Primus 210 won't hold pressure

Discussion in 'Fettling Forum' started by Fixed Blade, Jun 26, 2013.

  1. Fixed Blade

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    Greetings!
    Newbie here with what must be the #1 question you guys get here....Why won't my stove hold pressure?? Primus 210 made in 1943. Got it lit fine but when pumped up it quickly loses pressure and goes out unless I keep pumping. It seems to hold pressure better when the pump handle is held in as otherwise the pressure pushes it out and that's where it must be leaking?? I did put some oil on the leather washer. Maybe needs to be changed?? Any help greatly appreciated.

    FB in Vt.
     
  2. hikerduane

    hikerduane Subscriber

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    Pull the NRV out and maybe replace the pip in it. You may need a special tool to remove the NRV which is at the bottom of the pump tube. Sounds like you have the problem figured out already. Tools are available on the bay of evil or from our member here, Stu. Also check the fuel cap to see if that washer is soft.
    Duane
     
  3. SMolson

    SMolson Subscriber

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    Hi FB,

    It's as Duane stated, the NRV has to be removed and the pip (generally a cork plug for that age of stove) and/or spring replaced. For the NRV tool you'll find no better than those Stu makes. You'll be needing the smaller of the two sizes for your 210. Short of that you can use other NRV removal tools (many available on-line) but if it's stuck fast (like old ones generally are) you will risk damaging (stripping) the head of the NRV.
    Once removed from the pump tube you'll need to open the NRV and replace the cork pip with one made out of Viton rubber (make your own with 1/8th" viton or purchase online). When you replace the NRV back into the stove make sure you use a washer (rubber or lead) - it makes removing it next time much easier.

    As it seems you can pump your stove to generate pressure the leather pump cup should be ok but oil her if it's dry with a light oil like sewing machine oil.

    The fuel cap gasket will likely need to be replaced - they get very hard and brittle over time and won't hold pressure. If when you press down on the existing gasket (needle tip or blade) and it gives a little she may be ok, but if it's already cracked or dry as hardened clay you'll have to replace it. Dig out/remove the old one (exacto knives very handy here) and replace it with one you cut from viton, 1/16th" or buy online. I personally don't use rubber o-rings for washer replacement in fuel caps, but they can be an adequate temporary replacement. Other pressure leaks may occur where the burner screws into the fount, but you'll either see leaking fuel, vapor or flame if the stove is lit. Tightening it down properly should fix that (unless it's stripped...).

    Good luck and enjoy the stove.
     
    Last edited by a moderator: Jul 2, 2015
  4. cazna

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    Its probably back flowing kero into the tube as well if the nrv pip is shot.
     
  5. davidcolter

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    Get a washer kit from fettlebox via the banner on the right. You will need to make or buy an NRV tool, there are many threads about these on the rest of the forum.

    Replace the NRV pip and the fuel cap washer and that is probably all you will need to do. Dont trust the original fuel cap washer, they can work okay for short runs and then fail when you really need them (I speak from bitter experience, I had to borrow someones Campingaz stove to finish cooking my meal)
     
  6. Fixed Blade

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    I can see air bubbles leaking by on the pump shaft when it's extended and they stop when I push it in and hold it. It burns fine when I pump it up and manually hold the pump in. Is that the washer at the end?
     
  7. Rick b

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    Hi Fb, welcome to the forum. I think it still goes back to the pip being dried out and not sealing. The leather pump cup is probably stopping or slowing the fuel from coming up the pump tube when you push it in and it would be pushing fuel back into the tank. The washer makes it easier to remove the NRV if you have to remove it.

    Heres another post re the NRV

    https://classiccampstoves.com/threads/170
     
    Last edited by a moderator: Jul 1, 2015
  8. Spiritburner

    Spiritburner Admin SotM Winner Subscriber

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    To confirm a leaking NRV empty the tank of fuel. Ensure the burner storage cap (preferably) or burner is fitted, pump the pressure up & then remove the pump. Tip the stove so the pump tube is upright & pour water into the tube. Check to see if you get bubbles rising from the bottom of the tube (may need a well lit room or torch if the leak is slight).

    If you were to fix or fit a new valve & it still bubbles it could be the solder holding the end piece of the pump tube in place or a cracked pump tube from someone trying to loosen an over-tightened valve. Unlikely with a Primus.
     
  9. Fixed Blade

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    is there a glossary of terms & acronyms somewhere on this site as I'm at a loss to understand what you guys are really talking about....sorry
     
  10. snwcmpr

    snwcmpr SotM Winner Subscriber

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    You could start here ... Link and the Help & FAQ at the top of the page.

    Searching for a word or abbreviation will quite often get more than you need to know, and sorting through it will answer most questions.

    Welcome to CCS.

    Ken in NC
     
    Last edited by a moderator: Jul 2, 2015
  11. Wim

    Wim Subscriber

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    Hi FB,

    NRV is a Non Return Valve (keeps the pressure in), an SRV is a Safety (pressure) Release Valve (lets the pressure out on some self-pressurising stoves when pressure gets too high). Stoves with a pump need to be pumped to get them going, self pressurising stoves build up their own pressure (basically by expanding air and vapourising fuel in the fount). Mostly, these burn white gas/petrol. A pressure relief valve (there is one on your 210) will regulate the pressure in the fount and thus allows you to adjust the burner. Normally, these are only found on kerosene/paraffin stoves (dangerous on gas/petrol stoves: too many fuel vapours!). There is an awful lot more but you'll learn as you go! Even I managed to do the same, in a foreign (to me language! ;) :lol:

    Best regards,

    Wim