1. A relief valve discharges continuously. What five faults may cause this
problem?
• Faulty No. 1 check valve (F1CV).
• Faulty No. 2 check valve with backpressure (F2CVwB).
• Faulty relief valve (FRV).
• Relief valve plugged sensing line(s) (RVPSL).
• Relief valve leaking diaphragm (RVLD).
2. A relief valve discharges intermittently. What four faults may cause this
problem?
• Properly working assembly experiencing large line pressure fluctuations.
• No. 1 check valve reading is close to the relief valve opening point, combined
with small line pressure fluctuations.
• Water hammer.
• No. 1 check valve leak with intermittent flow through the assembly.
3. During RP Test 1, the relief valve discharges after the No. 2 shutoff valve is
closed. What does this indicate?
• This normally indicates a faulty No. 1 check valve (due to a dirty/damaged disc
or seat).
• Alternatively, it indicates a leak through the relief valve diaphragm.
4. During RP Test 1, the relief valve will not open and the differential on the
field test kit will not drop. What does this indicate?
• A leaky No. 2 shutoff valve with flow through the assembly (L2SVwF).
5. During RP Test 1, the relief valve will not open and the differential drops
to zero. What does this indicate?
• The relief valve is stuck closed due to corrosion or scale (RVSC).
• The relief valve sensing line(s) are plugged.
, 6. During RP Test 1, the relief valve opens too high (while the No. 1 check
reading is sufficiently high). What does this indicate?
• A faulty relief valve caused by a dirty or damaged disc or seat.
7. During RP Test 1 or 3, the No. 1 check valve reading is too low (less than
5.0 psid). What does this indicate?
• A dirty or damaged disc or seat.
• Guide members are hanging up.
• A damaged spring.
8. During RP Test 2, Check Valve No. 2 is leaking. What does this indicate?
• A dirty or damaged CV 2 disc or seat.
• CV 2 guide members are hanging up. (Note: Use only non-toxic lubricants for
reassembly).
9. During a DC Test for either check valve, the valve reads below 1.0 psid.
What does this indicate?
• A dirty or damaged check disc or seat.
• A damaged spring.
10.During a DC Test for either check valve, the valve reads above 5.0 psid.
What does this indicate?
• The installation of an incorrect spring (possibly an RP spring instead of a DC
spring).
11.During a PVB Air Inlet Test, the air inlet valve does not open and the field
test kit drops to 0.0 psid. What does this indicate?
• The air inlet disc is stuck to the seat.
• A broken or missing air inlet spring.
• An "old style" pressure vacuum breaker (non-loaded air inlet valve).
• The device is actually an SVB.
12.During a PVB Air Inlet Test, the air inlet valve does not open and the
reading on the field test kit will not drop. What does this indicate?
• A leaky No. 1 shutoff valve.
problem?
• Faulty No. 1 check valve (F1CV).
• Faulty No. 2 check valve with backpressure (F2CVwB).
• Faulty relief valve (FRV).
• Relief valve plugged sensing line(s) (RVPSL).
• Relief valve leaking diaphragm (RVLD).
2. A relief valve discharges intermittently. What four faults may cause this
problem?
• Properly working assembly experiencing large line pressure fluctuations.
• No. 1 check valve reading is close to the relief valve opening point, combined
with small line pressure fluctuations.
• Water hammer.
• No. 1 check valve leak with intermittent flow through the assembly.
3. During RP Test 1, the relief valve discharges after the No. 2 shutoff valve is
closed. What does this indicate?
• This normally indicates a faulty No. 1 check valve (due to a dirty/damaged disc
or seat).
• Alternatively, it indicates a leak through the relief valve diaphragm.
4. During RP Test 1, the relief valve will not open and the differential on the
field test kit will not drop. What does this indicate?
• A leaky No. 2 shutoff valve with flow through the assembly (L2SVwF).
5. During RP Test 1, the relief valve will not open and the differential drops
to zero. What does this indicate?
• The relief valve is stuck closed due to corrosion or scale (RVSC).
• The relief valve sensing line(s) are plugged.
, 6. During RP Test 1, the relief valve opens too high (while the No. 1 check
reading is sufficiently high). What does this indicate?
• A faulty relief valve caused by a dirty or damaged disc or seat.
7. During RP Test 1 or 3, the No. 1 check valve reading is too low (less than
5.0 psid). What does this indicate?
• A dirty or damaged disc or seat.
• Guide members are hanging up.
• A damaged spring.
8. During RP Test 2, Check Valve No. 2 is leaking. What does this indicate?
• A dirty or damaged CV 2 disc or seat.
• CV 2 guide members are hanging up. (Note: Use only non-toxic lubricants for
reassembly).
9. During a DC Test for either check valve, the valve reads below 1.0 psid.
What does this indicate?
• A dirty or damaged check disc or seat.
• A damaged spring.
10.During a DC Test for either check valve, the valve reads above 5.0 psid.
What does this indicate?
• The installation of an incorrect spring (possibly an RP spring instead of a DC
spring).
11.During a PVB Air Inlet Test, the air inlet valve does not open and the field
test kit drops to 0.0 psid. What does this indicate?
• The air inlet disc is stuck to the seat.
• A broken or missing air inlet spring.
• An "old style" pressure vacuum breaker (non-loaded air inlet valve).
• The device is actually an SVB.
12.During a PVB Air Inlet Test, the air inlet valve does not open and the
reading on the field test kit will not drop. What does this indicate?
• A leaky No. 1 shutoff valve.
