SOR Thermal Differential Flow Switch User Manual

T21 Thermal

low maintenance performance in the most demanding ap

Differential Switch

General Instructions

The T21 Point Level Switch is a state-of-the-art in liquid level and interface measurement
and control. Level detection is accomplished by using a high-resolution thermal differential
technique. The sensor wetted parts are of durable 316L series stainless steel, all-welded
construction and contain no moving parts. The switch is easy to install and adjustable
providing reliable, low-maintenance performance in the most demanding applications.

,

NOTE: If you suspect that a product is defective, contact the factory or the SOR®
Representative in your area for a return authorization number (RMA). This product should
only be installed by trained and competent personnel.

Design and
specifications are
subject to change

without notice.

For latest revision,

go to sorinc.com

Form 1024 (08.13) ©SOR Inc.

Installation

Mechanical ................................ 2-3

Electrical .....................................4

Set up and Operation ...........................5

Calibration for Level Switches ............. 6-7

Calibration for Flow Switches .............. 8-9

Dimensions .................................... 10

Cleaning ........................................ 11

Troubleshooting ........................... 11-12

Table of Contents

Registered Quality System to ISO 9001

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Mechanical Installation

The T21 has a 3/4-inch MNPT mount (standard), designed for easy installation
through a threaded port.

 Conduit is recommended for all wiring to the switch.

 Due to the pipe thread mounting, it may be necessary to make a trial fit, add

or remove teflon tape or other pipe thread sealant and reinstall to achieve a
satisfactory seal with the sensor properly oriented.

 Proper orientation is marked on the switch body for reference.

 It is generally recommended that the sensor tips be located at 1/4 of the pipe’s

inside diameter (I.D.) assuming pipe is full. (See

Level Application

 The switch body MUST be oriented with the two sensor tips aligned paralled to the

level being detected. (Disregard for top mount installation.)

Sensor

Tips

Tips

Sensor

Incorrect

Material
Direction

)

Material
Direction

Sensor

Tips

Sensor

Incorrect

Tips

Flow Application

 The swtich body MUST be oriented with the two sensor tips aligned perpendicular

to the flow being detected.

Material Direction

Sensor

For level and  ow applications the material you are monitoring MUST contact the
two sensor tips at the same time .

Use a 1-1/8”, open-end wrench to tighten at the HEX  ats of the MNPT of
a standard switch. Do not use the instrument head to tighten the switch
to the mounting port. Rotation of the instrument head with respect to the
sensor body may cause internal wiring damage.

Tips

Sensor

Tips

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Form 1024 (08.13) ©SOR Inc.

Pipe

h

p

pp

ll)

ead

t

Nozzle/

Coupling

Length

Thread

Thr

Engagement

ngagemen

Flow

*Sensor

ensor

Length

Lengt

Pipe Wall
Thickness

1/4 of pipe I.D. (preferred

/4 of pi

insertion assuming pipe

s fu

is full)

Unit can be mounted above or below pipe. Mounting on top of pipe is displayed above.

Nozzle/Coupling length

*Sensor Length =

+ Pipe wall thickness
+ 25% of pipe I.D.

- Thread engagement

Form 1024 (08.13) ©SOR Inc.

3/12

Electrical Installation



Remove the instrument enclosure lid by unscrewing in a counterclockwise direction.

 Loosen the two, board-retaining captured screws.
 Remove the printed circuit board by grasping the transformer on the center of the

board and, while rocking gently back and forth, pull firmly outward.

 Connect power and alarm relay wiring to Terminal Block TBB as shown in
 Reinstall the switch electronics and tighten the retention screws.

.

NOTE: Connections to sensors are factory installed and should not be disconnected in the  eld.

NOTE:
TBB8. For 115 VAC or 230 VAC operation, there is no polarity.

NOTE: Connect ground wire to the ground screw located in back of instrument enclosure. A
ground wire must be attached to the ground screw located inside and on the back of
instrument head for proper operation.

For 24 VDC operation (factory prepared), connect +24 VDC to TBB7 and 24 VDC return to

4/12

Form 1024 (08.13) ©SOR Inc.