A valve body adjusts opening of a supply passage in response to the position in a valve chamber. The method and apparatus includes including detecting an erroneous demodulation value based on backward-demodulation of received signals, using a difference between a received signal to be demodulated and a preceding signal of the received signals and correcting the error demodulation value. This moisture is then deposited on the regeneration side of the wheel upstream of a cooling coil, increasing the dew point of the air entering the coil.