Bought a special tool, stuck it down the nrv tube, got a good grip and turned left. The tool turned but the valve did not. I have somewhat of a grip left but i need to be careful to not destroy it more. I might need a better fitting tool Any tips for loosening the mechanical hold of an nrv valve without using force? From my days of fixing computers i used a trick with stuck harddrives to get them going long enough to salvage date. I put them in the freezer to shrink the metal some. Sometimes it worked and I could salvage photos or important papers and I actually saw tears of joy in some customer eyes. Hopefully the brass in a stove reacts the same way, shrinks and loosens. Currently my Radius No 21 is in the freezer for a try but I wanted to ask the experts here for some advice for other methods if this don't work.
Different thermal expansion rates of a steel shaft and a brass bush could account for a loosening effect but I'd be less optimisic when it's a brass component screwed into another brass component. Sadly, sometimes they won't unscrew and the pump tube must be unsoldered, the NRV unscrewed from the end of it (probably to discard if the head's chewed up) and a new one inserted after the pump tube has been soldered back in place. The removal tool in THIS tutorial from Stu is a nice refinement but not essential. Good luck! John
@swedmiro I have found that to get NRV's out,I first put some 50/50 % aceton/ATF oil in the pump tube. Let it stay for some days, then empty the pump tube and put hot water inside the tube. I do this a couple of times then use one of Stu's tools. This method has fixed many Primus 96 pumps. Good luck. Bjørn
Here is another 2 posts on removing NRVs https://classiccampstoves.com/threads/nrv-removal-tips.28407/ https://classiccampstoves.com/threads/removing-a-distorted-nrv.33058/#post-338008 Hope you win
@swedmiro I use a similar technique to @boknasild. I've once successfully removed a ruined NRV using a drill with an extractor (left hand thread) fitted - but if you go down this path be very careful not to damage the threads that the NRV screws into. Cheers Tony
@Tony Press Tony is correct the use of an extractor can make more trouble. But then the alternative is desoldering the pump tube. Info re these procedures can be found on this forum. Bjørn
Areo Kroil penetrant, wait a few days while sending it through temperature changes and some tapping, might work. Is your tool tight fitting? On my Kenyon, the NRV is exactly the same size as the seat for the cleaner on top. I made one out of an old leaf spring ubolt. very heavy but tight fitting and works well. Also, it is probably best to try all of these, patiently, before another attempt. "Well, that didn't work, I'll try something else" only works once, or a few times. Sounds like you may have one more attempt. Good luck.
heating the end of the tool and letting it transfer heat to the NRV can certainly help . just do not overdo the heat or you will melt the solder . i have had success using HDPE washers instead of lead . it does not jamb like lead does . kerry
Good, I had a similar problem and I ended up solving it by soaking it for one night with apple vinegar, it is a very good thing to eliminate rust or impurities. After that I loose without problems !!! It costs nothing to try. good luck!!!
I would be surprised if any penetrating oil got past the lead seal. It seals kero from going up the pump, so is also gonna seal anything from going the other way. That said, why not. I had a very stuck, damaged head NRV on a Handi stove. I stuck my propane torch down tube for a few seconds, stuck a 3/8" extension( methinks that is what I used) gave it a couple taps, then the tool and it came loose easily. that was my one-and-only stuck NRV, others will have more experience.
There has been talk of that here, and ways to get the penetrating oil onto the 'Other Side' of the NRV.
