Question 145General Subjects - Assistant Engineer

70% to pass

What are the operating characteristics of a "waterlogged" potable water system hydro- pneumatic header tank that needs to be recharged with compressed air?

AFailure of the potable water pump to start with demand on the system.
BExtremely long running and idle periods for the potable water pump.
CVery short and frequent running and idle periods for the potable water pump.
DFailure of the potable water pump to stop with zero demand on the system.
AI Explanation

The correct answer is C) Very short and frequent running and idle periods for the potable water pump. In a waterlogged hydro-pneumatic header tank, the compressed air cushion has been lost, causing the tank to become waterlogged. This leads to very short and frequent running and idle periods for the potable water pump. As the pump is activated, the water is quickly pumped out, causing the pump to shut off. However, without the air cushion, the water quickly refills the tank, triggering the pump to start again, resulting in this short, frequent cycling. The other options are incorrect because A) the pump would still start with demand, B) the pump would not have extremely long run times, and D) the pump would still stop when there is zero demand, just with very short cycles in between.

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