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SVEA 123R Disassembly

Discussion in 'Fettlers Master Class' started by Tony Press, Jun 5, 2016.

  1. Tony Press

    Tony Press Australia Subscriber

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    A new member was asking about his SVEA 123. As I was pulling this 123R (without its cleaning needle), I thought I would demonstrate my way of pulling one apart:

    1. I always use a lever to unscrew the burner bell if it won't easily come off by hand.

    IMG_9985.jpg


    2. Take off the nipple (jet). Use good quality tools, adjusted properly to make sure you don't burr the nuts etc.

    IMG_9987.jpg


    3. Take off the tank cap (by hand).

    IMG_9988.jpg


    4. Take off the vapouriser (generator) with a good quality wrench. NOTE: it is tightened so that the control spindle is aligned with the "1" on SVEA 123. This is where it needs to be re-tightened to. NOTE: The SVEA 123 (not the "R") has a nut on the vapouriser for unscrewing).

    IMG_9989.jpg


    IMG_9992.jpg


    5. Take off the packing nut. NOTE: if you're using a SVEA 123 with the cleaning needle, turn the control spindle fully to the cleaning position and release the cleaning needle.

    IMG_9990.jpg


    6. Unscrew the control spindle.

    IMG_9991.jpg


    7. Before fully disassembling the cleaning needle, make sure you note the position and orientation of all the pieces.

    IMG_9993.jpg


    8. If, and only if, you need/want to service the pressure release valve, take out the filler cap washer and apply some heat to the join between the filler cap and the pressure release screw. This is to unseal the 'loctite' that some are fitted with.

    IMG_9995.jpg


    9. Using the correct tool (in this case one of The Fettle Box multi tools using the penta end) unscrew the NRV screw. NOTE: Make sure you note how many turns so that you know how hard to re-tighten.

    IMG_9996.jpg

    IMG_9998.jpg




    So there is is fully disassembled.

    I then replace all the seals, check the wick is in good order, re-assemble and then check for leaks etc, by letting it get hot and running it for a while.

    Cheers

    Tony
     
  2. Giri

    Giri Canada Subscriber

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    Thank you for the great post.

    Does the tank cap always have a brass holder for the rubber pip?
    Or does it differ with the 123R and 123?
     
  3. sa3spd

    sa3spd United States Subscriber

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    Hi,

    I haven't taken many apart, but of those I have, all the "standard" caps such as Tony's picture shows had the brass holder for the SRV (safety release valve.)

    Now the caps for the Mini- and Midi-pumps have a different arrangement. There's an NRV (non-return valve) which has a molded pip, with a shoulder to locate the spring. I believe these are impossible to obtain. So you'll want to talk to Ross about getting a brass pip holder to hold his pips, and life should be good from there on. The SRV on those caps involves an O-ring as I recall. I don't have the size at hand, and couldn't find them on The Fettlebox at the time I needed them a couple of years back, so I bought a bag with about a triple lifetime supply one time from a different vendor. If you need a couple, please let me know. If I remember correctly, the ones I bought are Viton, just like Ross' gaskets and pips, too.

    Maybe we can sweet talk Tony into some photos of the pump style cap broken down for maintenance... please?

    Rick C
     
  4. Tony Press

    Tony Press Australia Subscriber

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    Last edited: Jun 6, 2016
  5. Funfundfunfzig

    Funfundfunfzig Australia Subscriber

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    Hi @Tony Press
    Another great post from a master stover!
    Are the pips in these caps smaller than a regular NRV pip? I have two sizes on hand 4mm and I think 4.5mm. Any idea which one these caps use?
     
  6. Tony Press

    Tony Press Australia Subscriber

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    @Funfundfunfzig

    No... It's larger than 4.5mm in diameter.

    I didn't measure it, I just used the brass pip holder to stamp a new one out of viton.

    Cheers

    Tony
     
  7. Funfundfunfzig

    Funfundfunfzig Australia Subscriber

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    Much obliged Tony!
     
  8. Rangie

    Rangie Subscriber

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    @sa3spd not so I'm afraid, it used the standard one for the non-holder Optimus 111 pump NRV. HERE :content:
    Other than the standard o-ring sizes, Optimus kept it in the family.... :mrgreen:

    Basecamp
    2252 Rubber cone for pump valve, all paraffin lamps & stoves, £ 2.60
    2252V
    Viton cone for pump valve, all petrol lamps & stoves, £ 2.60

    Alec.
     
  9. snwcmpr United States

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    For the SRV.....
    I made a 'punch' from a steel bolt.
    I cut the head off and drilled a hole .205" and then tapered the outside diameter. I heated to red, quenched, then heated again but not to red. (Poor mans temper)
    I use it in a drill, with some oil to make my own SRVs pips from Viton sheet.
    So far it has made enough for me.

    Ken in NC
     
  10. sa3spd

    sa3spd United States Subscriber

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    Hi,

    I didn't measure the ones I got from Ross, either, but they are definitely larger than 4.5mm. Just doing the math from the drawings Tony posted, it looks like 5mm should probably do the trick. I know whatever size Ross makes his, they were nice and snug, and required a bit of a push to install in my caps.

    Also, I haven't used sealer on mine, and apparently missed this part in looking at those drawings before, but it looks like a sealer was used between the pip and holder. I'll try that, "next time."

    Rick C
     
    Last edited: Jun 6, 2016
  11. sa3spd

    sa3spd United States Subscriber

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    Hi, Alec

    Just to make sure I read things correctly, are the Base Camp "cones" the same style as the original in your picture?

    If so, that's good news! Even if it comes after I "converted" all my pump caps to the brass holder/flat pip style.

    Thanks,

    Rick C
     
  12. Giri

    Giri Canada Subscriber

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    Thanks for all the great info!
     
  13. Rickybob United Kingdom

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    i have now got one of these 123s with the self cleaning jet, so i will try the above this next weekend - not the filler cap though i have checked the pip is not stuck by pushing back with a matchstick and that will have to do

    the stove arrived without a windshield but the one off the old stove fits perfectly, it has a normal tank cap and burner bell plus a mini pump and cap plus what appears to be an after market burner bell machined from brass - it fits on a coarsly threaded collar which is a push fit on top of the riser

    turning the bell allows for approx 4mm of vertical adjustment between the jet and the ( standard ) flame plate

    i cannot tell if it is a one off made by an enthusiast or a commercial product, i will ask my nephew to upload some pictures on saturday
    the bell weighs in at a whopping 4 ounces and i am baffled why anyone would want to fine tune the burner plate to that extent

    i can only think that being a mountaineering stove there might be an advantage in adjusting the height to suit different altitudes
    but i am not convinced that it would be needed - does anyone out there know?
     
  14. geeves

    geeves New Zealand Subscriber

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    4 ounce burner bell. That would take a week to preheat!
     
  15. Rickybob United Kingdom

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    good point - but it would take longer to get cold so perhaps intended for extreme cold/windy conditions - i am just guessing, my nephew has a smart phone so he knows how to upload stuff
     
  16. backpacker56 United States

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    Having the relief valve actually work (blow off during stove operation) sounds pretty extreme (jet of flame). But I suppose this would be better than explosive rupture of the tank. It would seem wise to check the valve to make sure it isn't stuck.

    Isn't the mechanism essentially the same as a valve on a pneumatic tire? When the pressure from the bicycle pump exceeds the air pressure within the tube, the valve opens and air is forced in. But sometimes the valve sticks, and even with 120 psi or more (by the pump gauge) the tire will not inflate. Then maybe the valve opens suddenly and the pressurized air rushes in. Or sometimes you have to disconnect the pump and depress the valve stem manually to break the seal, then try inflating again.

    So is there a way to test the stove's relief valve? Can you manipulate the valve manually to make sure it isn't stuck? Or has some clever person devised a test rig where you can pressurize the cap using a bicycle pump to see at what pressure the thing opens?

    Is the relief valve a one-shot device? After it blows, does it have to be rebuilt, or does it just reseal itself and go on like nothing happened?

    Thanks,
    John
     
  17. snwcmpr United States

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  18. Funfundfunfzig

    Funfundfunfzig Australia Subscriber

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  19. Billybaroo58 United States

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    I cannot get the generator spindle to release with a spanner wrench. Any tips on how to loosen it with damaging the spindle?
     
  20. ArchMc

    ArchMc United States Subscriber

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    Patience and gentle force, penetrating oil, gentle heat and cooling (heat the tank and cool the generator). If it's easier, clamp the generator/valve assembly in a padded vise and turn the tank with your hand. Careful, though. This procedure will minimize the chance you damage the spindle, but will increase the chance of damaging the tank (which is thinner brass than the generator).

    ....Arch