Features The model ST-201 De-humidistat is a wall mounted control that must be located in the space being dehumidified. It is 24 volt operated that is wired to the exterior low voltage panel on the dehumidifier by 2 low voltage wires. Location Mount control approximately 60 inches above the floor in freely circulated room air that is returning back to the dehumidifier. The location must not allow discharged dehumidifier to fall on it. Avoid locations near hot or cold sources from windows or doors or other HVAC equipment. Operation: Normal operation calls for the room humidity to be controlled between 50 and 60 percent RH differential built into the control. A rise of room relative humidity above the set point allows the dehumidifier to start and operate until the room relative humidity is lowered sufficiently below the set point at which time the dehumidifier stops. The control also offers a manual on or off mode.