JOINT AS-TUBE 9S9635 - Caterpillar

Air shutoff valves must be tested and inspected in order to ensure proper operation. Before testing, remove each limit switch and inspect each limit switch assembly for wear. The typical wear is erosion of the plunger. This is due to vibration of the plunger within the bore for the plunger. This usually causes the switch to jam or this causes the switch to become otherwise inoperable.Note: The limit switches are normally open switches. The switches are in the closed state when the air shutoff valves are latched in the open, or Run position. If the air shutoff valve is in the Closed position or the Stop position, the switch is in the open state, which will cause an emergency stop. This will shut down the engine or this will prevent the engine from starting. The engine will crank but the engine will not start.Electrically Operated Air Shutoff Valves
Power up the engine control panel with both air shutoff valves latched in the open position and both switches connected. Both valves should remain open. Check the wiring for the switch if both valves do not remain open.
With the power to the engine control panel ON, activate the emergency stop button. Both of the air shutoff valves should close. If both air shutoff valves do not close, check the switch wiring and the solenoid wiring. If both air shutoff valves close, proceed to step 3.
Turn the power engine control panel to the OFF position. Ensure that the emergency stop button is in the run position. Latch only the right side air shutoff valve to the open position and turn the power for the engine control panel to the ON position. The right air shutoff valve should close. If the right air shutoff valve closes proceed to step 4. If the right air shutoff valve does not close, check the switch and wiring for the right air shutoff valve.
Turn power for the engine control panel to the OFF position. Ensure that the emergency stop button is in the run position. Latch only the left side air shutoff valve to the open position. Turn the power for the engine control to the ON position. The left air shutoff valve should close. If the left air shutoff valve closes the test is complete. If the left air shutoff valve does not close, check the switch and the wiring for the left air shutoff valve. Note: Testing is only complete when the engine successfully passes step 1 through step 4.Hydraulically Actuated Air Shutoff Valves
Note: After checking the fluids in the engine, ensure that both air shutoff valves are latched in the open position. Start the engine and operate the engine at 1500 RPM. This will allow the fluids to warm up before proceeding with the test for the air shutoff valves.
Manually trip one of the air shutoff valves. This should cause an emergency stop condition and the remaining air shutoff valve should close. If the engine experienced an emergency stop condition but the remaining valve