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Lochinvar Knight boiler keeps locking out (propane)

lkhelp
lkhelp Member Posts: 29
Hello,

Received a lot of great insights last time I posted, thank you all, hoping to learn more!
I have a Lochinvar Knight 110N boiler that is hooked up to propane tank outside. It keeps locking out with the message "FLAME FAIL IGN". Basically, goes into pre-purge, ignition, then post-purge - repeat three times and then lock out. The installer says that this is due to having less than 30% of propane in the tank (500 gal), however all the propane delivery companies are saying they never heard of such, and it actually got locked out 3 times last night.
I went outside and smelled a strong propane smell, so I called the delivery company, they came - search for leaks (found none) and topped it off to 35% (don't want to fill up, because switching companies next week).
I guess 2 questions:
1) Is this for real that I need to keep propane above 30% full at all time? Today it was 35% but it still locked out once (at least).
2) Could the smell of propane be caused by post-purge? Does it expel whatever was not ignited and thus potentially cause the smell?

Thank you all very much in advance!

P.S. Bonus question - the system shows 650 ignitions and 804 ignition attempts, seems that 154 unsuccessful ignitions in less than a month is a bit excessive, but I don't know what is normal.
blackoakbob

Comments

  • HomerJSmith
    HomerJSmith Member Posts: 1,925
    How old is the boiler? Have you cleaned the spark igniter and rectifying probe.
  • JUGHNE
    JUGHNE Member Posts: 10,308
    I can only imagine the 30% fill factor comes into effect with serious cold temp...single digets.
    (Or LP supply issues...see below).
    I would do what homer says...clean the spark igniter and flame sensor (rectifying probe).

    If you shut the gas off and watch an ignition attempt you should be able to see and possibly hear the spark inside the chamber. Gas off because you may not want to be peeking thru that small window and get a delayed ignition of gas....it is unnerving to say the least. Also you would not get the LP fumes outside from the post purge as you mentioned above.

    Do you have a tank regulator and then another at the house for the propane supply?
  • Ironman
    Ironman Member Posts: 7,076
    edited January 2021
    Was was a combustion analysis done when the boiler was installed?

    As far as the 30% thing goes, you can pass the crackers now, the bologna has gone around.

    You can clean the flame rod with a dollar bill. If that doesn’t fix it, you need someone knowledgeable with a manometer and a combustion analyzer.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 13,136
    And in addition to the above posts 154 failures to light in one month is way out of wack.
  • HomerJSmith
    HomerJSmith Member Posts: 1,925
    edited January 2021
    The gap on a spark igniter is important and should be set to factory specs. The gap that's too close will spark at a lower voltage and temperature. Normally a 1/4" gap is about right, however, a gap too large will result in no sparking or sparking at the board.

    I've been told the thickness of two quarters placed together is an acceptable gap. If you need to widen or shorten the gap, don't do it against the porcelain as it may crack. Use two needle nose pliers to make the change.
    lkhelp
  • lkhelp
    lkhelp Member Posts: 29

    How old is the boiler? Have you cleaned the spark igniter and rectifying probe.

    Sorry for the delay, just realized that notifications were turned off for this post.
    Boiler is less than 1 month old.
  • lkhelp
    lkhelp Member Posts: 29
    JUGHNE said:

    I can only imagine the 30% fill factor comes into effect with serious cold temp...single digets.
    (Or LP supply issues...see below).
    I would do what homer says...clean the spark igniter and flame sensor (rectifying probe).

    I mean, it's been 20s when the lockouts happened mostly. Don't know if that's a factor but the tank is super old. The pressure was 11 inches water column when the propane company was looking for leaks.
    JUGHNE said:


    Also you would not get the LP fumes outside from the post purge as you mentioned above.

    Yikes... Where else could they be coming from?
    JUGHNE said:


    Do you have a tank regulator and then another at the house for the propane supply?

    Yes, I believe so. There's definitely a regulator at the house and I do believe there's one on the tank as well.
  • lkhelp
    lkhelp Member Posts: 29
    Ironman said:

    Was was a combustion analysis done when the boiler was installed?

    As far as the 30% thing goes, you can pass the crackers now, the bologna has gone around.

    You can clean the flame rod with a dollar bill. If that doesn’t fix it, you need someone knowledgeable with a manometer and a combustion analyzer.

    I am not aware of the combustion analysis being done at the time of installation (a month ago), I would be surprised if it was... Long story short - just moved into a house and the boiler/water heater died/leaked within a first week, so basically had to find someone ASAP to replace the whole setup. Might not have been the most knowledgeable folk...

    Thank you for the crackers/bologna line, looking forward to using it in the future.
  • lkhelp
    lkhelp Member Posts: 29

    And in addition to the above posts 154 failures to light in one month is way out of wack.

    Seemed very suspicious to me as well, but the installer said "I wouldn't worry about it" - pretty much his response for everything else...
    How would I get this fixed? As suggested above - someone with combustion analysis?
  • Zman
    Zman Member Posts: 7,434
    Let's hope your model 110 N "N" for natural gas has been converted to propane. I would be willing to bet that your installer does not own a combustion analyzer. You need to find someone who does and who knows how to use it.
    As for the propane tank, unless you have a ridiculously large load and very low temps, your installer is wrong. Did he have a manometer reading to go with the theory? If so, I would look hard at the regulator. Again if he knew how to setup that boiler he would have already performed a combustion analysis and checked the gas pressure.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • lkhelp
    lkhelp Member Posts: 29
    Zman said:

    Let's hope your model 110 N "N" for natural gas has been converted to propane.

    Yes, I overheard the installers by accident and they did say that they spent a lot of time "converting it", sounded like it was the first time they've ever done it. What does this conversion actually entail?
    Zman said:


    I would be willing to bet that your installer does not own a combustion analyzer. You need to find someone who does and who knows how to use it.
    As for the propane tank, unless you have a ridiculously large load and very low temps, your installer is wrong. Did he have a manometer reading to go with the theory? If so, I would look hard at the regulator. Again if he knew how to setup that boiler he would have already performed a combustion analysis and checked the gas pressure.

    Not sure whether they did that, but my guess is same as yours - they didn't. Do you think I need to find someone who specializes in Lochinvars or anyone with the combustion analysis skills could do it?
    blackoakbob
  • Zman
    Zman Member Posts: 7,434
    The conversion is probably just removing the gas valve and sliding in a new orifice. It will vary a bit model by model.
    Anyone that is competent with an analyzer and willing to read the manual should be able to take care of it. Many manufactures use the same valve so even if they have not tuned a Lochinvar, it will probably be familiar.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    lkhelp
  • blackoakbob
    blackoakbob Member Posts: 248
    There is a process after the conversion is done and it does need a combustion analyzer to perform.  I do have a thought though check to make sure the ignition wire is on the correct porcelain  it should be the one on the right side and don't  ask why I  know
    Best regards
    Blackoakbob
    lkhelp