McCall Refrigeration MCCR27 Benutzerhandbuch

6

After the unit is connected to power it will automatically 

begin operating. With the doors closed, the temperature of 

the cabinet should reach 0°F (-18°C) on freezers in about 

one hour. Continuous opening and closing of the doors will 

hamper the unit’s ability to maintain optimum temperature.
The electronic temperature control constantly monitors box 

temperature as well as evaporator coil temperature to maintain 

consistent product temperatures. As an added energy-saving 

feature, the electronic controller will switch the evaporator 

fan motor on and off with the compressor and condenser fan 

motor.
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. 
Service Alert: During normal operation the evaporator fan 

IMPORTANT NOTE 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 initial defrost is complete. 

This initial defrost cycle may take up to 15 minutes to 

complete, at which time the freezing cycle will begin. 
Whenever the freezer is plugged in, and the control has 

completed initializing including the initial defrost cycle (see 

above), the electronic temperature control will cycle the 

compressor, evaporator fan motor, 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 5-hours since the last defrost cycle OR 

if evaporator coil temperature drops below -34°F (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, whether manual 

or automatic, it switches off the evaporator fan motor, 

compressor and condenser fan motor, and switches on the 

defrost heater to warm the evaporator coil and melt 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. 
Electronic Temperature Control Location & Adjustment
Never turn the knob more than 1 dial number and always 

any additional adjustments. The control is located in the 

control box at the rear of the unit (see photo).  It is factory set 

at mid-range to maintain about -3°F (-18°C) 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. 

After the unit is connected to power it will automatically begin 

operating. With the doors closed, the temperature of the 

cabinet should reach 0°F (-18°C) on freezers in about one 

hour. 
A thermostat located in the evaporator housing on interior rear 

of the unit, controls the temperature in the box. The factory 

setting for the control is “4” and maintains about -3°F (-18°C) 

in the box. Set toward “1” for higher temperatures and toward 

“7” for lower temperatures.
Continuous opening and closing of the doors will hamper the 

unit’s ability to maintain optimum refrigeration temperature.
When the mechanical timer initiates a defrost cycle, power to 

the condensing unit and evaporator fans is interrupted and 

the defrost heater is energized. The defrost heater warms the 

evaporator coil thereby melting all frost accumulated during 

the previous refrigeration cycle. Once all frost is eliminated, 

the temperature of the coil continues to rise until it reaches 27 

minutes. The defrost control switches to refrigeration mode.  

Defrost will initiate every six hours.