Instruction Manual
D200160X012
4195K Controllers
July 2018
12
Pressure Connections
WARNING
To avoid personal injury or property damage resulting from the sudden release of pressure, do not install any system
component where service conditions could exceed the limits given in this manual. Use pressure‐relieving devices as
required by government or accepted industry codes and good engineering practices.
CAUTION
Do not use sealing tape on pneumatic connections. This instrument contains small passages that may become obstructed
by detached sealing tape. Thread sealant paste should be used to seal and lubricate pneumatic threaded connections.
Refer to figure 2‐5 for pressure connection locations. Supply, output, remote set point, external feedback, and vent
connections are 1/4 NPT, internal. Process pressure connections are 1/4 or 1/2 NPT (optional). Use 1/4‐inch or 3/8‐inch
pipe or tubing for supply, output, remote set point, and external feedback connections.
Process Pressure Connection
The connection marked A on the bottom of the case is the process input for all Bourdon tube controllers and those
capsular element controllers used in vacuum pressure applications. The connection marked B is the process input for
capsular element controllers used in positive pressure and compound pressure applications. See figure 2‐5 for the
location of the A and B connections.
When installing process piping, follow accepted practices to ensure accurate transmission of the process pressure to
the controller. Install a three‐valve bypass, shutoff valves, vents, drains, or seal systems as needed in the process
pressure lines. If necessary, install a needle valve in a process pressure sensing line to dampen pulsations.
If the instrument is located such that the adjacent process pressure lines are approximately horizontal, the lines should
slope downward to the instrument for liquid‐filled lines and upward toward the instrument for gas‐filled lines. This
reduces the possibility of air becoming trapped in the sensor with liquid‐filled lines or of condensation becoming
trapped in gas‐filled lines. The recommended slope is 83 millimeters per m (1 inch per foot).
If the controller is being used in conjunction with a control valve to control pipeline pressure, connect the process
pressure line in a straight section of pipe approximately 10 pipe diameters away from the valve and also away from
bends, elbows, and areas of abnormal fluid velocities. For pressure‐reducing service, the process pressure line must be
connected downstream of the control valve. For pressure‐relief service, the process pressure line must be connected
upstream of the control valve.
Supply Pressure Connection
WARNING
Severe personal injury or property damage may occur if the instrument air supply is not clean, dry and oil‐free, 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 Automation Solutions field office and industry
instrument air quality standards for use with corrosive gas or if you are unsure about the proper amount or method of air
filtration or filter maintenance.
