McCall Refrigeration MCCF27 manual Freezer Models MCCF48 & MCCSTF48 Temperature Control Operation

Compact Refrigerators and Freezers Service and Installation Manual

Freezer Models MCCF48 & MCCSTF48 Temperature Control Operation

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.

Turn the defrost timer screw ONLY in a clockwise direction, turning the screw counter-clockwise will break the cam motor.

Service Alert

During normal operation the evaporator fan may cycle and/or pulse independently of the compressor. Consult the service manual or contact Technical Support at 1-888-733-2446 if you are unsure of the proper function.

Freezer Models MCCSTF27 & MCCF27 Temperature Control Operation

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 may cycle and/or pulse independently of the compressor. Consult the service manual or contact Technical Support at 1-888-732-2446 if you are unsure of the proper function.

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 allow 8 hours for temperature stabilization before making 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.

6 For customer service, call (888) 732-2446 Fax (800) 669-0619, www.mccallrefrigeration.com