Delfield UCD4460N - Manual (Page 12)

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Delfield
Figure 6. Thermostat Location - Freezer
OPERATION
FREEZER CABINETS
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.
The control is located in the rear of the cabinet (See Figure 6.).
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.