INSTALLATION, OPERATION, &
MAINTENANCE MANUAL
TITLE: F7000 / 8000 Series Rev. V
Pilot-Operated Safety Relief Valve Page 19 of 41
B. F300 (Diaphragm-style) Assembly
NOTE: Exercise care in handling softgoods, nozzles, and other sealing surfaces.
1) Confirm pressure setting and associated parts required.
2) Place the valve body in a vise.
3) Install pipe plugs into the valve body.
4) Install backflow preventer (BFP) O-ring onto BFP piston.
5) Assemble BFP jam nut and seal onto BFP nozzle. For modified nozzle design with 00-2313-xx
O-ring on leading edge, install O-ring with light coat of lubricant to hold it in place in its gland.
6) Place BFP piston with O-ring into end of nozzle. Install BFP assembly into valve body until very
tight (conventional chamfered nozzle) or snug (O-ring-tipped nozzle), then tighten BFP jam nut so
as to crush the Teflon seal.
7) Assemble lock nut and proportional band screw seal onto proportional band screw.
8) Install the proportional band screw assembly into the valve body. Screw in CW until the screw
bottoms in the body, and then back out CCW 1-1/2 turns (also see Section 6.3 for band screw
adjustment). Tighten lock nut.
9) Insert inlet screen into valve body.
10) Lightly lubricate lower sleeve seal with Dow Corning Molykote 33 or equivalent, and install into
groove of sleeve.
11) Lightly lubricate upper sleeve seal and place onto the top of the sleeve. Install the seat into the
bottom side of the seat retainer nozzle, and assemble on top of the sleeve.
12) Lightly lubricate lower piston seal and install into groove of lower piston. Insert the lower piston
assembly into the sleeve until they are flush at the bottom. Then install the seat retainer sleeve
lower piston subassembly into the valve body until it bottoms. Check to ensure that all seals and
O-rings are correctly aligned. The PA screw cap can be used to verify proper fitup. Place the cap
on a flat surface; then lower the pilot body with subassembly onto the cap and push down until the
assembly snaps into place and is solid.
13) Place the plug seal onto bottom of the sleeve. Screw the internal plug into the body until tight.
Make sure that this plug is very tight.
14) From the top, install spacer pin into the recess in lower piston previously installed.
15) Lightly lubricate upper piston seal and install into groove of upper piston.
16) Place the diaphragm fastener seal onto the diaphragm fastener.
17) For the low pressure diaphragm style pilots (15-285 psig) place the diaphragm support disc and
diaphragm onto the diaphragm fastener. For the high pressure diaphragm style pilots (286-500
psig) place the diaphragm disc and diaphragm onto the diaphragm fastener. Apply a small
amount of Loctite onto the fastener threads. Make sure that the center counterbore area on the
diaphragm support disc faces the O-ring seal. NOTE: Older diaphragm support discs have an O-
ring counterbore on both sides.
18) Install diaphragm assembly into the upper piston and tighten firmly.
19) Assemble diaphragm support ring seal and diaphragm support ring onto valve body.
20) Insert upper piston / diaphragm assembly into valve body. Ensure that the spacer pin fits into the
recess in the bottom of the upper piston. Align the holes between the diaphragm and the support
ring. For the high pressure diaphragm style pilots (286-500 psig) place the diaphragm area
reducer onto the diaphragm.
21) Assemble spring and spring washers onto diaphragm fastener.
22) Install bonnet over spring and spring washers and onto diaphragm support ring. Align bonnet,
diaphragm, and support ring so that the unthreaded through-hole in the support ring lines up with
the bolt holes in the valve body, and the two small through-holes in the bonnet, diaphragm, and
support ring align and clear the valve body. The vent / bug screen opening (1/4 FNPT) in the
bonnet should face away from the main valve mounting surface.
23) Install the four long bolts through the bonnet / diaphragm / support ring into the valve body, and
tighten.
24) Install the four short bolts through the bonnet / diaphragm into the diaphragm support ring, and
tighten.
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