Manual

950XL TEST NO. 1
Purpose:
Test #1 check valve for drip tightness against reverse flow.
Requirement:
The valve must close tight against reverse flow under all pressure
differentials.
Procedure:
1. Close #2 and #1 shut-off valves.
2. Open test cocks #2 and #3.
3. Attach "VENT" hose to test cock #1, the "LOW" hose to test cock #2
and the "HIGH" hose to test cock #3.
4. Open by-pass valves "A" and "C", then open test cock #1.
5. Open test cock #4 to bleed air from valve and test kit.
6. Close by-pass valve "C". Slowly open by-pass valve "B" until differ-
ential gauge reads 5 PSID. Close by-pass valve "B".
7. The #1 check valve is considered tight if differential pressure is
maintained.
975XL TEST NO. 1
Purpose:
Test #2 check valve for tightness against reverse flow.
Requirement:
The valve must close tight against reverse flow under all pressure differ-
entials.
Procedure:
1. Attach the "HIGH" hose to test cock #2 and the "LOW" hose to test
cock #3.
2. Close #2 shut-off valve.
3. Open test cocks #2 and #3.
4. Open by-pass valves "C" and "A" and bleed to atmosphere until all
air is expelled.
5. Close by-pass valve "A". Open by-pass valve "B" and bleed to at-
mosphere until all air is expelled. Close by-pass valves "B" and "C".
6. Attach the "VENT" hose to test cock #4.
7. Slowly open by-pass valves "A" and "C" and keep by-pass valve "B"
closed.
8. Open test cock #4.
9. Indicated pressure differential will drop slightly. If pressure differen-
tial does not continue to decrease, the #2 check valve is considered
tight.
Testing Procedures
MODEL 950XL DOUBLE CHECK VALVE ASSEMBLY
950XL TEST NO. 2
Purpose:
Test #2 check valve for tightness against reverse flow.
Requirement:
The valve must close tight against reverse flow under all pressure differ-
entials.
Procedure:
1. Close test cock #1.
2. Attach "HIGH" hose to test cock #4 and "LOW" hose to test cock #3.
3. Open by-pass valve "C". Open test cocks #1 and #4.
4. Repeat step #6 of TEST NO. 1.
5. The #2 check valve is considered tight if differential pressure is
maintained.
Equipment Required: Differential pressure gauge test kit.
Equipment Required: Differential pressure gauge test kit.
MODEL 975XL REDUCED PRESSURE PRINCIPLE
ASSEMBLY
975XL TEST NO. 3
Purpose:
To test operation of the differential relief valve.
Requirement:
The pressure differential relief valve must operate to maintain the "ZONE"
between the two check valves at least 2 PSID less than the supply
pressure.
Procedure:
1. Close by-pass valve "C" and open by-pass valve "A".
2. Open by-pass valve "B" very slowly until 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.
975XL TEST NO. 2
Purpose:
Test #1 check valve for tightness and record pressure drop across #1
check valve.
Requirement:
The static pressure drop across the #1 check valve should be at least
3.0 PSID greater than the relief valve opening point (TEST NO. 3).
Procedure:
1. Close by-pass valve "A"
2. Close test cock #4, and disconnect "VENT" hose from test cock #4.
3. Open by-pass valves "B" and "C" bleeding to atmosphere, then close
by-pass valve "B" restoring the system to normal static condition.
4. Observe the pressure differential gauge and note this as the #1
check valve psid.
2
VENT HOSE
LOW SIDE HOSE
HIGH SIDE HOSE
BY-PASS
VALVE "B"
BY-PASS
VALVE "C"
BY-PASS
VALVE "A"
#1 TEST COCK
#2 TEST COCK
#3 TEST COCK
#4 TEST COCK
#1 SHUT-OFF
VALVE
#2 SHUT-OFF
VALVE
#1 TEST COCK
#2 TEST COCK
#3 TEST COCK
#4 TEST COCK
#1 SHUT-OFF
VALVE
VENT HOSE
LOW SIDE HOSE
HIGH SIDE HOSE
BY-PASS
VALVE "B"
BY-PASS
VALVE "C"
BY-PASS
VALVE "A"
#2 SHUT-OFF
VALVE
#1 CHECK VALVE
#2 CHECK VALVE