6
Test No.1
Purpose:
To test check valve No. 2 for tightness against reverse
flow.
Requirements:
Valve must be tight against reverse flow under
all pressure differentials. Slowly open the ‘high’ valve A and the
‘vent’ valve C, and keep the ‘low’ valve B closed. Open test
cock #4. Indicated pressure differential will decrease slightly. If
pressure differential continues to decrease (until the vent opens)
check valve #2 is reported as ‘leaking’.
Test No. 2
Purpose:
To test shutoff #2 for tightness.
Requirements:
After passing Test No. 1, continue to Test No. 2
by closing test cock #2. The indicated pressure differential will
decrease slightly. If pressure differential continues to decrease
(approaching ‘zero’), shutoff #2 is reported to be ‘leaking’.
Test No. 3
Purpose:
To test check Valve No. 1 for tightness.
Requirements:
Valve must be tight against reverse flow under
all pressure differentials. Close ‘high’ valve A and open test cock
#2. Close test cock #4. Disconnect vent hose at test cock #4.
Open valves B and C, bleeding to atmosphere. Then closing valve
B restores the system to a normal static condition. Observe the
pressure differential gauge. If there is a decrease in the indicated
value, check valve No. 1 is reported as ‘leaking’.
Test No. 4
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 2psi less than the supply pressure. Close ‘vent’ valve
C. Open ‘high’ valve A. Open the ‘low’ valve B very slowly until
the differential gauge needle starts to drop. 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.
Close test cocks #2 and #3. Use ‘vent’ hose to relieve pressure
from test kit by opening valves A, B and C. Remove all test
equipment and open shutoff #2.
CAUTION
!
To prevent freezing, hold Test Kit vertically to drain differential
gauge and hoses prior to placing in case.
Testing — Reduced Pressure Zone Assemblies
Ball Type Test Valves
(A)
(C)
(B)
Needle
Valve
High Hose
(Yellow)
Low Hose
(White or Red)
Vent Hose
(Blue)
Test Cock
No. 1
Test Cock
No. 2
Test Cock
No. 3
Test Cock
No. 4
Auxiliary
Test Cock
