Aspects of the present invention include point set matching systems and methods. Embodiments may include a system configured to identify a first unit of a particular item that has been picked from inventory of a materials handling facility and assigned to a first shipment. An engine icon represents an engine. In addition, by measuring an outer surface temperature of the water tank and then recognizing a water temperature in the water tank based on the outer surface temperature of the water tank, the heater is controlled to be turned onoff based on a range of the water temperature in the water tank.