Alex has let me know that you are currently having issues with the bottle flow adjust knob. I have experienced this problem in the past and it can normally be fixed easily. The bottle flow knob has a screw in it that holds the knob onto the part that physically controls the bottle flow amount. To tighten or loosen this screw you use what we refer to as a "allen wrench" which is a wrench that has a square end on it (picture attached). You will use that wrench to tighten or loosen the knob onto the valve that controls the bottle flow. What happens is if you tighten the bottle flow knob to much (put to much strength into turning it on or off) you will either damage the flow rate valve or you will loosen that screw that I was talking about earlier. If the knob itself has come loose and is not turning the valve anymore, all you need to do is tighten the bottle flow knob with the allen wrench until the valve will turn again. When opening and closing the bottle flow, you should never have to tighten it very hard or use a lot of strength to do it.
When tightening or adjusting the knob there will be two screws that use the allen wrench to tighten or loosen. The first screw is showing on the black turn knob that is installed. That screw doesn't actually connect to the valve at all. The screw only hold the black knob onto another silver knob. If you take the black knob off you will see the silver knob underneath it. This knob is the one that actually turns the bottle flow up and down. The silver knob underneath has the same allen wrench screw but its a different size and might need a different sized allen wrench to tighten or loosen. This silver knob needs to be checked if its tightened enough to actually turn the bottle flow up or down. If the silver knob turns but doesn't actually turn the bottle flow up or down then it needs to be tightened down until it starts turning the flow up and down again. This should fix your issues with the bottle flow not working.
If you would like to Skype with video I can help walk you through the processes if this email doesn't help you fix the problem. Just let me know what time you will be on either Thailand time or California time.
Thanks,