Optimus 221NA burner problems

Discussion in 'Fettling Forum' started by Krisse, Dec 9, 2020.

  1. Krisse Sweden

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    *Edit: changed the title to read 221NA for the burner after later clarification on this.

    Hey! First post here.Otherwise I am at CPL. Fairly new to stoves but renovated many lamps.

    Bought an Optimus 207 Burner NOS. But it does not burn well. Have tried everything it feels like but find nothing.
    3 different nozzles.
    Have been looking for leaks with hot burner. (Kown problem)
    Tried other dishes.

    Now the seller has tried one of his 207 burners and it gives the same symptoms. Anyone have any ideas or have a burner that behaves the same?

    FF8BFEE4-02F8-4EFD-9187-CA19775A745B.jpeg 160C6822-87F8-4386-BC0D-461F30377052.jpeg CF86834F-4AE2-44FD-8548-33235530E6EB.jpeg
     
    Last edited by a moderator: Dec 10, 2020
  2. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    @Krisse Welcome! I see you’re objecting to the red-glowing burner cap, which is colouring the flame.

    The flamelets are blue, which suggests the correct fuel/air ratio.

    Just after initial priming is the burner flame ok? - then getting worse?

    Try pressurising the tank a bit more (more diagnostics) and see if greater output gets the flames to blue up.

    A common sumptom when a brass outer cap is used, but yours appears to be steel. Even then, some steel caps do that and a change of cap (different manufacturer) might resolve matters.

    John
     
  3. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    I agree with @presscall advice. There is nothing wrong with the burner IMO. The flame pattern is a perfect blue but radiant heat from these small flamelets, close to the cap is causing the outer cap to glow.

    If you were to increase pressure/ power the flamelets will grow longer, and less radiant heating should reduce the outer cap temperature and red glow.

    Best Regards,
    Kerophile.
     
  4. Krisse Sweden

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    The picture is lying, I have high yellow flames and it smells a lot of unburned kerosene. I've really tried everything. The pressure I have tried from low to 20 pump. It also pops sometimes and burns inside the hat for a few seconds
     
  5. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    @Krisse What you describe now is over-fuelling. Are you tightening the jet nipples enough? It’s caught me out before now, fuel vapour escaping past the jet threads, producing the symptoms you describe.

    Failing that, over-sized jets - but on new burners?
     
    Last edited: Dec 9, 2020
  6. Krisse Sweden

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    Yes, I have run out of ideas, I am used to renovating lamps, so I think I have tried all the tricks in the book. has sprayed the burner with soapy water and passed it with a flame when it is hot. Can't find anything! Tried 3 different nozzles for kerosene. tried inner and outer hat from a Radius kitchen. Nothing helps. The strange thing is that the seller tried the same NOS burner and it had exactly the same problem. Run the same fuel that I have for all my lamps and kitchen with roar burner.

    But I agree that the burner gets too much fuel just can not find the fault

    The burner is NOS from the Norwegian Armed Forces
     
  7. Tony Press

    Tony Press Australia Subscriber

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    @Krisse

    Welcome to the dark side.

    I would go back to the nipple with smallest jet and carefully reset it firmly but not over tight.

    Is there a brass mesh filter in the fuel line between the tank and the burner?

    Tony

    PS: The next thing I’d do is boil a pot of water and see if the burner leaves soot that can be wiped of by your finger.
     
  8. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi @Krisse You said these particular burners came from the Norwegian Army....

    The Norwegian Army used several different forms of modified outer cap / burner body to ensure they could be “locked” together to prevent loss of parts.
    If you have such a modified burner body it means you must have the correct matching cap to get proper assembly and operation.

    Is it possible that you have a modified burner body with an incorrect cap/caps.

    Silent burner caps Norwegian Army

    111T Orange flame
     
    Last edited: Dec 9, 2020
  9. Krisse Sweden

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    the burner came complete with the hood and nozzle mounted. does not appear to have been touched since it ended up on any shelf many years ago. the outer hood should be right as it has the right locks.

    I thank you for all the answers but feel like I have already tried everything. This burner will haunt me :shock:

    03C9A482-86D7-436E-B6A6-9B98882BDC3C.jpeg
     
  10. Krisse Sweden

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    Aa same problem no solution ](*,):doh:
     
  11. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    Are you sure they’re not gasoline jets for the 111B?
     
  12. Krisse Sweden

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    Fairly safe, original nozzle, kerosene nozzle from Fogas and a Radius NOS kerosene nozzle. I try with the needle, everyone feels the same size
     
  13. Staffan Rönn

    Staffan Rönn SotM Winner SotY Winner Subscriber

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    Hej Krisse,
    Just one thought - is the strainer (rolled brass mesh) fitted as it should in the inlet tube? Without it, the flame can get distorted.

    BR/Staffan

    Small note - the denomination of this burner is 221NA (not 207). It's a regular 221 burner with the special bayonet joint fitting of the outer cap, designated for the Norwegian Armed Forces.
     
  14. JP2

    JP2 Subscriber

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    What is that? Can we see under please? Thanks
    1607585460696614123386~3.jpg
     
  15. threedots New Zealand

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    @Krisse . :-k I wonder about those retaining slots used for securing the outer cap. They may encroach too close to the upper vapour chamber therefore letting some needed pressure(and gas) out from under the outer cap's bottom lip. Lack off pressure under the outer cap could cause the flame pinnacles to burn too close the the outer cap therefore heating it to burn a hot cherry red. During operation, can you observe any sign of flame, burning under the burner skirt where those slots are? John
     
    Last edited: Dec 10, 2020
  16. Krisse Sweden

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    Hi Stefan, Ok then it's a 221.I do not know where I got 207 from. The brass net is there. I also took it out in frustration and cleaned it but it was, as expected, already clean
     
  17. tretrop

    tretrop Subscriber

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    Since I have the same burner and problem, I got @Krisse his burner from the same lot I got mine. So we both have the same problem. One test I did was to use a closed jet, preheat with alcohole and open the spindle, to see if there was any fuel getting our via cracks or anything else. But no, all was good. However, it may need a higher temp to open any cracks ?

    @threedots re the retainer slots, during a test last nigth, I did have nice blue flames coming out down from them holes!

    If these are from the same batch, with the same problem, @Timothy Epp might also be interested in our findings. But I am a bit surpice, there seem to be a problem with these 221NA´s and my surprice is that we have not seen and way to fix this ! @Staffan Rönn would yo know of any problems reorted re this secific burner from Norway in the past ?
     
  18. Staffan Rönn

    Staffan Rönn SotM Winner SotY Winner Subscriber

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    Hi @tretrop and @Krisse
    I'm actually puzzled with these performance problems. The thing is that each burner for the Norwegian Armed Forces were - as far as I can remember - always burn tested using paraffin at factory as an extra quality control. Many years have passed, but I cannot remember any specific issues with them.
     
  19. Radler

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    Hello @Krisse and @tretrop

    Usually the mixing tube ends flush with the top of the inner cap. However, most burners performs well, even with (India made) inner caps which are too low. If the gap between inner and outer cap is too wide, the gas stream will be slower there and turbulences may occur. This can influence the intake rate of air into the mixing tube.

    Here we have a Optimus inner cap with 9 holes. These holes and the 4 holes in the mixing tube are a invention of Valor, patented 1946. If underburn occurs, the gases move through the holes into the inner cap and back into the mixing tube and the underburn is extinguished by lack of oxygen.

    The gap between the caps seems to be too wide because the inner cap should be higher. This may create a gas stream turbulence, a lower gas speed and a partial flow back to the mixing tube. You could reduce the space between the caps with a large steel gasket as shown on the 3 pictures. For a first experiment you could cover the 9 holes of the inner cap with something and see what happens.


    DSC01427.JPG DSC01430.JPG DSC01429.JPG

    Radler
     
  20. manfrommanchester

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    Have you been using
    kerosene? I tried this for a period with one of mine. Same symptoms as you. Seems kerosene causes the tubes and jets to clog up