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Navien NCB210 Heating Help

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  • zanesilk
    zanesilk Member Posts: 27
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    SuperJ said:

    Can you do some detailed photos of the system?
    Wiring, jumpers, pump closeups, etc.
    Maybe something will jump out.

    In the meantime can you reduce the SWT set point to 160f? It might seem counterintuitive, but it should be plenty this time of the year, and keep you from bouncing off the safeties. If you hit a safety there might be a minimum off time.

    To get a good IR measurement, you need to be close, and you need a surface that is measurable (tape helps), and also know the laser doesn't do the measuring it just helps you point it. The actual measurement area is basically a cone that gets bigger with distance. If you point it at the tape on the copper pipe and move it around just note the highest temperature it registers.

    Ok i will lower to 160 now - house is at 168 so I will see if it will maintain it.
  • Gordy
    Gordy Member Posts: 9,546
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    Change the venting material Be done.
  • zanesilk
    zanesilk Member Posts: 27
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    > @Gordy said:
    > Change the venting material Be done.

    And leave temp at 180?
    Also ... with outdoor reset control can I make a custom profile to accommodate for my 180 ? The default profile appears to top out below that?
  • Gordy
    Gordy Member Posts: 9,546
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    You have to decide if setbacks are your daily wants. ODR and setbacks are counterintuitive.
  • SuperJ
    SuperJ Member Posts: 609
    edited December 2019
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    Yes, with the outdoor reset you can setup the min and max temperatures. The manual I linked to earlier covers this.
    What is the design outdoor temp for your location? it's concerning that you have to hit 180f to maintain temps when it's barely below freezing. 180f should be the max on the coldest days.

    Did you remove some baseboard, or cover it up some how?
    Are you sure all 65ft is getting hot?
    Is it possible there might be some paralleled sections not getting flow?

    Perhaps your existing boiler was running 190F+?
    You may have to add some emitters and split up your loop into parallel sections, to get the temp down.

    You can get some ideas from this document.
    https://www.caleffi.com/sites/default/files/file/idronics_25_na.pdf

  • Gordy
    Gordy Member Posts: 9,546
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    The OP said everything worked fine with old boiler.

    The s/r temps through out system, look spot on for 180. The issue is extended recovery periods. They also indicate primary, and secondary flow rates match.

    Adding odr is only going to amplify the issue. Unless more emitter is added to facilitate lowering supply temps. Which equals more money.His outdoor temps are fairly mild. Mid 30’s
  • zanesilk
    zanesilk Member Posts: 27
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    For me it is important that the boiler can go from 64 (when not home) to 68. I cannot be asking too much for this to happen within 1 hour. All emitters are hot. I just turned temp down to 160 and it’s holding 68. But getting it up to temp is where the struggle is. Again this cannot be right. 65 feet of emitters
  • Gordy
    Gordy Member Posts: 9,546
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    If That setback schedule worked before, you have to ask what’s changed. If nothing changed on the emitter side then that leaves the boiler side.

    As I said before the old ci boiler, and your new one are different animals. You were probably running 180 plus supply temps before.

    If you are admit about daily setbacks odr isn’t going to work very well. Odr maintains indoor temps based on outdoor temps. The supply water temp is adjusted accordingly. If you setback then you would have to implement the boost function to bypass the odr parameter to get up to set point.


    Your old boiler may have been low 70’s efficiency.

    I, and others have posted many charts from multiple sources that show efficiencies of mid/cons at high SWT. Low to mid 80%

    Your dhw will pick up some efficiency points as well if you went from a tank WH.

    My advice is change out the venting material. Use 180 supply. Let it run as such, and monitor gas usage. If it’s lower go with it with out ode. If it’s the same, or higher maybe implement odr with out using setbacks. See if that helps.
  • zanesilk
    zanesilk Member Posts: 27
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    @Gordy i really appreciate the help - as stated before 180 was able to raise the temp of the house. I will monitor gas usage and swap the exhaust piping Then set to 180z perhaps it would be a good idea to maybe add a bit more baseboard during renovation in April to bring the delta up To 20 ... measuring now I get 13-15.

    Thank you sir.
  • Gordy
    Gordy Member Posts: 9,546
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    The usual procedure (before) a boiler purchase is to do a heat loss calc, and an emitter survey. This would allow you to determine at what average water temp you can be to satisfy loads at design temp.

    Most times the emitter is more than adequate for the load, and a lower AWT can be used. This helps condensing boilers to gain efficiency. However I don’t think this is the case in your situation with the information provided.

    In Adding That extra future zone keep the above in mind. More emitter equals lower AWT.
  • Gordy
    Gordy Member Posts: 9,546
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    Dont get to hung up on the delta. For baseboard 20 is a design criteria number. Beyond that deltas are dynamic to the load. Usually less than 20. You’re right there.
  • Gordy
    Gordy Member Posts: 9,546
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    This is one of many charts showing efficiency at different supply temps, and % modulations.
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2019
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    As you can see at full modulation, and 180 swt you are still doing way better than your 40 year old boiler.

    Now if you want to spend more money to get those supply temps lower to pick up meh maybe 2% balls in your court, and wallet.
  • zanesilk
    zanesilk Member Posts: 27
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    Very well. I guess I’ll go for 190 degrees then LOL ! But all kidding aside it is what it is... I have a 3 year old I want to keep warm if it means running it at 190 to get to 70 degrees the so be it.
  • Gordy
    Gordy Member Posts: 9,546
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    You won’t get 190 out of that new boiler. Unless you meant 180.
  • Gordy
    Gordy Member Posts: 9,546
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    The real numbers are the gas bill. If it’s 1000 bucks a season, and you gain 2% that’s 20 bucks. Weigh that against dollars in upgrading to pick up 2% in efficiency.
  • zanesilk
    zanesilk Member Posts: 27
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    If it takes me 1100 instead of 1000 for the season I won’t care, I need to keep my family warm. I will update once cpvc is installed (hoping fo
    Gordy
  • SuperJ
    SuperJ Member Posts: 609
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    Sounds like a plan. I would track room by room where you could use more heat. And then add on or upgrade those emitters accordingly.

    Even if you’re willing to accept reduced efficiency due to high temps, you need to make sure you have the ability to actually heat the house to an acceptable space temperature under design outdoor temperature conditions with 180f or less water.

    There are lots of options to help bring the temperature down a bit.
    -more base board
    -high performance baseboard
    -building upgrades (air sealing, insulation, windows, etc).
    -parallel piping
    -added other emitter types like panel rads or kick space force flow heaters in series or parallel.
    -in my house I added some radiators in my basement that get fed from the return from my mainfloor zones this keeps my return water temp to the boiler in the upper 90’s and my Insulated basement cozy.
  • zanesilk
    zanesilk Member Posts: 27
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    @SuperJ thank you sir so if My supply is set to 180 what should the ideal return to boiler be?
  • Icarus
    Icarus Member Posts: 143
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    I may be missing something here, but it would seem to be a fundamental emitter issue. If you were running a old fashioned CI boiler with an output temp ~ 180, and now you are running a mod/con with output temps ~165, that is a significant btu loss net/net in output capacity net net. It is a roughly 25% reduction assuming a similar flow rate. The fin tube piping will “feel” hot at both temps. I’m guessing that the average person couldn’t really tell the difference “feeling” the pipe. It is also possible that the original boiler was running closer to 190-200f, leading to an even bigger loss.

    You could do a simple single room size heat loss calc and determine how many btus you need to maintain temp given the current temps and flow rates. Bottom line, absent raising the SWT (with the proper vent piping) you are going to need more emmiter length or higher capacity (low temp) fin tube.

    Correct me if I am missing something.

    Icarus
  • Gordy
    Gordy Member Posts: 9,546
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    You are not missing anything @lcarus.
  • Gordy
    Gordy Member Posts: 9,546
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    My personal opinion is that the HE boiler market is doing a great disservice to the consumer. By not having such charting, as I posted in their front line advertising.

    Seen this situation happen on here way to many times.
  • SuperJ
    SuperJ Member Posts: 609
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    Sounds like you've got your head around it.

    Perhaps once you get your basement loop online that will take some the load off the main floor loop.

    At least you've likely got a boiler with enough capacity to handle some additional emitters/upgrades, and it's unlikely to short cycle. You did a good job with the install. It's amazing how many systems don't get proper primary secondary piping.

    I would recommend some insulation in the basement especially anything close to or above grade. Ideally some sort of rigid/spray foam all the way from floor to ceiling. It will serve as insulation, moisture and air barrier
  • Icarus
    Icarus Member Posts: 143
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    One more unsolicited comment...why would anyone (manufacturer or installer) use PVC venting when there are certain ways to configure the boiler to run too hot for PVC, hence the CPVC requirement? It would seem, if the manufacture and UL/CE would simply require the highest temp rated vent that the boiler could produce it would save all kinds of risk.

    Additionally, the price difference between PVC and CPV is small enough to be considered a rounding error. Now the customer has to pay for the venting twice, which clearly is more expensive than simply using CPVC in the first place. (I realize that the customer here is also the installer)

    Icarus
    Gordy
  • Gordy
    Gordy Member Posts: 9,546
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    Icarus said:

    One more unsolicited comment...why would anyone (manufacturer or installer) use PVC venting when there are certain ways to configure the boiler to run too hot for PVC, hence the CPVC requirement? It would seem, if the manufacture and UL/CE would simply require the highest temp rated vent that the boiler could produce it would save all kinds of risk.

    Additionally, the price difference between PVC and CPV is small enough to be considered a rounding error. Now the customer has to pay for the venting twice, which clearly is more expensive than simply using CPVC in the first place. (I realize that the customer here is also the installer)

    Icarus


    PVC venting for boilers has had multiple discussions here. PVC manufacturers don’t even list it for that use......
  • zanesilk
    zanesilk Member Posts: 27
    edited December 2019
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    @SuperJ thank you for the kind words - first time tackling a “big” plumbing project - guys I appreciate everyone who responded and helped me out- I’ll get through the winter and make the necessary changes come spring!
  • zanesilk
    zanesilk Member Posts: 27
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    As far as the pvc goes when I tricked the boiler into giving me 180 - 185 ... pvc temp was 113 degrees which is way below PVC max temps...
  • Gordy
    Gordy Member Posts: 9,546
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    I’d still change the pvc out. You won’t be monitoring all the time. Let’s you sleep at night :)
  • Zman
    Zman Member Posts: 7,569
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    Are the rooms heating evenly?
    14 degrees in 6 hours seems good to me. I don't see any issues, it is not a drag race.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein

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