Instruction Manual
D100291X012
480 Series Actuators
August 2012
5
Table 4. Action Under Normal Operating Conditions
ACTUATOR DESCRIPTION
DESIRED PISTON MOTION
Down
Up
With Positioner
Direct-acting
Increasing input signal pressure to bellows
(1)
Decreasing input signal pressure to bellows
(1)
Reverse-acting
Decreasing input signal pressure to bellows
(1)
Increasing input signal pressure to bellows
(1)
Without positioner
Supply pressure loaded on top of piston,
exhausted from bottom
Supply pressure loaded on bottom of piston,
exhausted from top
1. Supply pressure is routed through relays to piston.
Installation
WARNING
Always wear protective gloves, clothing, and eyewear when performing any installation operations to avoid personal
injury.
Personal injury or equipment damage caused by sudden release of pressure may result if the valve assembly is installed
where service conditions could exceed the limits given in table 1 or 3 or on the appropriate nameplates. To avoid such
injury or damage, provide a relief valve for overpressure protection as required by accepted industry or local, state, and
Federal codes and good engineering practices.
Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
If installing into an existing application, also refer to the WARNING at the beginning of the Maintenance section in this
instruction manual.
Inspect this equipment on arrival to note any damage which may have occurred in transit. If the actuator is attached to
a valve body when received, install the valve in the pipeline with flow in the direction of the arrow on the valve body.
(Some valve types, notably various butterfly valves, can be installed with flow in either direction and are unmarked as
to proper flow direction.)
A three-valve bypass around the main valve is recommended to permit continuous operation during periodic
maintenance or inspection of the main valve.
Figure 4. Operation of Actuator with Positioner
BJ8256-A
A1286
BEAM
FIXED RESTRICTION
RANGE SPRING
BIAS
SPRING
RELAY B
SUPPLY
INSTRUMENT
BELLOWS REVERSED
POSITION
RELAY A
SUPPLY
FIXED RESTRICTION
INSTRUMENT PRESSURE
SUPPLY PRESSURE
TOP CYLINDER PRESSURE
BOTTOM CYLINDER PRESSURE
NOZZLE PRESSURE
