REGULATOR-WATER TEMPERATURE 4W4794 - Caterpillar

Illustration 1 g01033622
Pilot manifold (1) Swing brake (2) Travel (3) Implement
Illustration 2 g00939494
The cross section is identical for all of the solenoid valves. (5) Button for manual operation (A) Pilot pressure (B) Port (C) Port to tankThe pilot manifold includes solenoid operated pilot control valves. The following solenoid valves are cartridge type solenoid valves: swing brake (1), travel activation (2) and activation of the hydraulic implements (3) .Each solenoid valve includes a cartridge with a spool and a spring. A mechanical pin can be depressed in the head of the solenoid which permits manual operation of the valve.When the solenoid is de-energized, pilot pump oil pressure enters port (A) of the valve block. The oil flow from the inlet port (A) through the passage is stopped by the regulating spool.A connection is made between the pilot oil line (B) and the control device through port (C) to the tank return line so that the pilot line is without pressure.When the solenoid is energized, the connection between port (A) and port (C) is closed. Port (B) is connected to port (A) and pilot oil pressure can go to the respective control device.To relieve pressure in the spring chamber passage, the spool is connected to the tank return line when the solenoid is de-energized.