Undercounter Refrigerators and Freezers
PAGE 6
4A - REFRIGERAtoRs
Both refrigerators and Freezers do not require manual defrosting. During normal
operation, a refrigerator continuously circulates above freezing cabinet air through the
coil. A compressor “OFF” cycle occurs every 2 1/2 Hours for 20 minutes to melt any
frost which may accumulate on the coil during the compressor “ON” cycle. The control
will read “dEF” and the green water drop will be illuminated (Figure 2). With standard
holding refrigerators, high relative humidity is also maintained to prevent dehydration of
stored product.
4. oPERAtIon
FREEZER
SET
INTELA-TRAUL
°F
°C
4B - FREEzERs:
During normal operation, a freezer continuously circulates below freezing cabinet air
through the coil. The coil requires a periodic defrosting for proper operation. This is
accomplished by an automatic, time activated, temperature/time terminated, defrost
program, utilizing hot gas from the refrigeration system. The controller is preset at the
factory for six equally spaced defrost cycles within each 24-hour period.
At the start of a freezer defrost cycle, the compressor, condenser fan and evaporator fan
shut off. The hot gas relay will be energized, this will energize the hot gas solenoid valve
thru the normally open contacts and the condenser fan circuit will be de-energized thru
the (normally closed contacts), and the compressor will restart. When the evaporator
coil sensor reaches 400 F the coil is fully defrosted or if the maximum time of defrost
duration (20 minutes) is reached (which ever comes first) then the defrost hot gas relay
is de-energized. The condenser fan restarts and the hot gas solenoid valve closes, The
compressor system returns to the cooling mode. Total refrigeration system operation
is then resumed (green snowflake icon goes out) and the display will show def for
an additional 10 minutes then return to reading the inside cabinet temperature. The
evaporator fan(s) are delayed from starting at the termination of the defrost cycle and will
automatically resume by time or temp delay (5 minutes or 300 F coil sensor temperature,
whichever comes first ).
During freezer 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 terminated defrost at 20 minutes
in the event of sensor failure. This setting should never be tampered with, without first
consulting Kairak’s Technical Service department.
FIGURE 2
