Overpressure Protection; Startup; Adjustment - Fisher MR108 Series Instruction Manual

Type MR108

Overpressure Protection

!
Personal injury, equipment damage
or leakage due to escaping
accumulated gas or bursting of
pressure-containing parts may result
if this regulator is:
• Overpressured;
• Used with incompatible process fluid;
• Installed where service conditions
could exceed the limits given in the
Specifications section and on the
appropriate nameplate; or
• Where conditions exceed any ratings of
adjacent piping or piping connections.
To avoid such injury or damage, provide
pressure-relieving or pressure-limiting
devices to prevent service conditions
from exceeding those limits.
Overpressuring any portion of this equipment may
result in equipment damage, leaks in the backpressure
regulator or personal injury due to bursting of
pressure-containing parts. The system should be
inspected after any overpressure condition.
Backpressure control ranges are from 5 to 300 psig /
0.35 to 20.7 bar. The individual spring range of your
backpressure regulator is stamped on the nameplate.
Maximum inlet pressures depend upon body materials
and temperatures. See the Specifications section
for the maximum inlet pressure of the valve. The
valve should be inspected for damage after any
overpressure condition.

Startup

!
To avoid possible personal injury,
equipment damage or leakage due
to escaping fluid, make certain the
regulator is installed as instructed in the
Installation section.
8
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Pressure gauges must always be
used to monitor downstream pressure
during Startup.
1. Check that proper installation is completed and
downstream equipment has been properly adjusted.
2. Make sure all block and vent valves are closed.
3. Slowly open the valves in the following order:
a. Loading supply and control line valve(s), if used
b. Inlet shut-off valve
c. Outlet shut-off valve
4. If the regulator has the bleed valve option, slowly
open valve to allow air to escape from lower
casing. Once fluid starts to bleed out, close valve.
The regulator is factory-set as specified
on the order or at the midpoint of the
spring range. The allowable spring
range is stamped on the nameplate. If
a pressure setting other than the one
specified is desired, be sure to change
the pressure setting by following the
Adjustment procedure.
4. If resetting setpoint, then set the regulator
to the desired set pressure according to the
Adjustment procedure.

Adjustment

Key numbers are referenced in Figure 4.
!
Personal injury, equipment damage
or leakage due to escaping fluid may
result if adjusting screw (key 73) and
jam nut (key 72) are not installed
properly. Also, spring (key 68) may go
solid resulting in the backpressure
regulator not opening if jam nut is not
installed and adjusting screw is adjusted
completely down.
CAUTION
CAUTION
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