Troubles |
Causes |
Counter-measures |
[PID CONTROLLERS]
Output air pressure of pid controllers do not increase or decrease in spite of the change of detection input. |
When it does not increase.
- Supply air pressure is abnormal.
- Orifice of pilot relay is clogged.
- Leakage at the air piping at output side (due to cracking), or leakage at soldered joint or damage of diaphragm of control valve.
- Inferior connection or disconnection of link systems inside the controller.
- Leakage of various piping or tubes inside the controller.
- Damage of element at measuring part.
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- Adjust it into normal conditions.
- Press the cleaning push button.
- Adjust it into normal conditions.
- Adjust it into normal conditions.
- Replace the tube
- Replace the element.
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When it does not decrease.
- Nozzle at the flapper is clogged.
- Clogging of piping from pilot relay to piping from down of tube
- Loosening of pilot relay orifice
- Inferior connection or disconnection of link mechanism inside the controller.
- Leakage of various piping or tubes inside the controller.
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- Clean it with a wire of less than 0.4mm
- Adjust it into normal conditions.
- Retighten it
- Adjust it into normal conditions.
- Replace the tube
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[CONTROL VALVE]
Control valve life does not change due to the increase or decrease of output pressure of controller. |
Sticking of valve guide and valve stem.
- When positioner is provided sticking of positioner pilot.
- Disconnection of diaphragm stem and positioner.
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Inspection by disassembly.When foreign matters are caught into the parts, remove them and repair any possible damage.
- Repair the damage caused by sticking using fine mesh grinding paper or file.
- Adjust it into normal conditions.
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[FILTER REGULATOR]
Pressure does not increase even when setting knob is turned to increase pressure. Or pressure increase is abnormal or pressure does not go down. |
When pressure does not increase.
- Damage of diaphragm.
- Damage of setting spring.
- Sticking of pilot valve.
- Leakage at air piping at secondary side.
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- Replace the parts.
- Replace the parts.
- Repair the damage caused by sticking using fine mesh grinding paper or file.
- Adjust it into normal conditions.
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When pressure does not come down.
- Sticking of pilot valve.
- Clogging of exhaust hole of the cover.
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- Repair the damage caused by sticking using fine mesh grinding paper or file.
- Clean it.
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