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RobinInCali
RobinInCali Member Posts: 56
edited March 17 in THE MAIN WALL

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  • Ironman
    Ironman Member Posts: 7,903
    Have you tested the value of the sensors?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Dave Carpentier
    Dave Carpentier Member Posts: 640
    Can you soft-cap the max burn % on that boiler ?
    30+ yrs in telecom outside plant.
    Currently in building maintenance.
  • RobinInCali
    RobinInCali Member Posts: 56
    I have not tested the value of the sensors. I will ask about soft-capping the max burn.

    I will share some other data. Deep into the computer, I looked up and saw the Delta T Limit was 136 times, the Supply limit was 212, and the Delta T High was 487 times. That ain't so normal...

    I am trying to get another Navien tech in the Bay Area to come have a look. I've never had much trouble installing these, so troubleshooting is not my forte. It's plumbed right, was working fine, till the outdoor temps got into the 40s. Wow, so cold. Ha ha.
  • Ironman
    Ironman Member Posts: 7,903
    As far as system design and function, a 25* delta T should be fine and the boiler should have no problem operating within that range. Most I/O manuals allow it and even give pump flow rate charts showing 20*, 25*, 30* delta T.

    Again, you need to measure the value of the supply and return sensors to confirm their accuracy. You can also measure the inlet and outlet temps at the boiler and compare that to what the boiler’s seeing.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • RobinInCali
    RobinInCali Member Posts: 56
    Ding ding ding! And we have an answer!

    So after months of these error codes and visits by different Navien repair experts it turns out to be a malfunctioning check valve inside one of the brand new Grundfos pumps.

    This took three different Navien authorized repair people to solve. 

    And to the person here on the board who suggested a bad sensor you get credit also. One of the flow sensors wasn’t 100% so Navien is replacing that also. 

    This was about ten trips to my house, multiple flushes of the system, lots and lots of labor. 

    Grundfos says they won’t honor anything big because the check valve is a $6 part and ….

    Would anybody have known that or thought to check? We were flushing and we have a caleffi magnetic hydronic separator that I flushed regularly. I would have not though a new check valve could go bad. 

    Whew! Let’s hope this makes it go. It’s overwhelming to spend $25k on a new
    boiler system for a three unit apartment building with radiators, and to have it not work. And you lose heat and hot water regularly.  I hope those days are over. 
    Zman

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