Final answer:
The thermostat in the bleed air valve ensures temperature regulation by driving the regulating valve towards a minimum flow condition at high temperatures, while having no effect at low temperatures to prevent system damage.
Step-by-step explanation:
The sentence refers to the function of a component in the bleed air valve of an aircraft's pneumatic system. The thermostat in the bleed air valve protects against over-temperature. At high temperatures, the thermostat drives the regulating valve towards a minimum flow condition. At low temperatures, the thermostat has no further effect, allowing for normal operation. This temperature regulation ensures that the bleed air does not exceed safe operating temperatures, which could otherwise damage the system or the aircraft's structure.
The subject of this question is Engineering. The question is referring to the bleed air system in an aircraft. The bleed air valve in the system has a regulating valve that is controlled by a thermal sensor. When the temperature rises above a certain limit, the thermal sensor activates and drives the regulating valve towards a minimum flow condition to protect against over-temperature. At this point, the thermal sensor has no further effect.