I have a Senco Accuset pneumatic nailer model A250FN. It's over 10 yrs old but hardly used. As I was using it the other day it blew a valve seal. Problem is this part seems to now be obsolete. The part number is listed as B24013. Does anyone have a suggestion as to where I can find this part or repair this problem?

If you're willing to do a little work, I've found a way to rebuild the firing valve.

After a bit of hunting, discovered what's called machinable wax, which is a very hard and durable wax used in CNC machining applications. Got a free sample sent to me at no charge.

First, clear out all the waxy material that has broken up and caused the valve to leak, shooting air out the exhaust port. After removing the O-rings, set the firing valve in the oven at 275 degrees along with the wax (which was first shredded by drilling the sample block with a spade bit and placing the shavings in a glass ramekin). When completely melted, place the valve upright and carefully pour the wax into the recessed area. Allow to cool slowly. Using a straight edge, gently scrape the excess wax and finish by sanding with 100 grit sandpaper so that the face of the valve is completely flat and smooth.

Test fired 10 nails and it's working perfectly with no audible air leaking. Remains to be seen how well this holds up.
Good luck!!

I have the same nailer and the gasket blew out part #B24013.
What I did is remove all the gasket material and than bought 2 part epoxy by gorilla glue.
Mixed it up and applied in the channel and raised it to approx same height as original gasket.
Let it sit overnight than replace the parts.
The gun works

My A250FN stopped retracting the piston, and I dis-assembled it and found that the gasket on the firing valve had disintegrated, and a bunch of waxy stuff was clogging the exhaust ports. After searching the internet I found this thread. I wasn't sure the wax would be a durable solution, and I didn't want to permanently modify the firing valve with epoxy. I tried making some rubber gaskets, but those always came out of place. I then tried silicone seal, which was more promising, but it is very hard to get a smooth surface.

Looking at the parts list that came with my A250FN, I saw that there was a part #A34336 which seemed to be a replacement gasket for the firing valve. Unfortunately, I couldn't find any reference to this on the internet, and the parts diagrams I found online did not show this part at all. I had accidentally thrown out the upper firing air seal #A34337, and when I looked this up on the internet I found that it had been replaced with a new part, #BC0473. This was available for a currently supported finishing nailer from Senco.

When I went to buy it on Amazon, the page had one of those "frequently bought products" with a part #BC0472, that looked exactly like the firing valve gasket I needed. Also, the part number was just one less than that for the part that matched #A34337.

I decided to take a risk and buy it. Lo and behold, it fits into the groove on the A250FN firing valve perfectly (you need to push it in with the smaller thickness area on the inside of the ring facing out). After re-assembling my nailer, it now works perfectly!

Here is a link to the BC0472 seal:

www.amazon.com/gp/product/B00ZZFVQC6/ref...05_s01?ie=UTF8&psc=1

I hope it works out for you.