Nor-Lake Undercounter Laboratory & Pharmacy Refrigerators & Freezers - Manual (Page 2)

OPERATION
REFRIGERATORS
FORCED AIR UNIT COOLER MODELS
The forced air under counter refrigerators employ a unit cooler evaporator located inside the cabinet
as the heat-removing source. Through the refrigeration process, heat is captured in the evaporator,
transferred to the condensing unit located at the bottom of the cabinet, and expelled to the
surrounding outside air. It is extremely important to maintain the minimum four-inch clearance from the
bottom of the cabinet to the floor for the refrigeration process to function properly. The cabinet
cannot be operated without the legs or casters installed.
During the operation of these units, frost will periodically form on the coil surface. Each time the
refrigeration compressor cycles to the "off" position, the evaporator fans and condenser fans will
continue to run. This will tend to keep the interior of the cabinet at a constant temperature and at the
same time remove any frost build up on the unit by circulating the inside air over the coil. The water
produced will collect in the unit cooler drain pan and travel down a drain tube to the condenser drain
pan where the water will vaporize back into the air.
The refrigeration system is designed to provide a 3.3°C temperature. The system employs a
"constant cut-in" control. This device accomplishes control of the interior by sensing the evaporator
coil. Since the control features a non-adjustable "cut-in" temperature of 3.3°C, and the sensor tube is
embedded in the fins of the evaporator coil, nuisance coil icing is eliminated because the controller
will not permit compressor start up until the coil reaches 3.3°C. Adjusting the control knob on this
system will adjust the "cut-out" temperature only. The control knob on the refrigerator is located on
the unit cooler front panel.
COLD WALL MODELS
Some of the under counter refrigerators are available in a cold wall version. The cold wall models
employ evaporator tubing embedded in the sidewalls, back, and top of the unit. During the
refrigeration process, heat is removed through the evaporator tubing and expelled through the
condensing unit. With this type of design, condensation may form on the interior of the cabinet and
should be periodically wiped dry. In order to assure proper airflow, make certain the flow of air
behind the cabinet and through the front louver is not restricted.
The refrigeration system on this cabinet uses a temperature thermostat that senses the cut in and
cut out temperatures of the cold wall evaporator coil. The temperature can be adjusted by turning the
thermostat control knob that is located behind the lower front panel.
FREEZERS
FORCED AIR UNIT COOLER MODELS
The forced air under counter freezers employ a unit cooler evaporator located inside the cabinet as
the heat-removing source. Through the refrigeration process, heat is captured in the evaporator,
transferred to the condensing unit located at the bottom of the cabinet, and expelled to the
surrounding outside air. It is extremely important to maintain the minimum four-inch clearance as
described in this manual under "Location" for the refrigeration process to function properly. The
cabinet cannot be operated without the legs or casters installed.
After shutting the door on these freezer models, a short amount of time must be allowed before the
door can be reopened. This is due to the tight seal maintained between the door and the cabinet.
Waiting a few moments for the pressure to equalize permits the door to be opened easily.