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Interesting Biasi scenario, older B-3 with Beckett NX

GBart Member Posts: 746
edited March 2018 in Oil Heating
Just curious because I haven't worked on a lot of them and found no info or tech bulletins. We have one at the school and it seems the boiler rating info is wrong, it stated for a Beckett NX in a B-3 use a .55 nozzle at 180PSI, the mas boiler input is .55, that over fires the boiler. As far as I can tell we've always had issues with it, I decided to take it on and found not only was it impossible to get a zero smoke, the CO AF was 374PPM. The chamber had no liner so I start to suspect this is at least partly causing my CO and poor flame issues ( cold fire, impingement), then I found that in the boiler instructions there is listed a chamber liner but no reference as to installing it. Found new boiler literature that now states in a B-3 run a .40 nozzle at 150PSI to get the .55. Only problem is I am not crazy about running anything below a .65 with #2 fuel.

I settled on the .50 at 120PSI and with a new liner and the head set properly I'm happy to report CO AF is 40PPM and steady and the rest is perfect.

Just curious what others have found over the years and if there ever was a tech bulletin, etc regarding this?

Gene Bartholomew


  • GBart
    GBart Member Posts: 746
    edited March 2018
    I also see different boiler ratings of .55 and .50 for the B-3, adding to the confusion.
    HVACNUT Member Posts: 4,206
    I don't see a model B-3 Biasi.
    However, Beckett specs the NX with the B10-3 for a .50 60* A nozzle @180 psi with the 6 slot head. I wouldn't really deviate too much from that.
    Use the analyzer to bring down the CO. What's the CO2 and O2? 0 smoke?
    If the burner was a retrofit, I would go over all the dimensions per Beckett specs.
  • GBart
    GBart Member Posts: 746
    That's my abbreviation for the B10-3, do the math with a GPH calculator, .50 @ 180 PSI is over firing the boiler they rated at .55 then and .50 now.
  • GBart
    GBart Member Posts: 746
    It's running fine now, better than ever, it's just without the chamber liner it had terrible readings and high CO.
    EBEBRATT-Ed Member Posts: 10,345
    I don't care what any manufacturer says.

    Years ago it was thought that any fire (especially under 1 gph) needs a chamber or a liner. Heat reflected back into the flame produces better combustion. Many times high CO comes not from lack of air but from cold combustion. Many boilers produce CO when cold that goes away when they warm up. A chamber reduced the warm up time. A pot of cold water on a gas stove make plenty of CO

    Higher oil pressure reduces oil droplet size and improves combustion. This has been known for years. Iron Fireman was the first one that ran 240-300psi at the nozzle on their commercial burners and they did it 60 years ago.

    Why it took the residential burner manufacturers sssooo lllooonnnggg to catch on I will never know. Now they act like they invented something new.

    Charlie Burkhardts oil burner book written in the 50s talked about dropping the nozzle size and increasing the oil pressure to get better combustion especially with a marginal residential burner

    The basics don't change
  • GBart
    GBart Member Posts: 746
    Yes that's been my experience, any unit without a chamber of some sort will basically have a "cold" fire, flame retention burners hate it and CO rises and it becomes difficult to get a decent fire or 0 smoke. There were some Carrier warm air furnaces with no chamber just stainless steel lower section that ran awful.
  • ChasMan
    ChasMan Member Posts: 459
    This boiler came with a carpet originally? Is this the same one Slant Fin sells now with the Stainless liner?
  • GBart
    GBart Member Posts: 746
    It's listed in the parts box list with the aquastat, relief valve etc, then it lists how to install all except the liner, I'm at a school so I don't know if we got it new, it was a donation, or a student took the liner out etc. Biasi is Italian and has zero to do with SlantFin