The first thing to try is a pedal calibration. Start with the unit off.
1) Disconnent the PS0913B power supply from the power jack on the RP200
2) Press and hold the UP Footswitch while reconnecting the power.
3) Continue to hold the UP Footswitch until the Display reads TOE DN.
4) Rock the Expression Pedal forward to the toe down position.
5) Press either footswitch and the Display now shows TOE UP.
6) Rock the Expression Pedal back to the toe up position.
7) Press either Footswitch. The RP200 will return to the last selected Preset and the Expression Pedal is now Calibrated.