Do one or more SCVs on your 9 Family tractor appear to be operating slower than they should? If so, you might be experiencing a feature called hydraulic flow sharing.
After watching this video, you will be able to: • Explain purpose of hydraulic flow sharing • Connect SCVs to prevent hydraulic flow sharing, and; • Adjust SCV and ECO engine speed to resolve hydraulic flow sharing issues
9 Family tractors have a large amount of hydraulic flow capacity to operate implements that require large amounts of flow.
In certain conditions however, the Main Hydraulic pump cannot meet all hydraulic flow demands.
Flow Sharing was designed to protect systems operating in continuous flow, by reducing flow to other SCV’s when pump output is exceeded.
SCV’s that are in continuous detent are exempt from Flow Sharing as these are usually operating critical functions such as controlling seed rate.
Operators will likely know if hydraulic flow sharing is active by slower than expected raising and lowering of implements or other functions that are on SCVs with timed detents while at low engine speeds. SCVs that have a continuous detent will operate normally.
Fortunately, there are some tips that you can use to minimize the occurrence of hydraulic flow sharing.
The first thing you should do is verify all hydraulic return hoses are connected to either the SCV or power beyond return couplers. Do not connect these to the motor case drain coupler as this returns to the reservoir and not the charge pump.
If your tractor is equipped with high flow hydraulics, make sure that the required flow for the implement is balanced across both hydraulic pumps.
For example air seeder commodity carts with 2 fans should have 1 fan connected to the main hydraulic pump and the other fan connected to the high flow pump. The operator's manual identifies which SCVs are fed by which pump in Section 60.
Next, you need to adjust each SCV flow setting to supply just enough oil to satisfy the given function. The SCV controller calculates flow based on the flow setting and uses this information to help decide when to activate flow sharing. Higher settings than necessary may cause flow sharing more frequently.
There is a table in Section 60 of the tractor operator's manual that gives you the flow at each setting. For example, if one of the hydraulic functions requires 18 gallons per minute, set that SCV to approximately 7.6.
Also, set the detent time just long enough to fully operate each function. SCVs that are in continuous detent are exempt from flow sharing as these are usually operating critical functions such as controlling seed rates.
SCVs in timed detent will automatically reduce flow equally in order to satisfy the SCVs that are in continuous. If all SCVs are in continuous, then they will all reduce flow equally if needed.
You also need to verify that the engine speed is high enough to produce enough pump flow to meet the total flow for the implement.
In section 60 of the operator's manual there is a table that shows the pump flow at various engine speeds. Add up the flow for each SCV function to determine the required total pump flow and engine speed.
Lastly, if the engine is not operating fast enough, you will need to switch the transmission to Custom Mode and adjust the ECO OFF engine speed to the speed necessary to produce enough pump flow.
You may need to select an engine speed slightly higher than shown in the table to compensate for steering, braking and other tractor functions.
Beginning at model year 2019, a change was made to allow operators to enable or disable Flow Sharing.
This feature is also available as a software update to previous tractors. Contact your local John Deere Dealer for more information.
To disable Flow Sharing, navigate to SCV page by depressing SCV button on Navigation Bar.
Touch the “i” symbol found in the upper left corner of SCV page.
On SCV Information and Settings page, scroll down to locate Flow Sharing.
Touch OFF to turn Flow Sharing off.
However, remember that Flow Sharing was designed to prevent loss of oil flow to SCV functions that operate in continuous flow. Flow to these functions may now be reduced while making headland turns.
If you have tried all of these tips and are still having troubles, contact your John Deere dealer to see if there is a malfunction that needs to be repaired.
Now that you have watched this video you can: • Explain purpose of hydraulic flow sharing • Connect SCVs to prevent hydraulic flow sharing, and; • Adjust SCV and ECO engine speed to resolve hydraulic flow sharing issues