Groth 1721B - Manual (Page 9)

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TESTING AND SETTING PROCEDURE
1. Before starting to reassemble a valve, calculate the nominal pressure and vacuum pallet assembly weights, as shown in
Example 1. Weigh all pallet assemblies to ensure the correct settings. Record pallet assembly weight(s) on factory test
report.
Example: Pallet Assembly Weight Calculation (PAW)
6" Valve set at 7.5 OSI Read weight at 1.0 OSI from table 10 Weight = 3.04 Lb.
Multiple weight by set pressure PAW (*) = 3.04 x 7.5 = 22.8 Lb.
(*) = Includes pallet, retainer plate, stem, diaphragm, weight plates and fasteners.
TABLE 8 - NOMINAL PALLET ASSEMBLY WEIGHT
PER UNIT OF PRESSURE (*)
Valve Size
SET 2" 3" 4"
[Lb.] [kg] [Lb.] [kg] [Lb.] [kg]
1.0 OSI 0..41 0.18 0.84 0.38 1.42 0.64
1.0 IN WC 0.24 0.11 0.48 0.22 0.82 0.37
1.0 mbar 0.09 0.04 0.19 0.09 0.33 0.15
2. After final assembling, mount the valve on a Tank Vent Test Stand and slowly raise the pressure at the flow rate specified
below:
Valve Size Test Flow Rate
2" - 4" 0.5 SCFH
ACCEPTANCE CRITERIA: The pressure gauge shall maintain a pressure equal to or greater than 75% of set pressure for a
one minute period while the specified flow rate is maintained. This test shall be successfully performed three consecutive
times.
3. If the valve fails to meet the 75% criteria, it must be disassembled and the seat, pallet, and or diaphragms repaired or replaced.
4. Set pressure and / or vacuum must also be tested. To test for set pressure / vacuum, slowly increase the pressure / vacuum to
the valve being tested. Increase until there is audible leakage from the valve seat. Closely monitor the pressure / vacuum at
the gauge, when an increase in flow to the valve no longer raises the pressure at the gauge the set pressure / vacuum is
reached.
5. Repeat Step 4 three consecutive times. Record all three tests on the factory test report.
6. A copy of the Test Report shall be maintained with the Valve Maintenance Records.