Precautions During Maintenance And Inspection; Disassembly - Yoshitake GP-1000 Installation & Operation Manual

8.2 Precautions during maintenance and inspection

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Warning
(1)Completely discharge internal pressure from the valves, lines, and equipment, and cool
the valve down to a level where you can touch it with bare hands before disassembly
and inspection.
※Failure to do so may result in injury or burns due to residual pressure or spillage
around the valve.
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Caution
(1)In order to maintain original performance and function, examine daily and personal
inspection. And, periodical inspection must be examined according to the regulations of
every kind.
※ For general users, request to specialized dealer or manufacture.
(2)Pressure reducing valve shall be disassembled and inspected by qualified person or
manufacture.
※ Request the treatment to specialized dealer or manufacture in case of any problems.
(3)While disassembly, drain flow out from the valve, so catch it by container. And release
steam completely before disassembling.
※In case of no container for drain, it makes dirty surrounding the valve.
(4)Close the stop valves before and after the pressure reducing valve, and remove all
foreign matter and scales via the by-pass line before operation.
※ Failure to do so may prevent the valve from functioning correctly.
(5)When adjusting pressure, slowly turn the adjusting screw.
※ Incorrect adjustment may cause hunting, water hammer, etc., resulting in damage to
the valve and other equipment.
(6)Remove condensate completely from the line, and close the stop valves before and
after the valve when not using it for long periods of times.
※Rust generated in the valves and lines may cause malfunction.
(7)In case of no operation for a long period of time, perform operating exam before start
operation again.
※Request the treatment to specialized dealer or manufacture in case of any problems.

8.3 Disassembly

Be sure that the stop valves at inlet and outlet side of pressure reducing valve is closed and all internal
pressure and condensate have discharged before disassembling the valve.
(1) Pilot valve
1． Loosen the lock nut [10] and turn the adjusting screw [9] to release the spring [8] (no
compression). For the model with handle, turn the handle in counterclockwise while pushing
down in order to change the adjusting spring into free position.
2． Remove the bolt [33] of the spring chamber [4]. Remove the spring chamber, spring, top spring
plate [6], bottom spring plate [7], and diaphragm [5]. For the model with handle, remove the
handle and spring chamber by one since they cannot disassemble.
3． Remove the pilot valve assembly [19], [20] using a ring spanner or socket wrench (nominal size
22)
(2) Piston
1． Remove the bolt [34] of the top cover [2] and the top cover. Pick up the spindle [18], and
remove the piston ring [16] and the inner ring [17].
(3) Main valve
1． Remove the bolt [35] of the bottom cover [3]. Remove the bottom cover, main valve spring
[13], and main valve [11].
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■EPDT-081a■