I have an Iwata Smart Jet compressor. When try to lower the psi and unscrew the release valve at the bottom of the water trap, the pressure goes down but the machine constantly runs. It seems as if Iwata's solution to lowering the psi is to just let the air leak out? In essence, the "smart" part of the smart jet (the auto on/off) no longer works, and it becomes just loud.
Is this right?
Yes, according to the Iwata manual, the Smartjet does not have a pressure regulator. Does yours come with a manual? If not, here is the link.
1. When you first hook up your airbrush to your compressor and depress the trigger of your airbrush, the pressure that registers on your gauge is called your “working pressure.” Your working pressure can vary depending on the size of your airbrush’s nozzle. The smaller the nozzle size, the higher your working pressure. An average nozzle size of 0.3mm will expend a working pressure of approximately 25-28 psi with the Smart Jet.
2. You cannot increase your working pressure, but you can decrease your working pressure by using the air adjustment knob to open the bleed valve.
3. Adjust the air pressure by turning the air adjustment knob toward the + or – while spraying air from the airbrush.
4. When you open the bleed valve with the air adjustment knob, the Smart Jet’s Auto Shut-Off will disengage and cause your Smart Jet to run continuously. This only happens when you regulate the pressure to lower than the working pressure.
5. When you twist the air adjustment knob all the way back toward the +, it closes the bleed valve and re-engages your Auto Shut-Off feature.
You will need to move up to the Smartjet Plus or the Smartjet Pro to get the pressure regulator.