172-65260m-05 (S-COS/S-COSR Pressure Reducing Valve) 27 Oct 2008
16
Disassembling the Pilot Section
The diaphragm is removed by utilizing the notch in the pilot body. Loosen the pilot
valve seat with a box wrench and remove it. Lift the pilot valve spring up and out with
a pair of tweezers. Then loosen and remove the pilot screen holder to remove the
pilot screen.
Check for any fault on the seat of the pilot valve, flaws on the gaskets, and clogging
of the pilot screen. Check for deformation, corrosion or faults on the diaphragm. The
diaphragm should be convex (open downward), with the printed UP mark on the top.
Disassembling the Piston
Remove the pilot body after
loosening and removing the nuts from
the stud bolts. During this process,
pay attention not to lose the
connecting tubes (2).
Remove the piston and the cylinder
from the main body. Then remove the
piston rings and the tension rings
from the piston. Do not apply too
much force when removing the piston
rings and tension rings.
Inspect the interior of the cylinder, the
exterior of the piston rings, the small
hole on the piston and the gaskets for
any fault or abnormality.
Pilot Valve Body
Nut
Upper Pilot Body Gasket
Pilot Valve
Pilot Screen Holder
& Gasket
Pilot Screen
Notch
Pilot Valve Spring
Pilot Valve Stem
Pilot Valve Seat
& Gasket
Diaphragm
Connecting Tube
Piston Ring
Tension Ring
Cylinder
& Gasket
Lower Pilot
Body Gasket
Piston
Connecting
Tubes
Stud
Bolt
Piston Ring
Tension Ring
