Optimus Nova (Brunton) power loss

Discussion in 'Stove Forum' started by Mark jolly, Aug 10, 2020.

  1. Mark jolly

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    Hi all,

    Me again...

    For those of you that read my thread from a couple of weeks ago (fuel spill) I have now replaced the pump and hose with the new version. The good news is that it solved the problem where the CEJN connector would jam causing fuel to spill. I did however mention that I was also experiencing, what I thought to be a loss is pressure, but which I now believe to be something else, when running the stove. I wanted to updated the components first to see if that would solve the problem, which I now know it hasn't.

    So what is the problem: basically the stove lacks power. The flame is inconsistent, even cutting out completely. It's like there is something blocking the fuel getting to the stove.

    Something I did note was that when I was replacing the old hose, the bit on the stove that you connect the hose bolt to had something in it, not sure what, but it looks like it 'should' be there so I left it?? I've attached two picture which will hopefully help.

    Any help would be greatly appreciated.

    Mark
     

    Attached Files:

  2. theyellowdog

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    It is not a vital part. It serves two purposes...
    1) to stop the flame pulsing
    2) fuel filter

    You can buy replacements, but a small ball of cotton, like a bit off a shirt, will work fine.

    You can find more info about these by doing a site Search for mouse tampons
     
  3. Staffan Rönn

    Staffan Rönn SotM Winner SotY Winner Subscriber

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    Hi Mark,
    The "thing" at the burner inlet is a fuel filter, and it is probably blocked - thus the lack of power. The filter is white from the beginning, so it does look like it's time for replacement.
    In early generations of the Nova, the fuel filter was placed at the burner inlet. It was later moved to the tip of the fuel feed tube on the pump. Early filters were made of porous PTFE (teflon) material, later filters are made of sintered copper.
    The main purpose of the fuel filter is to balance the fuel flow to prevent the burner from pulsing when burning. You can use your stove without the filter (simply remove it), but as mentioned - the flame may then pulse a bit.
    One way of noticing when the fuel filter is clogging up is if output starts to increase when running the stove in the OFF mode (using up the fuel in the fuel line). Once compressed air starts running through the filter instead of fuel, flow increases and you will notice an increase in output until the flame goes out.
    BR
    Staffan

    Edit - theyellowdog was quicker on the ball...:thumbup:
     
  4. theyellowdog

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    @Staffan Rönn I think we posted at the same time, your response very interesting.I always thought the primary reason for the filter was to stop pulsing, but I wasn't sure.
     
  5. Staffan Rönn

    Staffan Rönn SotM Winner SotY Winner Subscriber

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    Yes we were posting at the same time...
    The primary reason is to prevent pulsing. And as a recommendation for the files on this topic, the newer copper filters are better (don't clog up as easy as the teflon filters). The copper filter has replaced the teflon filters in spares kits since several years, I recommend switching to the copper filters when replacing filters.
     
  6. Mark jolly

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    Thanks guys, brilliant info and advice. Seeing as I have just installed a new generation pump and hose, I suspect the filter is not necessary at all.

    I am also not sure I am pumping it hard enough either. It sounds stupid, but I never get to the point where there is resistance, but reading the manual again it says you should.

    I also realised a moment ago that the jet cleaner wasn't working properly, so I've sorted that and there was some definite soot build up.

    I am going to try pumping a bit harder and running without the filter. Along with the clean jet hole I am hoping all should be fine, but I will let you all know.
     
  7. theyellowdog

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    A nova does not need a lot of pumping to feel resistance, assuming your fuel bottle is reasonably full.

    The burners can get a surprising amount of soot build up. I would have thought mine had no soot in it, but when I heated it up to braise a new bolt to the bottom, a lot of carbon burnt off from below the jet hole. I only use kerosene.
     
  8. snwcmpr

    snwcmpr SotM Winner Subscriber

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    Great explanation with a great answer.
    I will look for the copper filter. I think that I have a few white teflon filters.
     
  9. Hazet

    Hazet Subscriber

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    If you haven't already done this, you should remove the fuel control spindle and thoroughly clean it, the inside of the tube, and replace the o-rings.
     
  10. Mark jolly

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    Hi all,

    Good news. Removed the additional filter, pumped a little more pressure and along with the now clean jet, the stove is back to it's earlier form, wohoo.

    It would be good for people who have an earlier model of Nova, like me, to know that if they spend a little money they can upgrade the pump and hose. Hopefully my threads on the matter will help.

    Something to note: the new hose is much longer than the original. Good for cooking but means it's not quite so compact when storing in its wee case (triangular one).

    Thank you all very much for your expertise and advice.

    Mark
     
  11. Hazet

    Hazet Subscriber

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    Would you let us know the part number, or give us a link to the hose you ordered?
     
  12. Mark jolly

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    I got the hose from Basecamp. I emailed to enquire and they confirmed they had stock. I then phoned to pay. Not sure about part number I'm afraid. The pump came from Amazon (UK)

    Pump £50 UK delivered (Amazon)
    Hose £22.35 UK delivered (Base-camp)