by Jim McNeece 2003 U320 40′ 7/7/13
The symptom was that in both rooms the hydraulic pump did not quit running when the room reached its inner or outer limit and the red light would not go out.
The diagnosis went like this.
I pulled into the HWH bay and explained the problem to the acting shop foreman. He called two of the electronic engineers who came over and when they heard my description of the problem, both of them said, in unison, “It’s the 3000.” To demonstrate that this indeed was the problem, one of the engineers picked up a piece of wire off the floor, stripped off the insulation on two ends and jumped some connections (I couldn’t see which ones) and had me cycle the room. The pump properly turned off and the red light went out. The foreman installed a new high-pressure switch within 2 minutes. Everything was fine after that.
The switch sits on top of the slide solenoid manifold and has two wires running out of it. When a room reaches its limit, the system reaches full pressure of 3000 psi and this switch shuts down the pump. Hence the name, “the 3000”.
