The Centrex 3000 AF (Air Flow) is a continuous compost flow design for very heavy cottage or medium residential use. With a continuous flow system, rotation of the drum moves compost along the larger and longer 3000 series drum, before it drops automatically into the collection housing at the end of the unit. Under normal operating conditions the drum will not have to be turned backwards for emptying. When used seasonally by up to 10 adults, compost will normally only need to be removed annually at the beginning of the following season. The Centrex 3000 AF features a 370 watt 120 volt thermostatically controlled heater in a sealed compartment beneath the unit coupled with the standard Sun-Mar 30 watt turbo fan and 2" vent stack. The Centrex 3000 AF is designed for use with a Sun-Mar Dry Toilet. A pipe piece, 45" in length and 10" in diameter, is supplied with the unit. The only restriction on installation is that the Dry Toilet needs to be directly above the unit so that there is a straight drop. This is long enough if the floor of the bathroom is up to 37.5" above the surface that the composter is placed on. The pipe piece can be cut to size and additional pieces ordered if necessary. All 3000 series units are supplied with a 1" drain hose which should be connected to the 1" drain at the bottom left of the unit. This particular model should be able to evaporate all liquids as long as the heater is on, and it is not being used heavily, so an overflow drain may not be necessary