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navien nhb 110

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bobby32x
bobby32x Member Posts: 34
Hello, I have a (rough guess) 2 year old navien. I installed this system with a little trial and error and 0 experience with heating systems. This year while running my navien,  I noticed a gurgling noise coming from the basement, so I headed down to investigate. Upon checking the system, I found that my combi-boiler condensate trap was a little backed up, so I dropped the trap, cleaned it out and reinstalled.  The sound appeared to go away, which is great, but now I am facing a new issue. I did an air purge of the system and definitely had some bubbles in the system, which I don't like the current location of my air scoop (not at the highest location), so I intend to replumb a little to get the air scoop higher in the setup.
  When I investigated the condensate issue, I also noticed that the inspection port sight glass was cracked and frayed (like it was mica or something). I have since replaced the inspection sight glass and I can see into the burn chamber again. 
  So, as far as the air, I feel confident that I removed it all, and the system itself sounds good, but I am here because I have a loud noise like a whirring coming from the boiler during high fire. When it meets temp, it kicks down and quiets right down to "normal sounds". By the way, manufacture suggests system pressures of 12-30 psi and mine is running around 19.3psi at 160+ degrees, so it's not that. Also, I have adjusted this pressure up and down and the sound coming from the boiler doesn't change.
  Is my heat exchanger screwed? I had considered that maybe my induction fan was going or something like that. Any suggestions are welcome. I'm lost at this point.

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  • GGross
    GGross Member Posts: 1,048
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    " I have adjusted this pressure up and down" Draining and then filling the boiler adds a ton of air, changing the system water also adds fresh minerals to deteriorate the system components. Depending on your system you want a cold fill pressure of 12-18 PSI , adjusting the system pressure often times means you need to adjust the expansion tank pressure. I don't think pressure is your issue, but just adjusting pressure up and down is generally only a smart move if you want to add a ton of air to your system. You need to fully purge the air between each fill you do

    "I have a loud noise like a whirring coming from the boiler during high fire" Did you set combustion using a digital analyzer when installing the boiler? what type of fuel is this on, and can you take pictures of your vent terminations

    Take pictures of the install, showing as much as possible
    Ironman
  • bobby32x
    bobby32x Member Posts: 34
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    Makes sense. I adjusted the pressure and then removed air from the system. As for the pictures, I am at work. I will see what I can do when I get home. Thx
  • HVACNUT
    HVACNUT Member Posts: 5,841
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    The flame inspection glass was cracked? How? Was the boiler ever tested for combustion? That doesn't crack by itself. 
  • Snowmelt
    Snowmelt Member Posts: 1,415
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    When you say air scoop, I get scared! Do you have a picture…..
  • bobby32x
    bobby32x Member Posts: 34
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    HVACNUT said:
    The flame inspection glass was cracked? How? Was the boiler ever tested for combustion? That doesn't crack by itself. 
    Only thing I can think of, was this all started prior to me emptying the condensate trap. I'm not sure, but prior to the condensate trap being plugged, this thing worked like a top. 
  • bobby32x
    bobby32x Member Posts: 34
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    Snowmelt said:
    When you say air scoop, I get scared! Do you have a picture…..
    Taco air air scoop. I'm not making it up. 
  • bobby32x
    bobby32x Member Posts: 34
    edited February 29
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    Ok, so bear with me, I'm a chemical worker with some DIY experience. That said, I've never put in a boiler before, but assumed it couldn't be too hard. In the included pictures here, you will see some copy, cut and pasted things. I was hoping to get through the heating season before I started tearing into anything, but like I said prior, the air scoop isn't at the highest point in the system. I have seen it mounted in different places on the internet, but I have come across a few posts about not having a 90°- 18" before the scoop. This system has a ch management system (also navien). I have had a heating guy to my house for other things and I showed him the combi boiler because it was making an odd sound once in a blue moon. I assumed it was maybe too much gas going into the chamber, but he said that was all setup correctly and the noise was nothing more than my little-giant condensate pump vibrating as it emptied. I resolved that noise. However, while he was here, he said "you did all this? Impressive" now, I know I am going to get slammed on my copy/paste job, but it's the internet, I suppose that's to be expected. It wouldn't be the internet, if not for a little criticism. 
     I have the mini loop connected at the bottom of the combi boiler, when I first plumbed it, I did not know it was a thing, but now I do and it no longer struggles to get to temp, like it did initially a few years ago. Anyway, even with the whirring noise, this thing fires up, runs adequate time and shuts off like normal. 
      Here are the pics 😬 also, since bleeding the air, this has been holding steady at 18.1lbs and no gurgling. I didnt get a ton of air out, but there was definitely a small pocket trapped at my downstairs ch pump. 2
  • pedmec
    pedmec Member Posts: 975
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    where is your system circulator?
  • bobby32x
    bobby32x Member Posts: 34
    edited February 29
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    pedmec said:
    where is your system circulator?
    I have 3 circulators 1 on the mini-loop (can't remember the terminology). 1 about 8 away from the bladder tank (roughly where I am standing for the picture of the bladder tank). This feeds the lower part of the house. And one off to the left of the bladder tank. This feeds the 2nd floor. 
  • bobby32x
    bobby32x Member Posts: 34
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  • GGross
    GGross Member Posts: 1,048
    edited February 29
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    Your condensate hose makes a little trap where it goes down to the neutralizer, I believe you have a condensate trap in the boiler, which makes it double trapped, it needs to drain freely, no traps outside of the boiler until the condensate either hits a pump or a drain, its also trapped a little after the neutralizer. you need to fill the trap after cleaning it out as it makes an open flue-way through the condensate hose if its open

    your air scoop does need about 18" inches of straight pipe leading up to it or it won't work very well, many installs don't do this, but for me if I needed to have it any less I would use a better air separator, a coalescing one like caleffi makes.
  • bobby32x
    bobby32x Member Posts: 34
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    I'm a little confused on the condensate neutralizer. The "outlet" is offset, I'm assuming for the "no open flu-way" you refer to? I did see a post where they suggested putting a loop with a ziptie, in the discharge from the condensate housing. In fairness, I just replaced the neutralizer beads like a month or so ago, and definitely did not refill anything. Assuming it would collect as normal, and it did, but if you are saying that is not a good idea, this is noted. 
      As for the coalescing air separator, I was considering this as a option just the other day. The literature said it does a great job at separating micro bubbles
      Last night I was listening to the boiler from my couch and though it still sounds louder than normal, it is much quieter than when I initially realized something was wrong. 
      Lastly, the condensate waste pump is currently sitting on a brick, which normally it rests on the floor, but I am working on the floor, and needed it to be temporarily moved, and this is why it looks like there is a trap on the discharge of the neutralizer. 
  • bobby32x
    bobby32x Member Posts: 34
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    GGross I reread what you said and understand what you mean now. However, the thing I mentioned about the neutralizer is still a thing. Meaning that it is oriented in such a way to get maximum absorption through the neutralizer beads. Water in, equals water out. Not sure how else that could be mounted. The pipe leading to the little giant could be piped in a 90 degree fashion with it all kind of hard piped, but as mentioned before, it won't be staying where it is, and I have since moved the pump away and the hose straightened out and removed that make shift trap after the neutralizer tank. Included is a picture of a caleffi air separator, are these what you were referring to?
    These have the coalescing screens in them as well. 
  • pedmec
    pedmec Member Posts: 975
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    @GGross Condensate neutralizers mounted in a horizontal position are always trapped as your suppose to install the offset outlet higher than the inlet. This allows the lime chips to neutralize the condensate. mod/con traps have vents built into them.
    bobby32x
  • bobby32x
    bobby32x Member Posts: 34
    edited April 7
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    In my situation, the line leading from the condensate trap on the boiler, down to the neutralizer, always had an air gap, so I always assumed this was correct. When my system backed, up, that hadn't changed. The only thing that was wrong was the trap in the boiler had a mud like consistency, from 2 years of running without cleaning. I will be adding this to my routine, so it shouldn't happen again. I suppose I might have to break down and have a hvac guy and give it his blessing. It could just be something as simple as a bad bearing on the induction fan, but I'm not certain where the noise is pinpointed. When I take the front panel off, standing in front of it, it sounds quiet. Upstairs is where I seem to hear the whirring noise the most. And, as I said before, it seems quieter than before, but still louder than normal.