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Will Logomatic work with 1/2" pipe?

jt27
jt27 Member Posts: 6
in Oil Heating
I got a quote on a Buderus system with the Logomatic reset. A second contractor said the system wouldn't help because our heat is carried via 1/2" pipe. If the outside temperature is cool, but not cold, the Logomatic will keep the boiler from generating enough BTUs to warm the house. He said we need at least 3/4" pipes. Does that make sense?

Comments

  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    No. What kind of heat emitters?
  • jt27
    jt27 Member Posts: 6
    I'm not sure exactly, but it's fin-tube baseboard.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    Well, that's your heat emitters :)

    It's been a long time since I've seen 1/2" piping in bb but it does exist. Like 3/4" piped bb (the norm) it's output is rated in so many BTU per linear foot based on a scale of hot water temperature the boiler produces. 1/2" puts out less heat per foot than 3/4" bb.

    But that's ok as long as the original installer put enough of it in each room to cover the heat loss of the rooms. And if that's the case, it is irrelevant to the Logomatic. It just adjusts water temps to the bb based on outdoor temps, providing the bb is sized correctly in length. If there was a different type of heat emitter such as cast iron radiators, or say, hydro air, or radiant floor, the Logo's temp control logic would need to be shifted accordingly.

    I am assuming you have a typical copper series loop fin tube situation and not some hybrid older monoflow or other with 1/2" branches to the bb and maybe 3/4" piping in the actual bb, or other. Not that it matters so much to the Logo. The piping and circulation pumping is a seperate issue.

    The Logomatic is a good investment IMO. It has a lot of other features wrapped up in one expandable control.
  • RobG
    RobG Member Posts: 1,850
    What Bob said is correct. Can you post some pictures of the boiler piping and baseboard (with the cover off and showing the ends)?

    Rob
  • jt27
    jt27 Member Posts: 6
    here are the pictures...


  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    Ahhhh yes...the Columbia Gem. If I had a dime for every one I put in in the early 90s. And a few more for firebox chambers that dropped over time. They weighed about 100 lbs and had a 600 degree stack temp.

    You are going to save fuel with the Buderus big time. Even without the Logo!

    Ho hum piping. Nothing special. Where is the 1/2" piping you were told about? The bb and loopslook 3/4".

    What's making your hot water? Are you going for an indirect water heater too?
  • jt27
    jt27 Member Posts: 6
    This is coming out of the boiler. Measuring, it looks like a 5/8". Is that possible? The pipe coming out of the wall to the bb
    is the same size.

  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    Apparently it IS 1/2". Thanks for the ruler. Dimensions are hard to judge on pictures sometimes. Every loop and all bb are 1/2"?

    Must have been having a sale on 1/2" copper that day :)

    I would want to verify your bb lengths in the rooms at this point, if it were my house. If you are short with 1/2" bb, the outdoor reset function on the Logo will compound the issue.

    Ask your contractor to do a room by room heat loss analysis and compare the bb you have, noting if it is indeed 1/2" and see where you land. If all checks out, the Logo will be a benefit.

    He might want to mull over his pump choice as well. If you are keeping the zone valves, a "smart" variable speed circulating pump would work well and address flow through the smaller than typical piping.
  • RobG
    RobG Member Posts: 1,850
    As Bob said, pictures are deceiving. Is the baseboard 3/4"? Are all of the pipes 1/2" coming out of the zone valves? Need more info.

    Rob
  • jt27
    jt27 Member Posts: 6
    All the pipes out of the zone valves are half inch except the one going to the water heater, which is 3/4". The bb is half inch.

    John
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    Ouch. This could stand a closer look. I would do that room by room bb analysis. The old way of thinking when oil was cheap was: not enough heat? Crank up the boiler to 211 degrees to get it done.

    Today, not so much. We strive for lower boiler temps to do the job with the right sized or over sized emitters. Have those lengths checked.

    Double ouch. You indicate a "water heater". Is this another zone off the boiler? That silver box in that loop? Not good where this is going :)
  • Eric_32
    Eric_32 Member Posts: 267
    What state do you live in?

    Have you ever had issues with the system not getting up to temp on "cold days"?

    How many feet of fin do you have on those zones?

    1/2" pipe can only carry so many BTU's before it has to be run back to the boiler to be reheated. Something like 15' (give or take) of baseboard is sticking in my mind.

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