Supply Pressure Connections - Fisher 3570 Instruction Manual

Instruction Manual
D200137X012
The connection marked VENT (see figure 4) should be left open if the actuator is installed in the vertical position.
However, the vent must be protected against the entrance of any foreign material that could plug it. Check the vent
periodically to be certain it is not plugged.
If the actuator is mounted in other than the vertical position, be sure there is a vent and drain at the lowest point of the
positioner. To do this, remove the pipe plug (key 36, figure 10) from the cover. Then, position the cover in such a way
that the hole in the cover is at the lowest point. Plug the vent connection because the positioner is now vented
through the cover.
Note
A remote vent is not possible with 3570P, 3570PC, 3571, 3576, and 3577 positioners.
If a remote vent is required, the vent line must be as short as possible with a minimum number of bends or elbows.
Vent line piping should have a minimum inside diameter of 19 mm (3/4‐inch) for runs up to 6.09 meters (20 feet) and
a minimum inside diameter of 25.4 mm (1‐inch) for runs from 6.09 to 30.5 meters (20 to 100 feet).

Supply Pressure Connections

WARNING
Personal injury or property damage may occur from an uncontrolled process if the supply medium is not clean, dry, oil‐free
air, or noncorrosive gas. While use and regular maintenance of a filter that removes particles larger than 40 micrometers in
diameter will suffice in most applications, check with an Emerson field office and industry instrument air quality standards
for use with corrosive air or if you are unsure about the proper amount or method of air filtration or filter maintenance.
WARNING
To avoid personal injury or property damage resulting from the sudden release of pressure, do not install the valve
assembly where service conditions could exceed the limits given in this manual or on the appropriate nameplates. Use
pressure‐relieving devices as required by government or accepted industry codes and good engineering practices.
WARNING
If the supply pressure medium is corrosive, make sure the tubing and instrument components that contact the corrosive
medium are of suitable corrosion‐resistant material. The use of unsuitable materials might result in personal injury or
property damage due to the uncontrolled release of the corrosive media.
The connection marked SUPPLY (see figure 4) must be provided with clean, dry air or a noncorrosive gas. Install a
40‐micrometer filter and suitable equipment to dry the supply medium. Establish a maintenance cycle to ensure that
the regulator and filter are working correctly.
CAUTION
The maximum allowable supply pressure to prevent damage to the components of the positioner, actuator, and valve is
normally stamped on the actuator nameplate. Use a suitable supply pressure regulator to reduce the supply pressure
source to the value stamped on the nameplate.
3570 Positioners
September 2015
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