    Why too large?

    Foam insulation is being installed, along with new windows and doors. Heat loss calcs out at about 30K but will be lower. the smallest boiler I have found is the Biasi, at 58K.

    If I had gas I'm sure I could find something in the correct size, but in oil it is hopeless.
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