172-65175MA-13 (COS Pressure Reducing Valve) 16 Feb 2022
17
Disassembly
NEVER apply direct heat to the float. The float may explode due to
increased internal pressure, causing accidents leading to serious injury
or damage to property and equipment.
WARNING
Use hoisting equipment for heavy objects (weighing approximately
20 kg (44 lb) or more). Failure to do so may result in back strain or other
injury if the object should fall.
CAUTION
When disassembling or removing the product, wait until the internal
pressure equals atmospheric pressure and the surface of the product
has cooled to room temperature. Disassembling or removing the
product when it is hot or under pressure may lead to discharge of fluids,
causing burns, other injuries or damage.
CAUTION
It is a recommended practice to dismantle and inspect the COS once a year for
preventive maintenance purposes. It is especially important to perform an
inspection immediately after the initial run of a new line or before or after equipment
such as a heater is out of service for a long period of time. (Installation, inspection,
maintenance, repairs, disassembly, adjustment and valve opening/closing should
be carried out only by trained maintenance personnel.)
Remove all steam from the piping (both upstream and downstream). If the steam
supply to the system cannot be shut off, change over to bypass operation. Close
shut-off valves at the inlet and outlet of the COS completely. Relieve residual steam
pressure by loosening slightly the spring housing hex bolt and screen holder or
plug. Wait for the body to cool before attempting to remove the COS from the line.
Then remove inlet and outlet flange retaining bolts and nuts to permit removal of
the COS. Secure the COS in a vise to perform the inspection.
Disassembling the Adjustment Section
Loosen the adjustment screw completely and remove the hex bolts. Having removed
the spring housing, you will see the diaphragm retainer, coil spring and spring
retainer.
Check for seizure or any damaged screw threads.
15 to 100 mm (
1
/
2
to 4 in)
Spanner Cap
Nameplate
Adjustment Screw
Ball
Spring Retainer
Coil Spring
Diaphragm Support
Hex Bolt
Spring Housing
Locknut