Fisher® 377 Trip Valve0 pages

Instruction Manual

377 Trip Valve

D200319X012

July 2014

Fisherr 377 Trip Valve
Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Scope of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Educational Services . . . . . . . . . . . . . . . . . . . . . . . . . 2
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Supply Pressure Requirements . . . . . . . . . . . . . . . . . 6
Operating Information . . . . . . . . . . . . . . . . . . . . . . . . . 8
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Principle of Operation . . . . . . . . . . . . . . . . . . . . . . . . . 9
377D Trip Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
377L Trip Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
377U Trip Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Periodic Operational Check . . . . . . . . . . . . . . . . . . . 13
Trip Valve Part Replacement Procedures . . . . . . . . 13
Replacing Diaphragms and Valve Plug Parts . . . . . 13
Replacing Stem/Plug Assembly Parts . . . . . . . . . . . 14
Parts Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Parts Kits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Figure 1. Fisher 377 Trip Valve Mounted on Size 130
585C Actuator

W8435‐1

Introduction
Scope of Manual
This instruction manual provides installation, operation, maintenance, and parts information for the Fisher 377 trip
valve. Refer to separate instruction manuals for information regarding the control valve, actuator, and accessories.
Do not install, operate, or maintain a 377 trip valve without being fully trained and qualified in valve, actuator and
accessory installation, operation, and maintenance. To avoid personal injury or property damage, it is important to
carefully read, understand, and follow all of the contents of this manual, including all safety cautions and warnings. If
you have any questions regarding these instructions contact your Emerson Process Management sales office before
proceeding.

Description
377 pressure‐sensing trip valves, shown in figures 1, 2, and 3, are for control applications where a specific
valve/actuator action is required when supply pressure falls below a specific point. When supply pressure falls below
the trip point, the trip valve cause the actuator to fail up, lock in the last position, or fail down. When the supply
pressure rises above the trip point, the 377 trip valve automatically resets, allowing the system to return to normal
operation. The trip valve can be top‐mounted on a manifold, yoke‐mounted, or bracket‐mounted to match the
application requirements. 377 trip valves are used with all types of piston actuators.

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