Maintenance And Inspection - Fisher CS403 Instruction Manual

1. Open valves downstream of the regulator.
2. Slowly close the upstream shut-off valve.
3. Inlet pressure will automatically be released
downstream as the regulator opens in response
to the lowered pressure on the diaphragm.

Maintenance and Inspection

WARNING
!
To avoid personal injury or equipment
damage, do not attempt any maintenance
or disassembly without first isolating
the regulator from system pressure and
relieving all internal pressure as described
in "Shutdown".
Regulators that have been disassembled
for repair must be tested for proper
operation before being returned to
service. Only parts manufactured by
Emerson™ should be used for repairing
Fisher regulators. Relight pilot lights
®
according to normal startup procedures.
Due to normal wear or damage that may
occur from external sources, this regulator
should be inspected and maintained
periodically. The frequency of inspection
and replacement of parts depends upon
the severity of service conditions or the
requirement of local, state and federal
rules and regulations.
Periodic inspection must be performed
on the Types CS403 and CS404 to ensure
that the integral monitor or slam-shut
overpressure protection modules,
respectively, protect the downsteam
system in the event of a failure to the
primary regulator. This inspection must
test that the integral monitor or slam-shut
functions as intended. The frequency of
this inspection must be at intervals not
exceeding 15 months, but at least once
each calendar year.
Disassembly to Replace Diaphragm
1. Remove the closing cap (key 60, Figure 8). Turn
the adjusting screw (key 65) counterclockwise to
ease spring compression.
2. Remove the adjusting screw (key 65) and control
spring (key 38).
3. Remove hex nuts (key 16) and cap screws
(key 15). Separate the upper spring case (key 1)
from the lower casing assembly (key 9).
If disassembling a CS400 Series
regulator, lift the upper spring case
straight up in order to avoid hitting the
stem (key 44).
4. Slide the diaphragm head assembly (key 55)
away from the body (key 70) to unhook the
pusher post (key 51) from the lever (key 10). Lift
off the diaphragm head assembly (key 55).
5. For none relieving units such as the
Types CS400IN and CS400EN, unscrew the
screw retainer (key 45, Figure 9) using a
5/8 in. / 16 mm wrench. The screw retainer fastens
the lower spring seat (key 43) to the pusher
post (key 51). Unscrewing the screw retainer
will separate the lower spring seat (key 43),
diaphragm head assembly (key 55) and pusher
post (key 51). For units with internal relief
such as Type CS400IR, press down on the
upper spring retainer (key 42, Figure 10) using a
9/16 in. / 14 mm box-end wrench and remove the
E-ring (key 58). Slide the upper spring retainer
(key 42), the relief spring (key 41), the lower spring
seat (key 43) and the diaphragm assembly
(key 55) off of the relief valve stem (key 44).
6. Reassemble in reverse order of the above steps.
Disassembly to Replace Valve Disk
and Orifice
1. Remove the cap screws (key 71, Figure 8) which
hold the lower spring casing (key 9) to the body
(key 70). Separate the lower casing (key 9) from
the body.
2. Check the body O-ring (key 21) for wear and
replace as necessary.
3. Examine the valve disk (key 36) for nicks, cuts
and other damage. Remove the disk clip (key 37)
that holds the disk to the stem (key 11) and
replace the disk if necessary.
4. Examine the seating edge of the orifice (key 25).
If it is nicked or rough, remove the orifice (key 25)
from the body (key 70) using a 1-1/16 in. /
27 mm socket wrench. Coat the threads of the
replacement orifice with a good quality lubricant
and install.
CS400 Series
Note
13