9
MR98 Series AD2000 Compliant
D-A-CH Region Only
Always use a pressure gauge to monitor pressure
when making adjustments.
All MR98 Series Regulator springs can be backed off
to zero pressure. Recommended set pressure ranges
available, maximum inlet pressures and temperatures
and color codes of the respective springs are shown in
the Specifications section and Table 2.
Types MR98H and MR98HH
1. Loosen the jam nut (key 17, Figures 3, 4 and 5).
2. To increase the set pressure or pressure setting,
turn the adjusting screw (key 15) clockwise. Turn
the adjusting screw counterclockwise to decrease
the set pressure or pressure setting.
3. Tighten the jam nut (key 17).
Shutdown
Relief Valve
1. Close the upstream shutoff valve to the
regulator inlet.
2. Close the downstream shutoff valve to the
regulator outlet.
3. Slowly open the downstream vent valve to vent
downstream pressure.
4. Leave the downstream vent valve open to vent
inlet pressure and to release all remaining
pressure in the regulator by opening the upstream
vent valve or by turning the adjusting screw
fully counterclockwise.
Backpressure Regulator
1. Close the upstream shutoff valve to the
regulator inlet.
2. Close the downstream shutoff valve to the
regulator outlet.
3. To avoid internal damage due to reverse
pressurization of main valve components, bleed
backpressure regulator inlet pressure first before
bleeding outlet pressure.
Maintenance
▲
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 relief valve
or regulator from system pressure and
relieving all internal pressure from the
relief valve or regulator.
To avoid possible personal injury from
spring or pressure-loaded actuator,
make sure that the adjusting screw is
completely backed off or the spring case
pressure is vented prior to disassembly.
Otherwise, the spring load or loading
pressure could forcefully eject the
spring case.
Relief valves or 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™ relief valves
and regulators.
Due to normal wear or damage that
may occur from external sources, this
relief valve or backpressure 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.
Due to normal wear and damage that may occur from
external sources, relief valve parts such as the O-rings,
gaskets, diaphragm, orifice and valve plug should be
inspected periodically and replaced as necessary. The
frequency of inspection and replacement depends upon
the severity of service conditions or the requirements of
state and federal laws.
Instructions are given below for disassembly of
the MR98 Series. These valves do not have to be
removed from the pipeline to inspect internal parts.
Suitable lubricants are indicated on the assembly
drawings. Apply the recommended lubricants as
the relief valve is being reassembled. Refer to
Figures 3 to 5 while servicing the relief valve.
