Models
FVBF: Brass
FVJF: Cast Iron
FVSF: Cast Steel
FVSSF: Stainless Steel
- API 520 & 614 Approved
- Chatter-free operation
- Mount in any position
- Suitable for continuous duty
Size Range: 1″ – 2″
Pressures: 2 – 1000 psi
Flow Rate : Up to 150 gpm

No Leaking, Dripping, Spills or Venting
The Fulflo FV-Series valve includes a new safer design that prevents liquid and gasses from venting out of the valve during normal operation and adjustment conditions. This valve has been specially designed to prevent the adjusting screw from backing out while making adjustments to the pressure setting. An o-ring has been incorporated around the adjusting screw to further prevent liquid from escaping.
INSTALLATION, MAINTENANCE & OPERATION
Installation
Fulflo valves can be mounted in any position. A tee may be inserted in the pump discharge line to mount the valve. The correct size of the valve should be installed, preferably matching the pump discharge line. Screw the valve into the nipple in the tee, or in the case of the flange style, bolt the valve to the companion flange screwed into the nipple. When the valve is used for frequent bypassing of oil pressure, its outlet should be piped back to the tank. Care must be taken to have the discharge well below the oil level in the tank to prevent air entrainment and erratic operation.
Fulflo valves are not designed to be positive shut-off and will pass a minimal amount of leakage before the set pressure. If a valve is required to bypass a given amount of fluid at a given pressure, a test stand having a flow meter in the pump discharge line must be available. With a valve adjusted for cracking pressure as above, continue closing the bypass until the required flow registers on the flow meter and observe pressure. Readjust pressure, if necessary, to obtain desired pressure at desired flow.
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Only if the valve is used as safety or overload relief and operates infrequently may its discharge be piped back into the pump suction line. Frequent or continuous operation under these conditions will cause excessive heating of the oil and possible damage.
Setting Valves
Valves may be set with a hydraulic hand pump for cracking pressure. If a test stand is available, the valve should be connected to the discharge header with the pump bypass open, and the bypass gradually closed until the desired pressure registers on the gauge. Adjust valve adjusting screw until valve slightly bleeds at the set bypass pressure and lock adjusting screw.
Maintenance & Operation
Fulflo valves provide reliable “chatter-free” operations when the system is free of abrasives and foreign matter. Continuous filtration of the liquid used is strongly recommended.
TYPICAL DISASSEMBLY OF STANDARD TYPE VALVE
To dismantle valve for inspection or cleaning:
- Remove cap “B”
- Remove O-ring “D”
- Remove lock nut “E”
- Remove bonnet “I”
- Remove adjusting screw “C”
- Remove spring “G”
- Remove piston “F”
- Remove stop ring “H” (Not Recommended-Special tooling is required to install a new stop ring)
Inspect valve bore and piston for wear and scoring. Replace broken or damaged parts. Clean all parts thoroughly and re-assemble by reversing the above procedure.

The Fulflo FV-Series valve includes a new safer design that prevents liquid and gasses from venting out of the valve during normal operation and adjustment conditions. This valve has been specially designed to prevent the adjusting screw from backing out while making adjustments to the pressure setting. An o-ring has been incorporated around the adjusting screw to further prevent liquid from escaping.
Operates Efficiently and Effectively
The FV-Series valves can be mounted in any position with sizes ranging from 3/8” through 2”, and will operate efficiently with any application or viscosity at pressures from 2 to 1000 psi. Flange or screw connections are available in brass, cast iron, steel, or stainless steel. All parts are completely interchangeable and convertible with other Fulflo V-Series valves.
Fulflo Valve Advantages
These valves offer Fulflo’s patented “chatter-free” performance and are ideally suited for hydraulic and lubricating system protection. All Fulflo valves include a patented modulating piston design with absolute or differential pressure operation. Our advanced modulating operation allows Fulflo valves to be used in many different applications including positive displacement or centrifugal pump and system protection. Fulflo valves can be mounted in any position.
ASSEMBLY NUMBER ID CHART
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Examples

Standard Pressure Range Chart

DIMENSIONS & PARTS
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Dimensions in Inches

Note: Dimensions reflect 150# and 300# only
Cutaway Drawing

Parts List

Recommended spare parts
*See Assembly Number Identification Chart, Symbol Number 9
**See Assembly Number Identification Chart, Symbol Number 11
PERFORMANCE DATA
All valve tests 110˚F to 120˚F Oil Viscosity 150 SSU at 100˚F
(Charts good from 30 to 500 SSU)
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Overpressure: The pressure increase or accumulation above the set pressure when the valve is discharging flow.
