INSTALLATION, OPERATION, &
MAINTENANCE MANUAL
TITLE: F7000 / 8000 Series Rev. T
Pilot-Operated Safety Relief Valve Page 35 of 43
6.2 FINAL ASSEMBLY TESTING
1) Thoroughly clean off the mounting surfaces on both the main valve and pilot valve face. Make sure
that the face seals are clean and in good condition.
2) Apply a light coat of lubricant (e.g., Dow Corning 33) to the face seals.
3) Assemble the pilot valve to the main valve with 5/16”-24UNF mounting bolts (4 for standard
construction; 6 for ‘IM’ construction). A light coating of Loctite or Vibra-tite should be applied to the
bolts. Tighten the bolts securely.
4) Install and tighten all pilot tubing connections, except for ‘IM’ construction valves.
5) Mount the assembly to the test stand and pressurize up to 90% of set pressure.
6) Check for leaks at all joints, including tubing connections, pilot valve mounting surface, field test
connection, cap, cap bolts, and at valve outlet. There should be no leaks anywhere.
7) Once testing is complete, the valve assembly is ready for installation. If applicable, flange
protectors should be installed and other protection measures taken during transport.
6.3 F300 PILOT VALVE PROPORTIONAL BAND ADJUSTMENT
A. Purpose
The FLOW SAFE F300 Series is a modulating-style pilot valve used with the F7000/8000 Series.
As received from the factory, the F300 is lockwired to prevent any adjustments to the set pressure.
This lockwire is also attached to the proportional band screw (see drawings on Page 17, 18, 20, or
21).
For the main valve to remain closed, system pressure must fill the valve dome at the same rate as
the buildup below the piston. In an application where the relief valve may be prematurely lifting due
to excessive inlet pressure increase, the proportional band screw may be adjusted to increase the
dome fill rate through the pilot assembly.
The proportional band screw setting also affects the spread between pilot first-bubble (exhaust)
and dome reduction required to open the main valve (see 5.2.1), by affecting the rate at which
dome reduction occurs. As the screw is adjusted in the CW direction, the spread between first
exhaust and dome reduction will decrease and dome reduction will occur at a faster rate. As the
screw is turned CCW out to the maximum setting noted in (5) below, the spread between first
exhaust and dome reduction increases slightly and the rate of dome reduction slows down.
This adjustment will not affect the set pressure of the valve.
B. Procedure
1) Relieve the pressure below the relief valve as much as possible.
2) Close the block valve, if available, below the relief valve.
3) Pressurize the relief valve inlet. The relief valve should remain closed as pressure increases.
4) If the valve still opens prematurely, cut the lock wire at the proportional band screw and loosen the
lock nut.
5) Back out the proportional band screw an additional 1/8 to 1/4 turn, but do not exceed a total of 2-
1/2 CCW turns. Retest the valve per step (3). NOTE: The band screw should be 1-1/2 turns out
(in the CCW direction) as a result of assembly performed per Section 4.3 or 4.4.
6) If the relief valve operates satisfactorily, tighten the lock nut and reinstall the lockwire.
7) If the valve continues to open prematurely, repeat step (5) as necessary. If the proportional band
screw is at its adjustment limit, attach a remote pressure pickup directly to the pilot as described in
Section 2.5 on Page 8.
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