Technical data: HBDF-MK2
HBDF-MK2 is a simple solution for automatic defrosting of evaporators. Optimal defrost periods result in energy savings and gain more freezing capacity. Experiences from existing installations show have shown that it can save up to 40% of energy and thereby quickly is recouping its costs. The sensor measures the thickness of ice built up between the fins and it sends a 4-20mA or digital ON/OFF signal to the control systems.
The defrost sensors are based on the capacitive measuring principle, in which an isolated steel wire acts as one conductor. The evaporator fins and tubes act as the second conductor, jointly forming a viable electrical capacitor. Changes in the measured signal occur when ice is built up between the fins, as the sensor is measuring the dielectric difference between the air and ice.
The sensor can be installed in less than one hour, both on new and old evaporators. It can be installed when the system is in operation. Therefore a system shutdown is not necessary. The electronic part is mounted on the evaporator’s frame by 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 clips or standard nylon strips. The HBDF-MK2 sensor is available in 3 versions, with a 10m, 20m and 30m wire.
The sensor with a built-in control relay will start the defrosting based on the ice thickness and stop the defrost when the ice is melted and the temperature outside the evaporator tubes rises above 0°C (32°F). Recommended setpoint for stop of defrost cycle is 5-10°C (41-50°F).
After the installation, the sensor should be calibrated/configured to the evaporator by using the HB-TOOL (PC-based software tool), which can be downloaded from our web-site.