Follett REF Series - Manual (Page 6)

Controller operation
In normal operation the controller displays cabinet temperatures in
°F (default) or user-selected °C. °C temperatures are displayed to 1
decimal point.
An LED located below the snowflake icon flashes when the
compressor is running.
Rocker buttons to the right of the temperature display control all
programming functions.
The controller is pre-programmed with a 34°F set point which provides a compressor cut-in at 38°F and cut-out
at 34°F. This may not meet your specific application needs. For example, many pharmaceutical manufacturers
recommend that their refrigerated medications be stored between 36°F and 46°F. Instructions for changing the set
point are found below.
Refer to the chart below for the set point for your application’s required temperature range:
All set points have a 4°F differential (HY setting on the controller). The 4°F differential means that with a 34°F set
point, for example, the compressor will turn off at 34°F and turn on when it reaches 38°F.
Caution: Do NOT change the differential (HY setting) except as indicated below in instructions for changing the
°C or °F display. Changes to the HY setting can cause short-cycling and failure of the compressor.
Because there is still refrigerant in the evaporator, there can be an additional 1° - 1.5°F of downward “drift” in
temperature after the compressor turns off. The temperature may momentarily display as low as 32°F (32.9°F and
below rounds down to 32°F) before beginning to rise again.
6
SET
prg
˚F
*
38
*
UP arrow
rocker button
SET rocker
button
DOWN arrow
rocker button
Fig. 8
Set point Cut-in/ Cut-in/ Normal display
°F/°C Cut- out °F Cut-out °C range temperature °F/°C
34° / 1.1° 38° / 34° 3.3° / 1.1° 32° - 38° / 0° - 3.3°
35° / 1.7° 39°/ 35° 3.9° / 1.7° 33° - 39° / .6° - 3.9°
36° / 2.2° 40° / 36° 4.4° / 2.2° 34° - 40° / 1.1° - 4.4°
37° / 2.8° 41° / 37° 5° / 2.8° 35° - 41° / 1.7° - 5°
38° / 3.3° 42° / 38° 5.6° / 3.3° 36° - 42° / 2.2° - 5.6°
39° / 3.9° 43° / 39° 6.1° / 3.9° 37° - 43° / 2.8° - 6.1°
40° / 4.4° 44° / 40° 6.7° / 4.4° 38° - 44° / 3.3° - 6.7°
41°/ 5° 45° / 41° 7.2°/ 5° 39° - 45°/ 3.9° - 7.2°