Hello!
It could be that the gas cylinder is not screwed tightly enough into the sparkling water maker. I recommend that you check that the cylinder is screwed in correctly and tightly. Sometimes a cylinder that is not screwed in tightly enough can result in less carbon dioxide being pumped into the bottle and a whistling noise when operating it. Please try screwing the cylinder in even tighter.

I hope this solves the problem. Kind regards!

Mine has already been replaced twice. Yes, Brus can leak occasionally. Very nice design, but rather poor quality. And yes, occasionally the pressure bottle can also come loose from the thread after prolonged use, then the compressed air blows off to the side. Tip: check the hold of the pressure bottle from time to time and tighten it again.

This looks like a valve or the transition to the bottle is leaking. For me 3-4 seconds are enough, a whistling sound is heard when you turn the knob all the way to the other side after filling with CO2