Control of a heating and/or air conditioning installation comprising a ventilator and filtration means

The system has an electric circuit with a supply source (42), a main switch, and a speed variation module (48) to selectively deliver a supply voltage to a pulser (4) based on speed selected by a control board (46). A commutation circuit (51) permits the connection of a photocatalyst type filter (34) with the source when air flow is present in a heating and air conditioning system. An Independent claim is also included for a method for controlling heating and air conditioning system control device.