Air Tanks and Drains Flashcards

What can happen if water is not drained from air tanks during cold weather?

Answer: The water can freeze and cause brake failure

Water left in air tanks can freeze in cold temperatures, blocking air lines and valves, which can cause total brake failure.

Which air tank typically accumulates the most water and oil contamination?

Answer: Supply (wet) tank

The supply or wet tank receives air directly from the compressor and therefore collects the most water vapor and oil before air passes to other tanks.

What type of drain valve removes moisture from air tanks automatically?

Answer: Automatic drain valve

Automatic drain valves expel accumulated moisture from air tanks without driver intervention, though they should still be checked during pre-trip inspections.

What is the minimum number of air tanks required in a basic single air brake system?

Answer: One tank

A basic single air brake system requires at minimum one air tank, though most systems use multiple tanks for reliability and separation of circuits.

Where are drain valves typically located on air tanks?

Answer: At the bottom of the tank

Drain valves are located at the bottom of air tanks so that gravity causes water and oil to settle there, making draining effective.

During a pre-trip inspection, what should you do with manual drain valves on air tanks?

Answer: Open them to drain moisture, then close them before driving

During pre-trip inspection, manual drain valves should be opened to release moisture buildup, then closed so the system can build and hold pressure.

What substance besides water commonly collects in air tanks and must be drained?

Answer: Oil from the air compressor

Oil from the air compressor passes into the compressed air supply and accumulates in air tanks, contaminating the brake system if not drained.