Oh right, wait. I need to clarify things a bit

First time, I activated the gas bottle squeezing the levers causing a usual noise of flowing CO2, then turned the gas bottle off. Then I flicked the switch for the dump valve the other way to what it was like previously, after that I activated the gas bottle like the last time and the noise of flowing CO2 sounded louder. I'm presuming the second time I activated the gas bottle after flicking the switch for the dump valve, the dump valve was open yeah?

Cheers