This pump is available for 120 or 240 VAC which is very handy as I needed a 240 VAC unit. In testing, I found that the check valve has a control handle to open or close, but that has no effect; The valve always functions as a simple check valve (a one-way valve that stops back flow to the tank from the outlet line). If it really worked as a valve and was detachable along with the exhaust line, it would be convenient to remove the line to drain the system for the winter.