Priority Inlet Section Operation - jcb 214e Service Manual

Backhoe loader

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Loader Valve - Variable Flow

Priority Inlet Section Operation

The priority inlet section houses the steering priority valve

and a relief valve assembly. Operation is as follows:

When the steering wheel is turned, a priority pressure

demand signal is sent from the hydraulic steer unit and

received at the priority inlet section (port PRLS). The signal

oil flows through port A into chamber C via gallery B.

The combined force of spring D and signal oil pressure

moves spool E up. The position of the spool now allows oil

from the pump inlet port P to flow out to the hydraulic steer

unit via priority work port PR.

It must be noted that relief valve assembly J is redundant.

This relief valve is part of the inlet section, however the

hydraulic steer unit also houses a steer system relief valve.

To ensure the relief valve in the hydraulic steer unit controls

the steer system pressure, valve J is set abnormally high

(172 bar; 2500 lb/in

Circuit Descriptions

Purchased from www.WorkshopManuals.co.uk

Component Key:

Load sense port (to pump)

Priority Load Sense Port (from steer unit)

Priority Work Port (to steer unit)

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