Reference Material I-2 / I-3 Valve
60 ©Vertical Express
Sequence of Events
(continued)
Down Valve Section The down portion of the valve consists of a piston that seats and can be controlled in
these positions:
• Closed to stop the car
• Partially open for slow speed
• Fully open for high speed
Down Start and Full Speed
1. To start the car down, the down fast and down slow solenoids are energized simulta-
neously, allowing the oil behind the piston to flow to the tank through the down start
adjustment. See Figure 11.
2. The reduction in pressure behind the piston causes the piston to lift. The down start
adjustment must be open more than the down stop adjustment so that the oil entering
through the down stop adjustment can be drained to the tank.
3. The size of the openings will govern how fast the piston moves and how rapidly the car
starts. The lowering speed adjustment limits the amount the piston can open, thereby
controlling the car down speed.
Figure 11 - Down Start and Full Speed Diagram
TANK
PUMP JACK
Lowering Piston
Down Slow
Solenoid (Open)
Down Start
Adjustment
Manual Lowering
Down Slowdown
Adjustment
Down Fast
Solenoid (Open)
Lowering Speed Adjustment
Down Stop Adjustment
Check Valve Piston
CONTROL FLOW
MAIN FLOW
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