A pressure regulating system that is suited to regulate the pressure of a gas includes a regulating device suited to regulate the pressure of a first gas stream, provided with an inlet for the gas at a supply pressure and with an outlet for the gas at a regulated pressure that is lower than the supply pressure; a vortex tube suited to receive a gas stream through an inlet, separate it into a hot portion and a cold portion and deliver the hot and cold portions through corresponding outlets; a heat exchanger coupled with the vortex tube in order to heat the first gas stream before it flows into the regulating device; a recovery duct suited to collect a first portion of the first gas stream at a collection point located downstream of the heat exchanger and to convey it to the inlet of the vortex tube.

In a sanitary installation part (1) which, along with a functional unit (7), forms a flow volume regulator, it is proposed that a regulating element (13), which can be adjusted along an adjustment path, be coupled to a temperature-sensitive drive unit (15) such that different regulating positions of the regulating element (13) are set in dependence on the temperature of the medium flowing through the installation part (1), wherein the different regulating positions realize in each case different volume-flow dependencies (11, 12, 45, 48) and/or flow resistances.