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Water & Wastewater Operator (WPI/ABC Class I) — Practice Exam

WD components: valves: practice questions

Our Water/Wastewater Operator bank has 6 questions on this topic. Here are 4 of them with answers; the full mock exam draws from every topic, like the real one.

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Question 1 · Water Distribution Class I

Why should distribution valves be exercised regularly?

  1. To increase chlorine residual
  2. Exercising valves raises system pressure and adds chlorine residual to the main
  3. To raise system pressure and increase the chlorine residual
  4. So they don't seize and can be found and closed in an emergency
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D. So they don't seize and can be found and closed in an emergency — Valve exercising programs are standard practice.

Question 2 · Water Distribution Class I

Why should large valves be closed slowly?

  1. Slow closure saves time and lowers the chlorine demand in the main
  2. It raises chlorine residual
  3. It doesn't matter
  4. Fast closure can cause water hammer that breaks mains
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D. Fast closure can cause water hammer that breaks mains — Water hammer is a pressure surge.

Question 3 · Water Distribution Class I

What does a pressure reducing valve (PRV) do?

  1. Stops all flow
  2. Raises pressure for customers at higher elevations
  3. Holds downstream pressure at a set lower value
  4. Measures flow to customers
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C. Holds downstream pressure at a set lower value — Used between pressure zones.

Question 4 · Water Distribution Class I

What does an air release valve do on a water main?

  1. Controls pressure
  2. Releases trapped air at high points
  3. Holds the main's pressure constant
  4. Lets water out at low points to drain the main for repairs
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B. Releases trapped air at high points — Air pockets restrict flow and cause surges.

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