Ames Fire & Waterworks 4000B-FP Bronze Reduced Pressure Zone Assemblies with Gear Operated Slow Close Isolation Valves - Manual (Page 6)

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PROBLEM CAUSE SOLUTION
A. Assembly discharges from Fouled first check Disassemble and clean No. 1 check valve
differential relief valve during Fluctuating inlet pressure Control supply line water pressure
no flow condition. Outlet pressure higher than inlet pressure Disassemble, clean #2 check valve &
& leak in No. 2 check valve identify cause of back pressure.
Leak through diaphragm or around Service relief valve (page 4)
flange bolt holes of relief valve
Pressure relief valve does not close See problem D
B. Assembly discharges from No. 1 check valve wedged open Disassemble and clean No. 1 check valve
differential relief valve during O-ring displaced from groove in 1st check Disassemble and replace
a flow conditions. Pressure relief valve does not close See problem D
Fluctuating line pressure
C. Differential pressure relief valve Differential pressure across No. 1 check Repair shutoff valves
does not open during test valve stays above 2psi due to leaking
outlet gate valve
Weak or broken relief valve spring Disassemble and replace relief valve spring
Shutoff seat tube bound in body Disassemble and repair
Plugged hydraulic hose Disassemble and repair
D. Pressure relief valve does Debris on sealing surface Remove relief valve and clean
not close Plugged hydraulic hose Disassemble and clean
Damaged seat or rubber shutoff disc Remove relief valve assembly and replace
Ruptured diaphragm Disassemble and replace diaphragm
Wrinkled or improperly installed diaphragm Disassemble and properly position diaphragm
Troubleshooting Guide
Problem Identification Procedures
When using differential pressure gauge:
A. Check differential across No. 1 check valve
READING PROBLEM
2 to 3 psid Leak in No. 1 or No. 2
check valve
4 to 7 psid and steady Malfunctioning pressure
relief valve
2 to 7 psid fluctuating Inlet pressure fluctuation
Without using differential pressure gauge:
A. Close gate valve No. 2
RESULT PROBLEM
If discharge stops Leak in No. 2 check valve
If discharge does Go to B
not stop
B. Open No. 4 testcock to produce a flow greater than
differential relief valve discharge
RESULT PROBLEM
If discharge stops Leak in No. 1 check valve
If discharge does Malfunctioning pressure
not stop relief valve