Balancing valve comprising a housing having a main fluid passage extending along a main flow axis, a valve body disposed within the housing in the fluid passage, wherein the valve body has a first through hole forming a first fluid passage with a variable first fluid passage cross section, and wherein the valve body has a second through hole distinct from the first through hole and forming a second fluid passage in the valve body, wherein the first fluid passage is a main fluid passage and the second fluid passage is a by-pass passage, wherein the valve body is movably mounted to the housing to select one of the first though hole and of the second through hole, between a working position in which the first through hole extends along the main flow axis, and a bypass position in which the second through hole extends along the main flow axis, and the balancing valve comprises a control element, wherein the variable first fluid passage cross section is adjustable by said control element inserted within the valve body, wherein the control element can be removed from the valve body when the balancing valve is in the by-pass position, the valve body is provided with a by-pass knob to rotate the valve body, and a balancing control knob for adjusting a cross section of the first through hole, characterized in that the by-pass knob has an asymmetrical orientation control element adapted to rotate for changing the direction of flow in the balancing valve, the asymmetrical orientation control element being adapted to cooperate with a removable bypass stop device provided with an orientation pin to block the asymmetrical orientation control element in a chosen orientation of the flow, and with a stop pin to stop the by-pass knob in the by-pass position. a housing having a main fluid passage extending along a main flow axis, a valve body disposed within the housing in the fluid passage, wherein the valve body has a first through hole forming a first fluid passage with a variable first fluid passage cross section, and wherein the valve body has a second through hole distinct from the first through hole and forming a second fluid passage in the valve body, wherein the first fluid passage is a main fluid passage and the second fluid passage is a by-pass passage, wherein the valve body is movably mounted to the housing to select one of the first though hole and of the second through hole, between a working position in which the first through hole extends along the main flow axis, and a bypass position in which the second through hole extends along the main flow axis, and the balancing valve comprises a control element, wherein the variable first fluid passage cross section is adjustable by said control element inserted within the valve body, wherein the control element can be removed from the valve body when the balancing valve is in the by-pass position, the valve body is provided with a by-pass knob to rotate the valve body, and a balancing control knob for adjusting a cross section of the first through hole, characterized in that the by-pass knob has an asymmetrical orientation control element adapted to rotate for changing the direction of flow in the balancing valve, the asymmetrical orientation control element being adapted to cooperate with a removable bypass stop device provided with an orientation pin to block the asymmetrical orientation control element in a chosen orientation of the flow, and with a stop pin to stop the by-pass knob in the by-pass position.