Timer ( PWA ) - Circuit Board NORTHSTAR series NS filter valves newer PWA = 7366685 ( with auxiliary connection available ).
Includes NSSFSSA, NSANSSA, NSTOFSSA, NSAPFSSA, and NSAPFXLA water filters ( not water softeners ).
Models after 2013 switched to DC ( from AC used on older model ).
AC board ( 7286699 ) is Obsolete ( no longer available ).
Uses DC Transformer 7351054 and Wiring Harness 7259927
Uses DC Solenoid 7322699 ( NOT AC 7287645 )
Works with DC Relay Box 7322681 ( replaced AC box 7276050 )
Replaces older PWA = 7286699 ( without auxiliary connection available ), and 7336363 ( with auxiliary connection ).
but ONLY if you switch to DC accessories ( Transformer, Solenoid, and if you have Relay Box, that too ).
Used with models such as NS AIIF2.
Link to NS AIIF2 Manual
NOTE: Many times the problem is with the microswitch, wiring harness, or turbine meter and not the actual Circuit Board.