Recommended Testing - Double Check Valve Assembly

Testing for a Leaking Shut Off Valve #2

1. Close all valves on tester.
2. Close shut-off valve #2.
3. Attach high-pressure hose to test cock #2.
4. Attach low-pressure hose to test cock #3.
5. Open test cocks #2 and #3.
6. Bleed air from hose and tester. Bleed low side last to establish differential pressure across check valve #1. Gauge should indicate at least 1 psid.
7. Attach by-pass hose to test cock #4 and open test cock #4.
8. Open high and by-pass valves on tester; a slight pressure loss on the gauge is expected.
9. Close test cock #2. Gauge should not drop to 0 psid. If it does, shut-off valve #2 is leaking and must be repaired before testing can be completed. (Record this reading on the test report in comments.)
10. Close test cock #4.

Testing Check Valve #1

1. Close all valves on tester.
2. Remove by-pass hose; leave high and low hoses in place.
3. Bleed through low side to re-establish differential pressure (test cocks #2 and #3 should remain open).
4. Gauge must indicate 1 psid or higher. If pressure drops to 0 psid, check valve #1 is leaking. If below 1 psid, the spring is too weak. (Record this reading on the test report where it indicates check valve #1.)
5. Close all valves on tester.

Testing Check Valve #2

1. Close test cocks #2 and #3.
2. Move low hose to test cock #4 and high hose to test cock #3.
3. Close all valves on tester, then open test cocks #3 and #4.
4. Bleed air from hoses and tester; bleed low side last to establish differential pressure across check valve #2.
5. Gauge must indicate at least 1 psid or higher. If pressure drops to 0 psid, check valve #2 is leaking. If below 1 psid, the spring is too weak. (Record this reading on the test report where it indicates check valve #2 and record “closed tight”.)