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Navien NCB-240 Grunts when calling for heat

CharlieACharlieA Posts: 2Member
The plumber had installed the unit, NCB-240,properly with the closed loop and there are no problems heating the house. The one problem is the grunting that it does when calling for heat. It has a Grundfos circulator and an expansion tank but the 2 are not side by side like I see in most diagrams. The plumber wants to wait a week or so to see if the system fixes itself and he thinks that there is too much water coming from the radiators back to the system causing the grunting. I'm just a novice and the noise is coming from the space heating supply side which is the left most copper piping on the bottom of the unit.




Comments

  • Paul48Paul48 Posts: 4,492Member
    edited November 2014
    Hard to figure out what he has done with the piping. It appears wrong. It looks like he has the closely spaced tees from the boiler on either side of an elbow. There is a circulator inside the boiler cabinet for that primary loop. Did he open the manual packet? The air scoop, to which the expansion tank is dangling from, has very specific piping location requirements, he didn't adhere to.
    That unnecessary circulator is also installed incorrectly, with the motor facing upwards.
  • Paul48Paul48 Posts: 4,492Member
    There should be at least one more circulator for you system, that is not shown in you pictures. Can you try and get some pictures that include that, or those?
  • Paul48Paul48 Posts: 4,492Member
    No disrespect to plumbers....My father and grand-father were both plumbers. You need a heating system specialist to install a modern heating system. It requires a skill-set that not all plumbers have.
  • IronmanIronman Posts: 5,233Member
    As Paul pointed out, you're pining is wrong, the circ is in the wrong loop and cannot be installed with the motor shaft vertical as it is now.

    On a lesser note: the Tee for the drip leg in the gas line is wrong also. It should be at the base of the vertical drop and cause the gas to change its direction of flow to horizontal as it passes through it. It's useless if the gas doesn't change it's flow direction going through the Tee.

    Pics that show some more of the heating loop to the right side would be helpful.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • Paul48Paul48 Posts: 4,492Member
    Kinda annoying, when you don't even know if the OP saw any of the responses.
  • CharlieACharlieA Posts: 2Member
    The plumber just left and he installed a mini-loop to the left of the Grundfos circulator and now it's not fighting against the internal circulator. This was the fix.
  • IronmanIronman Posts: 5,233Member
    CharlieA said:

    The plumber just left and he installed a mini-loop to the left of the Grundfos circulator and now it's not fighting against the internal circulator. This was the fix.

    Could you post some updated pics?

    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • jonny88jonny88 Posts: 1,139Member
    to my knowledge the navien has its own primary loop circ.I cant make out your primary loop on the pics where are the closely spaced tees and that air eliminator needs 18inches after a fitting it is not a spirovent.Interesting setup
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