-5-
Both refrigerators and freezers do not require manual
defrosting. However, manual defrost option is available on
the control, if required.
IV. a - OPERATION DISPLAY INDICATORS
During normal operation, the display shows either the
temperature measured or one of the following indications:
IV. b - REFRIGERATORS
During normal operation, a refrigerator continuously
circulates above-freezing cabinet air through the evaporator
coil. An Off-Cycle defrost occurs every 8 hours for a
maximum length of 50 minutes to melt any frost which may
accumulate on the coil during the compressor “ON” cycle.
With standard holding refrigerators, high relative humidity is
also maintained to prevent dehydration of stored product.
IV. c - FREEZERS
During normal operation, a freezer continuously circulates
below-freezing cabinet air through the evaporator coil. The
coil requires a periodic defrosting for proper operation.
This is accomplished by an automatic, compressor runtime
activated, temperature/time terminated, defrost program.
Depending on the door opening frequency and the ambient
condition, the defrost may occur 3 to 8 times within each
24-hour period.
At the start of a freezer defrost cycle, both the compressor
and evaporator fans are off. The microprocessor control will
read “dEF” (see figure 6).
IV. c - FREEZERS (cont’d)
The electric heaters (attached to the evaporator coil and
drip pan) are energized. When the temperature sensor
affixed to the coil senses 50°F, the coil and drip pan are
fully defrosted. Both heaters and compressor are off for 5
minutes to let the defrost water drip out completely. After
drip time, compressor will resume operation. The evaporator
coil fans are delayed from starting at the termination of a
defrost cycle. Fan operation is automatically resumed after
a short time or temp delay (whichever comes first). After
completion, the total refrigeration system operation is then
resumed. During defrost operation, heat is confined to the
coil enclosure to prevent any significant rise in temperature
within the food zone. The fan delay control function upon
termination of a defrost cycle is two-fold. First, to prevent
blowing warm air into the food storage area. Second, to
prevent any condensation on the defrost coil from being
blown into the food storage area.
The microprocessor control is set from the factory to
terminate defrost at 25 minutes for freezers in the event of
a sensor failure. This setting should never be tampered with,
without first consulting the factory.
IV. d - PREP TABLE & MEGA TOP REFRIGERATOR
The prep table and mega top refrigerator will function as
a refrigerator. Due to the open top feature, it runs slightly
lower evaporator temperature and builds more frost on coil
than the regular refrigerator. The prep table and mega top
therefore utilize electric heater for more effective defrost.
The defrost procedure is the same as in freezer described
in section IV.c, except the defrost will be terminated at 45°F.
IV. e - REFRIGERATING PRODUCT
Centerline compact models will satisfactorily refrigerate an
assorted load of food items. Allow space between articles to
permit free air circulation. Do not overload at any one time
with warm food products and expect immediate results. A
certain amount of time is required to remove heat from items
before operating temperatures can be attained. The system
is designed for storage of refrigerated or frozen product.
Opening the door or drawer will increase the temperature
in the cabinet and will require a certain amount of time
to recover. Also, after peak service periods or after warm
product is loaded, the refrigerator will require a certain
amount of time for the temperature to return to the normal
operating range.
Fig. 6
IV. OPERATION
V. OPERATION
