INSTALLATION, OPERATION, &
MAINTENANCE MANUAL
TITLE: F7000 / 8000 Series Rev. V
Pilot-Operated Safety Relief Valve Page 34 of 41
6.4 INSERVICE TESTING WITH THE FIELD TEST CONNECTION (FTC)
CAUTION: Extreme care must be taken when testing or servicing a pressure relief valve used in
gas or incompressible fluid service. The service medium may be volatile and under
high pressure.
CAUTION: If a solid 1/4” NPT plug is present in the field test body when performing Step (1)
below, do not remove it unless the relief valve inlet is depressurized. The shuttle
piston inside the FTC body likely has been removed, which will prevent routine field
testing with an external pressure source.
CAUTION: Performance of Step (4) below will cause the main valve to open, unless inlet
pressure is closed off by a block valve or the system is depressurized.
A. General
The FTC allows the user to verify set pressure and reseat pressure with the pressure relief valve in
service. An external pressure source is attached to the FTC to direct pressure to the pilot valve,
while blocking off system pressure to the pilot valve. Review 5.1 for definition of set pressure.
B. Test Procedure
1) Unscrew the 1/4” vented plug from the outboard side of the FTC. The 1/16” diameter vent hole
prevents pressure buildup behind the FTC piston and allows it to seat with system pressure.
2) Attach the test equipment to the FTC, as shown on Page 35. NOTE that the test pressure gage
location close to the main valve will yield pressure readings more representative of what the pilot
valve is sensing (especially the F100 or F300), without effects of pressure loss through the hose.
3) If there is a remote sense line with manual valve present, as shown on Page 9, close the manual
valve. If present, open lower manual valve in-line in pilot tubing to allow field test pressure to pilot.
With an external pressure source at a higher pressure than system pressure (but less than set
pressure), slowly open the block valve to the source. This will close off the FTC shuttle piston
against system pressure and open the passage between the hose and pilot valve.
4) a) Without dome gage installed: Set pressure will occur when pilot exhaust flow is detected on the
F200 pilot or slightly after (2-5% of nominal set pressure) initial exhaust flow is detected on the
F100, F300, or F500 pilot for ASME settings (at set pressure for DOT settings). Pilot flow may be
audible at the main valve outlet, or some valves may be fitted with a special test block for detecting
pilot flow. The F300 has an access port for detecting first exhaust with a tube and container of
water (See diagram on p. 29). NOTE that sufficient dome reduction by pilot will open main valve
with system pressure present at inlet.
If pilot exhaust flow cannot be detected at a field installation, set pressure of the F100 and F300 will
be approximated by a stop in inlet pressure rise if this pressure is increased very slowly. These
modulating pilots begin exhausting dome pressure before the main valve piston opens. The F500
pilot locks out dome from inlet as inlet pressure rises to 93-94% of set pressure, even throughout
the brief exhaust period corresponding to set pressure.
b) With dome gage installed: Continue to increase the external pressure until the dome gage
drops. The set pressure will be the pressure indicated on the test gage when the dome gage drops
to zero for the F200 pilot, or to the value listed in 5.2.1 (Page 26) for the F100, F300, or F500
modulating pilot set per ASME VIII. NOTE that sufficient dome reduction by the pilot will open the
main valve with system pressure present at the inlet.
5) Slowly open the bleed valve and decrease pressure to the pilot until the dome gage repressurizes.
If not using a dome gage, pilot exhaust flow stops completely upon reseat.
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