KAL - Thermal Flow Switch


  • Optimal Temperature Compensation
  • Simultaneous Monitoring of Temperature and Flow
  • Remote Probe Allows Installation with Minimal Clearance
  • Independent of Liquid Density
  • Can be Used with Extremely Low Velocities
  • No Moving Parts
  • Extremely Low Pressure Loss
  • Easy to Operate
  • Insensitive to Dirt



The KAL electronic flow switch continuously monitors the flow of liquid media. It can be used wherever flows must be monitored with a minimal loss of pressure. The KAL’s one-piece, stainless steel sensor has no moving parts making the KAL very reliable. High strength is another advantage inherent in this design allowing use at high pressures, and virtually eliminating any chance of mechanical damage.


The KAL design is based on the timeproven calorimetric principle. The sensor is internally heated to a few degrees above the temperature of the medium. Flow of the medium causes removal of heat from the sensor, resulting in a cooling effect. The degree of cooling is a measure of the flow velocity.

The KAL electronic modules allow the user to interface with the sensor to provide access to flow or temperature control in his process. The system can act as either a flow switch only, or a combined flow and temperature switch. Switching is achieved by means of internal SPDT relays.

The microprocessor based design of the KAL distinguishes it from the competition. Full temperature compensation of the switch point is readily obtained through a simple, one-time, calibration procedure. This assures elimination of set-point drift caused by temperature variations in the process liquid.



Housing: 304 SS
Cable: PVC cladding
Cable Gland: Ni-plated brass
Length: 6 feet (max. 330 feet)
Conductors: 2× 20 AWG
Media: Water-based Liquids
60 cSt max.
Switching Range
Water: 0.2 to 6.6 ft/s
Operating Conditions
Temperature: 0 to 176 °F
Option ”-HT“: 32 to 250 °F
Pressure: 1450 PSIG maximum
360 PSIG for models
KAL-5132 & 5140
Protection: NEMA 6
Display: ± 10%
Temperature: ± 2%
Reproducibility: ± 2%
Response Time
Typical: 5.6 seconds
Maximum: 10 seconds
Power: 3 W max. @24 VDC or 24/110/230 VAC
Relay: Fail-safe SPDT 3 A @ 250 VAC max.
Status Indicator: LED for relay & power
Adjustments: For type of liquid and switch point
via potentiometer
Amb. Temperature Range:
32 °F to 140 °F
Protection: NEMA 1
Housing: Polycarbonate
L×W×D: 2.95"×2.17"×4.33"
Fail Safe Features
Power Loss: 10 year memory retention
Switch: Relay energizes during normal operation
Cable Break: Alarm state signalled
Rail Mounting: DIN EN 50022 and DIN 46277

 KAL - Thermal Flow Switch

KAL - Thermal Flow Switch

Temperature Compensation

The KAL flow switch uses a microprocessor to compensate for temperature changes through use of an internal look-up table. End-users can easily adapt the equipment to the requirements of their unique installations.

Compared to conventional calorimetric flow switches, the technically advanced design of the KAL provides a switch point which changes negligibly with temperature.

Selecting a System

The electronic flow switch consists of:

  • the controller
  • the sensor

The connecting cable between the two parts may be up to 330 feet long. (with KAL-E300 series units, temperature correction is required with cable lengths above 33 feet.)


Three units are available. Each is compatible with the full series of sensors. Electronic circuitry is located in a standard DIN housing (NEMA 1) for quick installation on terminal rails.

KAL-E100 Series

The KAL-E100 is equipped with a flow
rate sensitive, isolated SPDT relay. The
relay status is indicated by means of a
green LED.

KAL-E200 Series

Same as the KAL-E100, but with a trend
indicator for flow rate and switch point.

KAL-E300 Series

Same as KAL-E200 but with a
temperature switch. In addition to
monitoring the flow, this model can be

used to monitor the temperature. The specified alarm temperature can be from 0–176 °F. SPDT relays are activated if the flow drops below the specified flow velocity, or if the temperature drops below the specified temperature.


All of the sensor models can be used with any of the three controllers.

Selection is a function of:

  • connector threads
  • max. operating pressure 1450 PSIG
  • max. medium temperature 176°F (250°F Optional)
  • sensor wetted parts


KAL - Thermal Flow Switch



KAL - Thermal Flow Switch