Defrost on Demand Sensor MK1

Techical data: HBDF

HBDF is a simple solution for energy-optimal automatic defrosting of evaporators. It results in energy saving, gain more freezing capacity with optimal defrost periods. The sensor measures the thickness of ice building up between the fins and sends a 4..20mA or digital ON/OFF signal to the control systems.

The Defrost sensors are based on capacitive measuring principles, in which an isolated steel wire acts as a conductor and the evaporator fins and tubes act as the second conductor jointly forming viable electrical capacitor. Change of the measured signal occurs when ice is build-up between the fins as the sensor is measuring the dielectric difference between air and ice.

The sensor can be installed in less than one hour, on both new and old evaporators. It can be installed when the system is in operation, and therefore, a system shutdown is not necessary. The electronic part is mounted on the evaporator's frame using 2 screws. The mechanical part consists of a thin PA12 or PTFE-coated wire, which is mounted between the fins of the evaporator in the air inlet side with special HB Snap-On plastic clips or standard Nylon strips. HBDF is available in 3 variants, with a 10m, 20m, and 30m wire respectively.

After installation, the sensor should be calibrated/configured to the evaporator it is mounted on. This is done using the HB-TOOL (PC-based software tool), which can be downloaded via this link.

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Product features

  Provides energy savings of up to 40 %, compared with conventional defrostning.
Reduces downtime and minimises system defrost time.
Split design, which makes the sensor easy to instll and service. The electronic part can be separated from the mechanical part.
Simple installation. Can be carried out in an hour without system shutdown.
Can be installed on all evaporator types from all manufactures.


Connection diagram

HBLC web 1


HBDF maalsat

Power supply
Voltage24 AC/DC + 10%
Max. possible resistance500 ohm
Max consumption50 mA
Plug connectionDIN 0627 - 5 pins
Analog output  4-20 mA, 1 A
Transsistor output - alarmPNP, 1 A
Contact function - alarm outputNO/NC (Programmable)
Environmental conditions
Ambient temperature-40...+50°C
Protection degreeIP65
VibrationsIEC 68-2-6 (4g)
Mechanical specifications
Mechanical installationSee drawing 
Material - mechanical partsAISI 304 / PTFE
Material - electronic partsPlast
EMC-Emission EN 61000-3-2
EMC-Immunity EN 61000-4-2
HBxC-M12/55 m - 5 wire
LED indication (option)Green, yellow & Red LED
ConfigurationPC tool

Ordering code

DescriptionWire lengthOrdering code
Defrost Sensor10 mHBDF-10
Defrost Sensor20 mHBDF-20
Defrost Sensor30 mHBDF-30
Electronic Part for HBDF Spare part must be calibrated on-siteHBDF-EL
HBDF-snapON ClipsPiping in mmOrdering Code
Bag of 25 pcs.8-10 mmHBDF-SnapONClip8-25
Bag of 50 pcs.8-10 mmHBDF-SnapONClip8-50
Bag of 25 pcs.10-12 mmHBDF-SnapONClip10-25
Bag of 50 pcs.10-12 mmHBDF-SnapONClip10-50
Bag of 25 pcs.12-14 mmHBDF-SnapONClip12-25
Bag of 50 pcs.12-14 mmHBDF-SnapONClip12-50
Bag of 25 pcs.14-16 mmHBDF-SnapONClip14-25
Bag of 50 pcs.14-16 mmHBDF-SnapONClip14-50
Bag of 25 pcs.16-18 mmHBDF-SnapONClip16-25
Bag of 50 pcs.16-18 mmHBDF-SnapONClip16-50
Bag of 25 pcs.19-22 mmHBDF-SnapONClip19-25
Bag of 50 pcs.19-22 mmHBDF-SnapONClip19-50
Bag of 25 pcs.22-25 mmHBDF-SnapONClip22-25
Bag of 50 pcs.22-25 mmHBDF-SnapONClip22-50
USB programming cableAccessoriesHBxC-USB


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