AMES 3000 CIV Series Instalasi, Servis, Kit Perbaikan, Pemeliharaan - Halaman 4

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Test Procedure for Double Check Valve Assemblies

The following Test Procedure is one of several that is recog-

nized throughout the United States for verification of the

functioning of Backflow preventers and is not a specific

recommendation. The Ames test kit is capable of performing

any of the recognized Backflow test procedures.

TEST PROCEDURES

TESTING OF #1 CHECK VALVE

Step 1: Close #1 and #2 shut off valves.

Step 2: Open test cocks No. 2, 3, and 4. Verify that

No. 1 shut off valve is holding tight by observing that

the discharge of water from test cock No. 2 stops.

Step 3: Attach test kit "Vent" hose to No. 1 test cock;

"Low" hose to No. 2 test cock and "High" hose to No. 3

test cock. At this point valves (A) and (C) should be

open and (B) should be closed.

Step 4: Close test cock No. 4.

Step 5: Open test cock No.1. The needle of the

differential gauge will indicate a pressure in excess of

15 psi.

Step 6: Slowly open needle valve (B) until the differen-

tial gauge reads 10 psi. Then close (B). The gauge

reading will not change if No. 1 check is holding tight.

If No. 1 check is leaking, the gauge will drop to 0.

Requirements: The check valve shall be tight against

reverse flow under all pressure differentials.

Symptom

1. Check valve fails to hold

backpressure.

2. Chatter during flow

conditions

3. Low flows passing

through mainline

valve (3000 CIV only)

RP/IS-2000/3000CIV 0035

using Ames Test Kit

TESTING OF #2 CHECK VALVE

Step 1: Close test cock No. 1.

Step 2: Open test cock No. 4.

Step 3: Change "Low" hose from test cock No. 2 to

test cock No. 3. Change "High" hose from test cock

No. 3 to test cock No. 4. On the test kit, valves (A) and

Step 4: Open test cock No. 1. The pressure differential

gauge will indicate a pressure in excess of 15 psi.

Step 5: Slowly open needle valve (B) until the gauge

reads 10 psi, then close. If the gauge reading does not

change, No. 2 check valve is holding tight. If No. 2

check is leaking, the gauge will drop to 0.

Note in the above testing: Minor leakage in shut off

valve No. 2 will not affect the test results. However, in

the testing the No. 1 check, leaking shut off valve No. 1

would cause a good first check to fail the test.

TROUBLE SHOOTING GUIDE

Cause

a. Debris on check disc

sealing surface

b. Leaking gate valve

c. Damaged seat disc or

seat o-ring

d. Damaged guide holding

check open

e. Weak or broken spring

a. Worn, damaged or

defective guide

a. Mainline check fouled

b. Meter strainer plugged

c. Damaged mainline seat

disc or seat

d. Broken mainline spring

EDP# 1915232

Vent

Low

High

Solution

Disassemble and clean

Disassemble and clean or repair

Disassemble and replace

Disassemble clean or replace

Disassemble and replace spring

Disassemble and repair or

replace guide

Disassemble and clean

Disassemble and replace

Printed in U.S.A.