Stafford, Texas

CLASSIC 800 Series, Switch and Transmitter for Flow, Level, Interface, and Temperature

CLASSIC 800 Series, Switch and Transmitter for Flow, Level, Interface, and Temperature

Every CLASSIC 800 Series switch and transmitter is user configurable for flow, level, fluids interface, temperature applications and is suitable for use in air, gases, water, liquids, and slurries. The CLASSIC 800 Series has several unique features which make it the world’s most advanced thermal flow and level switch including: temperature mode, 4-20 mA outputs, Modbus, digital temperature compensation, automated self-test diagnostics, and a simple, intuitive user interface.

Patented Design
The CLASSIC 800 Series patented designs provide the ultimate performance and features package for flow, level, interface, and temperature sensing and combine precision welded, highly accurate sensors, extremely rugged enclosures and advanced digital electronics. The CLASSIC 800 Series combines the failure resistance inherent in Thermal Dispersion technology with the performance and features usually reserved for much more expensive instruments.


  • Microprocessor based electronics, intelligent user interface
  • Continuous self-test diagnostics of electronics and sensor
  • Temperature compensation, variable heater power
  • Dual independent relays, factory set to monitor flow
  • Adjustable power-on start-up bypass timer, set point deadbands
  • 4 adjustable independent switch point timers
  • Display panel lock-out (controlled via the Kayden RCM software)
  • No mechanical jumpers or trim-pots
  • Process temperature via Modbus and/or one or both alarm relays


Flow Switch and Transmitter

As the process travels over the tip of the sensor, the increased flow of the process reduces the temperature of the heated RTD. This reduced temperature difference between the two RTDs is monitored by the electronics and the switch changes state once the set point is reached. Ideal for flow and no-flow monitoring and verification:

Air, gases, water, hydrocarbon-based liquids, viscous fluids, liquids with particulates and/or suspended solids and slurries
Pump Protection – Dry Alarm Pipeline / Material Storage Flare Gas Monitoring and Verification Relief Valve & Rupture Disk Flow Monitoring
Purge Air Flow Monitoring Emergency Eye Wash Stations and Showers Tanker Loading & Unloading Well Optimization
Leak Detection Flare Gas Monitoring Tank Overflow Protection Lube Oil Systems
Vent Monitoring Natural Gas to Boilers Drain Line Flow High Pressure Flows
Remote Indication of Flow via Analog Output & Digital Communications Chemical Injection, Additive Flow Monitoring

Ideal Process Conditions for Liquids, Air and Gas, Slurries, and Emulsions

  • Consistent process composition & temperature
  • Sufficient straight run flow profile, minimizes turbulence
  • Recommended minimum of 5 pipe diameters from any disturbance (Liquids applications only)
  • Clean and dry (Air and Gas applications only)
Level Switch and Transmitter

In a dry to wet application the rising liquid level covers the sensor and disperses some of the heat from the heated RTD. This reduced temperature difference between the two RTDs is monitored by the electronics and the switch changes state at this set point. Ideal for level detection:

Fast, Accurate and Repeatable at Low Flow Rates Drain Line Flow Lube / Seal Oil Systems Tank Overflow Protection
High / Low Level Detection with particulates and/or suspended solids and slurries: water,hydrocarbon-based liquids, viscous fluids, other liquids
Process Tank Batching Control Leak Detection (Accumulation Reservoir) Oil Separators & Treaters – High, Low & Interface Level Sumps – All Types of fluids ( Water, Oil, etc. )
Free Water Knock-out Tanks – High, Low and Interface Level Storage Tanks Sampler Systems Sand Separator

Ideal Process Conditions for Liquids, Slurries, and Emulsions

  • Consistent process composition
  • Non-turbulent (Liquids applications only)
Interface Switch and Transmitter
  • Separation Vessels
  • Knockout tanks
    – Oil
    – Pad
    – Water
  • Interface Control in Separation Vessels
  • Interface Detection
  • Interface Control & Level Detection in Settling Vessels

Ideal Process Conditions for Liquids to Liquids, Air or Gas to Liquids, Emulsions

  • Consistent process composition and temperature
  • Non-turbulent applications
  • Large differential in thermal conductivities (Liquids to Liquids applications and Emulsions applications only)
  • Dry gas (Air or Gas to Liquids applications only)
Temperature Transmitter
  • Process Temperature Monitoring
  • One relay configurable for process temperature

Live Monitoring, Remote Access, and Data Logging

The Kayden RCM (Remote Communications and Monitoring) Software allows all the settings to be configured remotely and saved as a file, transmitted as an email attachment, and/or printed for future reference. The Kayden RCM Software includes the option of locking the CLASSIC 800 Series Display Panel to eliminate field adjustments or tampering.

Discrete & Analog Outputs

Modbus allows multiple units to be connected to the same communications bus (via RS-485) and monitored simultaneously.

  • Modbus registers via RS-485 4-20 mA analog representation of Thermal Signal
  • Two SPDT sealed relay contacts rated @ 4 amps resistive 230 VAC or 24 VDC maximum

Advanced Diagnostics

The CLASSIC 800 Series uses an advanced microprocessor to perform continuous self-test diagnostics on the electronics and the sensor elements. Any open or shorted connection will result in a FAULT indication that also deactivates all relays and disables the heater circuitry.

Intelligent User Controls

The CLASSIC 800 Series Display Panel features very bright LED indicators for easy viewing even in direct sunlight. An adjustable power-on Start-up Bypass Timer is accessible from the Display Panel for low flow alarm pump protection applications. This makes it possible to disable a pump on low flow and have it automatically restart after a predetermined time in the event of a power interruption. Four adjustable delay timers allow the introduction of repeatable time delay into the (set point) relay trip function. For example, in a pump protection application this function will shut down the pump after the switch sensor has gone “dry” for the pre-set time (delay) limit.

CLASSIC 800 Series Displays Process Conditions, Adjusts of All Settings
  • The Blue LED on the Thermal Signal Bar Graph is a constant display of process condition (Flow / Level)
  • Power, relay states, fault conditions, set points and delay timers all have dedicated LED indicators
  • The push buttons replace internal dip switches, trim pots or slide switches and make set point, range, heater power, and delay timer adjustments easier

CLASSIC 800 Series Display Panel

Display Panel Indicators:

Relay 1: On steady when Relay 1 is energized
Relay 2: On steady when Relay 2 is energized
Fault: Indicates a self-test error or fault condition
Set Point 1: On steady when viewing Set Point 1
Set Point 2: On steady when viewing Set Point 2
Run Mode: Flashing when switch is operating
Bypass: Flashing when the Start-up Bypass Timer is active
Thermal Signal: Displays Thermal Signal

CLASSIC 800 Series Switch and Transmitter for Flow, Level, Interface, and Temperature Model Line-Up

1/2” to 2”
Flanged Flanged Retractable
Packing Gland
1” MNPT Threaded
Packing Gland
1” to 3”
3/4” FNPT (InLine) Flanged (InLine)
“U” Lengths
1.2”, 2”, 3”, 4”, 6”, 9”, 12”, 18” Standard (most models). Custom lengths available to 240”
316/316L Stainless Steel, Titanium Gr. 2,
Hastelloy C-276 & Monel 400
316L Stainless
316/316L Stainless Steel
c/w Nickel Braze
Universal AC & DC
Maximum: 6.0 watts (fully configured)
Communication RS-485
Outputs Two SPDT sealed relay contacts 4 amps resistive 230 VAC / 24 VDC
Modbus via RS-485. 4-20 mA current loop
Operating Temperature
-50˚ to 392˚F -50˚ to 320˚F -50˚ to 392˚F
Operating Temperature
Continuous use: -67˚ to 167˚F
Self Test Automated diagnostics performed on electronics and sensing elements