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eko 25 all hooked up but pump set up to run all the time.

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by ihookem, Nov 25, 2009.

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  1. ihookem

    ihookem Minister of Fire

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    I have a return thermostat in the basement to get water temps after it's been through the hx and the dhw. It's the water temp on it's way back to the boiler. I imagine it looses another degree of 2 by the time it gets to the boiler. This thermostat reads 10 degrees cooler than the boiler thermostat. I keep the temps up pretty good until 8 pm. then I let the fire die till morning. I built another fire this morning but might hold off till the mixixng valve, or loading valve is installed. I also don't let anything call for heat until the return temp reads at least 140-150. Then I turn up the house thermostat 1 degree at a time cause the water temp drops so fast.

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  2. Gooserider

    Gooserider Mod Emeritus

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    Sounds like you could probably get away with burning till you can get the protection installed... Assuming a 2 degree drop from the house back to the boiler, that would mean you are seeing 138-148 at the boiler return, which is pretty close to the 140°F minimum that you should have... As long as you can keep the return temp in the house at that 140+ level, you should be fine...

    Also make sure you look at and maybe print out some of the protection system diagrams to show to your boiler guy - the return system, especially if doing the 3-way valve approach needs to be plumbed properly with respect to the pump in order for it to work right, and if your guy hasn't done many, he might not be aware of how it needs to be done... Showing him the options might help both in getting it done right, and helping the two of you pick the most reasonably priced option.

    Also, while keeping the return temp up all the time is a good idea, it's a little bit less critical when the fire is dieing down, as at that point you have driven all the water vapor out of the wood and are just burning the charcoal, which produces relatively little water vapor to condense...

    Gooserider
  3. ihookem

    ihookem Minister of Fire

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    Thanks, goose, I just ordered a Delfoss valve from AHONA in New York. 219.00 total. My return temps after going through the hx and dhw is still about 150 -2 or so by the time it gets to the boiler. AHONA is goiing to call the heat guy for details. Thanks for everything.
  4. jdavi581

    jdavi581 New Member

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    What size of mixing valve are you guys using? My boiler does not have one, although my return temps are 150-160 so I am not worried about running it as is, but as the weather gets cooler this will become a problem I am sure. I am looking on Ebay, and I see lots of 3/4". Would I need more flow than this? Heat load calcs are 40,000 BTU/hr, boiler is small, but I would assume I am over this size.
  5. ewdudley

    ewdudley Minister of Fire

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    You can't do a simple pi-r-squared comparison between mixer valves. Check the Cv on any candidate mixer valve and then figure out what effect it would have when incorporated into the system.

    None of the smaller valves I've looked at would be suitable for boiler return applications.

    For instance a Taco 5000 0.75" valve has a dismal Cv of 3.5. At 10 gpm it would introduce over 8 psi of pressure drop, even if you could afford the electricity to run a pump that would push 10 gpm through a system incorporating such a valve.

    The 2.0 hectodollar 1.5" Danfoss on the other hand sports a Cv of 20.0, yielding a pressure drop of 0.25 psi at 10 gpm.

    Cheers --ewd
  6. jdavi581

    jdavi581 New Member

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    Hello,
    I am not sure if I am understanding correctly. After re-reading my post, I relized that I was not clear on which mixing valve I was talking about. I am running full temperature (180-200) though my in floor heat, no mixing valve. I am interested in sizing the mixing valve for the return water so that my temperatures aren't too cold comming back from the heat load. I am thinking that since I am running full temperature to the floor, I may not have an issue with return temperatures being too low jsut because I am running a high temperature out. So far I have been running this a week, lows in the 20s highs in the 50s which is still pretty warm for central WI. I do not circulate water below 180, the pump is hooked to the aquastat to ensure that the boiler is up to temperature so I don't have creosote problems. The blower for the induction is on up to 200, then the pump turns on down to 180, then the fan kick in and the pump turns off.
    Thanks!
  7. Gooserider

    Gooserider Mod Emeritus

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    The basic idea is that the valve is essentially a "T" that sits in the supply line heading out of the boiler, with a variable control between how much goes out the "branch" line to the return, and how much goes to the main load... Like ANY piece of plumbing, it puts a certain amount of restriction in the line, just from the turbulence going through it, even if it's wide open...

    It is important to size the valve so that it puts as little restriction on the line as possible, which means it should at least be the same size as the pipe that you are putting it in, and that it should have a low "Cv" that tells you how much restriction it puts on the line - the higher the number the better... Otherwise if you put an overly restrictive valve in the line, it will cause problems for the flow in the entire system...

    Gooserider
  8. ewdudley

    ewdudley Minister of Fire

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    Right, you could have a mixing valve to set the temperature supplied to the floor, and you could have a mixer to set the temperature of the return temperature to the boiler. (Or none, or both.)

    If a system has a mixer for controlling return temperature, it is usually set up such that a boiler circ pump pulls water through the mixer into the return port of the boiler. The mixer in turn is set up such that it can pull water from the supply outlet of the boiler and/or from the return side of the load.

    I'm saying that in order to flow enough water to pull full capacity out of a typical boiler, such a valve needs to be comfortably free-flowing. But then again depending on the delta-T through the boiler and how much capacity you really need, it's possible a smallish mixer might do the trick, but you'd need to get a handle on the critical parameters and do the arithmetic in order to have any confidence in going that route.

    I believe typically combustion control and circ control are two independent functions.

    Circ pump: If demand is calling and boiler temperature is high enough (e.g., greater than 160F), the circ runs. If no demand or boiler temp too low (e.g., 150) the circ shuts off.

    Combustion air: If demand is calling control combustion air to achieve supply temperature setpoint (e.g., 195F). If no demand suppress combustion, but maintain minimum boiler temperature (e.g., 160F).

    I would be concerned about leaving the circ off all the way up to 200F; hot spots, stress, warpage, flashing, stuff like that. (Not to mention dust, bacteria, and aldehydes of afraidium.) YMMV.

    Cheers --ewd
  9. jdavi581

    jdavi581 New Member

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    Thanks everybody for the excellent information, I understand why the valve is so critical. I have 1.25 black iron coming out of my boiler, which is way overkill for both my boiler and house. This goes to a black Iron manifold the necks down to 3/4" reducing Ts for each loop of 5/8" pex, four loops total. My house has 1000ft^2, and I would guess that my boiler is 60-80KBTU, and I see most houses run 1" copper for much larger boilers and houses. I will look into this further before purchasing the valve that I need and get out the old fluid dynamics books. Thanks for all your help!
  10. ihookem

    ihookem Minister of Fire

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    Just a few more questions, honest! My Eko 25 super gassifies like crazy but still has smoke coming out the chimney the last few weeks. After a while it doesn't smoke much but seems to always smoke. It's not damp wood and I clean the holes every other loading with the lever in the back. Does this happen when it gets real cold and dry. It's been cold and am wondering if that's why. I also wonder if the cleaning rods came loose because it doesn't seem to have any resistance and can't feel the brushes scrubbing. Could something have come off to clean the holes? Thanbks again!
  11. Gooserider

    Gooserider Mod Emeritus

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    My understanding is that you should crank the turbulators on EVERY loading, not every other... The things you are moving are not brushes, they are twisted metal strips known as "turbulators" essentially a flat strip of steel that has been twisted into a spiral that increases the turbulence in the exhaust gases and makes them spend longer in the boiler and contact the HX tube walls more - thus making them give up heat more efficiently...

    Not sure how much resistance there is supposed to be, but if you are burning clean and cranking properly, there shouldn't be much... Hopefully one of the EKO owners can fill in more on that, and what to look for to see if there is a problem...

    Are you sure what you're getting out the stack is smoke and not steam? Gasification can produce quite a bit of water vapor, especially early in the process, and this will condense as white steam under some climate conditions - usually it looks a bit "fluffy" and is white, rather than grey. Also it sometimes doesn't appear right at the chimney, but rather a couple feet away...

    Gooserider
  12. ihookem

    ihookem Minister of Fire

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    Thanks Goose, it is fairly white smoke and almost never the grey smoke. Yes, sometimes it seems to not smoke until a few inches above the pipe. I also didn't know gassifiers gave off so much steam. It must be mostly steam then. I ask because all I hear about is gassifiers not smoking at all. I will try to figure out it the brushes are working. If the turbulators are dirty or clogged will it still gassify? Mine gassifies like crazy .
  13. Gooserider

    Gooserider Mod Emeritus

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    Yes, that sounds like steam... remember that you are burning all the gases quite completely, which just makes C02 and water vapor - plus cooking off all the considerable amount of water that is still in your wood (even if it is down in the 15-20% range) makes for a lot of water vapor - it will condense as steam when it hits the cold air coming out of the chimney...

    Assuming that nothing is broken, if the turbulators were very dirty, you wouldn't be able to move them - however if you are gasifying well it is unlikely that they will build up much crud... Besides not being able to crank the handle, the primary symptoms of dirty turbulators would be lowered heat output to your boiler water, and higher than normal flue temps, as the crud acts to insulate the HX... It won't affect the gasification significantly until you have so much buildup that it's blocking the exhaust outlet...

    Gooserider
  14. mr.fixit

    mr.fixit Member

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    On my eko 40,if you look way in the very back of the lower ash chamber with a flashlight you can see the bottom of the turbulators.If you move the cleaning handle (or have somebody do it)you can see the turbulators move up and down.Also there is a removable panel on top to inspect the turbulators and linkage.There's not alot of resistance when moving the cleaning handle. Idid notice to more steam out the stack this week with the cold weather.
  15. Singed Eyebrows

    Singed Eyebrows New Member

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    My Atmos also has white smoke most of the time & this is with the cleaner burning GS model. I lose part of the coal bed at times & this is probably most of the problem. I've been up & running for an entire 1 week now, so I've got a lot to learn. Good luck, Randy
  16. ihookem

    ihookem Minister of Fire

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    Thanks fixit . I will look with a flashlight.
  17. Dave T

    Dave T New Member

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    Another possible cauprit is the bypass flapper in the rear of the loading chamber, it might have some soot on it not allowing it to fully close. I listen for a metalic clang when shutting the bypass, if your getting more of a thud, good possibility. On the next half warm day you might want to rip er down and clean everything, this also gives you a chance to learn more about your EKO. Dave
  18. hkobus

    hkobus Member

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    I agree with Gooserider, it sounds like steam when it show a few inches above the pipe. What I doo see from time to time, usually after reloading, some coals/embers fallen through the nozzle will burn in the bottom chamber and a large amount af wood gas will mess up the air/fuel mixture and creates a bit of light grey to light blue smoke. This is no more than a minute or so when this corrects it self.
    I have home made turbulators and no way of moving them without opening the clean out. This I will do when the stack temp goes up or every other weekend, I don't see much of a change in smoke before or after, just a reduction in stack temp.

    Henk
  19. Tony H

    Tony H New Member

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    Lots of good info from everyone hear are a couple other items to consider when adding the danfoss .
    Have them plumb a bypass with a valve ( ball or Gate) to allow you to bypass the danfoss, this will allow you to run the pump and move water thru the entire system when the system is off or down for service to keep water from freezing.
    With a setup like you have you can start with just wiring the pump thru 2 switches one connected to the output of the controller pump circuit this will allow the controller to turn off and on the pump relative to water temp of the boiler. ( you can add other controls later if you want.) this would be normal operation and the second switch connect to direct ac this will allow you to switch pump to constant run when you bypass the danfoss.
    I just had occasion to use the bypass and running the water thru the HX it maintained a water temp of about 70 - 75 F in the system my system has glycol but over the years it has lost some ability to prevent freezing and when I tested a little it turned to slush over night and in a couple days froze semi solid.
    BTW mine also sends out some steam in the cold weather heck my gas furnace does also when its cold out. I find it mostly in the hours just after a reload until the wood starts getting charcoalized.
  20. Gooserider

    Gooserider Mod Emeritus

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    If your glycol is old, you might want to consider getting a boiler water test... I've seen a lot of comments that glycol can break down over time and become corrosive - not only does it stop protecting you from freezing, but it can also attack your pipes...

    Gooserider
  21. Tony H

    Tony H New Member

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    Yes a test and new glycol is in order - had not heard of the corrosion issue however. I am going to shut the system down to repair a weld on the load door hinge so that may be a good time to check it out and pump in some new stuff. The other possibility is the guy who figured out the volume of the system was off and we didn't have enough glycol in there to do the job, time to measure some pipe I guess.
  22. Gooserider

    Gooserider Mod Emeritus

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    I've seen a lot of comments from different pros that it is really a good idea to get a test done annually, just to prevent problems - makes sense to me, as water chemistry can cause problems if its out of whack - there are various anti-corrosive chemicals and so forth that are recommended, all of which get used up over time (It's part of whats in your glycol mix)

    Gooserider
  23. ihookem

    ihookem Minister of Fire

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    Thanks Tony. I am going to figure out how to hook the pump up to the eko so it shuts off when the water cools down. It won't need to be anytime soon since it's going all the time anyway. Also, have you used your stove for cooling? I thought about this but forgot. It might actually cool the house in the summer.
  24. Hydronics

    Hydronics Feeling the Heat

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    Yes it is wise to check your glycol PH annually. The major contributor to consuming the inhibitor is mixing with hard water so check it before mixing. If the glycol has a significant PH drop it will begin to "eat away" the copper.
  25. Tony H

    Tony H New Member

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    To connect the pump to the EKO on mine there is a termination strip on the back of the controller.
    There has been some talk around here on the cooling subject you might be able to search and find some info
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