1. Remove the panels of the machine: Pro 300 Panel Removal

2. Remove the hose and 14mm fitting from the flow path.

3. Hold the elbow fitting below the check valve with the adjustable wrench and use the 17mm wrench to remove the entire top portion of the flow path.

4. Separate the 2 pieces of the check valve with the 17mm and 15mm wrenches.

5. Ensure that all the pieces of the check valve are clean of any debris, along with the gasket at the bottom of the check valve.