This video gives an overview of the modifications I did to this Yong Heng air compressor and tests its ability to fill a 6.8L carbon tank from 0 psi to 4500 psi without stopping, and without a 5 gallon bucket of water.
It's good to cool the last stage line to lower the dew point of the compressed air, but filling an empty bottle without a pmv will cause your water separator(s) to not work since it needs a minimum pressure of 2000 psi. Because this will also immediately saturate your dry filter, you will be pumping all that moisture into your bottle up to 2000 psi. To fill an empty bottle a pmv is a must, for refilling from 2000 psi the check valve is sufficient.
