Diagnosed Rheem R96VA0852521MSB gas furnace in Elkville reporting intermittent shutdowns. Testing revealed failed flame rectification circuit on existing SmartValve™ control. Multimeter showed irregular microamp readings fluctuating between 0.4-1.2μA. Replaced White-Rodgers 50M56U-843 control board and verified stable flame signal at 4.8μA. Multiple test cycles confirmed proper operation with consistent flame proving.