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Different water temps on same zone?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by tuolumne, Dec 21, 2007.

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  1. tuolumne

    tuolumne New Member

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    The main area the home we're building is essentially one room, therefore a single zone for that area makes sense. However, the kitchen lacks space for wall heaters, and in-floor radiant would be a good option. The rest of the space will have high output wall panel radiators. The radiators can run at 140-180 degrees, but the in floor radiant would need to be much less.

    Question 1 - Is there any way to mix down the water temperature in the radiant loop once that zone is moving?

    Question 2 - Would running the water through all the wall panels first, then through the radiant zone be a workable option. The kitchen floor will be wood, so I would not want temps greater than 110 or so. I could size the radiators for 140 degree water, which actually would work better for the heat storage system we're using on a wood boiler...but is losing 30 degrees likely?

    Question 3 - I'm not worried about a cold feel to the wood floor, so some type of toekick heater could work. I would rather stay away from something with a fan. Does such a thing exist?

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  2. Nofossil

    Nofossil Moderator Emeritus

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    You'll want to make sure that the water returning to the boiler is warmer than 140 to avoid corrosion from condensation inside the boiler. This is easier if at least some of your return water is relatively hot, although you'll probably end up with a bypass loop that just recirculates some water without passing thorough a heating zone.

    As far as I know, you'd need a mixing valve and a second circulator for the radiant. You mention not worrying about a cold kitchen floor, but we are skeptical. Has the WAF been considered in this equation?

    If you're considering heat storage now or in the future, radiant improves the performance of the system.
  3. Grover59

    Grover59 Member

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    My 2 cents worth, I have done some research and I a have come to the conclusion, and I am sure most would agree that with water storage radiant floor heat is the beat way to go if possible.
    I all ready have baseboard now and I am going to install two zones of radiant heat just because I believe it will allow me to pull my storage down to lower temps, and therefore have more BTU capacity.
    I only have one floor and putting up the radiant will be much easier then probably some others that have 2 floors.

    Steve
  4. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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  5. Grover59

    Grover59 Member

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    Joe if you are replying to me, yes the baseboard and the radiant will be two complete seperate zones if this is what you mean. I will basically use my DHW to circulate through the radiant when it calls for heat, the baseboard will stay as is. At this time my wood boiler has a loop to my oil boiler that circulates most all the time, I then have a electric hot water tank that I have put a circulator on to push dhw through the tankless coil on the oil boiler when the water heater calls for heat using the existing switch on the electric tank, the element is disconnected. I did it this way to give me a DHW buffer so the wood boiler had time to catch up when it started, and I didn't pull the wood boiler temp down to low, it works very well, we never run out of hot water, the water temp stays the same all the time, and I don't have to use a tempering valve. Also I have a strap on aquastat on the return pipe from my baseboard this shuts down the circulator on the hot water tank if a zone is calling for heat, I did this to also keep the wood boiler water temp from diving to low, this may be a little overkill but it works very well, temp nerver goes lower then 160.

    As far as heating the DHW tank with the heat storage tank, I will be using another flat plate hx with another circulator, to heat the hot water tank with the storage tank.

    Steve
  6. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    I was replying to the original post, but no worries.

    I'd definitely add a flat plate between the DHW tank and the radiant zone, if I were you.

    Joe
  7. tuolumne

    tuolumne New Member

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    Most of the house is radiant wall panels, sized for 140 degree supply water on the coldest days. That lets the water storage run down pretty far before lighting a new fire. Two zone piping with a single thermostat sounds fine for me, thanks Joe.

    Now to highjack my own thread...I have pricing for Biazi, Myson and Buderus wall panels. Biazi and Buderus are similar, with Myson being a little cheaper (Runtal was off the charts). Does anyone have experience with any of these? My biggest concern is durability since we currently have 5.5 little radiator climbers roaming our home.
  8. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    Personally, I use DiaNorm radiators. I like them. Very sturdy, and they mount easily without fighting.

    Joe
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