Chapter 4.  Maintenance
4-1.  Inspection of the Control Valve
Check the control valve in accordance with the following instructions in order to maintain 
proper performance, prevent accidents, and detect problems early. Daily inspection and 
periodic inspection (overhaul) must be carried out. When inspecting the valve, be sure to 
observe the instructions below.
4-1-1.  Daily Inspection
The following items should be checked in daily inspections of the equipment.
Checklist
(1)  Gland  
Check for a fluid leak from the gland. If a leak is found, take necessary measures, 
referring to 
“3-3. Troubleshooting”.
(2)  Flange connections 
Check the flange between the valve body and the bonnet, and the flange between the 
valve body and the piping, for fluid leakage. If a leak is found, take necessary measures, 
referring to 
“3-3. Troubleshooting”.
(3)  Control valve operation 
Check for any abnormal operation such as hunting. If the valve is hunting, take necessary 
measures, referring to 
“3-3. Troubleshooting”.
(4)  Abnormal noise or sound 
Check that there is no abnormal sound or vibration from the device during operation. If 
any problem is found, take necessary measures, referring to 
“3-3. Troubleshooting”.
4-1