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Wow! Did my storage DUMP into my slab?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by JP11, Sep 21, 2012.

  1. JP11

    JP11 Minister of Fire

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    Left the house at 4am this morning. It was cool in the basement. I decided.. OK, time for heat. Temp was about 66 degrees in the basement.

    Call it 2100sf of basement slab that's heated. I set it to 71.

    Tanks are 1k gal. Were at 185 degrees plus. I took a shower, my wife probably did too later in the morning... So possible that the domestic called a couple of times. That's maybe 10degrees worth of storage temp.

    I get here to Philly... log in. Tanks at 130! Done heating!

    WHOA! Could my slab really suck up 400k BTUs in 5 hours? I know it's slow to respond.. and it sure was plenty cool. Just surprised is all. Of course keeping it hot isn't near as hard as heating it up.

    JP

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  2. Clarkbug

    Clarkbug Minister of Fire

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    Sure your slab could suck that up no problem. Plus the air is cold down there too, so thats plenty to heat up.

    I dont want to start burning yet, that would mean summer is over. Im not ready to admit that yet.
  3. maple1

    maple1 Minister of Fire

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    Takes an awful lot of heat to heat up a cool slab.
  4. JP11

    JP11 Minister of Fire

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    Yeah.. I guess I forgot. I think the boiler ran 3 or 4 days straight when we turned it on in '08.. in March or so.

    JP
  5. jebatty

    jebatty Minister of Fire

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    I heat a 1500 sq ft slab, 2" foam insulation around the perimeter and under the entire slab. I have the slab sensor set at 61F, 1F differential. Assuming the floor starts at temp, when the floor temp drops and storage again feeds the floor, typical is a 10F drop in 1000 gal tank temp, or about 83,000 btu's, and the rate of feed is about 34,000 btuh. I feed the floor at 100F via a mixing valve.
  6. JP11

    JP11 Minister of Fire

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    Was a bit warm when I got home. :) 72 in the basement. Trimmed it back a bit.. and loaded the boiler up! Won't ride that roller coaster again for a while I hope.

    JP
  7. BoilerMan

    BoilerMan Minister of Fire

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    I remember my first expierence heating up 2200 square feet of concrete in January of 2010. I just kept throwing wood in the old new yorker and the return water just stayed at 50F. Three hours later it was 55F and so on. But after that it was smooth sailing. Cold slabs eat heat. Warm slabs radiate it!

    TS
  8. heaterman

    heaterman Minister of Fire

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    Return water temp protection is mandatory when heating a high mass load like a slab of concrete. As illustrated very well here even a 1000 gallons will be sucked "dry" trying to move slab temp even 5*.
  9. JP11

    JP11 Minister of Fire

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    It's plenty warm now.

    In fact.. Think I kinda over fired the vigas. Filled er up with hemlock. Jeez.. for "shoulder wood" it sure got the tanks hot! I got about a foot of red hot coals left.. and the tanks are 190s on top and 180 on bottom.

    learning curve is a bit steep.

    JP
  10. BoilerMan

    BoilerMan Minister of Fire

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    All I can say is yup.

    TS
  11. P3PPC

    P3PPC New Member

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    JP, you are using propane tanks for storage? Do you have a contact on finding used ones in central maine? I'm just North of LA and want to start gathering the pieces of my system (will probably be a Vigas 40 and 500 gal of pressurized storage). Also, does anyone have expierience with putting the storage oustide?
  12. Clarkbug

    Clarkbug Minister of Fire

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    A member here who used to frequent the boiler room (NoFossil) had his storage outdoors under his deck.

    Need lots of insulation and the ability to make sure it wont ever freeze....
  13. JP11

    JP11 Minister of Fire

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    I know there's a yard on washington ave in Auburn.. I see some used stuff. Not sure if it's Webber, or Amerigas or what. I didn't get mine there. I got them from a contractor down south, friend of a friend thing.

    There around.. and after you get one,,,, you'll see a dozen more.

    JP
  14. P3PPC

    P3PPC New Member

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    Thanks JP, they are now owned by weber out of bangor, as weber sold the delivery part off down here to down east? How can I send you my email contact? I'd love to take a look at your system. I've looked at a couple that Rocky Lake installed and they worked very well.
  15. heaterman

    heaterman Minister of Fire

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    Curious as to what water temperature you were dumping into the slab? Are you using a one temp thermostatic mix valve or something that modulates like and motorized valve or injection mixing?
  16. JP11

    JP11 Minister of Fire

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    Not motorized.. i know that. Temp going into slab is usually in the 105 to 108 range. So it's mixing in a lot of return water obviously. Once I got basement up to temp.. it hasn't used much at all. That first night was a doozy though.

    JP

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