Operating Depth Consistency-Narrow FLEX-FOLD Machines

High pressure oil on return side of depth control system (rod end port of smallest depth control cylinder) can be detrimental to consistent operating depth and system rephasing.

To keep return side pressure low, a pressure bleed-off circuit is added to the depth control circuit. This bleed-off circuit consists of a T-fitting (A) that is installed in depth control circuit return line (B), (from rod end port of smallest depth control cylinder), a by-pass hose (C), a restrictor (orifice) fitting (D), and a SCV coupler (E).

IMPORTANT: When pressure by-pass hose is connected to open SCV, place SCV control in "float" position for precise depth control. Float position opens a low-pressure drain path to relieve pressure build-up off depth control circuit.

This circuit bleeds high-pressure oil from return side of depth control system. The bleed-off circuit or by-pass line is plumbed into open SCV or low pressure return port. (See ATTACHING MACHINE TO TRACTOR procedures in Attaching and Detaching section.)

NOTE: Additionally, a thermal relief valve is added to depth-control circuit to prevent damage of circuit components during storage.

Consistent low pressure on return side allows depth control cylinders to settle back uniformly after rephase and maintain same operating depth on both wings and center frame.

The bleed-off circuit also prevents tractor's stand-by pressure from being trapped on return side of depth-control hydraulic system, causing cylinders to extend unequally, resulting in inaccurate and uneven cultivating.

N47730A


A-T-Fitting
B-Return Line
C-By-Pass Hose
D-Restrictor (Orifice) Fitting
E-SCV Coupler

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In addition, the by-pass line provides an escape path for stand-by pressure, which is trapped when the single point valve closes at operating depth. If not relieved through by-pass line, trapped stand-by pressure will cause hoses to expand and, as it dissipates through internal SCV leakage or by raising machine off single point valve, result in uneven cylinder extension and uneven working depth.

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