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| Illustration 1 | g00601015 |
(1) Relief valve (line). (2) Port. (3) Passage. (4) Passage. (5) Valve. (6) Pilot valve. (7) Passage. (8) Spring. (9) Spring. | |
The relief valve (line) (1) is attached to the valve blocks for the boom, the stick and the loading valve. The setting of the relief valves (line) for the boom and the stick is 23750 ± 250 kPa (3445 ± 36 psi). The relief valves protect the individual hydraulic lines from damage that occurs from pressure that is too high.
The oil enters the port (2) and flows to the passage (3) in the relief valve. When the pressure of the oil reaches the cut out pressure of the relief valve, the oil forces the pilot valve (6) to move to the right. The oil can then flow to the return passage through the passage. (7) .
When the pressure increases, the oil moves the valve (5) to the right. This allows oil to flow through the passage (4) to the return passage.
The springs (8) and (9) cause the valves to move back to the left when the pressure reaches the cut in pressure.