SUN HYDRAULICS
XRDCLNNAL/S

SUN HYDRAULICS
Material:XRDCLNNAL/S
Model:XRDC-LNN-AL/S
Summary:Y-assembly

Due to extremely high demand, please call 888-905-7411 for availability

***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 XRDCLNNAL/S (Material Number: XRDCLNNAL/S) is a specialized valve assembly designed to provide a flushing circuit for hydrostatic transmissions. This system efficiently manages the discharge of hot, dirty oil from the low-pressure side of the loop, replacing it with cool, filtered oil via the charge pump. The hot oil discharge is typically routed through the cases of both the pump and motor, effectively flushing out contaminants. A notable feature of this assembly is its hot oil shuttle, which allows for confirmation or adjustment of the hot oil relief setting when the transmission is in neutral. This assembly can be integrated into a system by teeing off the loop due to its common port designations; ports marked 1 are common as are those marked 2. The high-pressure relief on one side controls pressure on the opposite port, offering versatile control options. When in neutral, charge pressure is managed by the charge pump relief; upon activation of the hot oil shuttle, some or all charge pump flow redirects to the hot oil relief. For optimal performance and to ensure proper hot oil flow, it\u2019s crucial that the charge pump relief is set higher than the hot oil relief. The standard setting for this system\u2019s hot oil relief is 200 psi (14 bar) at a flow rate of 4 gpm (16 L/min). With a capacity of 10 gpm (40 L/min), this line-mount body type valve requires four mounting holes and does not feature anodized aluminum bodies due to considerations like cost and fatigue life implications.

Description

This valve assembly provides a flushing circuit for hydrostatic transmissions. The hot oil flushing circuit allows a discharge of oil from the low pressure side of the loop. The charge pump replaces the hot, dirty oil with cool, filtered oil. The hot oil discharge is often passed through the cases of the pump and the motor, flushing hot, dirty oil from them as well.

A unique feature of the hot oil shuttle is that the setting of the hot oil relief can be confirmed or adjusted when the transmission is in neutral.
The two ports marked 1 are common as are the two marked 2. Therefore the assembly can be teed off the loop rather than being plumbed into the loop.
The two ports marked 1 are common as are the two marked 2. The high pressure relief that is physically on the same side as port 1 controls the pressure on port 2 and vice versa.
When the transmission is in neutral the charge pressure is controlled by the charge pump relief. When the hot oil shuttle opens, some or all of the charge pump flow is redirected to the hot oil relief. The charge pump relief must be set higher than the hot oil relief to produce hot oil flow. The higher the differential pressure between the 2 reliefs, the higher the hot oil flow. The amount of hot oil flow is determined by the pressure vrs flow curves of the 2 reliefs and is difficult to quantify.
The standard setting of the hot oil relief is 200 psi (14 bar) at a flow of 4 gpm (16 L/min).
Hydraulic motors leak. Therefore a mechanical brake is recommended to positively lock any stopped live load.

Capacity	10 gpm40 L/min.
Body Type	Line mountLine mount
Mounting Hole Quantity	44

Show FAQ

Why doesn't Sun anodize their aluminum bodies?	Reasons to anodize: To increase corrosion resistance. Sun uses 6061-T651 aluminum. It is one of the most corrosion resistant aluminum alloys there is. Whether or not anodizing improves the corrosion resistance of 6061 aluminum is debatable. We have yet to have a manifold returned because of corrosion. Appearance (color). The 2 colors that would appeal to Sun would be blue or black. Unfortunately these are the colors that are hardest to do consistently. To provide a hard wear surface. Sun does not make parts-in-body valves. The manifold is just plumbing. We don't need a wear surface. Because everyone else does it. Bad reason. Reasons to not anodize: Cost. It's another process. Logistics. When you make tens of thousands of manifolds a month and you anodize hundreds, it's a problem. Consistency. See above. Stamping. After a body is anodized you cannot do any more stamping without making a mess.Inspection. Have you ever tried to look for burrs in a black anodized body? It's the old blackboard factory at night scenario. Torque. You will experience an increase in breakaway torque when removing items from an anodized manifold. Fatigue life. This is the best reason to not anodize. Fatigue failure is a very complex phenomenon. What it takes to initiate a crack is difficult to predict. What it takes to propagate a crack is readily defined. Anodizing produces a very thin, very hard, and very brittle surface on aluminum. The first time you pressurize an anodized aluminum manifold you have initiated fatigue cracks. Whether or not the stress is enough to propagate the cracks is a matter of pressure and manifold geometry. Anodizing an aluminum manifold grossly reduces the fatigue life by anywhere from 20% to 50%.
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.
How big is a drop of hydraulic oil?	There are exactly 250 Sun drops in a cubic inch or 15 in a cc.
Why does Sun use 6061 aluminum?	6061-T651 is relatively strong, relatively inexpensive, difficult to machine, readily available in all shapes and sizes and very corrosion resistant. 2024 is stronger and machines beautifully, but is expensive and falls to pieces in a corrosive environment.

Additional Resources

Notes:

Important: Carefully consider the maximum system pressure. The pressure rating of the manifold is dependent on the manifold material, with the port type/size a secondary consideration. Manifolds constructed of aluminum are not rated for pressures higher than 3000 psi (210 bar), regardless of the port type/size specified.

SUN HYDRAULICSXRDCLNNAL/S

Additional Resources

SUN HYDRAULICS
XRDCLNNAL/S