I found a paraffin stove while clearing out my Dad's garage. I think it is an Optimus 00 although it also has Primus parts. Replaced all the seals and fitted a new pip, fired it up and it burns as I remember it from 60 years ago. However it will not hold pressure, only keeps going by almost constant pumping. Eventually located the leak to the pump tube. Air is leaking from one spot around the NRV but the location changes each time I refit the NRV. I have tried lead and HDPE washers and also ones made from plastic bottle tops and also o rings but to no avail. There is no sign of any damage to the bottom of the pump tube or on the flat section of the NRV that mates with the washer. I have noticed that when I screw in the NRV that for the first few turns I don't have to apply much force then for the next turns more force is required before it eases of. Any suggestions would be very gratefully accepted. Regards, GHS
, Hi Ghs theres a possibility the thread on the NRV may be damaged or even the thread in the pump tube, have you tried a new NRV
@Ghs Another problem which has happened to me a couple of times the solder seal at the bottom of the pump tube where the NRV screws in to may have failed ' gh
First make a clear diagnosis: 1. Empty the fount 2. Put a tiny bit of candle wax (paraffin) on the jet (Size of ¼ rice grain) 3. Melt the wax by heating the nipple with a lighter, until the wax disappears in the jet. Let it cool down. Jet is blocked now. 4. Close the air bleed valve. 5. Pump until you have some pressure in the fount. 6. Take off the pump lid and plunger. 7. Pour a tiny bit of water in the pump tube. Only as much to just cover the NRV hole. 8. Now you can see where bubbles are escaping: - Out of the NRV hole >> pip is leaking - From under the NRV rim >> lead gasket is leaking or thread is damaged. - From where the pump bottom is soldered in >> re-soldering the joint (rather unlikely) 9. Take the opportunity to submerge the whole pressurized stove in water to check for other leaks. (Jet, air-bleed, filler, riser tube, spirit cup.) Dry out the pump with a kleenex. 10. No worry about the candle wax. It will vaporize, when you preheat the stove next time. Good luck! Radler
@Ghs Welcome to GSS. You have a British made equivalent to the Primus 210 in the shape of a Burmos 21. The tell tale is screw in the top of the burner that allows access to the jet / nipple through the top and not using a cumbersome universal jointed nipple tool and the colour of the tin. If you can get through the surface rust you will probably see some dark purple paint on the lid. There are plenty of reports on this site of problems with the pump tube being split. Including one of mine. I'll dig out a link to that thread when I have some more time. It looks like it has acquired a primus made wind shield, hence your confusion over the maker. Regards John
@Ghs In this thread I went from despair over a leaking NRV that I thought was the problem to finding and then repairing cracks in the pump tube. Even if it's taken me a while to provide the promised update. There are some useful links in that post to other contributors that I found useful at the time. Regards John PS tempus fugit! does not seem 9 years since I posted about it.
Thanks to all for the suggestions. Going to work my way through them while hoping it's not a crack in the pump tube. Thanks.
Hopefully not as mentioned earlier i have had two pump tube fails and the cause was the solder joint at the base of the pump, even if you do have a crack in the pump tube all is not lost you can salvage a new pump tube from a paraffin blowlamp, if so look for one that the lamp is not complete which is fit for spares and repairs, i have seen on ebay stove and blowlamp spares where just the pumps were for sale, if you have to go down this route on most blowlamps the pump tube is screwed into the tank and not soldered, so the union on the blowlamp pump tube will have to be de soldered and removed, but hopefully you dont have to go down this route. All the best in getting your OO up and running, i will look forward to seeing it working
Well think I have discovered the source of the problem. While removing the NRV to fit a new NRV the base plate of the pump tube came away completey and dropped into the tank of the Burmos. I will be going through John's messages to see if I can remove the tube and refit the base plate. When I started this it seemed a simple job - new seals, pump leather and nozzle but you get hooked and since it was my Dad's I'm determined to get it working. Nostalgia is a funny thing, already refurbished his Tilley lamp.
