I'm assuming you mean it's dripping from the hose end and not a fitting, correct?
All valves come from the manufacturer with an allowable leak rate. Usually it's nothing and we never see a leak. However, if it's a constant drip it could be a scratched gasket, o-ring, or diaphragm or it could be a piece of debris stuck in the solenoid valve.
Also, if the pressure on the line is higher than what the RODI is rated for, it could just be pushing past the valve from that.
In other words, there are several things that could potentially cause this to happen.
I know your system is brand new and you're getting it set up. Is the RODI new? You might contact the manufacturer?
