Operation; Automatic Defrost; Controller Operation - Follett 18688 Installation, Operation And Service Manual

Operation –––––––––––––––––––––––––––––––––––––––––––––––––––––––––
The temperature control board and P1 probe indicate when the refrigeration system is required to turn on and off.
The refrigeration system removes heat from the cabinet interior and rejects it to the surrounding room air. When
the cabinet interior temperature reaches 4 F (2.2 C) above the controller set point, the probe signals the controller
to turn the refrigeration system on. The normally open controller contacts close and energize the condenser fan
motor and compressor. The evaporator fan runs continuously. The compressor uses a PTC device to turn on the
compressor motor.
When the cabinet interior temperature falls to the set point, the probe signals the controller to turn the refrigeration
system off. The controller contacts reopen, which de-energizes the evaporator, condenser fan motors and the
compressor.

Automatic Defrost

REF Series refrigerators do not require manual defrosting. The unit defrosts automatically when the condensing unit
is in the OFF cycle.
Any accumulated frost on the evaporator coil melts during the OFF cycle. The condensate drains to a plastic drain
pan mounted below the condensing unit. The heat from the condensing unit evaporates any condensate in the drain
pan.

Controller Operation

In normal operation, the controller displays temperatures in degrees F
(default) or user-selected degrees C. F temperatures are displayed to the
nearest degree, C temperatures are displayed to one decimal point. A
snowfl ake LED displays when the compressor is running. The controller
is pre-programmed with a 38 F (3.3 C) set point.
Follett presets its refrigeration system to hold medications at
approximately 39 F (3.8 C).
If you are storing prepackaged food in this unit, NSF requires the set
point be changed to 36 F (2.2 C) to maintain food below 40 F (4.4 C).
All set points have a 4 F (2.2 C) differential. This differential means that
with a 38 F (3 C) set point, for example, the compressor will turn off at 38
F (3 C) and turn on when it reaches 42 F (6 C). This maintains product
temperature for medications within the recommended range of 36 F to
46 F (2 C to 8 C).
Note: Display (Fig. 8) always reverts to P2 product temperature display
after settings are accepted. It is important to note that P2 product
temperature probe drives all alarming functions.
To display temperature set point
1. Press and release SET and current cut-out temperature displays for approximately 5 seconds.
2. Display returns to current product temperature.
To change temperature set point
1. Press and hold SET for 3 seconds, until the current cut-out temperature displays and F or C fl ashes.
2. Press UP or DOWN arrows to set desired cut-out temperature.
3. Press and release SET and new cut-out temperature blinks three times.
4. Display returns to current product temperature.
Fig. 8
38
REF1/REF2 Compact Refrigerators
°F
9