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sidearm DHW: running intermittent-will it heat?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by barnartist, Jan 24, 2008.

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  1. barnartist

    barnartist Minister of Fire

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    If I were to change from a flat plate EX that heats my domestic water to a sidearm setup, can I run the water only part of the time and have enough heat?
    I currently have to run my boiler water continuously, and wish to only circulate that same water only when my house air furnace kicks on. The whole idea is that it may save some heat at my storage tanks. Heres the catch- the storage is 80 feet away. my furnace fan tends to kick on for 5-10 min, off for 15-20 unless below zero.

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  2. wdc1160

    wdc1160 New Member

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    Hey barn artist. I actually have run into a similar design decision. I know with your girls in the house you will have a higher demand than I. However, the answer always starts like this

    It depends. In the morning when everyone is showering it probably will need constant circ?? maybe? I think that type of problem solving will probably take a sensor and a valve. however,
    it was your post that they suggested this in "Anyone using a Laddomat system?"
    they said "a good way to take this on is a taco modulating pump that would open to a flat plate or sidearm, when a sensor noticed the water was cooling in your DHW."
    Do you not like this approach? Clearly, we were talking about storage there, but a zone is a zone. Why decriminate against DHW.


    I won't address the problem this way, but it is one method.

    I will use a controller and a valve.

    Did you find where all your electric is going???
  3. barnartist

    barnartist Minister of Fire

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    I didn't find the electric draw yet, but funny you ask- I was thinking about shutting down an old fridge in my garage, and even thought about doing the same to an upright deepfreez we have lots of old freezer burned items in and use very little. I'd like to find someone to trade down to a small chest unit really. Then see what that does to the bill.
    AS far as the DHW, just trying to justify the extra cost of putting in one of those sidearms, hate to spend the bucks for small changes in my wood pile. I did just now hook up my garage loop pump to only kick on if my air furnace does to see what happens. My thinking there was I was using about 60 feet of pex as a baseboard and saving the power of running the big fan. Sled_mack been telling me to do this for a while now, guess iv'e been stubborn. Garage has decent insulation in ceiling, but poor sidewalls-1" styrafoam.
    Im just thinking ahead before I invest my time and space requirements for the storage. Out of all the setups ive read from guys here on the forum, id love to have mine like Sleds. With the exception of NoFo, but thats the equivilant of landing on the moon again.
    Getting back to the DHW, I see what your saying there too as far as a sensor, but then there would need to be an additional pump, right? If I have a radiant zone, an air zone, and a DHW zone, wont something be asking for heat most of the time?

    Its gettin cold out there tonight. But im certain youve got some wind to deal with in Indy.
  4. wdc1160

    wdc1160 New Member

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    It would technically be a zone valve. You could use a 2 way 3way or 4 way valve. It would work like a zone. If you read through the previous post you submitted that is how they deal with reglating flow. I always like to read other peoples ideas on how to solve problems. That way looks quick and painless. Doesn't require any real hard work, but does not allow for monitoring or for electronic calibration.

    In otherwords all changes are made via the valve or the sensor.

    We have had real wind in Indy, but we have had such sunny days that solar gain has been tremendous. It has been 20 degrees out during the day, but it is not cold out because the sun seems so strong.


    Anyhow, electric daemons are the reason I get up in the morning.
    Keep fighting the good fight. I can tell you - that for you to notice the dollar amount of electric your likely looking at a loss not related to old refridgerators.

    Before you give them babies away unpluggem one at a time. Or even monitor their voltage. But really a compressor on a refridgerator has to be malfuntioning / shorting to create the draw you have told me about.

    A simple way of thinking of it is like this. In IN it costs 10 cents per kiowatthour
    one 20 amp service in your house could pull up to 2.4 kw -- this is pulling full out. Thats 24 cents an hour @ 24 hr that 5.76 a day or 172 a month.
    That is one smoking 20 amp service. Probably unreastic/ theoretical, but technially possible.

    You said that even after you removed DHW electric you could see 100 dollars over and above what you thought might be reasonable.
    you might be looking at 1000KW over what you think you should be paying. That is alot of juice.

    I believe that kind of malfunction could be viewed by killing circuits on your breaker panel and measurment with a pad of paper and a watch. Once you corner it to a circuit you've got it beat.
    Its tough to measure normally, but that kind of draw is significant. I said it once b4, but often times large heating elements have the largest draw in the house. U R sure its not a heating element for a water tank for a horse or maybe a
    renegade toaster right??

    Hope you find it.

    Bill
  5. mikeyny

    mikeyny Feeling the Heat

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    just a couple thoughts on the electric usage. If the fridge is in a cold garage the compressor will draw a significantly more amount of juice. Also, if you remove the electric panel cover you could put a clamp on amp probe on each individual circuit and watch it for a few min and see what happens. You could probably spend half the day monitoring the amp draw on all of your circuits. It might help narrow down the greedy circuit. You can buy one on harbor freight for about 30 bucks I think.

    Mike
  6. sled_mack

    sled_mack New Member

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    That would get my vote as well. You don't need accuracy to the fraction of an amp for this, so you don't need to buy a high end meter.
  7. sled_mack

    sled_mack New Member

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    Let me throw out the 80/20 rule here. Right now, I think he just has the flat plate exhchanger in series of the loop from the boiler. If he does the same with the sidearm, it will provide heat to the tank whenever the house is calling for heat. So with no additional controls, he'll get a decent amount of hot water with just installing the side arm. The bigger the tank, the more likely it will be that he will never run out. He might get 80% of his DHW needs for the least effort? Furthermore, he could try this, and if it's not enough DHW, he could add controls later. The plumbing might not have to change, just the wiring.

    Another option - do they make flow switches for domestic water use? Let's say he leaves his flat plate exchanger and connects a flow switch in the DHW line. Now, wire up the pump so that it runs if either the flow switch is on or the fan for the furnace is running. Probably worth spending money for a time delay relay, too. Once the flow switch is on, run it for a few minutes to be sure the hx is fully heated.

    It's possible to do something similar with a temp switch on the DHW pipe, too. I'm just not sure where best to put the switch.

    While the flow switch is an option (and it's just an idea - shoot it down if I'm missing the flaws in it), I like the side arm on the water heater better.
  8. barnartist

    barnartist Minister of Fire

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    I forgot about the flow switch. How does that even work? It just senses flow, eh? so I could put that sensor on the pipe on the water heater(cold in or hot out) and tell the pump to kick on, and have that same pump run too when the furnace does. Would I need some kind of three way wired deal then?
    Am I doing all of this for stratification? What I think id like to do, is be able to swith from how I run things now during the real cold days, to opening other tanks and drawing the heat from the tank then. During 35+ days I think. ^%*@!$# I dont know what I want. Just want it best.

    I have a kill-a-watt meter I use on some thinks the read power draw. That old fridge said 475 watts when it ran. I dont knowhow this compares to newer fridges, but sounds high. Bill, just to be sure you know, My bill runs about $120 bucks, and 150+ in the summer. The part I hate is the line on the bill that is "rider A charge". its sometimes 5 bucks, but sometimes 20. I called to ask what this was, and the way I understand it it is power they have to buy from other sources. Again, my hot water is electric, that breaker has been off since halloween. Whatever I save by heating my water is made up by my furnace fan I think.

    Sled, I wired my garage pump to kick on with that furnace. I found that the Laddomats pump still moves water through it though, enough flow for about 145-150F water.
    Its hard to believe that the house pump (much bigger pump)doesnt suck from that loop (I tee off my boiler, one loop to house,one to garage), but im thinking the Laddomat when wide open has enough to satisfy house flow, and still push some through garage. I actually beleive that running tha garage pump helps flow more water through the boiler, which is what I need I think down the road.

    Alot of stuff here. Sorry fellas.
  9. Eric Johnson

    Eric Johnson Mod Emeritus

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    If I understand your question correctly, barnartist, the sidearm should charge up your water heater tank and store the hot water. So you don't need constant circulation through the sidearm--just enough to keep the water in the tank hot.

    As a practical matter, any time my boiler is running, the pump is basically on, pumping water away from it. So the sidearm has plenty of time to charge up the hot water tank. When the boiler burns down and the pump shuts off, you've got 40 or 50 gallons of 170-degree water to play with.
  10. sled_mack

    sled_mack New Member

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    Scott,

    You need to put all of the pieces together into one big solution.

    If you have a hand valve in the garage loop try closing it part way to add a little restriction. That should slow down the "ghost" flow from the laddomat. Actually, try shutting it off (and turning off power to the stat) while you are there during the day to watch that it doesn't freeze. See if that makes any difference to your storage tank.

    The flow switch idea is just a wild idea on my part. I'd like someone else to chime in on that one. Theoretically, it would work. Finding a flow switch could be tough.

    Regardless of using the flow switch or using a temp sensor on the hot water heater, you could do it with just one loop in the house or you could split the loop in the house and do either DHW or heat. I'm not sure which has the most advantages? How much loss is there to putting those two loads in series, and passing water through the one that doesn't need it?

    I'd also consider leaving your flat plate exchanger in front of the DHW heater tank. That will help heat the water faster during long periods of demand.

    I would really consider trying as much of this as you can this winter - basically what ever you can try without buying more parts for now. See what helps, what doesn't. Gather as much info as you can. Then make a coordinated plan for next winter and work on it over the summer. I think you are probably close, but just need some teaking!
  11. barnartist

    barnartist Minister of Fire

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    Eric, then if you dont use any hot water in your house, and then your boiler cools off, it wont cool the water heater tank then.

    Its easy to close that valve Sled, whats your thought on my "more flow through the boiler" theory?

    Im recalculating some appliance wattage Bill. I'll post some of my findings.

    I see a warm spike in the weather comming up. Wondering what I should do with it. Maybe just run the chain saw.
  12. Eric Johnson

    Eric Johnson Mod Emeritus

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    If you have a flow control on the line feeding the sidearm (and assuming the flow is top to bottom, as it should be), then the heat can't thermosiphon out of the water heater when the pump isn't running. If the water in the tank is hotter than the water being pumped through the outside shell of the hx, of course, then you're going lose some back into the system, but your pump shouldn't be running if the temp is below 140, so it's kind of a moot point.

    Just to give you a real example, even on mornings when I wake up to a cold boiler, I can still get a very hot shower.

    The only time it becomes a problem is on warm days when the boiler doesn't run, or runs very little. Then you can use more hot water than is being produced. But since you have a heat storage tank, that shouldn't be a problem for you. You can circulate water from the tank through the sidearm.
  13. wdc1160

    wdc1160 New Member

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    475 is high for a fridge, and it will work harder out in a cold garage, but 475 requires constant running to acheive your 50+ dollar loss in electric.
    I don't disagree with mike or sled mack. I was just trying to stay low tech, about a detection method. Don't forget not testing at the breaker will not show inefficiencies in the cabling shorts that can occur.

    Thanks Bill
  14. barnartist

    barnartist Minister of Fire

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    Bill, how many watts are a kilowatt, 1000?
    Whats the going rate for a sidearm fellas?
  15. bjleau

    bjleau New Member

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    I asked that KW question a while back to a german friend so after getting an earful.

    Kilo = Thousand 1 KW = 1000 watts

    On the electric question...
    Do you have a well for water? I had a Pin hole in my pump pipe so my well pump was running and it started small like extra $10 and grew to $50 a month till I shut the breakers down on everythig and found it. Pretty Common issue wil a 30yr old well in MN.

    Later
  16. Nofossil

    Nofossil Moderator Emeritus

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    Metric prefixes are very useful. Did you know:

    'cent' means 1/100 so 1/100 of a mental journey = 1 centimental journey

    'kilo' means 1000 so 2000 mockingbirds = 2 kilomockingbird

    and so on......
  17. mikeyny

    mikeyny Feeling the Heat

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    On the electric question…
    Do you have a well for water? I had a Pin hole in my pump pipe so my well pump was running and it started small like extra $10 and grew to $50 a month till I shut the breakers down on everythig and found it. Pretty Common issue wil a 30yr old well in MN.

    Later

    ** Brilliant thought.*** That happens all the time. That alone could be a real big draw.
    The suggestions on this forum absolutely amaze me sometimes. Wood burning conversation turns into technical electrical troubleshooting discussion by a bunch of frugal energy saving fanatics. Are we all nuts or is it just me???

    Mike
  18. drizler

    drizler Minister of Fire

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    Yup , and thats about the first place you ever want to check too. You get something jamming the foot valve which is another common issue and it will do pretty much the same thing running more or less constantly trying to keep pressure.
  19. Eric Johnson

    Eric Johnson Mod Emeritus

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    No Mikey, we're all pretty nuts.

    But it feels so good........
  20. barnartist

    barnartist Minister of Fire

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    I'll check for pinhole, but I have both a cistern, and a well with the ability to switch to either on demand. Both seem to have equal power results, but i'll double check.
    Bill, rechecked the old fridge, It only draws 180 watts when running. I used the kill-o-watt thing, and in 7 hrs it drew .44 kw. I think. Maybe it isnt too bad.
    Maybe I should buy that power meter, as well as the moisture one.
    What are some of you guy's E-bills?
  21. sled_mack

    sled_mack New Member

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    Hmmm... Not sure what I'm thinking any more....

    What I was hoping to do was see if there is something that is draining more heat from your system than you think it is. The garage is a likely candidate, and an easy one to test. You might find that your solution isn't plumbing but insulation?

    As far as flow through the boiler, I don't know. I've got two Grundfoss UP26-64 pumps in parallel pulling through the boiler. I haven't seen an actual pump curve for the Laddomat, but I'd say that I'm probably pushing twice the water through the boiler than what you are. I just don't know if that is really better or not? It's working for me, but I have hx coils in a tank, not a pressurized tank. I don't really know/understand the Laddomat enough to comment on it. A big pump and the Termovar valve I can relate to.

    Maybe it'll make more sense to me if I sleep on it.
  22. wdc1160

    wdc1160 New Member

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    Sled you lost me what does that have to do with DHW problem or electric??

    You think he doesn't have enought boiler. I thought he was just trying to be more efficient.


    Bill
  23. barnartist

    barnartist Minister of Fire

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    Bill, Sled and I have been discussing my heat for a couple of seasons now. Im sure saved an e-mail. I'll take the info from whomever, whereever. I have plenty of boiler, NoFo thinks im way too big. I just have this tick in my brain saying "I can do much better" per load of wood.
    As far as the old fridge goes, at 12 hours it used .62 KW. So 24 hours would be 1.24K, X 30= 37.2K. I have my watts and kilowatts mixed up, thats not right.
    Unless its kWh, X 0.074 cents= 2.7 something. Thats off, maybe a decimal, cause 27$ sounds right.
    Bill, help me out.

    I insulated my boilers underbelly last night. Will post the results on the wood consumption thread.
  24. wdc1160

    wdc1160 New Member

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    1.24KW = in Lafayette @ 9.5 cent a KW thats 13 cents a day in running cost. Which is alot for a fridge. As someone said that fridge has to work harder in the winter months. The plates on the compressor are not made for the cold. Keep looking for the culprit.

    I don't think you should give away the fridge. Or, I could be by later to pick it up.


    What did you insulate underneath with.. I mean what material
  25. barnartist

    barnartist Minister of Fire

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    That fridge is inside the garage, where it stays between 55-70F. 12 cents a day seems cheap. Heck now im more frustrated, cause if it only costs 3,4 bucks to run that thing, how the heck is my bill freakin 120 bucks?
    The only thing big then we would run is the dryer. Maybe the cooking oven.
    %$#^%$&$!!!!!!!!!!!
    I used a thin layer of fiberglass, and 2" blue foamboard. Its early, but im 2 hours longer at this point on a burn. I havent been out to check it yet.
    Im heading out to a wood cutting party.
    When I get back I want this problem solved men.
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