Hi Stovies Please can you help me solve a problem with my Primus no 5. I have changed the leather pump washer. I have changed the filler cap seal. I have immersed in water and no bubbles come out. The flame burns a nice light blue. I have tested with a different burner head and I am still losing pressure. Can anyone suggest why...... PS The nipple has NOT been changed, but that does not mean to say it is correct as it was bought second hand from a Sales Room. Do you know if there are certain size nipples for certain models and how you tell the difference. Is there a list/link anywhere to show you which size nipples each model should have. Does the nipple size reflect the size of the fuel tank? How many different size nipples are there. Thanks Alison .
Hi Alison, most one-pint and two pint kerosene stove use a jet with an aperture of 0.32mm diameter. It is unusual to see any markings on them. Some smaller stoves, such as those of 0.5pint capacity, with "lipstick" type vaporisers, don't have a removable jet but the aperture is 0.23mm. Smaller Petrol-fuelled stoves, such as the Optimus 80 and Primus 71 have removeable jets, also with an aperture of 0.23mm. If you have already immersed the whole tank, and there are no leaks, but you believe that you are still losing pressure; I would suggest that you "paint" soap solution on the tank-riser joint and the heat-proof washers between riser and burner, whilst the stove is operating. They are potential leak sites. Hope this helps. Best Regards, Kerophile.
Hi Alison, here is the link you asked about: https://classiccampstoves.com/threads/9991 Best Regards, Kerophile.
Hello Alison It is hard to test a No5 for leaks by immersing the stove in water as the stove must be under pressure and at working temperature. This is made difficult by air constantly escaping from the nipple. Good advice from kerophile: With the stove burning well, I would also use a bubbly soap solution around the filler cap and air release. The leak will generate lots of soapy bubbles.
Hi Alison, There is a quite simple test method that I would suggest. 1. Empty the tank. 2. While you block the jet by your finger, pump and create enaugh pressure inside the tank. 3. Keeping your finger on the jet, immerse whole stove into water. And see.... What a brillant suggestion, isnt it?
What is wrong with...running a lighted match around the burner joints while under pressure...shouldn't leaks light up and burn?
Hi To be honest IMHO leaks from the riser upwards are uasually obvious. You can see and often smell paraffin vapour escaping. I think it's more likely a "air" leak which is as the name suggests a leak of the air above the paraffin in the tank.
Thanks to all you guys for your responses. My leak is now fixed. It was a very tiny hole around the neck of pressure release tube which needed a little soldering. However the washer inside the filler cap was the wrong one....hence it is presently running on full pressure. Cheers. Alison
