The electronic temperature control constantly monitors box temperature as well as evaporator coil temperature to maintain consistent product temperatures. The control also sends temperature readings to the digital temperature display. The control circuits continually self-check and if an error occurs, the digital display will switch from temperature read-out to error read-out, i.e. E1. Even when an error is displayed, the refrigeration and controls system should continue to function, however not at optimal performance. Whenever the display has an error read-out, McCall Service should be contacted.
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. The digital temperature display will not display temperature OR errors until the self-check is complete and the control has switched on the evaporator fan motor, compressor and condenser fan motor.
REGARDING FREEZERS: After initializing, the control will immediately enter a DEFROST mode and the display will read DEF. 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 display will continue to read DEF for an additional 30 minutes before displaying temperature.
The control is located in the control box in the top of the unit behind the hinged louvered front panel. Refrigerators are factory set at mid-range to maintain about 38ºF (3ºC) box temperature. Freezers are factory set at mid-range to maintain about 3ºF (-18ºC) 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.
Refrigerator:
Whenever the refrigerator is plugged in, and the control has completed initializing, the evaporator fans will run continuously and the optional digital temperature will display box temperature in degrees F. The temperature control will cycle the compressor and condenser fan motor to maintain box temperature at the control setting.
Refrigerator Defrost
The temperature control also monitors the evaporator temperature and will turn off the compressor and condenser fan motor when needed to allow accumulated frost on the evaporator to clear. During this defrost cycle, the digital temperature display will read dEF. After the defrost cycle is complete, the temperature
control will return to a normal cooling cycle, but the display will continue to read dEF until the evaporator returns to normal cooling temperatures (up to 15 minutes).
Energy Saver Switch
The energy saver switch is a rocker switch located next to the thermostat knob. The normal operating position for this switch is the OFF or “0” position. If excessive condensation is observed on the door opening, flip the energy saver switch to the ON or “-” position, (red portion of the rocker switch will be visible).
Freezer:
Whenever the freezer is plugged in, and the control has completed initializing including the initial defrost cycle, the evaporator fans will run continuously (except during a defrost cycle) and the digital temperature display will display box temperature in degrees F. The temperature control will cycle the compressor and condenser 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.)
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.
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 digital temperature display will now read dEF. 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. The digital temperature display will continue to read dEF until the evaporator has returned to normal freezing temperatures (up to 30 minutes).
Dual Temperature Refrigerator/Freezer Cabinets
These units combine both a refrigerator compartment and a freezer compartment in the same cabinet. Each compartment has its own separate refrigeration unit.
