Optimus 155w

Discussion in 'Fettling Forum' started by ARW, Oct 12, 2021 at 5:21 PM.

  1. ARW United Kingdom

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    Stove was bought new (Hytta.de) in 2009. Was in storage until 2016. From then it is only used about 1/2 dozen times a year - faultlessly. This year issues with both burners.

    After a while, there is a "pop", the flame from the cap "deflates" and roars under the cap (glows red), there is a small yellow flame from the jet.

    I have researched this site and others:
    • Can't believe the vapour tubes are clogged with carbon after 5 years and 30 fire-ups.
    • Fuel is paraffin & supposed to be best quality (from Base Camp I think).
    • Pricking / cleaning jet has no effect.
    • There is no appreciable surging that I can see.
    • Happens when tank under high or low pressure.
    • As it's virtually a new stove, jets are still as Optimus fitted (and worked perfectly for 4 years)
    Any advice, please?
     
  2. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi @ARW you describe classic under-burning, where ignition of the flammable fuel mixture occurs under the outer burner cap and can destroy the cap by melting if the flame is not stopped soon enough.

    Under-burn commonly occurs during the priming/ lighting the burner stage, when the flammable mixture is inadvertently ignited under the outer cap, instead of well above the cap.

    Burner problem

    However, you describe the under-burn occurring unexpectedly under normal operation. This implies a flame sneaking under the outer cap and igniting the fuel mixture.

    Two possibilities come to mind:

    1. The burner caps are not seated properly. Check that the mating surfaces of the inner and outer caps are clean and smooth and make a good matching seal with the burner head.

    2. There could be a build-up of carbon and rust particles on the inside of the burner head and the caps. If so these deposits can reach incandescent temperatures in use and ignite the fuel air mixture under the caps. Use an abrasive cloth or wire brush to ensure all inner surfaces are clean.

    Tell us how you get on,

    Best Regards,
    Kerophile.
     
    Last edited: Oct 12, 2021 at 8:28 PM
  3. ARW United Kingdom

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    Apologies for delay - unwell.

    Burner components on face of it didn't look too bad.
    IMG_5032.jpeg
    IMG_5033.jpeg

    Then cleaned:

    IMG_5035.jpeg

    Right burner OK (the one previously an issue), but left dropped out after about 90 sec.
    (Is there any way to post a video?)
     
    Last edited: Oct 15, 2021 at 8:31 AM
  4. ARW United Kingdom

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    Apparently I cannot post a video as it is deemed as "spam or inappropriate content"???

    Try Vimeo and search for "632683932"
     
  5. ARW United Kingdom

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    Update:

    Removed jets and gave proper seeing to. All perfectly OK now.

    Many thanks for help.
     
  6. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi @ARW I am pleased that you have successfully fettled your Op. 155. These are great stoves and you should get many more years out of it.

    Best Regards,
    Kerophile.