Hi. Just got a replacement kit/board for a Lennox G60UHV furnace replacing the 18M99 controller. The White-Rodgers-Emerson 21V51U-843 / 50V51-843 control board has pretty bad explanations relating to dip switch S3 and S4 Motor Optimization. Can anyone tell me what - No Signal, Positive Half Wave, Negative Half Wave and Full Wave ??