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Always air-bound after vacation

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dpschuste
dpschuste Member Posts: 7
in THE MAIN WALL
Hi everyone, I have a forced air unico mini-duct system heated by an oil-fired boiler. Every time we leave for a few days, the system becomes air bound & blows cold air. Otherwise it runs fine—it’s only when we go away. This is annoying when we come home & have to bleed the system, but especially concerning b/c pipes could freeze if heat is off while we’re away.  Any idea why this is happening and suggestions for a permanent fix? Thanks! 

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  • Grallert
    Grallert Member Posts: 644
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    When you get a chance show us the boiler and its related piping. Air's getting in and pictures could very well tell the story.
    Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
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    The obvious answer is to not go on vacation!

    If that is not an option, then we need more information.
    First is the location of the Unico air handler in reference to the boiler location. If the air handler is located several stories above the boiler, for instance, the static pressure of the water in the system may need to be increased.

    Another possibility is that air from the expansion tank is finding its way to the air handler heat exchanger. Pictures of the boiler piping from ceiling to floor and from at least 2 different angles (more is better). And maybe some of the air handler piping.

    Finally, what is your procedure for bleeding the air? that may also give a clue as to what is happening.

    Looking forward to hearing from you.

    Yours truly,
    Mr.Ed
    Never Use The Parts Cannon.jpg

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • Jon_blaney
    Jon_blaney Member Posts: 316
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    When you go away, what do you do to the system that is different than normal?
    ethicalpaul
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
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    When you say air bound, you mean the oil line that needs to be bled, correct?

    There was an error rendering this rich post.

    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
    edited March 2021
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    STEVEusaPA said:

    When you say air bound, you mean the oil line that needs to be bled, correct?

    I assumed the hydronic coil needed to be bled. I should have thought of that oil thing.
    I guess if you are a hammer, everything looks like a nail. I glossed over the Oil-fired statement and went for the air in the Hydronic System.



    Never Use The Parts Cannon.jpg

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    Grallert
  • Grallert
    Grallert Member Posts: 644
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    I made the same assumption about the hydronic side of the thing.
    Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
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    Grallert said:

    I made the same assumption about the hydronic side of the thing.

    I, Betting on the Hydronic side too, but @STEVEusaPA has been correct once or twice before.
    Never Use The Parts Cannon.jpg

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • Jamie Hall
    Jamie Hall Member Posts: 23,324
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    So did I...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
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    3 votes for Water... 1 for Oil.

    I hope the OP returns to let us know who is right!
    Never Use The Parts Cannon.jpg

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • HVACNUT
    HVACNUT Member Posts: 5,841
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    I assumed the hydro loop as well.
    If it is the oil line, a Tiger Loop wont fix it. It might act liked it's fixed, but we all know it's not. 
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
    edited March 2021
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    If it looks fixed, and it acts like it's fixed, and it walks like it's fixed. Then it must be a Duck in a Tiger costume.

    And you know that your comment is the only reason I posted that @HVACNUT. Now I can edit that out LOL

    5 Hydro to 1 OIL
    Never Use The Parts Cannon.jpg

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    edited March 2021
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    It's probably on the heat side, but I like to ask questions before providing answers.

    There was an error rendering this rich post.

    ethicalpaulEdTheHeaterMan
  • ethicalpaul
    ethicalpaul Member Posts: 5,704
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    Jon_blaney said:

    When you go away, what do you do to the system that is different than normal?

    Here's my favorite question! The system doesn't know you're on vacation--there must be some other change.
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
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    ethicalpaul said:

    Jon_blaney said:

    When you go away, what do you do to the system that is different than normal?

    Here's my favorite question! The system doesn't know you're on vacation--there must be some other change.
    You never know... there may be a smart thermostat!

    Never Use The Parts Cannon.jpg

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    ethicalpaulbucksnortErin Holohan Haskell
  • ethicalpaul
    ethicalpaul Member Posts: 5,704
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    That's a great point, Ed, I totally missed that possibility
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
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    Still think @dpschuste just needs to stop all winter vacations, Paul
    ethicalpaul said:

    That's a great point, Ed, I totally missed that possibility

    Never Use The Parts Cannon.jpg

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

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