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CH-240 Navien Combi. Boiler

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Moiz
Moiz Member Posts: 5
Hello,

I am new here so any help or suggestions would be greatly appreciated. Ever since i bought this house (2 years ago), I have had nothing but issues with this combi boiler. From all of the reading and research i have done it seems to me that the local "Navien Dealer" did a piss poor job on the installation. The 2 bedrooms in the basement hardly get any heat. I have bled as much as i can for days and it gets heat just not nearly enough. This has nothing to do with poor insulation in the basement walls. I had a friend of a friend who does that kind of stuff who said the cheap "pex" they used which is allowed is 1/2" which according to the installation manual should be 1". Many of the installations i have seen on youtube seem to show at least 3/4". I assume thats why i am not getting much flow to the rads. Thats one of the many issues i have had. The latest which is getting annoying is a loud "thud" or knocking you hear coming from the unit and it echos all the way upstairs. The other symptom is the hot..cold..hot..cold water when you open any tap as well as the shower. Is this a flow sensor issue or a 3 way valve?

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  • Canucker
    Canucker Member Posts: 722
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    Sounds like it could be a flow issue. Do you have any pics of the near boiler piping?
    You can have it good, fast or cheap. Pick two
  • Moiz
    Moiz Member Posts: 5
    edited May 2017
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  • Moiz
    Moiz Member Posts: 5
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    This is an over view
  • Ironman
    Ironman Member Posts: 7,378
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    What type of emitters do you have?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Moiz
    Moiz Member Posts: 5
    edited May 2017
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    Ironman,

    I dont know what you mean by emitters. If you mean heat than its Baseboard Radiators.
  • Zman
    Zman Member Posts: 7,572
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    You definitely have some issues. Both circs are pumping towards the expansion tank rather that away as they should.That makes air elimination difficult.

    What model number is the gold circulator? How long would you estimate each run of 1/2" tubing.
    The tubing looks very brown. What does it say on it? Aquapex? Hepex? How may feet of actual baseboard is on each zone?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Ironman
    Ironman Member Posts: 7,378
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    It certainly looks like AquaPex, which would mean it has no oxygen barrier. That would also explain the bronze circ.

    The best flow rate that could be expected with 1/2" pex is 1.5 gpm per loop. That translates to 30k btus available for the entire house - unless there's something else not shown.

    How many square feet is your house and what's its age?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Moiz
    Moiz Member Posts: 5
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    The house is 1169 Sq. ft. I am currently at work and will get the rest of the info later on.