Air processing unit for providing compressed air to a supply port, in particular for use in a pneumatic system with a pneumatic unit pneumatically connected to the supply port, preferably wherein the pneumatic system is adapted for a vehicle, the air processing unit comprising: - an inlet port for receiving the compressed air, in particular from an electrically controlled compressed air supply; - an air drying unit having an input port pneumatically connected to the inlet port and configured to dry the compressed air received, and - a supply line configured to exchange, in particular supply, dried compressed air between the air drying unit and the supply port and a return pneumatic line (116, 116.1, 116.2) configured to exchange, in particular return, compressed air of the supply port to the air drying unit, in particular from the supply line to the air drying unit, wherein - an electrically controlled valve is arranged between a first section of the return pneumatic line (116.1) that is connected to the supply port and a second section of the return pneumatic line (116.2) that is connected to the air drying unit, and - a purge valve (109, 110) configured to control a flow of purge air via a pneumatic exhaust line, wherein the pneumatic exhaust line pneumatically connects the input port of the air drying unit to an exterior via an exhaust port; and wherein - in an air drying phase dried compressed air is supplied via the supply line from the air drying unit to the supply port, and - in a regeneration phase returned compressed air is returned via the return pneumatic line from the supply port to the air drying unit, wherein - a return flow control unit comprises the electrically controlled valve and is arranged and configured to enable, during the regeneration phase, a flow of the returned compressed air, in dependence of an electric control signal, from the return pneumatic line via the electrically controlled valve and via the supply line and the air drying unit to the pneumatic exhaust line; characterized in that - the electrically controlled valve is provided as a single and only electrically controlled valve of the return flow control unit. - an inlet port for receiving the compressed air, in particular from an electrically controlled compressed air supply; - an air drying unit having an input port pneumatically connected to the inlet port and configured to dry the compressed air received, and - a supply line configured to exchange, in particular supply, dried compressed air between the air drying unit and the supply port and a return pneumatic line (116, 116.1, 116.2) configured to exchange, in particular return, compressed air of the supply port to the air drying unit, in particular from the supply line to the air drying unit, wherein - an electrically controlled valve is arranged between a first section of the return pneumatic line (116.1) that is connected to the supply port and a second section of the return pneumatic line (116.2) that is connected to the air drying unit, and - a purge valve (109, 110) configured to control a flow of purge air via a pneumatic exhaust line, wherein the pneumatic exhaust line pneumatically connects the input port of the air drying unit to an exterior via an exhaust port; and wherein - in an air drying phase dried compressed air is supplied via the supply line from the air drying unit to the supply port, and - in a regeneration phase returned compressed air is returned via the return pneumatic line from the supply port to the air drying unit, wherein - in an air drying phase dried compressed air is supplied via the supply line from the air drying unit to the supply port, and - in a regeneration phase returned compressed air is returned via the return pneumatic line from the supply port to the air drying unit, wherein - a return flow control unit comprises the electrically controlled valve and is arranged and configured to enable, during the regeneration phase, a flow of the returned compressed air, in dependence of an electric control signal, from the return pneumatic line via the electrically controlled valve and via the supply line and the air drying unit to the pneumatic exhaust line; - the electrically controlled valve is provided as a single and only electrically controlled valve of the return flow control unit.