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Heat Issue

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HeatNovice
HeatNovice Member Posts: 29
I have what I believe you call a hydro system. My upper floor vents only blow out cold air when the temperature is very cold outside about 10 degrees or below. Once temp outside gets to 25 degrees it works fine again. I touched the pipe in the basement that services the upper floor and it’s very warm/hot. I’m available for discussion please. Thank you 
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  • Big Ed_4
    Big Ed_4 Member Posts: 2,806
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    need more boiler temp to produce heat at 10* What is high limit now ?

    There was an error rendering this rich post.

  • HeatNovice
    HeatNovice Member Posts: 29
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    BE,

    I’m sorry, I’m a novice. Can you help me check?
  • Big Ed_4
    Big Ed_4 Member Posts: 2,806
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    What is the reading of the temperature gauge of the boiler ?

    There was an error rendering this rich post.

  • HeatNovice
    HeatNovice Member Posts: 29
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    I will take pic tomorrow and post.
    HVACNUT
  • Ironman
    Ironman Member Posts: 7,379
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    If the upper floor Air Handling Unit is in the attic, the pipes may be freezing and blocking flow.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • HeatNovice
    HeatNovice Member Posts: 29
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    AHU is in attic. Checked in past pipes hot to the touch 
  • HeatNovice
    HeatNovice Member Posts: 29
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  • Jon_blaney
    Jon_blaney Member Posts: 317
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    Is there an attic pipe temperature difference when the system is not heating? Is it the same when it is working? One pipe should be cooler that the other. Maybe a pump controller setting issue. Are you new to the house? Could the second floor be locked out in extreme cold?
  • HeatNovice
    HeatNovice Member Posts: 29
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    JB, Have been in house for several years, this is the 3rd heating season experiencing issue when approx 10 or below. The pipe usually feels hot/very warm when I touch it. I can go back to attic and double check both pipes.
  • neilc
    neilc Member Posts: 2,707
    edited December 2020
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    take a picture while you're up there,
    show the pipes as they enter the air handler,
    Is there a bypass up there? and is valve throttled? wide open? shut?
    and are pipes burning hot / 180* that you can't touch or hold on to?
    known to beat dead horses
  • Jon_blaney
    Jon_blaney Member Posts: 317
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    This has been going on since you moved in?
  • HeatNovice
    HeatNovice Member Posts: 29
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    Nelic-I will take pics and show.

    JB- First 5,years all good. Last 3 issues 
  • neilc
    neilc Member Posts: 2,707
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    and same questions in the basement,
    I'm assuming there is a air handler down there also, and it works, and that your hot water is going there first, cause it's the easier route,
    looking for throttling valves , , ,
    known to beat dead horses
  • HeatNovice
    HeatNovice Member Posts: 29
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  • HeatNovice
    HeatNovice Member Posts: 29
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    I have 2 other AHU all well. No issues. Only one in attic when very cold doesn’t provide enough heat to 2nd floor. What does acthr
  • HeatNovice
    HeatNovice Member Posts: 29
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    Throttle valve look like?
  • neilc
    neilc Member Posts: 2,707
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    assuming first pic is return pipe,
    where is supply?
    where is, or is there a, control valve?

    throttling valve would be if supply continues/loops to return, and a way to throttle loop flow,
    coil supply and return would branch off attic loop (w/control valve)

    Throttle valve look like?

    simple ball valve(?)

    known to beat dead horses
  • neilc
    neilc Member Posts: 2,707
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    and are those pipes burning hot?
    known to beat dead horses
  • HVACNUT
    HVACNUT Member Posts: 5,863
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    That duct system is zoned. All thermostats connected to that air handler are set correctly? Are the dampers working?
  • HeatNovice
    HeatNovice Member Posts: 29
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    Remember your dealing with a rookie. I don’t have all the answers. The first pic pipe is very warm. There is another pipe on top that is room temp.Valves are in basement at furnace.
  • HeatNovice
    HeatNovice Member Posts: 29
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    Only when very cold doesn’t work. Now 25 degrees all is fine.
  • neilc
    neilc Member Posts: 2,707
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    is "very warm" too hot to hold onto?
    known to beat dead horses
  • neilc
    neilc Member Posts: 2,707
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    like as hot as the hot pipe coming out of the boiler?
    known to beat dead horses
  • HeatNovice
    HeatNovice Member Posts: 29
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    I can hold it, for quite sometime. Downstairs at furnace can’t touch. Way too hot.
  • neilc
    neilc Member Posts: 2,707
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    you are not getting circulation to the attic, or it would be burning hot.
    that is just gravity/incidental flow.

    can you post pictures of valves at the boiler?
    do you see a dedicated pipe in the basement to the attic?
    and to the other airhandlers?
    are there valves on these lines?
    how many circulators down there?
    pictures
    known to beat dead horses
  • HeatNovice
    HeatNovice Member Posts: 29
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    Definitely not burning hot. I will take pics very soon and post. Dedicated pipe to 2nd floor. I will show you.
  • HeatNovice
    HeatNovice Member Posts: 29
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  • HeatNovice
    HeatNovice Member Posts: 29
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    The one with the white tag attached services the second floor.
  • Jamie Hall
    Jamie Hall Member Posts: 23,433
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    No one seems to have mentioned this, but... I would be very suspicious of that pipe freezing, somewhere up in the attic or on its way up or down. It wouldn't take much -- even an inch or two of ice and you'd get no circulation at all. Nor would it necessarily damage the pipe, if it were a short section.

    Try this: you mention that once the temperature gets above 25 or so, it seems to work. OK, when you have circulation going up there -- keep it going. Don't let the pump that runs that circuit turn off. If you don't want the heat at times, turn the fan on the air handling unit off -- but leave the circulation going. See if that helps.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • neilc
    neilc Member Posts: 2,707
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    so a circulator to each AH ?
    is one of those black? and go to the attic?
    and older? and it's not working?
    sorry, which one goes to the attic? 1, 2, or 3?
    and one more picture of the 3 lines on the other side of the boiler where they come out and any valves or devices there.
    also a picture of the device those circs are wired to,
    known to beat dead horses
  • HeatNovice
    HeatNovice Member Posts: 29
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    Thx JH. So if I set thermostat to 68 and all going well, do I have to increase to say 70 when rooms get to 68 so it doesn’t stop?
  • neilc
    neilc Member Posts: 2,707
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    working with Jamie's idea,
    and my thinking the circ may be bad,
    push the heat up to 75 to see if that circ is working,
    with the heat turned up,
    please go feel that pipe up there again,
    it should be burning hot
    known to beat dead horses
  • HeatNovice
    HeatNovice Member Posts: 29
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    #2 goes to attic. Pic with tag. Works when not too cold.
  • neilc
    neilc Member Posts: 2,707
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    neilc said:

    working with Jamie's idea,
    and my thinking the circ may be bad,
    push the heat up to 75 to see if that circ is working,
    with the heat turned up,
    please go feel that pipe up there again,
    it should be burning hot

    we keep passing missing messages
    known to beat dead horses
  • HeatNovice
    HeatNovice Member Posts: 29
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    I wil do this but will have to “pause” and swing back around. Does this all make sense if everything is working fine at 25 degrees? Could circa still be bad if working at 25 degrees?
  • neilc
    neilc Member Posts: 2,707
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    the attic pipe would be boiler hot if the AH was calling, and the circ was working,
    was the attic unit calling when you were up there last?
    that's why I'ld say push up the thermostat, and check again
    known to beat dead horses
  • HeatNovice
    HeatNovice Member Posts: 29
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    Heat was set at 64 and not calling for additional heat.Will put to 75 and advise. Thank you!!
  • Jamie Hall
    Jamie Hall Member Posts: 23,433
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    I wil do this but will have to “pause” and swing back around. Does this all make sense if everything is working fine at 25 degrees? Could circa still be bad if working at 25 degrees?

    Yes. It is quite possible for it to work splendidly at 25 degrees. Then it shuts off -- perhaps for only 20 minutes -- on a night colder than that, and the pipe freezes. Then you ask for it again -- and nobody's home. In fact, of all the possibilities, that's the one which is really temperature sensitive.

    You really are looking for something which is sensitive to the outdoor temperature here. That's the only variable which you report as being closely related.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • HeatNovice
    HeatNovice Member Posts: 29
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    As requested, here are a couple of pics of the back of the furnace. Also I touched the pipe thus evening that serves the second floor-the pipe at the basement-very hot. Saturday, I will crank up heat and see if AHU pipe is hot.
  • neilc
    neilc Member Posts: 2,707
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    I do not like that mc and loose bushing and 120V wire entering that questionable circulator , , ,
    that all needs to be checked out, and corrected and made safe and solid,
    and then,
    let's see the other end of that circulator electrical, at the controller, preferably with the cover off and showing any indicator lights.
    known to beat dead horses