Maintenance
Regulator parts are subject to normal wear and must be
inspected and replaced as necessary. The frequency
of inspection and replacement of parts depends upon
the severity of service conditions or the requirements
of local, state and federal regulations. Due to the
care Emerson takes in meeting all manufacturing
requirements (heat treating, dimensional tolerances,
etc.), use only replacement parts manufactured or
furnished by Emerson.
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WARNING
To avoid personal injury, property
damage or equipment damage caused by
sudden release of pressure or explosion
of accumulated gas, do not attempt any
maintenance or disassembly without
first isolating the regulator from system
pressure and relieving all internal
pressure from the regulator.
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. Restart gas
utilization equipment according to normal
startup procedures.
General Maintenance
1. Visually inspect the regulator and its parts for
any damage.
2. Ensure tight connections, tight seals and safe
operation. If there is an evidence of leakage
or unstable internal motion, a rebuild with seal
replacement and relubrication may be necessary.
3. Observe the blanketing pressure.
4. Inspect the inlet pressure for the proper pressure
(stamped on the regulator nameplate).
Body Area
Perform the following procedure to gain access to the
disk assembly, orifice and body seal O-ring. Release
all pressure from the regulator before performing
the following steps. Key numbers are referenced in
Figures 4, 5 and 6.
1. To inspect and replace the disk assembly (key 13),
remove the back body cap (key 43).
2. Remove the disk assembly (key 13) from the disk
spacer (key 44) and replace if necessary.
3.
To inspect the orifice (key 5) on Types T208 and
T208M or throat seal O-ring (key 31) and machine
screw (key 34) on the Type T208M, remove the
cap screws (key 2) and separate the diaphragm
casing (key 4) from the body (key 1).
4. Remove and inspect the body seal O-ring (key 11)
and the backup ring (key 49). Replace if damaged.
5. For a Type T208M, inspect the throat seal O-ring
(key 31) by removing the machine screw (key 34).
Replace if necessary. To install a throat seal, place
the throat seal O-ring on the machine screw and
thread into guide insert (key 18) to seal.
6.
Inspect and replace the orifice (key 5) if necessary.
Lightly lubricate the threads of the replacement
orifice with a good quality lubricant and install with
340 to 470 in-lbs / 38.5 to 53.1 N•m of torque.
7. Place back-up ring (key 49) into the body (key 1).
Then place the body seal O-ring (key 11) into
the body.
For external square head adjusting screw
1. Loosen the locknut (key 20).
2. Turn the adjusting screw (key 35) either clockwise
to increase outlet pressure or counterclockwise to
decrease outlet pressure. The regulator will go into
immediate operation. To ensure correct operation,
always use a pressure gauge to monitor the vapor
recovery pressure when making adjustments.
3. After making the adjustment, tighten the locknut
(key 20).
Shutdown
1.
Close the nearest upstream shutoff valve.
2.
Close the nearest downstream shutoff valve to
vent the regulator properly.
3. Open the vent valve on both the upstream and
downstream sides of the regulator. All pressure
between these shutoff valves is released through
the open vent valve. For a regulator with control
line, close the valve in the control line and vent
the diaphragm casing to the atmosphere.
6
T208 Series
