And from the way mine reads, you need to completely dispense the cart before you remove it from the keg or the post.
I know this is an old thread, but anyone have a way to not have the cart shoot off when switching carts? Here's what happened my first time using mine (luckily I did this outside):
1. Released headspace pressure, attached gas QD to keg and attached empty charger with base removed to disconnect. Inserted cartridge into base and screwed into assembly.
2. When finished, I held the trigger to make sure all co2 emptied into the keg. Even pulled the trigger a few more times to make sure.
3. When unscrewing the bottom, the cartridge shot out of the bottom like a rocket, hit me in the leg and then ended about 15 feet away on the deck.
Is there any way to prevent this? I got a 2.5G keg and want to serve inside for the holidays. I'm definitely installing/switching/disconnecting this charger outside since it's pretty unstable in my eyes.
Edit: I think I just realized that by leaving the QD attached to the keg and unscrewing, the keg pressure reached equilibrium with the empty cartridge, forcing a few psi back in. By not taking off the QD first, the few psi of pressure caused the cartridge to shoot out.