Freezer Temperature Control - Delfield 4400 Series Installation & Operation Manual

Compact Refrigerators
Freezer Cabinet Operation
The electronic temperature control constantly monitors
box temperature as well as evaporator coil temperature to
maintain consistent product temperatures.
At initial start-up or anytime power is disconnected, then
reconnected to the unit, the control will delay all operations
for a short time (up to 10 minutes.) While in this delay period,
the control initializes the control parameters and confirms
that the temperature sensors and circuits are operational.
REGARDING FREEZERS: After initializing, the
control will immediately enter a DEFROST mode.
The compressor and condenser fan as well as the
evaporator fan will remain off until initialization
defrost is complete. This initial defrost cycle may
take up to 15 minutes to complete, at which time
the freezing cycle will begin.
Temperature Control Knob Access
Freezers
The control is located in the rear of the cabinet. Freezers
are factory set at mid-range to maintain about -3ºF
(-19ºC) box temperature. To adjust for colder temperatures,
turn the knob clockwise. For warmer temperatures, turn
the knob counter-clockwise. Turn the knob fully counter-
clockwise to turn the refrigeration system off. Never turn
the knob more than 1 dial number and always allow 8 hours
for temperature stabilization before making any additional
adjustments.
Freezer cabinets with two evaporators have counter-rotating
fans to ensure even airflow throughout the cabinet. The left
evaporator has a CCW motor and a clear fan blade and the
right evaporator has a CW motor and a black fan blade.
The evaporator fan(s) and condenser fan will cycle off and on
with the compressor to conserve energy.
Freezer:
Whenever the freezer is plugged in, and the control has
completed initializing including the initial defrost cycle.
The temperature control will cycle the compressor and
condenser fan motor and evaporator fan motor to maintain
box temperature at the control setting.
Freezer Automatic Defrost
The control also monitors compressor total running time
and will enter a defrost cycle after total compressor running
time is greater than 4-hours since the last defrost cycle OR
if evaporator coil temperature drops below -34ºF (-37ºC)
(indicating excessive frost on the coil.)
When the control enters the defrost mode, it switches off the
evaporator fan motor, compressor and condenser fan motor,
and switches on the defrost heater to warm the evaporator
coil. Thereby melting all frost accumulated during the previous
refrigeration cycle. The control will continue the defrost
cycle for a MINIMUM of 8 minutes and a MAXIMUM of 30
minutes depending on the amount of frost accumulated on
the evaporator coil.
After the defrost cycle is complete, the control returns to a
normal refrigeration cycle, however the evaporator fan motor
will not switch on for 2 minutes AFTER the compressor and
condenser fan motor have begun operating.
Freezer Manual Defrost
If a manual defrost is desired, simply unplug the unit for several
seconds, then plug unit back in. This will cause the control
to re-initialize and then enter a defrost cycle.
Service Alert
During normal operation the evaporator fan may cycle
and/or pulse independently of the compressor. Consult
the service manual or contact Technical Support at
1-800-733-8829 if you are unsure of the proper function.
Cooling Cycle
Compressor On
Evap Evap
Fan On Fan Off
4500
X
Freezer
Defrost Cycle
Compressor Off Compressor Off
Evap Evap Evap
Fan On Fan Off Fan On Fan Off
X
Evap
X
15