Emerson Anderson Greenwood 9300 Series Installation And Maintenance Instructions Manual page 24

Anderson Greenwood SerieS 9300 Pilot oPerated Safety relief ValVeS
InstallatIon and MaIntenance InstructIons
3.5 Pilot adjustment for non-flowing
modulating pilots (series 400b)
the pilot may be set separate from the main
valve provided there is access to a pilot test
system similar to the one shown in figure 14.
3.5.1 Adjustment of set pressure
1. install the pilot valve onto the pilot test
system and attach gage sensing lines to
the supply and dome connections.
2. remove cap.
3. Screw the set pressure adjustment screw
clockwise until it is screwed iN 80% to 90%.
4. increase the supply pressure to nameplate
setting and slowly back out the adjustment
screw until flow through the pilot exhaust
begins.
5. Continue to back the set pressure
adjustment screw out until the dome
pressure is 70% of the supply pressure.
When the dome pressure reaches 70% of
the supply pressure read the supply gage
pressure. if it is below set pressure, you will
need to tighten down on the pressure screw,
or back off it if you are high. tighten the locknut
once the desired set pressure is achieved.
note: adjust the set pressure for 101% ± 1%
of the nameplate set pressure.
6. Cycle the pilot valve a minimum of 5 times
to assure that the dome pressure reduction
at set pressure is consistent. increase
the pressure very slowly in order to obtain
an accurate reading of the cracking
pressure and to expose any erratic
performance.
note: cracking pressure on vacuum pilots
is that pressure at which the initial dome
pressure change is noted.
7. Hold the pilot valve at set pressure to obtain
the dome pressure reading.
note: the first 6 steps should be
completed before this step is undertaken.
in modulating 400B pilots, the dome
pressure decreases proportional to increase
in inlet pressure.
full dome reduction (dome pressure)
occurs ≤ 6% over pressure.
8. Check the pilot exhaust for leakage when
the pilot is in null position between crack
and reseat.
note: maximum leakage allowed is
60 bubbles per minute.
3.5.2 Reseat pressure
reseat is defined as that supply pressure when
the dome pressure is 75% of the supply pressure.
note: blowdown adjustment is not required on
Series 400B pilots.
3.5.3 AdjustMent tolerAnces
Pressure tolerance
Set pressure ± 3%
Crack pressure 98% of set
reseat pressure 96% of set
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