Question 1758 · Truck theory test
What does an unloader valve do?
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Correct answer
It releases excess air pressure in the braking system.
Official explanation
An unloader valve prevents the build-up of excess pressure in the air tanks of a vehicle fitted with air brakes. The valve is fitted between the compressor and the air tanks. It opens and closes at pre-set pressures, and you will hear a change in the sound of the compressor as it operates.
- Topic
- Technical matters · Braking Systems
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