Height adjustable yarn guide for false twist texturing machine

A yarn false twist texturing machine in which an advancing yarn is deflected by a feed yarn guide at a deflection position which is between a heater and a cooling member, and which is at an elevation outside the reach of the machine operator. The feed yarn guide is height adjustable, and it is disposed on a sliding element, which is movable upwards and downwards on a guide rail by means of a linear drive. In the event the electrical energy supply of the machine fails, the linear drive is activated by means of a control device in such a way that the sliding element and the yarn guide move downwardly to a predetermined parking position just below the yarn deflection position, so as to automatically remove the yarn from the heater and thereby prevent yarn damage.