INSTALLATION, OPERATION, &
MAINTENANCE MANUAL
TITLE: F7000 / 8000 Series Rev. T
Pilot-Operated Safety Relief Valve Page 12 of 43
3.2 REASSEMBLY OF THE F7000 / 8000 SERIES MAIN VALVE
1) Reassembly of these valves is basically the reverse of disassembly. Care must be taken in the
handling of all items, particularly sealing surfaces and softgoods. All parts should be clean and
free of any debris or contaminants.
2) Reinstall the liner and liner seals into the body. Do not nick or excessively stretch the liner seal O-
rings. The bottom O-ring may be carefully set in its sealing area in the body before the liner is
inserted, or it may be fitted onto the liner and, if necessary, held in place with a suitable lubricant
(e.g., Dow Corning Molykote 33). Lightly press top seal into place in its groove, such that it is
evenly spread around the liner circumference and will not be pinched by the cap.
3) Insert the O-ring or plastic seat into the bottom of the piston, using care to position the seat
completely within the piston cavity. NOTE that any scratches, gouges, or particles on the seat may
result in a sealing problem. Carefully position retainer plate over the seat. For the F8000 series,
position the annular flow plug over the retainer and, if applicable, the spring pin in the piston. Apply
Loctite or Vibra-tite to the retainer bolt. Insert bolt and tighten to: 4-5 ft-lbs (1/4” bolt); 12-14 ft-lbs
(3/8”); 34-37 ft-lbs (1/2”); 120 ft-lbs (3/4”). IMPORTANT: Retainer bolt must meet firm resistance
against locking Heli-Coil in piston. Replace Heli-Coil if worn or damaged.
4) Install piston seal. Dow Corning Molykote 33 or equivalent may be lightly applied to the O-ring
style (F7050 or F8050 model only). If the valve has a vacuum setpoint based on piston weight,
Lubriplate 105 or other suitable slippery lubricant is recommended for the piston seal. Do not
lubricate the Teflon V-seal used in the F7040/F8040 model.
5) Fit the wear / wedge ring(s) in their proper groove in the piston assembly. The flat wear ring(s) do
not require any lubricant. If a wedge ring is used, it should be installed with a coating of Desco 600
(or equal) grease on the outside face. While holding the rings (especially free ends) in place, lower
the piston assembly into liner. It is critically important that this installation result in even seating of
the soft seat onto the raised nozzle lip in valve body.
To Next Page
Loading...
Need help?
General
