Pilot Set Pressure Field Test Procedure - Emerson Anderson Greenwood Type 443 Installation And Maintenance Instructions Manual

Anderson Greenwood SerieS 400 PiSton Pilot PoPrV
InstallatIon and MaIntenance InstructIons
6 pilot set pressure Field test
proCedure
6.1 General
CAution
If the pressure relief valve is not isolated from
the process media while performing this test, the
main valve will open if system pressure rises to
set point or above.
the set pressure of valves equipped with a field
test accessory can be checked with the valve
installed, in operation. the field test accessory
consists of a check valve in the pilot supply line
through which test pressure from an external
source can be supplied to the pilot. A test
set-up similar to that shown in Figure 14 and
procedure similar to the following should be
used. this procedure accurately checks the set
pressure; it does not provide an accurate check
of reseat pressure.
note
Gas flows through the flexible hose and vents past the
indicator plunger to atmosphere when the plunger
begins to retract. With gas flowing through the hose,
there will be a pressure drop from the gas bottle
to the field test fitting port. to ensure an accurate
reading of set pressure, the flexible hose should be
a ⅜" inside diameter hose and if the length exceeds
10-feet, the test gauge should be positioned at the
alternate location (see Figure 14). if the test gas is
supplied through a regulator, the effective orifice
diameter of the regulator should be a minimum
of 0.125-inch.
the main valve will not open while performing
this field test as long as the process pressure
remains below the set pressure. to cause the
main valve to open, slowly increase the test
pressure above the set pressure until the piston
lifts and process media is discharged through
the main valve. to close the main valve, close
block valve 'A' and open vent valve 'C'.
6.2 procedure
A. Connect flexible hose from test gas bottle to
field test fitting port.
B. Close vent valve 'C'.
C. open block valve 'A' slowly to increase
pressure until the indicator actuates. the
set pressure will be the pressure indicated
on the test gauge at the time gas vents past
the indicator plunger and/or the indicator
plunger retracts (test gauge reading will
decrease if rate of pressure increase is
sufficiently slow).
Vent valve 'C'
FiGUre 14
wArninG
Keep all parts of body clear of indicator plunger
during test to avoid contact with gas venting past
the indicator plunger.
D. to remove set up, close block valve 'A', open
vent valve 'C', and remove flexible hose from
field test fitting port.
Gas vent
(indicator plunger)
Field test
test gauge alternate location
Block valve 'A'
Gas bottle
Flexible hose
test gauge
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