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Why must air tanks (reservoirs) be drained regularly?
- A.Draining removes excess air so the governor can rest
- B.Compressed air carries moisture and some compressor oil into the tanks, and the collected water and oil must be removed before they damage the system or freeze
- C.Tanks collect fuel vapor that must be released daily
- D.Water in the tanks improves brake response if left alone
Correct answer
B. Compressed air carries moisture and some compressor oil into the tanks, and the collected water and oil must be removed before they damage the system or freeze
Why
Every charge of air brings in humidity that condenses as the air cools in the tanks, along with traces of oil from the compressor. Left in place, that mixture corrodes parts, fouls valves, and can freeze solid in cold weather.
Manual topic: Air Brakes - Air Tanks and Draining · From the Air Brakes practice bank (AB-216).