11002347AA
date of change: 20.08.2014
Page: 4/19
2 General description of the control unit
Model
FR4.1
is an electronical control unit (78x35mm) suitable for applications on medium or low
temperature refrigeration units, which has three relay outputs to control compressor, defrost and
evaporator blower as well as two PTC-/NTC-sensor-inputs in order to measure the room tempera-
ture and evaporator temperature. Defrosting can be recirculation air as well as hot-gas defrosting.
The blower can be activated during defrosting upon request. The sensor is suitable for refrigera-
tion. The control unit FR4.1 is suitable for refrigeration as well as heating applications (only hot-gas
heating). Supply voltage may be between 10 and 28V.
The following functions can be adjusted:
•
room temperature („only refrigeration“ or „refrigeration and heating with hot gas “)
•
automatic defrosting (hot gas or recirculating air)
•
manual defrosting (hot gas or recirculating air)
⇒
Faults are shown in the display via flashing indication (see point 4).
This present instructions for installation and service is amended by the „operating in-
structions for refrigeration units“, KONVEKTA no: BBA-FR4-2AB.
2.1 LED-display
The display shows information about the current control mode via different LED.
The functions are listed as follows:
LED
STATUS
FUNCTION
illuminated
compressor is active
blinking
minimum off-duration of compressor is active
illuminated
Blowers active
illuminated
defrosting active
blinking
Manual defrosting active
blinking
active fault
2.2 Programming Menu
The programming menu includes all parameters of the unit
(Service level!).
For this level you
need a password
, see example in point 5.1.
