Maintenance - Emerson Fisher 4320 Instruction Manual

Instruction Manual
D103621X0CN

Maintenance

WARNING
Avoid personal injury or property damage from sudden release of process pressure or bursting of parts. Before performing
any maintenance operations on an actuator‐mounted instrument or accessory:
D Always wear protective gloves, clothing, and eyewear.
D Provide some temporary measure of control to the process before taking the instrument out of service.
D Provide a means of containing the process fluid before removing any measurement devices from the process.
D Disconnect any operating lines providing air pressure, electric power, or a control signal to the actuator. Be sure the
actuator cannot suddenly open or close the valve.
D Use bypass valves or completely shut off the process to isolate the valve from process pressure. Relieve process pressure
from both sides of the valve.
D Vent the pneumatic actuator loading pressure and relieve any actuator spring precompression so the actuator is not
applying force to the valve stem; this will allow for the safe removal of the stem connector.
D Use lock‐out procedures to be sure that the above measures stay in effect while you work on the equipment.
D Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
When using natural gas as the supply medium, or for explosion proof applications, the following warnings also apply:
D Remove electrical power before removing any housing cover or cap. Personal injury or property damage from fire or
explosion may result if power is not disconnected before removing the cover or cap.
D Remove electrical power before disconnecting any of the pneumatic connections.
D When disconnecting any of the pneumatic connections or any pressure retaining part, natural gas will seep from the
unit and any connected equipment into the surrounding atmosphere. Personal injury or property damage may result
from fire or explosion if natural gas is used as the supply medium and appropriate preventive measures are not taken.
Preventive measures may include, but are not limited to, one or more of the following: ensuring adequate ventilation
and the removal of any ignition sources.
D Ensure that all housing caps and covers are correctly installed before putting this unit back into service. Failure to do so
could result in personal injury or property damage from fire or explosion.
Instruments Mounted on Tank or Cage
WARNING
For instruments mounted on a tank or displacer cage, release trapped pressure from the tank and lower the liquid level to a
point below the connection. This precaution is necessary to avoid personal injury from contact with the process fluid.
4320
September 2022
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