HOOD & GUARD GP 1026126 - Caterpillar

Illustration 1 g00541475
Pilot pressure control valve (1) Manifold (2) Pressure reducing valve (3) Relief valve (A1) Pilot pressure port (P1) Pump pressure port (T1) Tank portThe pilot pressure control valve is located behind the access panel on the right side of the machine near the rear. The pilot pressure control valve controls the pressure that is sent to the pilot control valves for the boom and hook winches.Pump pressure from port (P1) on the counterweight control valve enters manifold (1) through port (P1). This pressure travels through a shuttle valve to pressure reducing valve (2). Pressure reducing valve (2) reduces the pressure for the pilot control valves. The pressure setting for this valve is approximately 5000 170 kPa (725 25 psi).The reduced pressure travels through a check valve and the oil exits manifold (1) through port (A1). The pressure from port (A1) travels to the pilot control valves for the boom and hook winches. This pressure also charges the accumulator for operation of the hook winch when the engine is turned off.If the pressure that is exiting port (A1) becomes too high for pressure reducing valve (2), the excess pressure is relieved through relief valve (3). This excess pressure exits manifold (1) through port (T1) and the oil flows to the tank.