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Safe operating temps for boiler with storage.

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by salecker, Nov 18, 2013.

  1. salecker

    salecker Feeling the Heat

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    Northern Canada
    Hi All
    I built my own system a few yrs ago using a Econoburn 200 and 1000 gals storage in it's own building.120 ft to house with spray in trench foam.The first yr we heated only the basement,second yr the house above got the heat which escaped through the floor.This yr we keep the house heated to room temp,so far with a large temporary rad which will be replaced with cast iron rads throughout the house.
    Anyhow the boiler came with a preset max temp 165 and the manual says" Don't change preset" or something along those lines.Everything has been working fine,my wife has no problems starting or tending the boiler.But as the heat load increases i would like to increase the temps in storage.I'v read about guys running up to 195 and read about the additional BTU's in the higher temps.
    So my questions are Pro's? Con's? and how do you reset the temps on the factory control?
    We are getting close to finishing the inside of the house,then i hope to tweek the heating system some more.Insulating pipes different controls ect.
    Thanks Thomas

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  2. Clarkbug

    Clarkbug Minister of Fire

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    If you are going to use the cast iron rads, you should be fine to run at the lower temp. I understand what you are saying RE: increasing the amount of heat in storage, and technically its more BTUs. I just dont know that you will need it.

    Not sure how to change the controls on that boiler, sorry!
  3. jebatty

    jebatty Minister of Fire

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    This surprises me. The 3 other gasification boilers I have worked with all have maximum operating temps in the 185-190+ range. I looked at the manual, available on the web, and on page 21 it says the draft fan controller is normally set at 160F but it is adjustable. Page 21 also has a drawn picture of the control panel and it shows the draft fan controller set at 180F.

    I see nothing in the manual that says you can't change this. What page do you find the instruction not to change the draft fan off setting? On page 10 it explains the overheat relay which is set at 220F. All of this tells me, and consistent with other boilers mentioned, go ahead and push the button to increase the off point of the draft fan controller to what you want it to be. It may have a maximum setting but if not, I would use 190F as the maximum. And I would use 160F as the minimum setting.
  4. woodsmaster

    woodsmaster Minister of Fire

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    Don't Know about your controls but if you could heat up the storage to 190 and mix the temp down to your rads that would get you the most out of your storage. the only downfall I see to heating the water hotter is it may be slightly less efficient.
    BoilerMan likes this.
  5. jebatty

    jebatty Minister of Fire

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    Mixing down for radiant is super "cool." I can heat 1000 gal storage to 190F, top to bottom, and then mix down to 100F for the in-floor, and I easily get two days heat from the storage, so I burn every other day at most, and less often in milder outdoor temperatures.
  6. airlina

    airlina Member

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    I have an econoburn 100 (4th year ,no storage) that came with the same 160 deg preset temp. My heat transmission is thru old style baseboard units. I regularly change my boiler preset depending on heat load required. 160 is the low end for me , usually I bump it up to 175 which does a better job in colder weather.
  7. maple1

    maple1 Minister of Fire

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    I would second this nomination.

    It would kill me to have 1000 gallons of storage but only be able to heat it up to 165°. Your boiler will work better and your heat will respond much better at an upper limit of 190° - and your storage mileage will go way up.

    What's your burn routine like now? Doesn't sound like you have a real big house - you might be able to burn every second day with 1000 gallons (and your large temporary rad) up to full temp.
  8. salecker

    salecker Feeling the Heat

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    Hi All
    Thanks for the reply's,I've found my manual and on page 21 of mine in the first paragraph it states their normal setting of 160.Now mine is the first run of controllers which a few people had issues with.It goes on under the diagram of the controller to say factory preset do not change.And also explains how to adjust temps.:rolleyes:
    Anyhow that just leaves the Pros? Cons? debate.
    Right now we fire once a day,the lenght depends on the temp,tonight it will be -34C and today it got up to -25C,so today we started the fire at 3pm and it should hit idle by 10-11pm.Last week we would start fire 5-6 ish.
    As to the higher temp water not sure if i would need to mix down?
    Jebatty how do you mix down?Is it right in your floor manifold?I have a manifold for in-floor heat which has little thermostats for each run.
  9. jebatty

    jebatty Minister of Fire

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    If all zones use the same temp water, then a mixing valve before the manifold to reduce temperature to what you want. Just be sure the mixing valve flow rating is sufficient to handle total flow through the zones. If zones required different temp water, then perhaps a mixing valve(s) on the zones that need reduced temp water. A mixing valve is plumbed with the circ pulling water through the valve.

    Another way that may work is to plumb return water from high temp zones to supply water for low temp zones and "reuse" the relatively high temp return water before returning to the boiler.
  10. Nofossil

    Nofossil Moderator Emeritus

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    I was going to add some insightful comment, but I think the issues have pretty much been covered. In my understanding, I'd summarize it this way:

    Pros
    • Higher effective storage capacity
      • Fewer fires, longer time between fires
    • Quicker response to heat demand
    Cons
    • Slight loss in boiler efficiency (pretty much unmeasurably slight)
    • Less reaction time between system failure (circulator fail, power fail) and overheat
    • More storage standby loss
    I vary my boiler outlet temp during the course of a fire. When storage is cool and there are other heat demands, I run my boiler outlet as low as 160. As I'm topping off storage. I'll move the target up to 190, which allows the actual temp to go as high as 195.
  11. JP11

    JP11 Minister of Fire

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    Repeatedly run mine to 195. Storage temps if I let the boiler go all the way to idle will be 197 top of tank, 195 at the bottom.

    Lasts pretty good mixing down for 110 for in concrete radiant.

    JP
  12. heaterman

    heaterman Minister of Fire

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    Personally I like to see max system temps for any cordwood boiler at 180-185 max if for no other reason than having a little margin for error and safety.
    That being said, the first thing i would do if in your shoes would be to make a call to Econoburn and get their input on changing your control set point temp. As far as I know that should not be a problem.
  13. goosegunner

    goosegunner Minister of Fire

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    I guess I am confused, My indoor Econoburn goes much higher. I usually have it set to 190. It does not get to that point when I am charging my tank. I am flowing enough water to have a nice delta T.

    I weigh the wood I put in so my output is falling off as the tank is reaching its upper temp. My tank temp depends mostly on when I can fire it again. When it is cold I will go to 190 but typically it is 185.

    gg

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