Section 1 - General Information
Terms and Definitions
Colour Coding
1 - 32
1 - 32
9803/4180-08
Black and White Codes
The following black and white coding, used on illustrations
to denote various conditions of oil pressure and flow, is
standardised throughout JCB Service Publications.
Neutral Circuit Pressure
Pressure generated by the operation of a service. Depending on application this may be anything
between Neutral Circuit Pressure and MRV Operation Pressure.
Oil trapped within a chamber or line preventing movement of components (lock up).
Exhaust.
Pressure that is above Neutral Circuit Pressure but lower than that denoted by the operation of a
service.
Oil pressure used in controlling a device (servo).
Oil subject to a partial vacuum due to a drop in pressure (cavitation).
