GSi GRA, Инструкция по установке и эксплуатации

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8. Troubleshooting
32 PNEG-2174 Sampler - Model GRA
Directional Solenoid Valve Troubleshooting
There must be at least 60 PSI pressure at the valve. The valve pilot operators are air assisted. If there is
insufficient pressure the valve will not shift or may not shift completely.
Observe the pressure gauge. Assume the gauge indicates sufficient pressure when the sampler is idle,
85 PSI for example. If the pressure drops significantly to perhaps 55 PSI when the valve shifts, a blocked
or damaged air line should be suspected.
Figure 8A Condensed Moisture Blocking Airline
One often overlooked cause of insufficient air flow is moisture condensing and collecting in a low spot in
the supply line.
Figure 8A illustrates an exaggerated example of such a problem. It can be seen that if the
pipe sags only slightly over a long distance and water collects in the low spot over an extended period of
time, the airline could be partially or completely blocked. A similar condition often occurs where there is a
junction of horizontal and vertical sections of an air line.
This problem is particularly prevalent when there is high ambient humidity and the equipment operates
infrequently and intermittently, as in the case of a sampler.
NOTE: All horizontal runs of an airline should have a moisture trap and the traps should be drained
frequently, at least once a day, especially, when humidity levels are high.
Symptom Possible Cause Corrective Action
Valve does not shift but 120
VAC signal is present at the
terminal strip inside the control.
No or low air pressure.
Turn ON air supply and set regulator
to 80-100 PSI.
Faulty field wiring. Check for full line voltage at the solenoid.
Solenoid coil burnt out. Replace coil if no continuity through coil.
Valve clogged or stuck. Remove and clean. Or replace.
Valve leaks air continuously out
an exhaust port.
Defective valve seals.
See Valve vs. Cylinder Leak Test
on Page 34.
Defective cylinder seals.
See Valve vs. Cylinder Leak Test
on Page 34.
Ref # Description Ref # Description
1 Condensed Moisture 3 Water Level
2 Airline 4 SAG of Pipe greater then internal diameter
Junction of Horizontal and
Vertical Sections of Airline Piping
Long Horizontal Run of Airline Piping