Control valve for hydronic installations, comprising: a valve housing providing a valve inlet and a valve outlet, said valve inlet and valve outlet being connectable into a pipe of the hydronic installation; a valve plunger acting together with a valve seat, whereby the valve is closed when the valve plunger is pressed against the valve seat, and whereby the valve is opened when the valve plunger is lifted up from the valve seat; a presetting unit for adjusting a presetting value of the valve; characterized in that said presetting unit comprises at least a housing element, a driver element, a pinion element and an indicator element, wherein the housing element of the presetting unit is fixedly attached to the valve housing and houses said driver element, said pinion element and said indicator element; the driver element and the indicator element are both rotatable around a rotation axis relative to the housing element, wherein the rotation of the driver element causes an adjustment of the presetting value of the control valve; the pinion element is guided by the driver element in such a way that the pinion element follows the rotation of the driver element; the pinion element comprises an external toothing acting together with a first toothing of the housing element and with a second toothing of the indicator element, wherein the number of teeth of the first toothing is different from the number of teeth of the second toothing thereby causing a relative movement between the indicator element and to the housing element upon rotation of the driver element, and wherein the position of the indicator element relative to the housing element indicates the presetting value of the control valve. a valve housing providing a valve inlet and a valve outlet, said valve inlet and valve outlet being connectable into a pipe of the hydronic installation; a valve plunger acting together with a valve seat, whereby the valve is closed when the valve plunger is pressed against the valve seat, and whereby the valve is opened when the valve plunger is lifted up from the valve seat; a presetting unit for adjusting a presetting value of the valve; characterized in that said presetting unit comprises at least a housing element, a driver element, a pinion element and an indicator element, wherein the housing element of the presetting unit is fixedly attached to the valve housing and houses said driver element, said pinion element and said indicator element; the driver element and the indicator element are both rotatable around a rotation axis relative to the housing element, wherein the rotation of the driver element causes an adjustment of the presetting value of the control valve; the pinion element is guided by the driver element in such a way that the pinion element follows the rotation of the driver element; the pinion element comprises an external toothing acting together with a first toothing of the housing element and with a second toothing of the indicator element, wherein the number of teeth of the first toothing is different from the number of teeth of the second toothing thereby causing a relative movement between the indicator element and to the housing element upon rotation of the driver element, and wherein the position of the indicator element relative to the housing element indicates the presetting value of the control valve. the housing element of the presetting unit is fixedly attached to the valve housing and houses said driver element, said pinion element and said indicator element; the driver element and the indicator element are both rotatable around a rotation axis relative to the housing element, wherein the rotation of the driver element causes an adjustment of the presetting value of the control valve; the pinion element is guided by the driver element in such a way that the pinion element follows the rotation of the driver element; the pinion element comprises an external toothing acting together with a first toothing of the housing element and with a second toothing of the indicator element, wherein the number of teeth of the first toothing is different from the number of teeth of the second toothing thereby causing a relative movement between the indicator element and to the housing element upon rotation of the driver element, and wherein the position of the indicator element relative to the housing element indicates the presetting value of the control valve.