Hi, Just found this site and it looks good. I have been given a Primus No.5 stove and although this lights and burns OK it slowly loses pressure. All of the usual suspect seals/joints are good but an immersion test show slight leakage from the pump tube so it looks like the NRV is in need of some TLC. Can anyone give me the across-the-flats dimension of the stub on the NRV please so I can fabricate an accurately fitting removal tool? Dave.
Hi Dave, and welcome to CCS. Check out this post: https://classiccampstoves.com/posts/64230 Best Regards, Kerophile.
Thanks for the welcome folks and also for the excellent information. I have made a tool that is a nice snug fit but, as I thought would be the case, the NRV is pretty solid. I imagine it's been in there for a good few years and brass on brass, locked together for some time, tends to seize up somewhat. I have put a few drops of searching release oil in there and will try to shift it tomorrow. Any tips for releasing it? The stove was made in 1948. It's nothing fancy, just a standard silent burner. Dave.
I tried the cordless drill but the chuck on mine couldn't cope and kept slipping so, before trying the boiling water, I gripped the tool in a bench vise and rotated the stove body .... success. The problem seems to have been caused by a build up of debris as, when I dismantled the valve and popped it into a small cup of white spirit, a load of grunge floated out - time to clean out the tank, methinks. The cup seal looks like it could do with replacing as it is deeply grooved and generally decrepit looking - am I correct in thinking that I can make one from nitrile? The spring and the tube (contact face) both look serviceable. RE: tank cleaning. Would a spray of carburettor cleaner followed by hot water+detergent and a rinse be OK? Dave
When you wash the tank throw in a handfull of small nuts and then agitate. Will help scrub out much of the hard grime, that given time might come loose.
Just an update. I gave the tank a good clean out and re-assembled the NRV - as the original seal (pip) was cork, I decided to make a replacement out of a piece of close grained cork and also made a lead washer to ensure the valve seated correctly in the tank (there wasn't one fitted). When reassembled it lit easily and burns much better without any loss of pressure. The stove after a quick polish. At Simmer At full pressure Although you cannot see from the photo, at full pressure the top row of flamelets are pushed away from the damper. This is the first pressure stove I have owned but I do have a few Tilley lamps to play with... The person who gave me the Primus also gave me an Optimus 8R ..... but that's another story! .... Dave.
Hi Dave, Nice flame pattern! I'm glad your now fixed up. Time for the next stove.... Best Regards, Kerophile.
