Overreactive Firing Valve

[marauder]

My Gorgon keeps firing whenever the PRV should kick in. Instead of the PRV opening up and the excess pressure being released back into the reservoir the firing valve opens up and it starts firing. Any idea why this is happening? I have never heard of this issue before.

[HBWW]

Haven't heard of this happening on any blaster either. I haven't worked with BBT pull valves, but from what I know, they should work very similar to Larami's, so this doesn't make much sense initially.

My first try would be the classic rubber band fix. That's generally fixed problems with those valves not staying closed when they're supposed to.

Perhaps a leaky check valve could be the problem? That would create backpressure/flow while pumping, which creates a suction force at the valve and causes it to open. This is how pilot valves work, and I wouldn't be surprised if this is what's happening. Another possibility is that the PRV itself is causing this backpressure, which is in turn, opening the valve.

[marauder]

Also, if I actually pull the trigger and release it stops shooting. It's also less likely to happen if I push down on the nozzle selector. Rob and I noticed that the Gorgon stock nozzle selector comes pretty loose. I have devised an easy and cheap fix for this which I'm going to try this week. If that doesn't solve the problem then I'll break open the gun and have a look at the pull valve. The great thing about the Gorgon is that it is screwed in to one half of the shell, so you can take the other half of the shell off and the gun is still fully operational. You can actually watch the mechanics move when you pull and release the trigger or when you pump.

[soakinader]

I actually have heard of this problem before. I'm also pretty sure my Gorgon did this once or twice. I believe the problem stems from the diameter of the firing valve being too small- so basically, the pressure holding the valve closed isn't enough to counter the pressure from pushing the valve open- and once the valve is open, fluid dynamics kicks in and the water starts surging out.
There really isn't anything you can do about it other than using a stronger spring to hold the valve closed (or a rubber band???), or having a larger/weaker OPRV (which isn't really what you want).

[HBWW]

^In that case, I think it could more likely be a defective by design kind of issue. It seems like it would depend on the PRV releasing more water at a time in order to trigger the suction that opens up the pull valve.

Ironically, this is exactly how their air powered dart blasters work. There is a piston sitting loose at the end of the PC. When pressurized, the piston blocks the opening due to the air pressure behind it, and seals that way. A tiny valve is on the other end, which consists of a spring pushing a piston shut, and a button on the outside that opens it when pushed. The trigger pushes this button, which releases a small amount of air, creating suction and opening the larger piston for the rest of the air release.

Anyway, I think the rubber band repair should mitigate this problem. If not, I would say that the PRV is defective. Standard check valves rarely have problems in most stock blasters I've worked with.