Binder KB 23 - 15 Defrosting During Refrigerating Operation

KB 23 / KB 23-UL (E3.1) 02/2019 page 59/87
Safety controller set-point types
Setting in the user level (chap. 10) of the RD3 program controller.
Limit
Absolute maximum permitted temperature value.
Example:
Temperature set-point 40 °C / 104 °F
Limit value (safety controller set-point) set to 42 °C.
Offset
Maximum over temperature above the active temperature set point. The maximum
temperature changes internally and automatically with every set-point change it.
Example:
Temperature set-point 40 °C / 104 °F
Offset value (safety controller set-point) set to 2 °C.
Regularly check the safety controller setting for set-point type “Limit” or “Offset”
• in Fixed value operation mode according to the entered set-point temperature value
• in Program mode according to the highest temperature value of the selec
ted temperature
program
Set the safety controller set-point by approx. 2 °C to 5 °C above the desired temperature set-
point.
15. Defrosting during refrigerating operation
BINDER cooling incubators are very diffusion-proof. To ensure high temperature precision there is no
automatic cyclic defrosting device. The DCT™ refrigerating system largely avoids icing of the evaporation
plates. However, at very low temperatures the moisture in the air can condense on the evaporator plates
leading to icing.
Always close the door properly.
• Operation with temperature set-points above +5 °C / 41 °F at an ambient temperature of 25 °C /
77 °F:
The air defrosts the ice cover automatically. Defrosting is continually performed.
• Operation with temperature set-points below +5 °C / 41 °F:
Icing on the evaporator is possible. Defrost the chamber manually.
With temperature set-points < +5 °C / 41 °F, regularly defrost the chamber manually:
• Set the temperature to 40 °C / 104 °F (in Fixed value entry mode)
• Let the chamber operate for about 30 minutes with the door closed.
Excessive frosting of the evaporator is indicated by reduced refrigerating performance.
The cooling power decreases when the fan speed is reduced to 20% or below.