SUN HYDRAULICS
PVFA8WN

$179.20 USD

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SUN HYDRAULICS
Material:PVFA8WN
Model:PVFA-8WN
Summary:Cartridge

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***Disclaimer: The following summary contains information gathered from various sources such as product descriptions, technical specifications and catalogs. While efforts have been made to provide accurate details, inaccuracies may occur. It is advised to verify all information by contacting Sun Hydraulics directly.***
The Sun Hydraulics PVFA8WN (PVFA8WN) is a versatile 3-way, normally open modulating valve designed for precise pressure control in hydraulic systems. This externally drained valve features an integral pilot control cavity compatible with any T8A pressure control cartridge, allowing it to reduce high primary pressure at inlet port 2 to a steady reduced pressure at port 1, while also providing full flow relief from port 1 to tank port 3. The differential pressure between the reduced pressure port and the drain port is determined by the setting of the pilot cartridge. The valve's maximum operating pressures are notable: up to 3000 psi at port 3 and up to 5000 psi at the drain port, which should not be exceeded. It employs a bias spring that determines maximum inlet pressure, with options tested for different differentials. The PVFA8WN exhibits low deadband transition between reducing and relieving modes and maintains stability with low hysteresis due to its flat pressure-flow characteristics. Additionally, it incorporates Sun's floating style construction to prevent internal binding from excessive torque or machining variations. For installation, it's crucial that the main stage valve is torqued correctly before installing the T8A pilot control valve. This model supports various pilot control operations including electro-proportional and solenoid options, which are sold separately. If reverse free flow is necessary in a circuit, incorporating an additional check valve is advised. With a capacity of 20 gpm and compatibility with Viton seal kits, this model offers reliable performance in demanding applications where precise hydraulic modulation is required.

Description

This valve is a 3-way, normally open modulating element, externally drained, that incorporates an integral pilot control cavity. The pilot control cavity will accept any T-8A pressure control cartridge. The valve reduces a high primary pressure at the inlet (port 2) to a constant reduced pressure at port 1, with a full flow relief function from port 1 to tank (port 3). The pilot cartridge's setting determines the difference in pressure between reduced pressure (port 1) and the drain (port 4).

Maximum pressure at port 3 should be limited to 3000 psi (210 bar).
Pilot operated valves exhibit very low dead-band transition between reducing and relieving modes.
Pressure at port 4 should not exceed 5000 psi (350 bar).
Pilot operated valves exhibit exceptionally flat pressure/flow characteristics, are very stable and have low hysteresis.
Pressure on the drain (port 4) is directly additive to the valve setting at a 1:1 ratio and should not exceed 5000 psi (350 bar).
Maximum inlet pressure is determined by the bias spring. The D spring is tested with 2000 psi (140 bar) maximum differential pressure and the W spring is tested with 5000 psi (350 bar) maximum inlet pressure.
NOTE: With the -8 control option, the main stage valve should first be installed to the correct torque value. The T-8A pilot control valve should then be installed into the main stage valve to its required torque value.
The -8 control option allows the pilot control valve to be incorporated directly into the end of the relief cartridge via the T-8A cavity. These pilot control cartridges are sold separately and include electro-proportional, solenoid, air pilot, and hydraulic pilot operation. See Pilot Control Cartridges.
Full reverse flow from reduced pressure (port 1) to inlet (port 2) may cause the main spool to close. If reverse free flow is required in the circuit, consider adding a separate check valve to the circuit.
Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge machining variations.

Cavity	T-22A
Series	2
Capacity	20 gpm80 L/min.
Maximum Operating Pressure	5000 psi350 bar
Control Pilot Flow	10 - 15 in³/min.0,16 - 0,25 L/min.
Pilot Control Cavity	T-8AT-8A
Valve Hex Size	1 1/8 in.28,6 mm
Valve Installation Torque	45 - 50 lbf ft61 - 68 Nm
Model Weight	.60 lb0,30 kg
Seal kit - Cartridge	Viton: 990-022-006

Show FAQ

How big is a drop of hydraulic oil?	There are exactly 250 Sun drops in a cubic inch or 15 in a cc.
Direct acting or pilot operated - what do I use?	Direct-acting valves are used to prevent over pressure, and pilot-operated valves are used to regulate pressure. If you are unsure, use a direct-acting valve. Sun's direct acting valves are very fast, dirt tolerant, stable, and robust. Sun's pilot-operated valves are moderately fast, they have a low pressure rise vs. flow curve, and they are easy to adjust.
Can I back flow through a reducing valve from port 1 to port 2?	Yes. A reducing or reducing/relieving valve is normally open. If the pressure in the secondary circuit is less than the setting, it will be open.2 caveats: (1) If the valve is in the reducing mode and you suddenly reverse the flow, the valve will not have time to open and will shift into relieving mode or (2) If the back flow generates a pressure drop through the valve that exceeds the setting, the valve will shift into the relieving mode.When in doubt, use a reverse flow check.
What are the tolerances on pressure settings for Sun's pressure control valves?	Pressure setting tolerances are listed in our Performance Data page. A link to this page can also be found in the Additional Resources tab of the applicable product page.
I need a reducer on B. Can I connect the drain to A?	Yes. If you look in the sandwich section you will see that we offer many such packages. When you are pressurizing B, A is connected to tank, allowing the reducer to do its job. When you reverse, the drain or tank port of the reducer is pressurized by A. This increases the setting of the reducer and helps keep the reducer open in the reverse flow direction.
What do you mean by maximum differential?	Our reducing valves are outside-in valves; the supply pressure on the outside of the working parts is higher than the inside. At some pressure differential, the outside (sleeve) will close in on the piston and cause the valve to stick. A D range is adjustable from 25 to 800 psi with a maximum differential of 2000 psi. This means you could set the valve at 600 psi and expect it to work correctly with a supply pressure of 2600 psi. The valve may work at higher differentials, but we do not recommend it. The W and C ranges are tested over their entire range with an inlet pressure of 5000 psi. All direct-acting valves are tested with an inlet pressure of 5000 psi.
Will your reducing/relieving valve relieve my pump to tank?	No. A reducing/relieving valve throttles a supply of oil to maintain a set pressure in a secondary circuit. The valve is open until the secondary or downstream pressure rises to the setting of the valve at which time it starts to close to limit the pressure. If the secondary or downstream pressure is caused to go above the setting, the valve shifts into relieving mode and throttles the secondary circuit back to tank to prevent over-pressure. At no time can the valve connect the supply to tank.

Additional Resources

Notes:

Compound cartridge (pilot and main stage) assembly information is provided for reference only. Cartridges must be ordered separately and assembled at point of use.

SUN HYDRAULICSPVFA8WN

Additional Resources

SUN HYDRAULICS
PVFA8WN