Backflow Prevention And Cross Connection Control Exam Questions And Answers | Rated A

BACKFLOW PREVENTION AND
CROSS CONNECTION CONTROL
EXAM



Relief valve discharges continuously. Problem May be caused by what 5 faults? -
Correct Answers -1. Faulty No. 1 check valve (F1CV)
2. Faulty No. 2 check valve with backpressure (F2CVwB)
3. Faulty relief valve (FRV)
4. Relief valve plugged sensing |ine(s) (RVPSL)
5. Relief Valve leaking diaphragm (RVLD)

Relief valve discharges intermittently. Problem May be caused by what 4 faults? -
Correct Answers -1. Properly working assembly with large pressure fluctuations
2. No.1 check valve reading is close to RV opening point, with small line pressure
fluctuation.
3. Water hammer
4. No. 1 check valve leak with intermittent flow through assembly.

During RP Test 1, Relief Valve discharges after No. 2 shutoff valve is closed. What
does this indicate? - Correct Answers -1. Normally indicates faulty No. 1 check valve
• Dirty or damaged disc
• Dirty or damaged seat: or,
2. Leak through relief valve diaphragm

During RP Test 1, Relief valve would not open; differential on the field test kit would not
drop. What does this indicate? - Correct Answers -1. Leaky No. 2 shutoff valve with flow
through the assembly (L2SVwF)

During RP Test 1, Relief valve would not open, differential drops to zero. What does this
indicate? - Correct Answers -1. Relief valve stuck closed due to corrosion or scale
(RVSC).
2. Relief valve sensing line(s) plugged.

During RP Test 1, Relief valve opens too high (with sufficiently high No. 1 check
reading). What does this indicate? - Correct Answers -1. Faulty relief valve
• Dirty or damaged disc
• Dirty or damaged seat

, During RP Test 1 or 3, Check Valve No. 1 check reading too low (less than 5.0). What
does this indicate? - Correct Answers -1. Dirty or damaged disc
2. Dirty or damaged seat
3. Guide members hanging up
4. Damaged spring
What is the purpose and requirement of the RP Test # 3: Tightness of # 1 Check Valve
(USC Ch 10 pg 245) - Correct Answers -Purpose: To determine the tightness of # 1
check valve, and to record the static differential
pressure across # 1 check valve.
Requirement: The static differential pressure across check valve # 1 must be greater
that the
relief valve opening point (as determined in test # 1) and at least 5.0 psid.

What is the purpose and requirement of the DC {Double Check Valve Backflow
Prevention Assembly) Test # 1: Tightness of Check Valve # 1 (USC 10th ed pg 278)? -
Correct Answers -Purpose: To determine the static differential pressure across check
valve # 1.
Requirement: The static differential pressure across DC check valve # 1 must be at
least 1.0 psid.

What is the purpose and requirement of the DC {Double Check Valve Backflow
Prevention Assembly) Test # 2: Tightness of Check Valve # 2 (USC 10th ed pg 281)? -
Correct Answers -Purpose: To determine the static differential pressure across DC
check valve # 2
Reguirement: The static differential pressure across check valve #2 shall be at least 1.0
psid

During RP Test 2, Check Valve No. 2 is Leaking. What does this indicate? - Correct
Answers -1. Dirty or damaged CV 2 disc
2. Dirty or damaged CV 2 seat
3. CV2 guide members hanging up
NOTE: Lubricants should only be used to assist with the reassembly of components,
and must be non-toxic.

During DC Test for either check valve, the Check valve is reading below 1.0 psid. What
does this indicate? - Correct Answers -1. Dirty or damaged check disc
2. Dirty or damaged check seat
3. Damaged spring

During DC Test for either check valve, the Check valve reading above 5.0 psid psid.
What does this indicate? - Correct Answers -1. Incorrect CV spring, possible RP spring.

During PVB Air Inlet Test, Air inlet valve does not open, as field test kit drops to 0.0
psid. What does this indicate? - Correct Answers -1. Air inlet disc stuck to seat
2. Broken or missing air inlet spring
3."O|d style" pressure vacuum breaker (non- loaded air inlet valve)