check valve

Check valve is usually installed on the tubing coupling above the pump assembly to prevent the well fluid in tubing from flowing reversibly through pump into annulus causing the motor back spin while the unit is shut down. A bleeder valve is installed above the check valve. Before pulling out the unit from well to surface, throw a bar into the tubing to break the break-off plug in the valve, the well fluid in tubing drain to the annulus through the plug hole prior to pulling out the tubing string.