2680 Controller Instruction Manual

Instruction Manual Form 5372 August 1999

2680-268T Series

2680-268T Series Liquid Level Controllers Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 Scope of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Installation

................................ 3 Welding Information . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Attaching Vertical Displacer . . . . . . . . . . . . . . . . . . . 4 Attaching Horizonal Displacer . . . . . . . . . . . . . . . . . . 4 Screwed Connections . . . . . . . . . . . . . . . . . . . . . . . . 4 Flanged Connections . . . . . . . . . . . . . . . . . . . . . . . . . 4 Pressure Connections . . . . . . . . . . . . . . . . . . . . . . . . 5 Vent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Type 2680E Electrical Connection . . . . . . . . . . . . . . 5

Changing Controller Action or Mode

.. 5 Type 2680 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Type 2680A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Type 2680E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Proportional Band Adjustment

......... 6 Preliminary Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Type 2680 Direct-Acting Throttling Controllers . . . 7 Type 2680 Reverse-Acting Throttling Controllers . 7 Type 2680 Direct-Acting On-Off and Type 2680A Direct-Acting Snap-Acting Controllers . . . . . . . . 7 Type 2680 Reverse-Acting On-Off and Type 2680A Reverse-Acting Snap-Acting Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Maintenance

Parts Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . .

Parts Kits

12

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Parts List

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Introduction

................... 8

.............................. 9 Removing the Controller From the Sensor . . . . . . . 9 Replacing the Sensor O-Rings . . . . . . . . . . . . . . . 10 Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Replacing the Controller Relay . . . . . . . . . . . . . . . 10 Replacing the Controller Supply Filter . . . . . . . . . 10 Removing the Switch From Type 2680E Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Scope of Manual This instruction manual includes installation, adjustment, maintenance, and parts ordering information for 2680 Series liquid level controllers and Type 268T displacer-type sensors.

Only personnel qualified through training or experience should install, operate and maintain this controller. If there are any questions regarding the instructions in this manual, contact your Fisher Controls sales office or sales representative before proceeding.

D102172X012

Principle of Operation

W6159 / IL

Figure 1. 2680 Series Controller with Type 268T Sensor

2680-268T Series Table 1. Specifications

Available Configurations Controllers: See table 2 Type 268T Sensor: Displacer-type liquid level sensor for mounting to side of tank. Displacer travel is transmitted to controller by pivotal movement of displacer rod Input Signal(1) Type: Liquid level or liquid-to-liquid interface Level Change Required for Full Change in Output Signal in 1.0 Specific Gravity Liquid, with 20 Psig (1.4 Bar) Supply, Direct Action, and Standard 1-7/8 X 12-Inch (48 x 305 mm) Vertical Displacer with Standard Lever Arm Length: Type

2680 2680A

Control Mode

Maximum Proportional Band Level Change, Inches (mm)

Minimum Proportional Band Level Change, Inches (mm)

Throttling

4 (102)

12 (305)

On-off

5 (127)

12 (305)

Snap-acting

0.5 (13)

0.8 (20)

Supply Pressure Requirements Type 2680 Controller On-Off: Any desired pressure between 20 and 50 psig (1.4 and 3.4 bar).

Throttling: 20 psig for 3 to 15 psig output signal (1.4 bar for 0.2 to 1.0 bar output signal) and 35 psig for 6 to 30 psig output signal (2.4 bar for 0.4 to 2.0 bar output signal) Type 2680A Controller: Any desired pressure between 20 and 50 psig (1.4 and 5.2 bar) direct, and 20 and 35 psig (1.4 bar and 2.4 bar) reverse Do not use supply pressure below 20 psig (1.4 bar) Steady-State Air Consumption(4) Type 2680: ≤1.0 scfh (0.03 normal m3/hr) at 20 psig (1.4 bar) supply pressure Type 2680A: ≤1.0 scfh (0.03 normal m3/hr) at 20 psig (1.4 bar) supply pressure or ≤1.5 scfh (0.04 normal m3/hr)at 35 psig (2.4 bar) supply pressure in tripped condition; air consumption increases during trip Nominal Displacer Sizes

Minimum Specific Gravity(2) Type 2680: Minimum specific gravity, or specific gravity differential for interface applications, is 0.4 Type 2680A: Minimum specific gravity, or specific gravity differential for interface applications, is 0.1 Type 2680E: Minimum specific gravity, or specific gravity differential for interface applications, is 0.3 Output Signal(1) Type 2680 and 2680A: Pneumatic on-off or proportional pressure signal Ranges: On-Off: 0 (off) or full supply pressure (on) Throttling: 3 to 15 psig (0.2 to 1.0 bar) or 6 to 30 psig (0.4 to 2.0 bar) Action: Field-reversible between direct (increasing level increases output signal) and reverse (increasing level decreases output signal) Type 2680E: Same as signal to switch (see electrical rating) Electrical Rating Type 2680E: Single-pole, double-throw (SPDT) or double-pole, double throw (DPDT) switch: 11 amperes, 1/4 horsepower at 125/250 volts ac; 5 amperes resistive, 3 amperes inductive at 28 volts dc; 2 amperes resistive, 1 ampere inductive at 48 volts dc

1-7/8 x 12 inches, 33 in3 (48 x 305 mm, 541 cm3) 2-3/4 x 8 inches, 47.5 in3 (70 x 203 mm, 778 cm3) Maximum Displacer Working Pressure(3) Polyvinylchloride (PVC) Displacer: 3750 psig (258.5 bar) Stainless Steel Displacer: 1440 psig (99 bar) cold working pressure. 1330 psig (92 bar) at 400 F (204 C) Maximum Displacer Insertion Length Horizontal Displacers: 1-7/8 x 12-inch PVC, standard lever arm length plus one 6-inch extension 1-7/8 x 12-inch SST and all standard 2-3/4 x 8-inch, standard lever arm length Vertical Displacers: All standard 1-7/8 x 12-inch, standard lever arm length plus one 6-inch extension All standard 2-3/4 x 8-inch, standard lever arm length Maximum Sensor Working Pressure(3) See table 3 Operative Ambient Temperature Limits(1)(3) Controller: –20 to 160 F (–29 to 71 C)

–continued–

2

2680-268T Series Table 1. Specifications (continued)

Process Temperature Limits(1)(3) PVC Displacer and Highly Saturated Nitrile O-Rings: –20 to 175 F (–29 to 79 C) Stainless Steel Displacer and Highly Saturated Nitrile O-Rings: –20 to 200 F (–29 to 93 C) Stainless Steel Displacer and Fluoroelastomer O-Rings: 0 to 400 F (–18 to 204 C) Standard Supply, and Output Pressure Gauge Indications Triple scale gauges in 0 to 60 psig/0 to 0.4 MPa/0 to 4.0 bar Hazardous Area Classification The 2680 Series controllers have no hazardous area approvals. For approvals on the electrical 1.

2.

3.

4.

switch component of the Type 2680E, see Hazardous Area Classifications bulletin

Controller Connections Supply: 1/4 in. NPT female located on the bottom of the case Output: 1/4 in. NPT female located on the top of the case Case Vent: 1/4 in. NPT female with vent screen assembly located on the back of the case

Type 2680E Electrical Connection Size 1/2-inch (12.7 mm) NPT male

This term is defined in ISA Standard S51.1.

Depends on float rod/displacer orientation and length. Contact your Fisher Controls sales office or sales representative for further information.

The pressure and temperature limits in this document and any applicable code limitations should not be exceeded.

Scfh—Standard cubic feet per hour (60 F and 14.7 psia). Normal m3/hr—Normal cubic meters per hour (0 C and 1.01325 bar, absolute)

Table 2. Available Controller Configurations TYPE NUMBER

CONTROL MODE On off On-off

2680 Throttling 2680A and 2680E

Snap acting

Table 3. Sensor Connection Types and Maximum Working Pressure

CONTROL ACTION Direct Reverse

CONNECTION SIZE

CONNECTION MAXIMUM WORKING PRESSURE TYPE(1)

Direct Screwed (NPT)

Reverse Direct Reverse 2-inch

Description These rugged 2680 Series liquid level controllers use a Type 268T displacer type sensor (see figure 1) to detect liquid level or the interface of two liquids of different specific gravities.

The Type 2680 and 2680A low-bleed controllers use a single four-mode relay to provide the applicable control and action. The device delivers a pneumatic output signal to a control valve.

The Type 2680E electrical controller is similar except it opens and closes an electrical switch in response to rising or falling levels.

Specifications Specifications for these controllers and sensors are listed in table 1.

Slip-on flange

Sch X BWE Sch 80 BWE Sch 40 BWE

Consistent with Class 1500 pressure temperature ratings per ASME B16.34 up to maximum pressure of 3750 psig (258.5 bar) Consistent with pressure temperature ratings of coupling used per ASME B16.34 up to maximum pressure of 3750 psig (258.5 bar) Consistent with Class 1500 pressure temperature ratings per ASME B16.34 up to a maximum pressure of 3750psig (258.5 bar)

1. All connection types available in NACE materials.

Installation WARNING To avoid personal injury or property damage caused by the sudden release of process fluid, be certain the service conditions do not exceed the sensor pressure limits listed in table 3. Use pressure-limiting or pressure-relieving devices to prevent service conditions from exceeding these limits.

CAUTION If the Type 2680-268T level controller is installed on a vessel that is to be

3

2680-268T Series spring, replace the spacer (key 5) and hex nut (key 6) on the displacer rod.

CORRECT CONTROLLER MOUNTING HOLE ORIENTATION WHEN MOUNTED ON VESSEL A6639 / IL

Figure 2. Sensor Orientation for Flange Welding

shipped to a different location (e.g. skid mounted units), remove the displacer and displacer rod extensions before shipment. Failure to do so could result in damage to the displacer rod due to vibration and impact loading during shipment. After the vessel is installed at its final location, reassemble the displacer and displacer rod extension.

1. Be sure there are no obstructions inside the tank that will interfere with displacer installation or operation.

2. Provide the appropriate connection in the tank wall to match the sensor connection. Locate the tank wall connection such that the displacer will be at the desired control level.

3. If necessary, reinforce the tank connection so that it will be capable of supporting the sensor and controller.

Welding Information When installed, the controller case must be plumb and level to allow proper operation. To ensure proper positioning, observe the following before welding a flange to the Type 268T sensor. Refer to figure 7 for key number locations.

1. For proper operation, the arms of the sensor pivot base (key 12) and pivot body (key 11), shown in figure 7, must be horizontal when the sensor is mounted on the tank. Mounting the sensor connection on the vessel so that the controller mounting hole pattern is as shown in figure 2 assures that these arms are horizontal.

2. Before welding on the sensor connection (key 4), the pivot base (key 12) (see figure 7) must be removed to prevent subjecting the O-rings and anti-extrusion rings to excessive heat. To remove the pivot base, unscrew the hex nut (key 6) and remove the spacer (key 5) and spring (key 7). After removing the

4

From the displacer end, pull the displacer rod away from the sensor connection (key 4) to pull the pivot base (key 12) loose from the sensor connection. Remove the hex nut (key 6) to permit removing the displacer rod, pivot base, pivot body, and spacer from the sensor connection.

3. Place a shield in the bore of the sensor connection (key 4) to prevent weld splatter from getting into the pivot base and O-ring areas.

4. Before welding the welded-on flange to the sensor connection (key 4), be sure that the sensor connection is positioned so that the controller mounting hole pattern will be as shown in figure 2 when the flange is bolted to the vessel.

Attaching a Vertical Displacer Refer to figure 7 for part locations.

1. Thread jam nut (key 2) all the way onto the threaded portion of the universal joint assembly (key 8).

2. Thread the displacer (key 1) all the way onto the threaded portion of the universal joint assembly.

3. Tighten the jam nut (key 2) against the displacer (key 1).

Attaching a Horizontal Displacer Refer to figure 7 for part locations. Thread the displacer (key 1) all the way onto the displacer rod (key 3) or extension (key 20).

Screwed Connections Insert the displacer end of the controller-sensor assembly into the tank connection, and screw the sensor threads into the tank connection. Tighten sufficiently to seal the threads. Make sure that the controller case is level.

Flanged Connections Perform the steps listed below. Refer to figure 7 for key number locations.

1. Orient the controller so that the case is level.

CAUTION Do not pick up the controller/sensor by lifting the displacer rod (key 3). This action could place excessive stress on the displacer rod and cause the unit to malfunction.

2680-268T Series Table 4. Type 2680E Wiring Codes Wire Color Red Brown Blue Green Black Yellow Purple

SPDT

DPDT Switch 1

Normally Closed Common Normally Open Ground

Normally Closed Common Normally Open Ground

Vent

DPDT Switch 2

WARNING Ground Normally Closed Common Normally Open

2. Install a suitable flange gasket.

3. Insert the displacer end of the sensor into the tank connection. Position the sensor flange so it can be bolted to the tank flange.

4. Complete the sensor flange to tank flange connection.

Pressure Connections

WARNING Personal injury or property damage may result from an uncontrolled process if the supply medium is not clean, dry, oil-free, or non-corrosive gas. Industry instrument air quality standards describe acceptable dirt, oil, and moisture content. Due to the variability in nature of the problems these influences can have on pneumatic equipment, Fisher Controls has no technical basis to recommend the level of filtration equipment required to prevent performance degradation of pneumatic equipment. A filter or filter regulator capable of removing particles 40 microns in diameter should suffice for most applications. Use of suitable filtration equipment and the establishment of a maintenance cycle to monitor its operation is recommended.

1. Provide a source of clean, dry air that meets the requirements of ISA Standard S7.3 as the operating medium. Refer to table 1 to determine supply pressure.

If a flammable, toxic, corrosive, or reactive gas is to be used as the supply pressure medium, personal injury or property damage could result from fire or explosion of accumulated gas or from contact with toxic, corrosive, or reactive gas. The controller/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. 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.

The vent opening or the end of the remote vent pipe, if one is required, must be protected against the entrance of all foreign matter that could plug the vent.

Use 1/2-inch (13 mm) diameter pipe for the remote vent pipe. Check the vent periodically to be certain it is free of any obstructions.

Type 2680E Electrical Connection For standard action, connect electrical wires as shown in table 4. To reverse the action, refer to table 4 and reverse wiring for normally open (NO) switches and normally closed (NC) switches.

Changing Controller Action or Mode WARNING To avoid personal injury caused by a sudden release of pressure, shut off the supply pressure and bleed pressure from the supply lines before performing any procedure in this section.

Type 2680 2. Connect the supply pressure to the 1/4-inch NPT female connection on the bottom of the controller case.

3. Connect the output signal line to the equipment being operated and to the 1/4-inch NPT output connection on the top of the controller case.

The action of a Type 2680 controller may be changed between either direct or reverse, and the control mode may be changed between either on-off or throttling.

Refer to figure 3. Loosen the four switch retention screws on the relay. Move the switches to the control

5

2680-268T Series SWITCH RETENTION SCREWS 1

SWITCH RETENTION SCREWS 1

DIRECT ACTION THROTTLING CONTROL MODE

DIRECT ACTION ON OFF CONTROL MODE

REVERSE ACTION THROTTLING CONTROL MODE

REVERSE ACTION ON OFF CONTROL MODE

NOTE: ALL FOUR SWITCH RETENTION SCREWS SHOWN ONLY ON THIS VIEW. 1 B2339 / IL

OTHER VIEWS SHOW ONLY TWO SWITCH RETENTION SCREWS IN ORDER TO ILLUSTRATE THE SWITCH CONFIGURATION.

Figure 3. Type 2680 Controller Switch Positions for Changing Action and Control Mode

action and control mode required by the application.

Tighten the four switch retention screws.

Proportional Band Adjustment

Type 2680A

Except where indicated, key numbers referenced in the following procedures are shown in figure 8. The span levers and other proportional band information are shown in figure 5.

The action of a Type 2680A controller may be changed between either direct or reverse. The control mode is always snap acting.

Preliminary Checks

Refer to figure 4. Loosen the four switch retention screws on the relay. Move the switches to the control action required by the application. Tighten the four switch retention screws.

Type 2680E For standard action, connect electrical wires as shown in table 4.

To reverse the action, refer to table 4 and reverse wiring for normally open (NO) switches and normally closed (NC) switches.

6

1. Check the supply pressure gauge (key 10) to be certain that the supply pressure is at the desired value. Adjust the supply pressure as required.

2. Adjust the displacer rod to the horizontal position with the spring adjustment (key 4).

3. Bounce the end of the displacer rod (key 3, figure 7) up and down to check that the sensor is operating freely.

4. Place the span adjuster (key 9) at the desired position (see figure 5).

5. Check figures 3 and 4 for correct control action and control mode.

2680-268T Series

SWITCH RETENTION SCREWS

SWITCH RETENTION SCREWS

DIRECT ACTION

REVERSE ACTION

NOTE: ALL FOUR SWITCH RETENTION SCREWS SHOWN ONLY ON THIS VIEW. 1 B2340 / IL

OTHER VIEWS SHOW ONLY TWO SWITCH RETENTION SCREWS IN ORDER TO ILLUSTRATE THE SWITCH CONFIGURATION.

Figure 4. Type 2680A Controller Switch Positions for Changing Action

6. Adjust the relay adjustment screw (key 51, Type 2680) or the valve assembly (key 53, Type 2680A) so that the gap between the span levers (see figure 5) is equal when lever A is contacting the displacer rod.

Type 2680 Direct-Acting Throttling Controllers 1. Make certain the Preliminary Checks procedure at the start of this section has been completed.

2. Lower the liquid level so that it is below the bottom of the displacer or at the lowest desired operating point on the displacer. For interface applications, completely cover the displacer with the lighter fluid. The heavier fluid should be below the bottom of the displacer or at the lowest desired operating point on the displacer.

3. Adjust the spring adjustment (key 4) until the output pressure is 1 to 2 psig for a 3 to 15 psig output range, or 2 to 4 psig for a 6 to 30 psig output range.

3. Adjust the spring adjustment (key 4) until the output is 16 to 17 psig for a 3 to 15 psig output range, or 31 to 34 psig for a 6 to 30 psig output range.

Type 2680 Direct-Acting On-Off and Type 2680A Direct-Acting Snap Acting Controllers 1. Make certain the Preliminary Checks procedure at the start of this section has been completed.

2. Lower the liquid level so that it is below the bottom of the displacer or at the lowest desired operating point on the displacer. For interface applications, completely cover the displacer with the lighter fluid. The heavier fluid should be below the bottom of the displacer or at the lowest desired operating point on the displacer.

3. Adjust the spring adjustment (key 4) until the output pressure is at full supply pressure.

4. Readjust the spring adjustment (key 4) until the output pressure goes to zero psig.

Type 2680 Reverse-Acting Throttling Controllers

Type 2680 Reverse-Acting On-Off and Type 2680A Reverse-Acting Snap Acting Controllers

1. Make certain the Preliminary Checks procedure at the start of this section has been completed.

1. Make certain the Preliminary Checks procedure at the start of this section has been completed.

2. Lower the liquid level so that it is below the bottom of the displacer or at the lowest desired operating point on the displacer. For interface applications, completely cover the displacer with the lighter fluid. The heavier fluid should be below the bottom of the displacer or at the lowest desired operating point on the displacer.

2. Lower the liquid level so that it is below the bottom of the displacer or at the lowest desired operating point on the displacer. For interface applications, completely cover the displacer with the lighter fluid. The heavier fluid should be below the bottom of the displacer or at the lowest desired operating point on the displacer.

7

2680-268T Series LEVER A SPAN LEVER GAP

LEVER B

MOST SENSITIVE POSITION FOR TYPE 2680 CONTROLLER. LEAST SENSITIVE POSITION FOR TYPE 2680A CONTROLLER LEVER A CONTACTING THE DISPLACER ROD

LEAST SENSITIVE POSITION FOR TYPE 2680 CONTROLLER. MOST SENSITIVE POSITION FOR TYPE 2680A CONTROLLER 42B2949-D C0752-3 / IL

Figure 5. Proportional Band Adjustments

3. Adjust the spring adjustment (key 4) until the output pressure goes to zero psig.

4. Readjust the spring adjustment (key 4) until the output pressure goes to full supply pressure.

Principle of Operation The operation of the Type 2680 and 2680A controllers in combination with the Type 268T sensor is based on Archimedes Principle, which states that a body immersed in a liquid will be buoyed up by a force equal to the weight of the liquid displaced. The buoyant force

8

and resultant movement of the displacer in the liquid is transmitted to the controller which delivers a pneumatic signal to a control valve.

Figure 6 shows a simple schematic of the controller and sensor. In its normal position, the counterclockwise moment due to the weight of the displacer about pivot point O is balanced by the clockwise zero spring moment and the counterclockwise relay zero force moment applied through lever A to the displacer rod.

The weight of the displacer decreases when the liquid level increases and the subsequent buoyant force increases causing a force imbalance between the zero spring, relay, and displacer forces. This force imbalance is transmitted to the relay by levers A and B. The

2680-268T Series LEVER B DISPLACER ROD PROPORTIONAL BAND ADJUSTMENT

RELAY

PIVOT POINT O

ZERO SPRING LEVER A

DISPLACER

A5592 / IL

Figure 6. Operational Schematic

relay compensates for the force imbalance by converting it to a pressure output to a control valve and bringing the forces back into equilibrium.

For throttling control, the relay pressure output will be proportional to the buoyant force. For on-off control, the relay pressure output will be either zero or equal to the supply pressure over the range of liquid level change. The liquid level change required to fully operate the relay is adjusted by sliding the proportional band adjustment along lever A to vary the lever ratio between levers A and B. With reverse-acting proportional control, the principle of operation remains the same as that for direct action; however, the controller delivers an increasing pneumatic signal to the control valve when the liquid level falls.

Operation of the Type 2680E is similar, except rising or falling levels opens or closes the electrical switch.

al tolerances, etc.), use only replacement parts manufactured by Fisher.

WARNING To avoid personal injury or property damage caused by the release of pressure or process fluid, observe the following before starting maintenance: Provide some temporary means of control for the process before taking the controller out of service.

Provide a means of containing the process fluid before removing any measurement devices from the process.

Vent any trapped process pressure.

Shut off electrical power to Type 2680E.

Removing the Controller From the Sensor

Maintenance Parts are subject to normal wear and must be inspected periodically and replaced as necessary. The frequency of parts inspection and replacement depends upon the severity of service conditions. When inspection or repairs are required, disassemble only those parts necessary to accomplish the task.

Due to the care Fisher Controls takes in meeting all manufacturing requirements (heat treating, dimension-

Observe the warning given at the start of the Maintenance section.

1. Disconnect the supply and output pressure lines.

2. Slide the hook end of the zero spring (key 5, figure 8) over and off the controller end of the displacer rod (key 3, figure 7).

3. Remove the four controller mounting screws (key 11, figure 8), and pull the controller straight away from the sensor.

9

2680-268T Series Replacing the Sensor O-Rings Observe the warning given at the start of the Maintenance section. Refer to figure 7 for key number locations unless otherwise indicated.

Disassembly 1. Remove the controller from the sensor by following the procedure outlined in the previous section.

2. Remove the sensor from the tank.

3. Unscrew the hex nut (key 6) and remove the spacer (key 5) and spring (key 7). After removing the spring, replace the spacer (key 5) and hex nut (key 6) on the displacer rod.

From the displacer end, pull the displacer rod away from the sensor connection (key 4) to pull the pivot base (key 12) loose from the sensor connection. Remove the hex nut (key 6) to permit removing the displacer rod, pivot base, pivot body, and spacer from the sensor connection.

4. Slide the pivot base (key 12), retaining ring (key 15), anti-extrusion ring (key 14), and O-ring (key 13) off the displacer rod. Remove the O-ring (key 16) and backup ring (key 17) from the pivot base.

4. Insert the displacer rod (key 3) into the vessel side of the sensor connection (key 4).

5. The pivot base must seat in the slots cast in the sensor connection. These slots will be horizontal when the sensor connection (key 4) is oriented as shown in figure 2.

6. To reduce the possibility of nicking the O-ring (key 16) on the pivot base, keep the displacer rod centered in the sensor connection as much as possible while pushing the pivot base into the sensor connection. Be sure the pivot base seats in the slots cast in the sensor connection.

7. Slide the spring (key 7) and spacer (key 5) onto the displacer rod and secure with the hex nut (key 6). Fully tighten the hex nut (key 6).

8. View the sensor connection from the vessel side.

Ensure that the pivot body arms remain aligned with the pivot base arms (the two pivot body points are seated in the pivot base slots).

9. Install the sensor on the tank.

Replacing the Controller Relay Observe the warning given at the start of the Maintenance section. Refer to figure 8 for key number locations unless otherwise indicated.

Assembly

1. Disconnect the supply and output pressure lines.

WARNING Improper assembly of the O-rings, antiextrusion ring, and backup ring could result in O-ring extrusion and permit leakage of process fluids. To avoid personal injury or property damage from leaking process fluid, be sure the Orings, anti-extrusion ring and backup ring are assembled in the order shown in figure 7.

1. Place the pivot body (key 11) on the displacer rod (key 3) so that it is positioned as shown in figure 7.

2. Slide the O ring (key 13), anti-extrusion ring (key 14) and retaining ring (key 15) onto the displacer rod assembly (key 3). Be sure the O-ring, anti-extrusion ring, and retaining ring are in the order shown in figure 7. Slide the pivot base onto the displacer rod so that the points of the pivot body (key 11) will engage the slots in the pivot base (key 12).

3. Install the O-ring (key 16) and backup ring (key 17) into the groove on the pivot base (key 12). Be sure the backup ring is on the downstream pressure side of the O-ring as shown in figure 7.

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2. Remove the two relay mounting screws (key 34), and pull the relay away from the controller base (key 1).

3. Install the new relay using two relay mounting screws (key 34). Make certain that the relay mounting O-rings (keys 45 and 46, not shown) are completely in their mounting bosses before installing the relay. Make certain span lever B (see figure 5) is in line with and pushing in on the end of either the relay adjustment screw (key 51, Type 2680) or the pilot valve plug of the valve assembly (key 53, Type 2680A).

Replacing the Controller Supply Filter Observe the warning given at the start of the Maintenance section. Refer to figure 8 for key number locations unless otherwise indicated.

1. Disconnect the supply and output pressure lines.

2. Loosen the filter cap screws (key 15), and rotate the filter cap (key 14) to the side to uncover the supply filter (key 16).

3. Remove the old filter (key 16), and remove any debris from the filter boss.

4. Install a new supply filter. Reinstall the filter cap (key 14), and tighten the filter cap screws (key 15).

2680-268T Series

C

VIEW C C C

B

SECTION A A

A

SECTION A A WITH FLANGE & HORIZONTAL DISPLACER

A

VIEW B

44B5016-A / IL

Figure 7. Type 268T Sensor

11

2680-268T Series Removing Switch from Type 2680E Observe the warning given at the start of the Maintenance section. Refer to figure 9 for key number locations unless otherwise indicated.

Key 5

Description Zero Spring, 17-7PH SST Type 2680/2680A (25 lb. spring) Type 2680A (5 lb. spring) Type 2680E (5 lb. spring) Span Lever Assembly, stainless steel (2 req’d for Type 2680 & 2680A) (1 req’d for Type 2680E) Span Lever Assembly, stainless steel Type 2680E Shoulder Screw, stainless steel (2 req’d)

22B8033 X012 12B2900 X012

8 9 10* 11

Flanged Bearing, nylon (4 req’d) Span Adjustor, stainless steel Pressure Gauge (2 req’d) (Type 2680/2680A) Mounting Screw, stainless steel (4 req’d)

12B2901 X012 22B2902 X012 11B4036 X022 12B2903 X012

12 13* 14 15

Case Cover Screw, stainless steel O-Ring, nitrile Filter Cap, reinforced plexiglass Square Nut stainless steel (2 req’d)

18A1080 X012 1D1346 06992 22B2898 X012 16A6711 X022

16* 17* 18 19*

Filter (Type 2680/2680A) O-Ring, nitrile (Type 2680/2680A) Machine Screw, stainless steel (2 req’d) Sensor Gasket, composition

11B2307 X012 14A1968 X012 5908124 0X12 12B2933 X012

20 21

Cover, marine grade aluminum Cover Lens, plexiglass (2 req’d) Type 2680/2680A Type 2680E Gasket, neoprene (2 req’d) Retaining Ring, steel (2 req’d)

42B2895 X012

6

1. Disconnect conduit and wires from the controller.

2. On the back of the controller (outside the switch, key 62) is a set screw. This set screw retains the spacer (key 64). Loosen the set screw.

3. Open the controller, and remove the spacer (key 64).

4. Push the switch down into the housing far enough to remove two C-rings (key 63).

5. Pull the switch out through the top of the controller.

6. Reverse the steps to install a new switch.

Parts Ordering When corresponding with the Fisher Controls sales office or sales representative about this equipment, always mention the serial number of the controller.

The serial number can be found on the nameplate (key 56, figure 8). When ordering replacement parts, also specify the complete 11-character part number of each part required as found in the following parts list.

6A 7

22* 23 24* 34

Parts Kits Key

51 53 54

Cover Gasket, nitrile Relay Mounting Screw, stainless steel (2 req’d) (Type 2680/2680A) Relay Mounting O-Ring, nitrile (not shown) Type 2680/2680A Relay Mounting O-Ring, nitrile (not shown) Type 2680/2680A Relay Adjustment Screw Valve Assembly Valve Assembly O-Ring

55 56 57 58

Self-Tapping Screw, stainless steel (2 req’d) Nameplate Screen, stainless steel Hex Nut, stainless steel

59A*

Filter Gasket For Type 2680/2680A w/integral mounted filter/regulator only Neoprene Silicone Spacer Type 2680/2680A w/integral mounted filter/regulator only O-ring Type 2680/2680A w/integral mounted filter/regulator only Nitrile Viton Cap Screw, stainless steel (2 req’d) Type 2680/2680A w/integral mounted filter/regulator only Sealant Zinc-plate No. 770 (Type 2680/2680A) (not furnished with controller)

45*

Description Part Number Controller Repair kit includes O-rings (keys 13 and 17) and gaskets (keys 19, 22, and 24) R2680X00012 Relay Repair kits include relay assembly, relay mounting screws, and O-rings (keys 34, 45, and 46) Type 2680 Low temperature 32B2951X012 High temperature 32B2951X022 Type 2680A Low temperature 32B2951X032 High temperature 32B2951X042 Sensor Repair kit includes keys 13, 14, 16, and 17 (highly saturated nitrile O-rings, retaining ring, anti-extrusion ring, and nitrile backup ring) R268TX00012

Parts List

46*

59B

59C

Controller 1

2 3 4

12

Controller Base, marine grade aluminum Type 2680/2680A Type 2680E Zero Spring Seat, 316 SST Zero Adjustment Bolt, stainless steel Spring Adjustment, 316 SST

42B2894 X012 33B8086 X012 22B2904 X012 12B2907 X012 22B2896 X012

60

61

*Recommended spare parts

Part Number 12B2893 X012 12B2957 X012 12B2957 X012

12B2897 X012

1R1922 05032 1R1922 X0022 1V5521 06992 11A6502 X012 12B2905 X012 12B2921 X012 10A3804 X012 10A8217 X042 Incl in Parts Kits Incl in Parts Kits Incl in Parts Kits 1P4269 28982 --0L0783 43062 1A4117 X0012

1C8986 03012 1N8740 04142

T2104 3T0012

1E5914 06992 1E5914 X0062

1C1970 X0012

2680-268T Series

TYPE 2680 RELAY ASSY

A

A

INTEGRAL MTD REGULATOR

2680 CONTROLLER

VIEW A A TYPE 2660A RELAY ASSEMBLY APPLY LUB/SEALANT

2680A CONTROLLER

42B2950-D / IL

Figure 8. Type 2680 and 2680A Liquid Level Controllers

13

2680-268T Series A

A

SECTION A A

APPLY LUB/SEALANT 33B8327-B / IL

Figure 9. Type 2680E Liquid Level Controller

Key

Description

Part Number

Key

Key numbers 62 through 71 are for the Type 2680E only.

62*

63 64 65 66 67* 68 69 70* 71 72 73

Switch, stainless steel SPDT DPDT Split Ring, steel/zn pl (2 req’d) Spacer, 316 SST Self Tap Screw, stainless steel Label, alum O-Ring, nitrile Machine Screw, stainless steel Square Nut, stainless steel O-Ring, nitrile Pipe Plug, 316 SST (2 req’d) Label, relay action Lubricant, Dow Corning 33 (not furnished with controller)

20B5075 X012 20B5076 X012 13B8088 X012 23B8089 X012 13B8090 X012 13B8091 X012 13B8326 X012 16A6935 X022 16A6711 X022 1U8790 06562 1A7675 35072 23B8328 X012

Sensor 1

14

Displacer 1-7/8x12-inches PVC 304 SST

12B2936 X032 12B2956 X042

2 3 4

5 6 7 8 9 10 11 12

Description 316 SST 2-3/4x8-inches PVC 304 SST 316 SST Hex Nut, 316 SST (vertical displacer only) Displacer Rod, 17–4 SST (17-4PH SST) Sensor Connection 2-inch NPT Connection 2-inch slip-on Connection 2-inch Sch 40 BWE 2-inch Sch 80 BWE 2-inch Sch XX BWE

Part Number 12B2956 X032 12B2958 X032 12B2959 X042 12B2959 X032 1A3421 X0042 14B5018 X012 34B4962 X012 34B5019 X012 34B5022 X012 34B5023 X012 34B5024 X012

Spacer, 304 SST (304 SST) Hex Nut, 316 SST Conical Spring, 316 SST Universal Joint, 316 SST (vert displ only)

12B2945 X012 1A4117 X0022 12B2931 X012 13B8749 X012

Nameplate Drive Screw, stainless steel Pivot Body, CB7CU-1 (17-4PH SST) Pivot Base, CF8M (316 SST)

——— 1A3682 28982 24B4960 X012 24B4967 X012

*Recommended spare parts

2680-268T Series Key 13*

14* 15 16*

17*

18

Description O-Ring, Highly Saturated Nitrile Fluoroelastomer Anti-Extrusion Ring, PTFE Retaining Ring, 304 SST O-Ring Highly Saturated Nitrile Fluoroelastomer

Part Number 17B3305 X012 17B3305 X022 14B4964 X012 14B4965 X012 10A3716 X062 10A3716 X022

Backup Ring Nitrile 14B4940 X012 Fluoroelastomer 14B5017 X012 Flange Assembly, steel (includes flange and 2-inch slip-on sensor connection, key 4) W/2x2 Flange Class 150 RF 34B5013 X012 Class 300 RF 34B5013 X022 Class 600 RF 34B5013 X032

*Recommended spare parts

Key 18

19 20 21 22

Description Part Number Flange Assembly, steel (includes flange and 2-inch slip-on sensor connection, key 4) W/2x2 Flange (cont’d) Class 600 RTJ 34B5013 X042 Class 1500 RF 34B5013 X052 Class 1500 RTJ 34B5013 X062 W/4x2 Flange Class 150 RF 34B5013 X072 Class 300 RF 34B5013 X082 Class 600 RF 34B5013 X092 Class 600 RTJ 34B5013 X102 Class 900 RF 34B5013 X112 Class 900 RTJ 34B5013 X122 Class 1500 RF 34B5013 X132 Class 1500 RTJ 34B5013 X142 Lubricant, Lubriplate Mag-1 (not furnished with sensor) Extension, S31600 12B2953 X022 Instruction Label 13B8106 X012 Instruction Tag 17B0397 X012

15

2680-268T Series

Fisher, Fisher-Rosemount, and Managing The Process Better are marks owned by Fisher Controls International, Inc. or Fisher-Rosemount Systems, Inc. All other marks are the property of their respective owners.

Fisher Controls International, Inc. 1995, 1999; All Rights Reserved

The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not to be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. We reserve the right to modify or improve the designs or specifications of such products at any time without notice.

For information, contact Fisher Controls: Marshalltown, Iowa 50158 USA Cernay 68700 France Sao Paulo 05424 Brazil Singapore 128461 16 Printed in U.S.A.