I need a control drawing of a bypass valve and fan control.
you should post this in the controls form
"Yeah I can figure out whats wrong with it, but you were here first and there isn't room for two, plus it's cold up here, I'll be in the van"
how about some help instead of worrying about where it is posted
Use 1 pilot signal with the bypass valve positioner set up to close at 50% of span, then the pressure switches for the fans staged on the top 50% of the pilot span.
Or use separate signals for the bypass and the fan staging.
God Bless the USA