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8. Maintenance guideline
Be aware of foreign materials in the piping since many of faults in the pressure reducing valve
are caused by existence of foreign objects. Faulty pressure gauge, clogged strainer and leaking
stop valve of bypass pipe develop symptoms that look like those indicated by faulty pressure
reducing valve. Note that a clogged strainer will decrease the outlet pressure, and a leaking
bypass pipe will increase the outlet pressure. Before attempting to troubleshoot the pressure
reducing valve, verify the cause of the trouble.
8.1 Warning and precaution on maintenance and inspection
WARNING
Before disassembling or inspection, completely release the pressure from the pressure
reducing valve, piping and equipment and cool the pressure reducing valve if hot fluid has
been processed. Never touch the pressure reducing valve with bare hands until it cools off.
R esidual pressure may cause bodily injury or burn injury or contaminate surrounding.
※
CAUTION
(1) To maintain the functions and performance of the pressure reducing valve, perform
periodic inspection.
U ser should refer such tasks to specialist, maintenance agency, or the manufacturer.
※
(2) Only properly trained, qualified individuals or service representatives should disassemble
and check the valve.
I f problem is found, consult a repair shop or agency.
※
(3) Before flowing fluid, close the stop valve at upstream and downstream of the pressure
reducing valve and completely remove the foreign objects through the bypass pipe.
F oreign residues in the pressure reducing valve degrades the valve performance.
※
○ P eriodic replacement of consumable parts
Life expectancy of consumable parts depends on frequency and condition of use. Rough
standard of life estimation is given below. (Part number shown in the table below refers to the
number in Section 8.3, Fig.4 GD-400 exploded drawing.)
Diaphragm
Balance diaphragm
Disc
O-ring
○ P eriodic inspection of pressure reducing valve
Check the items shown below at the specified interval.
Parts
Part number
3
4
、
、
Check item
Check pressure setting
Check for external leakage
12
Replacement interval
22
3 years
7
3 years
10
3 years
3 years
2 0
3 6
、
Check interval
Once a year, or more
■ E P D T - 1 7 9 c ■
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