User guide

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