Emerson Fisher 377 User manual

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Fisher™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 sales office or Local Business Partner 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.
Instruction Manual
D200319X012
377 Trip Valve
June 2017

Instruction Manual
D200319X012
377 Trip Valve
June 2017
2
Figure 2. Typical Fisher 377 Trip Valve
W4292-1
Figure 3. Simplified Sectional View of Trip Valve
UPPER
DIAPHRAGM
EXHAUST
PORT
RESTRICTION
PORT A
PORT B
PORT D
PORT E
PLUG
ASSEMBLIES
PORT F PORT C
VALVE
PLUG SPRING
SUPPLY
CONNECTION
LOWER
DIAPHRAGM
W4303‐1
Specifications
Specifications for 377 trip valves are given in table 1.
Educational Services
For information on available courses for 377 trip valves, as well as a variety of other products, contact:
Emerson Automation Solutions
Educational Services - Registration
Phone: [phone] or 1-800-338-8158
E-mail: [email protected]
emerson.com/fishervalvetraining

Instruction Manual
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377 Trip Valve
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Table 1. Specifications
Available Configurations
377 Trip Valve: Includes check valve, but no volume
tank: user configured for locking position. For field
use or replacement.
When supply pressure falls below the trip point,
377D Trip Valve: Fails actuator piston down. Includes
check valve and volume tank.
377L Trip Valve: Locks actuator piston in the last
position.
377U Trip Valve: Fails actuator piston up. Includes
check valve and volume tank.
377CW Trip Valve: Fails fully clockwise to close valve.
Requires check valve and volume tank. Trip valve
moves piston to either up/down position and requires
actuator configuration for actual clockwise
movement.
377CCW Trip Valve: Fails fully counterclockwise to
close valve. Requires check valve and volume tank.
Trip valve moves piston to either up/down position
and requires actuator configuration for actual
counterclockwise movement.
All 377 Trip Valves can be converted to any of the
above fail modes with minor hookup changes
Allowable Supply Pressure for Trip Valve(1)
Maximum: 10.3 bar (150 psig)
Minimum: 3.8 bar (55 psig)
Outlet Pressure
Normal Operation: Pressure from control device
Fail‐Up or Fail‐Down Mode: Maximum volume tank
pressure
Lock‐In‐Last‐Position: Respective cylinder pressure
Trip Point(2)
Adjustable from a minimum of 2.8 bar (40 psig) to a
maximum of 72 percent of supply pressure;
see figure 4
Reset: 12.5 to 33 percent above adjusted trip point
Flow Coefficients (Cv)(3)
Depends on flow path (shown in figure 3) as follows:
Port A to Port B and Port D to Port E: 0.5
Port B to Port C and Port E to Port F: 0.6
Pressure Connections
1/4 NPT internal
Temperature Capabilities(1)
Nitrile Diaphragms and O‐Rings: -40 to 82_C
(-40 to 180_F)
Fluorocarbon Diaphragms and O‐Rings: -18 to 104_C
(0 to 220_F)
Volume Tank Maximum Internal Working Pressure
(for 377D, 377U, 377CW and 377CCW trip valves)
Standard: 10.3 bar (150 psig) for non‐ASME approved
applications. See note on page 7.
ASME Approved Applications: Rated 10.3 bar (150
psig), maximum; 9.3 bar (135 psig), recommended.
See note on page 7.
Hazardous Area Classification
Complies with the requirements of ATEX Group II
Category 2 Gas and Dust
377 SST
Safety Instrumented System Classification
SIL 3 capable - certified by exida Consulting LLC
Mounting
Top‐Mounted: Manifold‐mounted between a Fisher
3570 positioner and 480 actuator (manifolds cannot
be supplied with Fisher 585C, 685, 1061, 1066, and
1069 piston actuators)
Side‐Mounted: Yoke‐mounted or bracket‐mounted
for use with a FIELDVUE™DVC6200, DVC6200f,
DVC6200p, DVC6000 or DVC6000f digital valve
controller
Approximate Weight
Trip Valve
Aluminum: 0.95 kg (2.1 pounds)
SST: 2.31 kg (5.1 pounds)
Mounting Manifold: 0.5 kg (1.2 pounds)
Volume Tank: Varies between 5.4 and 363 kg (12 and
800 pounds) depending on size
-continued-

Instruction Manual
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377 Trip Valve
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Table 1. Specifications (continued)
Declaration of SEP
Fisher Controls International LLC declares this
product to be in compliance with Article 4 paragraph
3 of the PED Directive 2014/68/EU. It was designed
and manufactured in accordance with Sound
Engineering Practice (SEP) and cannot bear the CE
marking related to PED compliance.
However, the product may bear the CE marking to
indicate compliance with other applicable European
Community Directives.
1. The pressure/temperature limits in this document and any applicable standard or code limitation should not be exceeded.
2. If the trip point is not specified, the trip point is factory set at 72 percent of supply pressure or 2.8 bar (40 psig), whichever is higher.
3. Values represent nominal Cvmeasures for each port pair using a trip valve/actuator combination.
Figure 4. Maximum Trip Point Settings
10.3
45 67 8 910
110
100
90
80
70
60
50
40
7.6
7
6
5
4
3
1501401301201101009080706055
NOTES:
1 TRIP POINT MAY BE SET TO ANY VALUE BETWEEN 2.8 BAR (40 PSIG) AND THE MAXIMUM TRIP POINT LINE.
2 RESET OCCURS AT 12.5 TO 33 PERCENT ABOVE ADJUSTED TRIP POINT.
TRIP POINT, PSIG TRIP POINT, BAR
SUPPLY PRESSURE, BAR
SUPPLY PRESSURE, PSIG
A2779‐2
MAXIMUM TRIP POINT
SETTING TO ENSURE
RESET
2
1
Installation
WARNING
Avoid personal injury from sudden release of process pressure. Before mounting the controller:
D Always wear protective clothing, gloves, and eyewear when performing any installation operations to avoid personal
injury.
D Overpressuring any system component could result in personal injury or property damage due to fire and explosion
caused by venting or leakage of the supply medium. To avoid such injury or damage, provide suitable pressure‐relief or
pressure‐limiting devices if the supply pressure is capable of exceeding the maximum allowable pressure of the system
component.
D Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
D If installing into an existing application, also refer to the WARNING at the beginning of the Maintenance section in this
instruction manual.

Instruction Manual
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377 Trip Valve
June 2017
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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.
The 377 trip valve is normally ordered as part of a control valve assembly. Follow the procedure in the appropriate
valve body and actuator instruction manual when installing the control valve in the piping.
If the 377 trip valve is shipped separately from the control valve assembly, the installation procedure depends upon
the type of actuator and accessory equipment required for the individual control valve system. Install any accessory
equipment in the control valve system so that the overall functioning of the specified trip valve pressure line
connections is not disrupted. Figures 7, 8, and 9 are schematics showing the pressure line connections for each of the
three possible fail‐mode configurations of the trip valve.
CAUTION
377 trip valves are leak tested to ensure that the intended actuator fail mode is maintained upon loss of supply pressure.
Control system accessories, such as volume boosters with hard seats, compromise the integrity of the entire system due to
leakage. Therefore, using control system accessories, such as volume boosters, between the trip valve and the actuator is
not recommended. If this cannot be avoided and a volume booster is required, a volume booster designed for tight shutoff,
such as the Fisher 2625, provides a higher probability of control system integrity. Refer to figures 5 and 6 for proper
installation of 377 trip valves with 2625 volume boosters.
Figure 5. Fisher 2625 Volume Booster used with 377U or 377D Trip Valve
2625
1/2 O.D. TUBING
PISTON
ACTUATOR
POSITIONER
3/4 NPT
CHECK VALVE
3/4 NPT OR
1/2 NPT PIPING SUPPLY
377U
3/8 O.D.
TUBING
TYPICAL
1
NOTES:
1 THE HOOK UP OF PORT C AND F ARE REVERSED FOR 377D.
2. 3/4 NPT CHECK VALVE, 1/2 OR 3/4 NPT PIPING, AND 1/2‐INCH (OUTSIDE DIAMETER) COIL TUBING FOR THE VOLUME TANK ARE REQUIRED.
3. THE SUPPLY PRESSURE REGULATOR SPECIFIED MUST HAVE ADEQUATE CAPACITY FOR 2625 BOOSTERS. ALSO, IF THE 2625 BOOSTER IS TO BE NIPPLE MOUNTED, THE BOOSTER MUST BE
MOUNTED TO A 1/2 NPT OR LARGER CYLINDER CONNECTION. SOME SMALLER CYLINDERS CANNOT BE TAPPED THIS LARGE; CONTACT YOUR EMERSON SALES OFFICE FOR AVAILABILITY ON
SPECIFIC TYPES AND SIZES.
3/4 NPT OR
1/2 NPT PIPING
E1570
1/2 O.D. COIL VOLUME
TANK TUBING
VOLUME
TANK
VENT
FISHER i2P-100/
67CFR
INPUT SIGNAL

Instruction Manual
D200319X012
377 Trip Valve
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Figure 6. Fisher 2625 Volume Booster used with 377L Trip Valve
2625
1/2 O.D. TUBING
PISTON
ACTUATOR
POSITIONER
3/4 NPT
CHECK VALVE
3/4 NPT OR
1/2 NPT PIPING SUPPLY
377L
i2P-100/67CFR
3/8 O.D.
TUBING
TYPICAL
NOTES:
1. 3/4 NPT CHECK VALVE AND 1/2 OR 3/4 NPT PIPING ARE REQUIRED.
2. THE SUPPLY PRESSURE REGULATOR SPECIFIED MUST HAVE ADEQUATE CAPACITY FOR 2625 BOOSTERS. ALSO, IF THE 2625 BOOSTER IS TO BE NIPPLE MOUNTED, THE BOOSTER MUST
BE MOUNTED TO A 1/2 NPT OR LARGER CYLINDER CONNECTION. SOME SMALLER CYLINDERS CANNOT BE TAPPED THIS LARGE; CONTACT YOUR EMERSON SALES OFFICE FOR AVAILABILITY
ON SPECIFIC TYPES AND SIZES.
3/4 NPT OR
1/2 NPT PIPING
E1571
INPUT SIGNAL
Supply Pressure Requirements
WARNING
Severe personal injury or property damage may occur if the instrument air supply is not clean, dry, and oil free. While use
and regular maintenance of 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 instrument industry 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.
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.

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A supply regulator, if used, must have a flow capacity greater than the required combined capacity of the trip valve and
actuator. In order to ensure proper selection of a supply regulator, be sure the Cvvalue of the regulator is greater than
the appropriate flow path Cvvalue listed in table 1 for the trip valve. A regulator with insufficient capacity may allow
supply pressure to droop, which can cause the trip valve to trip again and begin a trip‐reset cycle. An example of an
appropriate supply regulator to use with a 377 trip valve is a 64 regulator; its capacity is usually great enough to meet
the demands of most trip valve/actuator combinations. Determine the requirements of your trip valve/actuator
combination for proper selection of a supply regulator.
Note
During normal operation, an adequately sized supply regulator maintains a greater supply pressure than the pressure demand of
the trip valve and control devices. However, if the normal actuator piston position is not relatively close to the actuator piston fail
position during startup, or during the restoration of supply pressure, the regulator supply pressure may droop and cause the trip
valve to trip again and begin a trip‐reset cycle. To prevent this, perform the following steps:
1. Adjust the instrument (control device) pressure to position the actuator piston as it is positioned in the fail mode.
2. Restore the supply pressure to the normal operating range.
3. Manually reset the instrument pressure for normal operation.
WARNING
If a flammable or hazardous gas is used as the supply pressure medium, personal injury or property damage could result
from fire or explosion of accumulated gas or from contact with hazardous gas. The positioner/ actuator assembly does not
form a gas‐tight seal, and when the assembly is enclosed, a remote vent line, adequate ventilation, and necessary safety
measures should be used. However, a remote vent pipe alone cannot be relied upon to remove all hazardous gas. 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.
Note
To ensure trip system integrity upon loss of supply pressure, a 377D or 377U trip system requires a volume tank and check valve as
shown in figures 7 and 9.
State and local regulations may require the use of ASME approved volume tanks. Determine requirements and applicable
regulations for proper volume tank selection.
For ASME approved applications, the volume tank is rated at 10.3 bar (150 psig) internal working pressure, and has a safety valve
with a 10.3 bar (150 psig) set pressure mounted on the volume tank for pressure relief. Avoid supply pressure too near the safety
valve set pressure. To ensure safety valve seat tightness and longevity, the recommended maximum supply pressure is 9.3 bar
(135 psig).
Standard volume tanks supplied in Europe must conform to Directive 2009/105/EC for simple pressure vessels. The maximum
pressure rating is stated on the tank.
For standard applications (not ASME approved), a DOT tank is used. This tank is rated at 14.5 bar (240 psig) in LP service. When
used with air, the rating should be considered to be 10.3 bar (150 psig), consistent with the maximum pressure allowed for the
377 trip valve.
1. Before installing the trip valve, inspect it to be sure it is free of any foreign material.
2. Be sure all connecting tubing is free of foreign material.
3. Use acceptable piping practices when installing the trip valve. Coat all external threaded connections with a pipe
compound.

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CAUTION
To avoid damage and possible operational impairment to the trip valve, be careful not to get excessive pipe compound on
the connections. Excess compound could result in improper pilot and cylinder valve operation.
CAUTION
To ensure the integrity of control systems utilizing a 2625 volume booster in conjunction with a 377 trip valve, apply supply
pressure to the volume booster and to the volume tank (volume tank not required on 377L trip valve) through a check
valve. Failure to install the check valve properly will allow the cylinder pressure to bleed back through the open volume
booster supply port upon loss of supply pressure. The actuator may not fail as intended.
WARNING
Personal injury or property damage could result from bursting of parts due to temperature fluctuations or extreme heat. If
temperature fluctuations or extreme heat cannot be avoided, use a relief valve to protect the volume tank.
4. Read the following information before making pressure connections:
a. Trip valve port A must receive the operating pressure that is intended for the top of the actuator cylinder.
Depending on the actuator type and accessories being used, this operating pressure will be from a valve
positioner or switching solenoid.
b. Trip valve port B must provide operating pressure to the top of the actuator cylinder. Depending on the actuator
type and accessories being used, connect this port to the manifold assembly, to the top of the cylinder, or to the
cylinder connection on the hydraulic snubber (if one is used).
c. Trip valve port C must provide a fail‐mode outlet for the operating pressure to or from the top of the actuator
cylinder. For the fail‐down mode, connect this port to the volume tank. For the fail‐up mode, vent this port to
atmosphere. For the lock‐in‐last‐position mode, plug this port.
d. Trip valve port D must receive the operating pressure that is intended for the bottom of the actuator cylinder.
Depending on the actuator type and accessories being used, this operating pressure will be from a valve
positioner or switching solenoid.
e. Trip valve port E must provide operating pressure to the bottom of the actuator cylinder. Always connect this
port to the bottom of the actuator cylinder.
f. Trip valve port F must provide a fail‐mode outlet for the operating pressure to or from the bottom of the actuator
cylinder. For the fail‐down mode, vent this port to atmosphere. For the fail‐up mode, connect this port to the
volume tank. For the lock‐in‐last‐position mode, plug this port.
Operating Information
Calibration
This calibration procedure assumes that the trip valve is mounted on the actuator (or other device) and that all piping
and the appropriate volume tank (if necessary ) are installed. All key numbers refer to figure 10. For the appropriate
fail‐mode schematic, see figure 7, 8, or 9.

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WARNING
The following procedure requires taking the trip valve out of service. To avoid personal injury and property damage by an
uncontrolled process medium, provide some temporary means of control of the process medium while the trip valve is out
of service.
1. Remove the adjusting screw cap (key 1).
2. Loosen the hex nut (key 3), and turn the set screw (key 2) counterclockwise until all loading is removed from the
spring (key 6).
3. Connect an adequately sized gauge for the supply pressure reading to the supply line. To make the fail action more
visible, adjust the control device signal so that actuator stem movement is visible when the trip valve is actuated.
4. For the lock‐in‐last‐position mode, remove the plugs from ports C and F.
5. Set the supply pressure at the required trip point pressure (refer to table 1 for the trip point limits).
Note
For proper calibration, completely back out the set screw (key 2) until there is no spring compression. Then, set the trip point by
turning the set screw clockwise to compress the spring.
6. Slowly turn the set screw clockwise to compress the spring until the trip valve trips. When the trip valve trips in the
fail‐up or fail‐down mode, the actuator stem moves to the appropriate position. In the lock‐in‐last‐position mode,
the actuator stem does not move, however, air will be heard escaping from ports C and F. This is because pressure is
being released from both sides of the actuator cylinder.
7. Tighten the hex nut (key 3), and install the adjusting screw cap (key 1).
8. For the lock‐in‐last‐position mode, reinstall the plugs in ports C and F.
9. Reset the control device for normal operation.
Principle of Operation
377D Trip Valve
Figure 7 illustrates trip valve operation in the fail‐down mode.
In normal operation, supply pressure loads the upper diaphragm of the trip valve. The valve plug spring keeps the
exhaust port closed. Supply pressure also loads the lower diaphragm through the restriction, causing the plug
assemblies to move down and isolate ports C and F while connecting port A to B and port D to E. Normal actuator
control pressure from the control device is applied to the top of the cylinder through ports A and B and to the bottom
of the cylinder through ports D and E. A volume tank is charged to the maximum supply pressure through a check
valve. The check valve maintains maximum supply pressure in the volume tank if the supply pressure drops.
When the supply pressure falls below the trip point, the exhaust port opens venting the supply pressure that is loading
the lower diaphragm. This causes the upper ports of the plug assemblies to close and disconnect normal pressure from
the control device to the actuator.
Volume tank pressure is then applied through ports C and B to the top of the actuator cylinder, while pressure in the
bottom of the actuator cylinder is vented through ports E and F. The pressure imbalance created forces the actuator
piston down.

Instruction Manual
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377 Trip Valve
June 2017
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When supply pressure is restored, it again loads the upper and lower diaphragms causing the trip valve to reset. The
exhaust port closes, the upper ports of the plug assemblies open, and the lower ports close. Normal actuator control
pressure from the control device is restored through ports A and B and ports D and E. The check valve opens and
recharges the volume tank to the maximum supply pressure.
GE08412‐A
A6905‐1
Figure 7. Fisher 377D Trip Valve Shown in Tripped Condition
SPRING
VALVE PLUG
UPPER
DIAPHRAGM
EXHAUST
PORT
SUPPLY
PRESSURE
LOWER
DIAPHRAGM
PORT D
PORT E
LOWER
PORTS
PORT F PORT C
PLUG
ASSEMBLIES
UPPER PORTS
PORT B
PORT A
VENT
MAIN SPRING
ACTUATOR
CONTROL
DEVICE
CHECK
VALVE
VOLUME
TANK
SUPPLY PRESSURE
CONTROL PRESSURE TO TOP OF CYLINDER (BLOCKED)
CONTROL PRESSURE TO TOP BOTTOM OF CYLINDER (BLOCKED)
PRESSURE TO TOP OF CYLINDER (FROM VOLUME TANK)
PRESSURE FROM BOTTOM OF CYLINDER (VENTING)
LOWER DIAPHRAGM LOADING PRESSURE (BEING VENTED)
DVC6200
377L Trip Valve
Figure 8 illustrates trip valve operation in the lock‐in‐last‐position mode.
When supply pressure falls below the trip point, the exhaust port opens venting supply pressure from the lower
diaphragm. This causes the upper ports of the plug assemblies to close and the lower ports to open. Because ports C
and F are plugged, no pressure change occurs on either side of the actuator piston and the piston is pressure‐locked in
position. No volume tank is necessary in this mode.
When supply pressure is restored, the plug assemblies move back into the normal operating position. Supply pressure
from the control device is applied to the actuator through ports A and B and ports D and E.