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Lochinvar Noble KNB110N Ignition Noise

Thunder
Thunder Member Posts: 20
I'm hoping the link works. I have never shared a video like this before. I have had several technicians tell me this is not a normal noise. We have replaced the gas valves and they start out quiet but the noise ALWAYS come back. Some times it's quieter than others. Some times its very loud and scares me. I spoke with a Lochinvar Agent today who said that if we have replaced the valves several times, then it must just be a normal noise because no one else has ever complained about it. That just doesn't seem right since technicians at my house say it's not a normal noise but don't know what else to do. They say it sounds like it's the solenoid.

https://vimeo.com/manage/videos/687322342/privacy

Comments

  • GroundUp
    GroundUp Member Posts: 1,406
    *NKB

    The normal inducer pre-purge, ignitor, and fire is all I can hear. Was it before or after any of those, to better narrow it down?
  • Thunder
    Thunder Member Posts: 20
    Its the noise at 37 seconds that has me wondering. When first installed, it ignites with just a small "poof like" air sound, but about 3 months into the first one, it began this noise. A second gas valve was installed per technician. It also was quiet for several months and then began that noise. A third gas valve was installed and it was only quiet about 3 weeks and then it began that noise. Sometimes it's quieter than others. Rarely now, it will start up nice and quiet. Other times I hear it from the second floor and it makes me jump.
  • Ironman
    Ironman Member Posts: 6,869
    Was a combustion analysis done with a digital analyzer? If so, what were the numbers?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    HomerJSmith
  • HomerJSmith
    HomerJSmith Member Posts: 1,565
    edited March 12
    Look at your gas pressures and gas valve voltages. Out Door Reset would be helpful,too. Sounds like a duck quacking?
  • Thunder
    Thunder Member Posts: 20
    Combustion was done yesterday. On high fire, we are getting the "manual" ranges. O2 was about 4.7. CO2 was 10.8. CO PPM was 136. We got the CO down after making a high fire adjustment to the valve per Lochinvar tech because it was nearly 200 ppm. However, the Low fire reading was O2 - .1 CO2 was 13.8 and CO was 2000 ppm....yep 2000. So after making low fire adjustments to the gas valve, we were only able to move the O2 to .7 and the CO2 dropped to about 13.3 but we got CO PPM down to about 15 - 20 ppm. The Lochinvar tech was satisfied because the PPM was in what he called a good reading. And he said that he figured the tech's combustion analyzer was off, however, that makes no sense to me because we saw it work good for high fire, so if it was off, how can we be sure high fire tests were accurate?

    Gas Pressure on the gas line was 11.8. Lochinvar tech said it would be no lower than 8 and no higher than 12. So the tech adjusted the gas pressure down to 8.6. This did not change the noise at all.

    I am curious however about the flame value. The lochinvar tech was saying something about where we like to see the flame at on both high and low fires, but I can't remember what he was saying. I feel like he said he didn't want to see a big drop, but I don't know if this is considered a big drop or which direction he was talking about. Before yesterday the flame almost always sat at 10 - 11.7 uA, but now today I get about 11.8uA between 10% and 60% run but as it goes higher it and sits up around 93% run it drops the flame to between 8 and 9.3 uA.

    I am seeing some improvements since making these adjustments to how it is running in general. This boiler has been a nightmare. Improvements include the extremely irritating harmonics on low fire are basically gone now today. The flow issues have also improved after he changed a couple pump settings and made sure all of the manifolds were open.

    Still having this loud pre-ignition noise that the lochinvar tech said "must just be normal" even though no one seems to know what it is. The DHW still runs for a very long time to satisfy my side arm on low fire, but like I said, at least I am not getting the harmonics today on low fire.

  • JUGHNE
    JUGHNE Member Posts: 9,765
    Are the Loch Nobles water tube or fire tube?
  • Thunder
    Thunder Member Posts: 20
    JUGHNE said:

    Are the Loch Nobles water tube or fire tube?

    Fire tube
  • GroundUp
    GroundUp Member Posts: 1,406
    Would you be able to post a photo of the system? I am curious about the piping of both the water and the gas.
  • psb75
    psb75 Member Posts: 570
    I had noise problems with my first Lochinvar Noble 80 install. It made a loud fog-horn "hooting" noise when ramping up and down, that woke the homeowners (and neighbors) up! Many calls to tech support. Local rep came out. No love. Finally got regional rep to come (3 hour drive, one way). I had already replaced a motherboard that was reconfigged at home office. Then he went away and sent ANOTHER one that he re-reconfigged again at the 'home office.' The problem had to do with a particular resonance in the combustion fan cycle. He programmed the board to 'skip' over that particular fan speed. There was nothing I could do but 'swap' motherboards. I certainly am not going to 'tweak' a motherboard. I didn't get charged for the motherboards but also didn't get compensated for many hours of my time and phone calls. I haven't chosen or offered to install another Lochinvar. I do believe they are generally good machines. The first one I got was a 'lemon.' And the 'lemonade I made' from it....was kinda sour.
  • Thunder
    Thunder Member Posts: 20
    edited March 13
    GroundUp said:

    Would you be able to post a photo of the system? I am curious about the piping of both the water and the gas.




    This is after the repipe that was done in January so it's as it is currently. Let me know if you want to see something closer or at another angle. The service tech who was here the other day is talking about needing to have the installers repipe some more things for better operation (like I no longer have mixing valves, so adding them back in so we can let the boiler get up to 180 degrees to finish my water heater faster). Let me know if you see anything here that you think could be contributing to the noise. The piping has been an issue from the get go - hence the repipe in January, which did not solve any of my complaints. Prior to January the regulator was basically on top of the boiler, now it's within the distance the manual suggests. Also prior to January the gas pressure was at 14 inches of water column, that got reduced to about 12 in January and a bigger regulator was added and now sits at about 8.6. With the repipe in January, I lost my furnace coil and just run my LP furnace as intended now. That also didn't solve any of the issues. I really would like my coil back.

    As psb75 said, I also have a spot where the RPMs create vibration - sort of a "foghorn" but not super loud. It's annoying, but much better since the tech adjusted some other things on Friday. That happens right around 5000 rpm on fan speed. I am hoping we can get the repipe taken care of and get everything dialed in so I can stop having a service call every month
  • GroundUp
    GroundUp Member Posts: 1,406
    Thank you. No amount of mixing valves will cure the fact that the water heater is piped wrong- the pump behind the expansion tank should be pulling from the boiler loop, not the secondary loop. Basically there should be another tee under the boiler for that supply, similar to the way the return is teed in below the boiler. I'm not sure how a mixing valve could even be integrated into that 2 zone dual temp system with only one circ pump- the whole thing should pretty much be repiped in order to make this function properly. While none of that should not be contributing to this noise (which I still can not hear for some reason), I will say that CSST gas piping like this, especially 3/4" at 7-14" which this seems to be, tends to make a bunch of funky noises at different firing rates and fan speeds. Most are foghorn-esque. I really wish I could hear the sound you're referring to, but without that, I'm going to bet a fresh donut on the gas piping being at least some of the culprit. I'm really not a fan of those small bore gas cocks either as I've found they can make some noises as well as some flow/pressure fluctuations. Full port ball valves eliminate that potential issue.
  • Thunder
    Thunder Member Posts: 20


    GroundUp said:

    Thank you. No amount of mixing valves will cure the fact that the water heater is piped wrong- the pump behind the expansion tank should be pulling from the boiler loop, not the secondary loop. Basically there should be another tee under the boiler for that supply, similar to the way the return is teed in below the boiler. I'm not sure how a mixing valve could even be integrated into that 2 zone dual temp system with only one circ pump- the whole thing should pretty much be repiped in order to make this function properly. While none of that should not be contributing to this noise (which I still can not hear for some reason), I will say that CSST gas piping like this, especially 3/4" at 7-14" which this seems to be, tends to make a bunch of funky noises at different firing rates and fan speeds. Most are foghorn-esque. I really wish I could hear the sound you're referring to, but without that, I'm going to bet a fresh donut on the gas piping being at least some of the culprit. I'm really not a fan of those small bore gas cocks either as I've found they can make some noises as well as some flow/pressure fluctuations. Full port ball valves eliminate that potential issue.

    https://vimeo.com/manage/videos/687712738

    Any chance you can hear the sound here better. It's at about 6 seconds
    GroundUp
  • JUGHNE
    JUGHNE Member Posts: 9,765
    On water tube boilers, I can hear the ignition/light off if near the boiler.
    Those sound like a small sneeze.

    If those heat exchangers are dirty then it is a loud sneeze or even a small explosive "pop".

    FWIW
  • HomerJSmith
    HomerJSmith Member Posts: 1,565
    So you have LP. When the LP conversion was done was the correct kit selected? Was the air shutter required and properly installed?
  • Thunder
    Thunder Member Posts: 20

    So you have LP. When the LP conversion was done was the correct kit selected? Was the air shutter required and properly installed?

    I have never heard anyone mention "air shutter". I will have to ask. Is that standard on Nobles?

  • Ironman
    Ironman Member Posts: 6,869
    If you’re getting a “foghorn” sound, it’s because of the CSST gas tubing between the regulator and the boiler. Adjusting  the fuel to air ratio to the richest setting that the manual allows may resolve it. If not, the CSST needs to be replaced with hard pipe.

    I’ve got hundreds of hours of field experience with foghorning issues and the CSST is the culprit. I’ve even seen an atmospheric boiler do it when it temporarily had a 20’ coil of CSST connected. As soon as that was removed and hard pipe installed, the foghorning immediately went away.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    HomerJSmith
  • wesPA
    wesPA Member Posts: 27
    I would also suggest the CSST, it wouldn't take much to remove it and tie it in with black iron. 
    I remember doing an LP conversion when installing the NKC150 in my house, I think it was a replacement venturi/air shutter...
    Is that an approved LP regulator?  Vented to the outdoors? I'm not used to seeing a residential LP regulator indoors, but that may be just my area
  • Thunder
    Thunder Member Posts: 20
    edited March 15
    wesPA said:

    I would also suggest the CSST, it wouldn't take much to remove it and tie it in with black iron. 
    I remember doing an LP conversion when installing the NKC150 in my house, I think it was a replacement venturi/air shutter...
    Is that an approved LP regulator?  Vented to the outdoors? I'm not used to seeing a residential LP regulator indoors, but that may be just my area

    The indoor regulators (one for furnace and one for boiler) got added by the gas company when they also installed the 2lb regulator outside in April. He was hopeful it would help but he put it too close to the boiler. It used to be directly over it. When they repiped in January they moved it farther away "per the book". I guess I don't know if the book specifies if it should have indoor regulators, but no one has questioned there being on that's looked at the system.

    I'd be interested in what an air shutter is. I emailed Lochinvar to ask and he also poo pooed me and said since we are getting the proper readings and valve adjustments, he think it was done properly.
  • HomerJSmith
    HomerJSmith Member Posts: 1,565
    edited March 15
    A regulator should be at least 10' from the boiler. Check with Lochinvar Tech Support at 615-889-8900, have model and serial # handy.



  • Ironman
    Ironman Member Posts: 6,869
    The regulator being installed indoors is okay if it has a vent limiter and it’s positioned horizontally (the regulator body).
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.