Hello fettler, Hope you are doing well. I need your help to remove a stuck NRV on my optimus 48. I used all kind of tools, heat, penetrating oil etc. Best regards
A last attempt could be soldering something directly to the remains of the nrv to use as a lever for removal, while carefully protecting the end of the pump tube with nail varnish or similar to avoid solder sticking to it?
Considering that you have already desoldered everything, heat the rest of the valve up to red glow then quench in water to unlock it… you will be able to unscrew it with pliers. Nicola
Hi, Thanks you for your tips. I applied heat and tried to unscrew it. Seems to have some prometting results but still stuck. I will try heat and cold water. I will let you know asap Thank you
Another tip when you will then resolder the cap to the pump tube… after heating to glow, the tinned part won’t be good anymore for a good soldering… so after you have removed the rest of the valve, clean with brass brush the cap and tin it again with some flux and solder… then you can solder it back on the tube. Nicola
Hi all, The cold water trick solved the problem. Thank you. Time for a new NRV. The old NRV had no washer and the thread seems damaged and the new NRV don't srew easily. If I force it, I will have the same problem years later. Thank you @Nicola Francesco Elia for the soldering tips. I will let you know for any update. Best regards.
Sometimes the lead washer get squashed into the threads… use a dentist tool or something sharp to remove any trace of lead from the end cap threads so the new NRV can screw in it easily. Consider that maybe you tried to screw it with your hand, with the tool force it will screw easily. Nicola
Well done for getting it undone, and to Nicola for the successful heat and quench tip. Brass threads are very easy to overtighten and damage... vehicle brake unions only need gentle tightening, but of course the natural instinct which needs to be overcome is to really lean on the spanner...
Hi @Blackdog and @Nicola Francesco Elia. The the new NRV don't go straight and when I try to overtight it becomes loose and turn in the void. The thread need to be remade I think. I will look for thread screw tool to fix it. Best regards.
It does look like the threads on the old NRV are damaged so most likely damage has been done to the threads in the pump tube end cap as well. As the new NRV is turning freely it sounds like there is not enough metal left to repair with a tap- sadly a more serious repair or replacement will probably be needed.
Having a donor stove in this cases is very useful… probably the end cap must be replaced. Otherwise just solder the new NRV head to the cap, then screw the back side to the NRV and re install the pump tube. Not the best solution, but you will be ok for some years. Nicola
I have exactly the same problem on a 111b and I can't convince myself to weld a permanent NRV. WHAT ARE THE THREADS SIZE ON A NRV? MAYBE POSSIBLE TO MAKE A NEW CAP.
