The pump valve (NRV - non-return valve) in this 1949 Primus 991 was possibly the hardest to remove I’ve ever had from any lamp or stove. [There may have been an Aladdin 1A from many years ago that was this hard but it didn’t require removal of the pump tube from the tank.] The NRV was fitted metal to metal. The head of the NRV had already been rounded by the previous owner; and the tank was very dirty (mud wasps?) and corroded inside. 1. I tested the NRV with my @loco7lamp NRV remover. It was stuck fast. 2. I boiled the tank in clean water for an hour. I then tested the NRV: it was stuck fast. 3. I soaked the pump tube in penetrating oil for two days, while cleaning the inside of the tank by soaking with water and detergent. 4. I then heated the end of the NRV tool to hot and placed it over the NRV. I then tested the NRV: it was stuck fast. Repeated a few times with same result and the NRV head was starting to round a bit more. 5. I then tried using the squared pointy end of a chainsaw file hammered into the hole in the top of the NRV, gripped with pliers and rotated anticlockwise. Damn! The steel snapped inside the NRV!… meaning that I could not drill a hole into the NRV through the pump tube to use an “easy-out” (which of course I should have done instead of trying the chainsaw file, given how stuck the valve was). 6. At this point the only solution was to remove the pump tube from the tank. Process: Water in the bottom of the tank; wet cloths around all the soldered parts (see photo below of putting the pump tube back in). Carefully used a propane torch to melt the solder and pull the pump tube from the tank. 7. Now, to get at the NRV itself: First I took off the bottom of the NRV. I the tried to unscrew the NRV head from the outside, but that failed, resulting in twisted brass of the bottom of the NRV. 8. Next I drilled through the NRV from the outside with a 3mm drill, being very careful to keep the drill bit centred on the NRV. Next, I inserted an “easy-out” into the top of the NRV through the pump tube. I clamped the extended easy-out in a vise and twisted the pump tube by hand. A great deal of force was required. After a few failed attempts I finally heard the “click” of the NRV coming free. Fortunately the thread at the end of the pump tube was undamaged. Here is the now free NRV head reinserted into the pump tube to check the thread was OK. Here is my extended easy-out. Putting it back together After cleaning the corrosion off the pump tube and checking the repaired NRV was fitting properly I refitted the pump tube to the tank. 9. Setting up. Masking the areas where you don’t want solder to run and stick. Wet cotton cloth over areas that are soldered; water in bottom of the tank. Note: The NRV was not fitted for soldering the pump tube back into the tank. I used electricians solder. 10. End result before cleaning up the soldering. I’m very happy with this effort. Cheers Tony
@Tony Press My compliments Tony, for your frank and frankly terrifying encounter with the NRV from Hell. Cheers, John
Thanks, John. It was going to be “one of those lamp fettles I can knock over in an afternoon”. But no… that was not to be. I don’t worry about getting things finished quickly these days. I quite like meeting problems with patience and pondering solutions. I tend to learn more that way — as you obviously do with your approach to repair, maintenance, and innovation. While working on this lantern’s NRV I think I’ve solved the problem of what to replace those thick asbestos washers at the top of the hood with. I’ll test this material and let everyone know if it works or not. I also now have a very clean inside of the tank! Cheers Tony @presscall
I’ve known those, indeed. Flip side of the coin are those I’ve been putting off as likely to be problematical that come off easily.
Good intresting post of your trauma with the NRV. glad you managed to sort it and well done too Tony Think this would have beaten a lot of fettlers to giving up to resigning to a shelf queen cheers pete
You got there! I have also had some trying hours with that style of NRV., and that increased my appreciation of Tilley pumps.
Great idea Tony. I have been working on a similar problem as there are heaps of asbestos washers of varying sizes in Tilley irons. There are certainly suppliers of CNAF (Compressed Non-Asbestos Fibre washers) online but they seem expensive and the iron has varying sizes including one particularly large one. I have seen ceramic washers that appear to be that size but my hope is to be able to build up a set of the washers as cheaply as possible for the DN. 250 and DN. 250A irons so that they work without risk. @podbros recently mentioned this risk in a separate post related to the Tilley iron he was working on.
