Complete the following actions before starting the test procedures.
• Ensure all needle valves are closed on the test kit.
• Open test cock No. 4 and flush test cocks No. 1, No. 2, and No. 3 on the reduced pressure
assembly then close test cock No. 4.
• Attach the hoses as shown in the diagram. Bleed air from the kit then close the No. 2 shutoff.
LF909-QT-FS
No. 2 shutoff
Bleed Valve A
Bleed Valve B
High
(red)
Bypass
(yellow)
Low
(blue)
Test No. 1 - Check Valve No. 2
Purpose:
To test check valve No. 2 for tightness against reverse flow.
Requirements:
The valve must be tight against reverse flow under
all pressure differentials.
1. Slowly open the needle valves “A” high (red) and “C”
bypass (yellow). Keep the needle valve “B” low (blue) closed.
2. Open test cock No. 4.
3. Observe that the pressure differential decreases slightly. If the
pressure differential continues to decrease (until the vent opens),
the No. 2 check valve is reported as “leaking.”
Test No. 2 - Shutoff Valve No. 2
Purpose:
To test shutoff valve No. 2 for tightness.
1. After passing Test No. 1, continue to test No. 2 by closing test
cock No. 2.
2. Observe that the pressure differential decreases slightly. If pressure
differential continues to decrease (approaching “zero”), the No. 2
shutoff valve is reported to be “leaking.”
A leaking No. 2 shutoff always gives a false reading in tests
No. 3 and 4.
Test No. 3 - Check Valve No. 1
Purpose:
To test check valve No. 1 for tightness.
Requirements:
The valve must be tight against reverse flow under
all pressure differentials.
1. Close needle valve A high (red) and open test cock No. 2.
2. Close test cock No. 4. Disconnect the bypass hose (yellow) at
test cock No. 4.
3. Open needle valves B low (blue) and C bypass (yellow), bleeding
to atmosphere. Then close needle valve B (blue) to restore the
system to a normal static condition.
4. Observe the pressure differential gauge. If there is a decrease in
the indicated value, the No. 1 check valve is reported as “leaking.”
Test No. 4 - Pressure Differential Relief Valve
Purpose:
To test operation of pressure differential relief valve.
Requirements:
The pressure differential relief valve must operate to
maintain the “zone” between the two check valves at least 2 psi less
than the supply pressure.
1. Close needle valve C bypass (yellow).
2. Open needle valve A high (red).
3. Open needle valve B low (blue) very slowly until the differential
gauge needle starts to drop.
4. Hold the valve at this position and observe the gauge reading
at the moment the first discharge is noted from the relief valve.
Record this as the opening differential pressure of the relief valve.
The differential gauge needle must drop slowly. This is important
to maintain stability.
5. Close test cocks No. 2 and No. 3. Remove the hoses from test
cocks No. 2 and No. 3.
6. Use the bypass hose (yellow) to relieve pressure from the test
kit by opening needle valves A, B, and C and bleeding valves
A and B.
7. Remove all test equipment and open No. 2 shutoff.
4
CAUTION
!
To prevent freezing, hold the test kit vertically to drain the differential
gauge and hoses before placing the kit in the case.
For additional testing information, refer to IS-TK-DL, IS-TK-9A,
IS-TK-99E, or IS-TK-99D.
Test Procedure for Reduced Pressure Assembly
NOTICE
NOTICE
