Hi Dupe,
An Expression Pedal like the Yamaha FC7 can control many different functions. When used for VOLUME, the operation is as follows:
1. The pedal only affects the parts that are activated in the Pedal Settings (Assignable display).
2. You can only DECREASE the volume of the affected parts with the pedal. The volume when the pedal is fully depressed is the same as when the pedal was not connected.
I recommend setting the volume pedal so that it only affects the RIGHT parts (if desired also the LEFT part). The accompaniment (style, multi pad, MIDI / audio song) should not be affected by the volume pedal.
As I wrote in my post above, Registrations can change Pedal Settings if they contain DIFFERENT settings. If the "Pedal" checkbox was not ticked when memorizing a registration, this registration will not change the current pedal settings later. However, if a registration contains different pedal settings, i.e. the pedal jack to which the volume pedal is connected is switched to a different function, the volume for the parts controlled by the pedal immediately jumps to full value (as if the volume pedal would be not connected). This is absolutely normal.
The only way to ensure that the current pedal settings are unintentionally changed by registrations is, as already mentioned, to use the FREEZE function.
Best regards,
Chris