Instruction Manual
D101728X012
3710 and 3720 Positioners
September 2017
20
Supply pressure must not exceed the following limits:
D
For the positioner, do not exceed the maximum pressure rating of 10.3 bar (150 psig).
D
For actuator pressure, refer to the appropriate actuator instruction manual for maximum allowable pressures.
D
For the valve body assembly, do not exceed the maximum allowable torque or thrust of the specific valve.
Output Connections
Use 3/8‐inch tubing between the actuator and positioner.
For diaphragm rotary actuators (single‐action output from the positioner):
Plug OUTPUT A. Connect OUTPUT B to the
diaphragm casing connection.
For piston rotary actuators (double‐action output from the positioner):
To extend the actuator stem with increasing
instrument input signal, connect OUTPUT A to the lower actuator cylinder connection and OUTPUT B to the upper
actuator cylinder connection. To retract the actuator stem with increasing instrument input signal, connect OUTPUT A
to the upper actuator cylinder connection and OUTPUT B to the lower actuator cylinder connection.
Instrument Connection
Use 3/8‐inch tubing to connect the output from the control device to the INSTRUMENT connection on a pneumatic
positioner. For the electro‐pneumatic positioner, refer to the Electrical Connection section.
Vent Opening, Purge Option, and Actuator Vent Connection
WARNING
Personal injury or property damage could result from fire or explosion of the accumulated gas if a flammable gas is used as
the supply pressure medium. Personal injury or property damage could also result from contact with the hazardous gas.
The 3710 positioner/actuator assembly does not form a gas‐tight seal and flammable or hazardous gas could leak from the
assembly. Therefore, if the assembly is enclosed, install a remote vent line from the enclosure. However, a remote vent
pipe from the enclosure alone cannot be relied upon to remove all hazardous gas. Use adequate ventilation and other
necessary safety measures. Vent line piping should comply with local and regional codes and should be as short as possible
with adequate inside diameter and few bends to reduce case pressure buildup.
WARNING
3720 and 3722 do not meet third party approvals for use with natural gas as the supply pressure medium. Use of natural
gas as the supply medium can result in personal injury or property damage from fire or explosion.
