6
Test Procedure
Test Procedure for Reduced Pressure Assembly
A. All needle valves must be closed on test kit.
B. Open test cock No. 4 and flush test cocks Nos. 1, 2 and 3 on reduced pressure assembly then close test cock No.
4.
C. Attach hoses as shown. Bleed air from kit, close No. 2 shutoff.
Step 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.
Step 1
Close needle valve “C” bypass (yellow).
Step 2
Open needle valve “A” high side (red).
Step 3
Open needle valve “B” low (blue) very slowly until the dif-
ferential gauge needle starts to drop.
Step 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.
NOTICE
It is important that the differential gauge needle drops slowly.
Step 5
Close test cocks Nos. 2 and 3. Remove hose from test
cocks Nos. 2 and 3.
Step 6
Use bypass hose (yellow) to relieve pressure from test kit
by opening needle valve “A”, “B” and “C” and bleed
valves “A” and “B”.
Step 7
Remove all test equipment and open No. 2 shutoff valve
of the device.
Test No. 1 - Check Valve No. 2
Purpose:
To test check valve No. 2 for tightness against reverse
flow.
Requirements:
Valve must be tight against reverse flow under all
pres-sure differentials.
Step 1
Slowly open the needle valve “A” high side (red) and “C”
bypass (yellow). Keep the “B” low (blue) closed.
Step 2
Open test cock No. 4. Open test cock No. 2 and test
cock No. 3 after opening test cock No. 4.
Step 3
Indicated pressure differential will decrease slightly. If
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.
Step 1
After passing Test No. 1, continue to test No. 2 by clos-
ing test cock No.2.
Step 2
The indicated pressure differential will decrease slightly. If
pressure differential continues to decrease (approaching
“zero”) the No. 2 shutoff valve is reported to be “leaking”.
Note: A leaking No. 2 shutoff will give a false reading in
tests No. 3 and 4
Test No. 3 - To test No. 1 Check Valve
Purpose:
To test check valve No. 1 for tightness.
Requirements:
Valve must be tight against reverse flow under all
pressure differentials.
Step 1
Close needle valve “A” high side (red) and open test
cock No. 2.
Step 2
Close test cock No. 4. Disconnect bypass hose (yellow)
at test cock No. 4.
Step 3
Open needle valve “B” low (blue) and “C” bypass (yel-
low), bleeding to atmosphere, then closing needle valve
“B” (blue) restores the system to a normal static condi-
tion.
Bleed Valve A
Bleed Valve B
995 shown
Low
(Blue)
High
(red)
Bypass
(yellow)
No. 2
Shutoff
Summary of Contents for 995 Series
Page 7: ...7 Notes...
