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  1. #14
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    67,763
    No problem.
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    How many times must one fix something before it is fixed?

  2. #15
    Join Date
    Jun 2008
    Location
    Connecticut
    Posts
    2
    Quote Originally Posted by dbuck50 View Post
    I appreciate your advice and knowledge. Thank you very much.
    I just started reading this and agree lose the tankless coil and get a indirect and a honeywell 4006 aquastat to cold fire the boiler when a call for heating from the house or the indirect calls for heat. you will see your oil bill drop doing this! why waste the energy of having the boiler maintain 180 degrees? Just my opinion I have converted my parnets to this same set up.

  3. #16
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
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    No need to get a L4006, you just rewire teh triple to bypass the reverse action/low limit.
    Works the same as an L4006 then. Takes one minute if you milk it.
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  4. #17
    Join Date
    Aug 2006
    Posts
    42
    Won't the cold firing of the boiler be hard on the boiler if it is waiting for heat or hot water calls? I always thought that they need to stay hot to be relatively efficient (at least in firing).

    Also, do you literally remove the tankless coil in doing this method? or just not use it.

  5. #18
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,763
    Just don't use it.

    If your going to cold fire a boiler.Some evaluation should be done.
    The burner needs set up to burn clean, not just an eye set up.
    And some times a thermal bypass needs added to temper the water.
    Most baseboard systems don't hold enough water to effect the boiler.
    Cast Iron rad systems generally need a thermal bypass.

    A boiler is less efficient when the water temp is at 180*, then when the water is at 140*.
    The colder it gets outside, the warmer the boiler stays between heat calls.

    Most steam boilers are cold fired.
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  6. #19
    Join Date
    Aug 2006
    Posts
    42
    OK, so if I understand this correctly, the tankless coil gets capped off, and the indirect is used as a new zone to provide domestic HW. My existing combination of baseboard and radiant heat zones still operate as is---and I'm guessing indirects don't need to be at 180 to be effective.

    The end result should be that my boiler operates less frequently for DHW, but will operate the same for heating needs but only when called on. Since I supplement my heat with my wood stove, I am thinking I should see less oil use than I have in the past.

    I just got my electric bill last night...it is up to $.18 now...ouch.

  7. #20
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,763
    Yes, thats the way it operates with an indirect.

    Wow, that is a painfull electric rate.
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  8. #21
    Join Date
    Jul 2005
    Location
    Branford,Ct.
    Posts
    37
    Very good advise so far. If I could step in and add that an outdoor reset used on the boiler if you're going indirect or electric for your hot water would dramatically decrease fuel usage. A Heatmanager form Beckett or HW+ from Intellidyne would also save money and both come with a 10% savings promised or your money back. I personally use outdoor reset.

  9. #22
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,763
    OD reset would save more then the heat timer.

    Making that many changes at once, it would be hard to tell how much savings he got from OD reset or the timer.
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  10. #23
    Join Date
    Jul 2005
    Location
    Branford,Ct.
    Posts
    37
    I can personally vouch for the savings potential of an ODR. Can't speak for timers, but in europe I understand they use them alot. The only thing I might caution against is modifying the wiring on the aqua-stat. If doing so might void UL approval I wouldn't and haven't done it. I have seen it done in the field many times though and it seems to operate properly. Just my own personal feeling regarding liability etc.

  11. #24
    Join Date
    Nov 2007
    Location
    New Jersey
    Posts
    110
    Letting tankless coil boilers go cold isn't always easy on them. Too much possibility the coil gasket will start leaking. There is also the likelihood of increased scale accumulation in the boiler flueways, especially in a pin-type boiler. Better to lower the aquastat to about 120 and use a relay for the indirect that will start the burner with the circulator. The high side of the aquastat then comes into play. Maintaining some boiler temp provides faster DHW recovery, especially if the boiler is not oversized. After the hot water call is satisfied the boiler temp will drop back to the low setting.

    You can use a Beckett AFG with outside air kit instead of the Riello BF. This does reduce considerably air infiltration. It takes almost 1400 cu ft of air to burn one gallon of oil. It has to come from somewhere and if that somewhere is the house outside air comes in to replace it. In winter that air is cold and requires fuel to bring it to room temperature.

  12. #25
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,763
    Quote Originally Posted by coryc View Post
    The only thing I might caution against is modifying the wiring on the aqua-stat. If doing so might void UL approval I wouldn't and haven't done it. I have seen it done in the field many times though and it seems to operate properly. Just my own personal feeling regarding liability etc.
    Its just the low limit that you by pass, not the high limit.
    The only thing it does. Is stop the aqua stat from maintaining temp, and shutting the circ off if the water temp drops below the low limit setting.
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  13. #26
    Join Date
    Aug 2006
    Posts
    42
    What is the average sized indirect for 2 normal HW usage people? Seems like 30 gallons would suffice, but thought I would ask. I was thinking Weil or Superstor.

    I just want to say I appreciate all this great knowledge...helps to be a little educated when discussing options with my tech!

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