I have a Chicago pneumatic QRS 25 that keeps going up and pressure until it shuts the machine off. I replaced the transducer I’ve replaced and rebuilt the inlet valve but it keeps shutting the machine off. It doesn’t stop at 125psi. It goes way too high 150psi and shuts the compressor off…
Did you also check the loading solenoid?
The loading solenoid controls the control air supply to the inlet valve.
Normally, on most machines, it works like this:
- no power to solenoid
- solenoid closed
- no control air to inlet valve
- inlet valve closed
- power to solenoid
- solenoid open
- control air to inlet valve
- inlet valve open
Please check this first, and let me know what you find 🙂