2
Type MR108
have accumulated. To prevent such
injury or damage, provide piping or
tubing to vent the fluid to a safe,
well-ventilated area or containment
vessel. Also, when venting a
hazardous fluid, the piping or tubing
should be located far enough away
from any buildings or windows so to
not create a further hazard and the
vent opening should be protected
against anything that could clog it.
Personal injury, equipment damage
or leakage due to escaping fluid
or bursting of pressure-containing
parts may result if this backpressure
regulator is overpressured or is
installed where service conditions
could exceed the limits given in
the Specifications section or where
conditions exceed any ratings of the
adjacent piping or piping connections.
To avoid such injury or damage,
provide pressure-relieving or pressure-
limiting devices (as required by
the appropriate code, regulation or
standard) to prevent service conditions
from exceeding limits. Additionally,
physical damage to the backpressure
regulator could result in personal
injury and property damage due to
escaping fluid. To avoid such injury
and damage, install the backpressure
regulator in a safe location.
Clean out all pipelines before installation of the
backpressure regulator and check to be sure the
backpressure regulator has not been damaged or
has collected foreign material during shipping. For
NPT bodies, apply pipe compound to the external
pipe threads. For flanged bodies, use suitable line
gaskets and approved piping and bolting practices.
Vertical installation with the actuator oriented up
or down is recommended. The unit will operate in
horizontal installation with actuator on the side,
however, this could result in premature wear of parts.
Make sure that flow will be in the same direction as
that indicated by the body arrow. Orientation of the
two vents should always be down. Vents may be
rotated after regulator installation so that the vent
screens are down.
A control line must be installed to allow inlet pressure
to register on the actuator’s diaphragm. It should
be installed four to eight pipe diameters upstream
of the regulator and in an area of pipe that is free
of turbulence.
Note
It is important that the backpressure
regulator be installed so that the vent
hole in the spring case is unobstructed
at all times. For outdoor installations,
the backpressure regulator should be
located away from vehicular traffic and
positioned so that water, ice and other
foreign materials cannot enter the
spring case through the vent. Avoid
placing the backpressure regulator
beneath eaves or downspouts and
be sure it is above the probable
snow level.
Overpressure Protection
Maximum inlet pressures depend upon body end
connections, materials and temperatures. Refer
to the nameplate for the maximum inlet pressure
of the valve. The valve should be inspected for
damage after any overpressure condition.
Fisher
®
backpressure regulators are NOT ASME safety
relief valves.
Startup
The backpressure regulator is factory set at
approximately the midpoint of the spring range
or the pressure requested. If a pressure setting
other than specified is desired, be sure to change
the pressure setting by following the Adjustment
section. With proper installation completed, slowly
open the upstream and downstream shutoff valves
(if applicable).
Adjustment
To change the control pressure, loosen the locknut
and turn the adjusting screw clockwise to increase
pressure or counterclockwise to decrease pressure.
Monitor the control pressure with a test gauge during
the adjustment. Tighten the locknut to maintain the
desired setting.
Taking Out of Service (Shutdown)
!
WARNING
To avoid personal injury
resulting from sudden release of
pressure, isolate the backpressure
regulator from all pressure before
attempting disassembly.