Replacement fan for FAN1057 and FAN2115 are both SV04 systems using a 200mm 3-speed centrifugal fan. 
FAN1057 is the older Positive2 digital version and FAN2115 is the Evolve/tablet-controller version.  
AC 3-speed
You’ll will re use 
•the SmartVent housing
•mounting plate
•controller box