How do I fix overflow constantly running on ROS drinking water faucet?

[xbitgeek]

I have a ROS small faucet for drinking water. The main faucet in the kitchen works find. I recently replaced the main faucet but after reconnecting everything, the overflow on the ROS drinking water faucet will not stop running. The only thing connected to the ROS that I manipulated was an in-line cut off valve to supply water to the ROS. Turning on/off the valve still functions correctly but the overflow constantly runs on the ROS water faucet. I have a 3 filter unit attached to the inside of the sink cabinet with a 6"x1.5" enclosed PVC filter laying on the bottom of the sink cabinet. Could any of these pieces be causing issues with the overflow not shutting off correctly? Any advice or pointing me in the direction to fix this would be appreciated. Trying to save the hundreds of dollars it would cost to have someone come out and start replacing parts. I can supply pictures if needed.

Thank you