Controller Operation; Temperature Sensor Readings - Follett FZR20-LB Installation, Operation And Service Manual

After defrost terminates, there is a 2 minute drip time delay to allow excess condensation to drip off the evaporator
coil before the compressor and condenser fan motor cycle on. The evaporator fan motor is off during defrost and
is delayed an additional 4 minutes for a total delay of 6 minutes after defrost terminates before cycling on. The
heat from the compressor, condenser and hot gas discharge line along with the airflow from the condenser fan
evaporates any condensate in the drain pan as well as providing preliminary cooling of the high pressure vapor
prior to entering the condenser. As a safety feature, two temperature safety switches are mounted on the inside
of the evaporator enclosure. One is mounted on the back of the evaporator and the other on the bottom of the
evaporator drain pan. These switches automatically turn off either the evaporator defrost heater or evaporator
drain pan heater if the temperature exceeds 27 C (80 F), regardless of controller operation.
Note: If defrost terminates on time, it will display "Defrost Timed Out" on the main menu screen. This may indicate
that the evaporator has not completely defrosted.

Controller operation

BEFORE MAKING ANY CHANGES TO FACTORY-DEFAULT REFRIGERATION SETTINGS, CONTACT FACTORY.
The controller displays product temperatures in degrees C or F (C is factory default) to 1 decimal point.
The controller is pre-programmed with a -31.0 C (-23.8 F) set point on PL models and a -24.0 C (-11.2 F) set point
on LB models. This provides a compressor cut-in at -30.0 C (-22.2 F) on PL models and -23.0 C (-9.4 F) on LB
modles. The compressor will cut-out at -32 C (-25.6 F) on PL models and -25 C (-13 F) on LB models. This will
correlate to a product temperature of approximately -30.0 C (-22.2 F) on PL models and -23.0 C (-9.4 F) on LB
models.
All set points have a 1 C (1.8 F) differential.
Product temperature will be displayed on the digital temperature display and chart recorder (if equipped).

Temperature sensor readings

To view temp sensor probe readings:
1. Press Menu button (Fig. 57).
2. Use to scroll and highlight Refrigeration Controls (Fig. 58).
24 Service
ATTENTION
Fig. 57
- 3 0 . 0 C
B o t t o m Te m p - 3 0 . 0 C
M e n u
Fig. 58
R e f r i g e r a t i o n C o n t r o l s - 3 0 . 0 C
P a s s w o r d o n / o ff
P I N
S e t Ti m e / D a t e
B a c k E n t e r
00981795R03 – FZR20/25 LB, PL