I have a NR90AE . It's been used about 8 hours. It suddenly would not work at all when I pulled the trigger. The compressor seems fine. This is the first air nailer Iv'e owned and know nothing about them.

Over time the orings within the nailer will dry out causing problems. Adding oil thru the air inlet will not get oil to all the orings. If the gun had been in storage, add a few drops of oil into air inlet and spray silicone (or teflon) spray lube into air discharge opening at the top of the gun (it is difficult for oil to get into the head from air inlet). Before you connect the air, remove the nails and make sure that the drive piston is at top of cylinder. You can verify by inserting long metal tool (slightly larger in diameter than nail shaft) into nose of the gun and tapping firmly. This will move the piston up against the headvalve and hopefully reset it and allow oil the lube orings. If the headvalve is stuck, gun will not fire. Make sure that the safety foot is depressing the firing pin at trigger valve all the way in. Retest gun for proper action. If still no joy, remove the head and lube orings with silicone paste lube(silicone past has better sealing action but dries out over time). Good luck