SUN HYDRAULICS
RED-REL CART
PVFALDN

$172.20

SUN HYDRAULICS
Material:PVFALDN
Model:PVFA-LDN
Summary:Cartridge

Quantity in stock: 9

***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 PVFALDN (PVFALDN) is an externally drained, pilot-operated pressure reducing/relieving valve designed to manage high primary pressures at the inlet port 2, reducing them to a consistent lower pressure at port 1 while providing a full-flow relief function from port 1 to tank port 3. This valve is engineered to remain unaffected by pressure at tank port 3 due to its external drainage feature and offers remote control capabilities through pilot or two-way valves. It is crucial that the maximum pressure at port 3 does not exceed 3000 psi (210 bar). The valve demonstrates minimal deadband transition between reducing and relieving modes, ensuring stable operation with low hysteresis. The recommended maximum inlet pressure varies with adjustment ranges: D, E, N, and Q support a differential of up to 2000 psi (140 bar), while ranges A, B, and H accommodate up to 3000 psi (210 bar). Ranges C and W can handle an inlet pressure of up to 5000 psi (350 bar). The valve's pilot section should not exceed a pressure of 5000 psi (350 bar), as it directly impacts the valve setting in a 1:1 ratio. This model incorporates Sun's floating style construction, minimizing internal binding risks due to installation torque or machining variations. With a capacity of 20 gpm (80 L/min) and factory settings established with blocked control ports deadheaded, the PVFALDN operates under a maximum operating pressure of 5000 psi (350 bar). The control pilot flow ranges between 10-15 in\u00b3/min (0.16-0.25 L/min), with adjustable settings increased by clockwise turns. The valve features a hex size of 1-1/8 in. (28.6 mm) for installation torque ranging from 45-50 lbf ft (61-68 Nm), and its locknut requires a torque of 80-90 lbf in. (9-10 Nm).

Description

Externally drained, pilot-operated pressure reducing/relieving valves reduce 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). Draining the pilot section at port 4 makes these valves insensitive to pressure at tank (port 3) and provides a means for remote control by pilot or 2-way valves.

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.
Recommended maximum inlet pressure is determined by the adjustment range. Ranges D, E, N, and Q are tested with a 2000 psi (140 bar) maximum differential between inlet and reduced pressure. Ranges A, B, and H are tested with a 3000 psi (210 bar) maximum differential between inlet and reduced pressure. Ranges C and W are tested with 5000 psi (350 bar) of inlet pressure.
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).
Pilot operated reducing, reducing/relieving valves by nature are not fast acting valves. For superior dynamic response, consider direct acting valves.
W and Y controls (where applicable) can be specified with or without a special setting. When no special setting is specified, the valve is adjustable throughout its full range using the W or Y control. When a special setting is specified, this setting represents the maximum setting of the valve.
By controlling the pressure at the drain (port 4), the effective setting of the valve can be increased over the nominal valve setting.
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.
Factory Pressure Settings Established at	blocked control port (dead headed)blocked control port (dead headed)
Maximum Operating Pressure	5000 psi350 bar
Control Pilot Flow	10 - 15 in³/min.0,16 - 0,25 L/min.
Adjustment - Number of Clockwise Turns to Increase Setting	55
Valve Hex Size	1 1/8 in.28,6 mm
Valve Installation Torque	45 - 50 lbf ft61 - 68 Nm
Adjustment Screw Internal Hex Size	5/32 in.4 mm
Locknut Hex Size	9/16 in.15 mm
Locknut Torque	80 - 90 lbf in.9 - 10 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:

Maximum pressure differentials for spring ranges: A and B are 3000 psi (210 bar) D and E are 2000 psi (140 bar) W is 5000 psi (350 bar) inlet pressure

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Additional Resources

SUN HYDRAULICS
RED-REL CART
PVFALDN