I recently moved into a house that has an Aprilaire 700 humidifier. After turning it on this season I noticed excess water around the furnace. Further investigation showed that the humidifier will turn on when the furnace/blower is and is not running. I was going to just leave the blower on at all times, but the humidifier will not run when the furnace blower is switched to the ON position on the thermostat, instead of the Auto position. The humidistat R/C terminals are connected to the R/G terminals on the furnace board at the same place the thermostat is connected. Would this be an installation problem or a malfunctioning humidistat?

Humidifiers - Aprilaire - 700 Humidifier