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单选题
Condensate must be drained periodically from the air compressor receivers to prevent （）.
A
second stage cylinder lockup
B
oil sump contamination
C
faulty operation of pneumatic valves
D
corrosion of air receiver baffles
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单选题Which of the following problems can occur if you continually fail to drain off condensate from a starting air receiver?（）A
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Gumming of the tank relief valvesC
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Oil vapour in air piping are dangerousB
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Oil vapour in air piping should be drainedD
Oil in air piping should not be drained
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The coolant temperature must be maintained at 180℃B
The thermostatic bypass valves must be manually opened before the engine is startedC
The pressure cap must be removed while the engine is securedD
Electrical power to the heater must be secured before the cooling system is drained
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