Optimus 111 pressure valve won't create a seal

Discussion in 'Stove Forum' started by MarkG, Jul 5, 2020.

  1. MarkG

    MarkG Subscriber

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    I thought i would be good and replace the pressure valve pip on my 111 with one from the Fettlebox kit that i bought (not sure if i will replace any more at this rate!) so soaked the filler cap in Isopropyl alcohol overnight and then with a little heat from a small chefs torch i was able to remove it, i counted two turns to undo it, cleaned anything that needed it, fitted the pip, tightened two turns but it won't seal now, have i managed to make the spring lose its tension? it doesn't seem to be weak or is there something i'm missing?
    Thanks.
     
  2. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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  3. MarkG

    MarkG Subscriber

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    Thanks again @kerophile

    I watched that video a while back just before i bought the safety valve tool as i knew i would be attempting a few of the valves in future, two things i noticed though, my pip is quite small and doesn't sit proud of its holder and the spring in the video protrudes out of the valve much more than on my one so both of those issues could be the cause of the leak couldn't they.
     
  4. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Yes. If the pip you removed is still supple you could just re-fit it and see if it seals properly.
    If the new pip is thinner that the original it stands to reason that you will need to tighten the cap more than before...so perhaps try 3 turns or so and see when it seals.
    Best Regards,
    Kerophile.
     
  5. MarkG

    MarkG Subscriber

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    The pip was a little hard so ended up in the bin and i have tightened the valve quite tightly, i may need to clean off what is left of the thread seal and try again though, thanks.
     
  6. MarkG

    MarkG Subscriber

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    Threads cleaned, spring stretched a little, valve done up as tightly as possible, still leaking,

    Pip fitted to holder, looks like a call to basecamp tomorrow.
    IMG_0389.JPG
     
  7. snwcmpr

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    Can you take photo of the above parts separated and in the order and position you assembled them?
     
  8. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi @MarkG The pip and its holder should be pointing down into the tank. It is there to contain the working pressure. If the pressure inside the tank increases above a pre-set level, it exceeds the pressure of the spring, lifts the pip and de-pressurises the tank to the pre-set level.

    Best Regards,
    Kerophile.
     
  9. Cookie

    Cookie United States Subscriber

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    I replaced a pip recently that gave me a fit afterwards also. After testing I determined that it wasn't sealing so I disassembled it once again. I found that the pip did not re-seat itself properly as the tiny indention left on it was a half moon shape instead of a full circle. I re-assembled it with greater care and it has worked since. Perhaps yours has a similar issue.
     
  10. MarkG

    MarkG Subscriber

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    I refitted the parts in reverse of the way they came out as like you say the pip faces the fuel tank, unlike in the video the threaded cap will only go in as far as leaving one thread showing whereas his one threads right in, i cannot see any burrs on the threads or any issues with the valve seat, i did notice when removing the pip for the photo that it has been damaged so maybe the spring is twisting it unevenly when refitting, it is a shame that this pip does not protrude from the pip holder, i have had the same issue with some Tilley lamps, i buy service kits from three suppliers and only one supplies a protruding nrv pip which so far seems to be the only one that seals properly every time. IMG_0391.JPG
     
  11. hikerduane

    hikerduane Subscriber

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    Some pips come punched wrong, but for me only seems to be ones for a NRV. Sometimes (at least in the NRV equipped stoves) the pip will hang up or the spring gets enlarged and won't slide without catching. May take different pips to get one that works.
    Duane
     
  12. MarkG

    MarkG Subscriber

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    Thanks Duane, yes i've tried two now which were both small and not that well formed, hopefully i can get a decent one from basecamp, possibly another spring too, i think in future i will test the original pressure valve with a flat pin or matchstick and only remove/replace if needed, the two or three that i've had in the past seemed fine,
     
  13. MarkG

    MarkG Subscriber

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    It must be the spring as i have found that a pip from an Optimus lantern fits perfectly, protrudes from the holder and yet the valve still won't seal and is now so bad that you can't even hear the air escaping from it like you could before, the stove is building pressure fine when my hand is over the fuel filler.
     
  14. hikerduane

    hikerduane Subscriber

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    Building experience. School of hard knocks.
    Duane
     
  15. MarkG

    MarkG Subscriber

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    Yes, same with the No 12.
     
  16. snwcmpr

    snwcmpr Subscriber

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    Your last picture shows the right order of assembly. That was what I was looking for.
     
  17. MarkG

    MarkG Subscriber

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    I have just ordered a new filler cap and been advised not to replace the safety valve pips so think i will give them a miss in future.
     
  18. snwcmpr

    snwcmpr Subscriber

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    Even new filler caps can have hard seals and pips. It is good to know how to fettle them.
     
  19. MarkG

    MarkG Subscriber

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    Yes, i will be more careful on the petrol versions if i have to, maybe i heated that one for too long and the spring lost its tension somewhat or it may have been unserviceable beforehand as i didn't try it, i will definitely test in future and if they seem ok i will leave them well alone,
    In this case i could not get a new spring so had to bite the bullet and buy a new filler cap.