CHANNEL 4410528 - Caterpillar

Excavators ( 51U6258-Up, 76U5505-Up)The hydraulic tanks on 225 Excavators are now pressurized. An electric motor operates an air compressor to maintain a pressure of 48 14 kPa (7 2 psi) in the hydraulic tank. The pressure in the hydraulic tank is needed to prevent cavitation in the hydraulic pumps.
To monitor the operation of the air compressor, a yellow (amber) warning light has been added to the console in the cab. The master fault light on the console monitors the air pressure in the hydraulic tank.
When the engine is first started, the air compressor warning light comes ON. As soon as air pressure reaches 48 14 kPa (7 2 psi) in the hydraulic tank, the air compressor warning light goes OFF.
If the pressure in the hydraulic tank does not increase within a four minute period, the air compressor warning light stays ON, the air compressor motor shuts off and the master fault light comes ON. If this occurs, shut the engine off and check the air compressor system.
Always make sure the filler cap for the hydraulic tank is tight. When the pressure in the hydraulic tank is less than 48 kPa (7 psi), the machine can be operated temporarily at a reduced engine speed of 1700 rpm with no damage to the hydraulic pumps.