BACKFLOW PREVENTION AND
CROSS CONNECTION CONTROL
CORRECT 100%
Relief valve discharges continuously. Problem May be caused by what 5 faults? -
ANSWER1. 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? -
ANSWER1. 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? - ANSWER1. 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? - ANSWER1. 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? - ANSWER1. 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? - ANSWER1. Faulty relief valve
• Dirty or damaged disc
• Dirty or damaged seat
During PVB Air Inlet Test, Air inlet valve does not open, and reading on field test kit will
not drop. What does this indicate? - ANSWER1. Leaky No. 1 shutoff valve
2. Parallel installation with leaky No. 2 shutoff valve
, During PVB Air Inlet Test, Air inlet valve opens below 1.0 psid, and reading on field test
kit will not drop. What does this indicate? - ANSWER1. Dirty or damaged air inlet valve
disc
2. Scale buildup on seat
3. Damaged spring
During PVB Check Valve Test, Check valve reading below 1.0 psid. What does this
indicate? - ANSWER1. Dirty or damaged check valve disc
2. Dirty or damaged seat
3. Damaged spring
During PVB Check Valve Closing Point Test (Test No. 2), water runs continuously from
test cock No. 2. What does this indicate? - ANSWER1. Leaky No. 1 shutoff valve
During SVB (Either) Test, air inlet valve does not open, as field test kit drops to 0.0 psid.
What does this indicate? - ANSWER1. Air inlet disc stuck to seat
2. Broken or missing air inlet spring
3. Parallel installation with leaky No.2 shutoff valve
4. PVB not SVB
During SVB (Either) Test, Air inlet valve does not open, and reading on field test kit will
not drop. What does this indicate? - ANSWER1. Leaky No. 1 shutoff valve
During SVB (Either) Test, Air inlet opens below 1.0 psid. What does this indicate? -
ANSWER1. Dirty or damaged air inlet disc
During SVB (Check Valve Closing Point) Test 1, Check valve reading below 1.0 psid.
What does this indicate? - ANSWER1. Dirty or damaged check disc
2. Damaged seat
3. Leaking diaphragm/seal
During SVB (Air Inlet Opening Point) Test 2, water runs continuously from vent screw
valve. What does this indicate? - ANSWER1. Leaking No. 1 shutoff valve
What is the purpose and requirement of the RP Test # 1: Relief Valve Opening Point
(USC 10th ed pg 231) - ANSWERPurpose: To test the operation of the differential
pressure relief valve.
Requirement: The differential pressure relief valve must maintain the zone between
the two check valves at least 2 psi less than the supply pressure.
What is the purpose and requirement of the RP Test # 2:Tightness of # 2 Check Valve
(USC 10th ed pg 241) - ANSWERPurpose: To test the # 2 check valve for tightness
against backpressure
Requirement: The # 2 check valve shall be tight against backpressure.
CROSS CONNECTION CONTROL
CORRECT 100%
Relief valve discharges continuously. Problem May be caused by what 5 faults? -
ANSWER1. 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? -
ANSWER1. 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? - ANSWER1. 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? - ANSWER1. 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? - ANSWER1. 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? - ANSWER1. Faulty relief valve
• Dirty or damaged disc
• Dirty or damaged seat
During PVB Air Inlet Test, Air inlet valve does not open, and reading on field test kit will
not drop. What does this indicate? - ANSWER1. Leaky No. 1 shutoff valve
2. Parallel installation with leaky No. 2 shutoff valve
, During PVB Air Inlet Test, Air inlet valve opens below 1.0 psid, and reading on field test
kit will not drop. What does this indicate? - ANSWER1. Dirty or damaged air inlet valve
disc
2. Scale buildup on seat
3. Damaged spring
During PVB Check Valve Test, Check valve reading below 1.0 psid. What does this
indicate? - ANSWER1. Dirty or damaged check valve disc
2. Dirty or damaged seat
3. Damaged spring
During PVB Check Valve Closing Point Test (Test No. 2), water runs continuously from
test cock No. 2. What does this indicate? - ANSWER1. Leaky No. 1 shutoff valve
During SVB (Either) Test, air inlet valve does not open, as field test kit drops to 0.0 psid.
What does this indicate? - ANSWER1. Air inlet disc stuck to seat
2. Broken or missing air inlet spring
3. Parallel installation with leaky No.2 shutoff valve
4. PVB not SVB
During SVB (Either) Test, Air inlet valve does not open, and reading on field test kit will
not drop. What does this indicate? - ANSWER1. Leaky No. 1 shutoff valve
During SVB (Either) Test, Air inlet opens below 1.0 psid. What does this indicate? -
ANSWER1. Dirty or damaged air inlet disc
During SVB (Check Valve Closing Point) Test 1, Check valve reading below 1.0 psid.
What does this indicate? - ANSWER1. Dirty or damaged check disc
2. Damaged seat
3. Leaking diaphragm/seal
During SVB (Air Inlet Opening Point) Test 2, water runs continuously from vent screw
valve. What does this indicate? - ANSWER1. Leaking No. 1 shutoff valve
What is the purpose and requirement of the RP Test # 1: Relief Valve Opening Point
(USC 10th ed pg 231) - ANSWERPurpose: To test the operation of the differential
pressure relief valve.
Requirement: The differential pressure relief valve must maintain the zone between
the two check valves at least 2 psi less than the supply pressure.
What is the purpose and requirement of the RP Test # 2:Tightness of # 2 Check Valve
(USC 10th ed pg 241) - ANSWERPurpose: To test the # 2 check valve for tightness
against backpressure
Requirement: The # 2 check valve shall be tight against backpressure.
