Normally most volume and expression pedals with jack connectors should work but we recommend pedals within the range of 30KOhm to 200 KOhm for best performance.
It becomes critical if the resistance is more than 260KOhm when the pedal is at max. expression/volume. Resistance down to 1KOhm should not be a problem but we recommend higher values.
Make sure you choose the appropriate pedal type and please use the pedal calibration tool.
You can find both in the UTILITY menu. Choose CONFIG, and set the pedal type to Alternating. Choose PEDAL CALIBRATION and press ENTER. Follow the instruction on the screen to calibrate your pedal.