Faulty operation
(5)
Leakage
Failure phenomenon
Possible causes
Excessive amount of lubricant
(2)
(3)
(4)
Swollen spool valve
Low pilot pressure
(1)
Though pilot valve does
shift, main valve will not shift
or will be sluggish.
Foreign matter caught in the spool valve
(2)
Poor seal on actuator (cylinders, etc.) side
Spool has not completely shifted
Intrusion of foreign matter
Leakage from the
connecting port.
Leakage from the gasket
(manifold)
(2)
(6)
Wear of packings of the spool valve
Countermeasures
(7)
Inferior tightening of installation screw
Troubleshooting
Should any trouble be found during operation, trace the source of the trouble in the following order and take
corrective action.
No.
Countermeasures
(1)
Adjust pressure so that pilot pressure will fall within operating pressure range during operation.
(2)
In case of intrusion of foreign matter, to remove foreign matter by air blow of piping and then replace valve.
(3)
If incorrect oil has been used for lubrication, remove the oil with air blow and replace the valve with a new one.
If a lubricant is used in the system after the replacing the valve, use turbine oil Class 1 (ISO VG32).
If there is a large amount of condensate or condensate cannot be removed completely, mount an auto
drain or install a dryer and replace the valve.
(4)
Reduce the amount of lubricant to the degree that no oil splashes out of the air exhaust port (R port).
(5)
Repair or replace actuators.
(6)
Replace the valve.
(7)
After stopping air and re-tighten the bolts.
If no improvement is achieved in spite of the above countermeasure, inside of the valve may have some abnormality.
In this case, stop using the valve immediately.
If any of followings are carried out, inside of the valve may have some failure. In this case, stop using the valve immediately.
The oil supplied was not the specified type.
Lubrication was stopped during operation. Or, lubrication was interrupted temporarily.
The product was directly exposed to water.
Severe impact was applied.
Foreign matter such as condensate or dust has entered the product.
Other than the cases mentioned above, any usage which falls into the precautions given in this Operation Manual.
∗
If the product has failed, then please return the valve as it is.
- 8 -
VT301
∗∗
-OMH0007-B
