Merloni Full Sized - No Frost - Fridge Freezers

This manual covers a range of appliances. The following combinations are the First/First & Second Digits of the Model No’s covered.

	MT - Double Door - eg MTA332V
	MB - Combined - eg MBA3841C
	T - Double Door - eg TA3PXUK
	B - Combined - eg BE13PSUK

No Frost with LCD Display

No Frost with Standard Controls

Controls

Sensors

	Freezer Evaporator Sensor
	Freezer Air Sensor
	Fridge Air Sensor
	Fridge Door Switch (Magnetic Reed on PCB behind control panel)

	Freezer Evaporator Sensor
	Freezer Air Sensor
	Fridge Air Sensor
	Fridge Door Switch (Magnetic Reed on PCB behind control panel)

Inter PCB Connection

Ribbon cable that passes through fridge door and fridge door hinge area

Not Applicable

Main Components

	Compressor
	Fridge Lamps
	Defrost Heating Element
	Freezer Fan
	Fridge Fan
	Thermal Fuses

	Compressor
	Fridge Lamps
	Defrost Heating Element
	Freezer Fan
	Fridge Fan
	Thermal Fuses

Diagnostics of Main Components Compressor

The following conditions will prevent the Compressor from running even though compartment temperatures have dropped below set temperatures.

	Compressor Protection - This prevents the compressor from switching on for 8 minutes from the time that it last switched off.
	After 4 hours of continuous running - The compressor will automatically cease running if this situation has occurred.
	Pause After Defrost Cycle - After every defrost cycle there is a 10 minute pause period before the compressor starts to run. This ensures that the water from the defrost has time to run off before cooling down starts.

Possible causes of any Compressor Malfunctions

	Electronic PCB Management
	Compressor Control Circuit on PCB
	Wiring Connections/Harnesses
	Faulty Compressor
	Temperature sensors Open/Short Circuited

Testing The Compressor can be forced on by pressing the Super Freeze button. (Remember the 8 minute rule) Defrost Heaters

The start and end of the defrost cycles are controlled by the Electronic PCB, which will take the following circumstances into account.

Start of Defrost:

	The total run time of the compressor since the last defrost cycle (on average 11 hours). However the run time between two defrost cycles will be 30 hours maximum and 8 hours minimum.
	The duration of last defrost cycle
	The amount of door openings

End of Defrost:

The cycle will end when the temperature of the evaporator reaches approx. 15°C, which in most cases is approx. 40 mins after the cycle has begun.

Possible causes of any Defrost Heater Malfunctions

	Electronic PCB Management
	Defrost Heating Elements Control Circuit on PCB
	Wiring Connections/Harnesses
	Thermal Fuses
	Heating Elements
	Blocked Drain Hole

Testing Use the Autotest procedure Fridge Fan

The following situations will prevent the Fridge fan from operating.

	If the fridge door is open even if the compressor is running
	After the door is closed the fan will operate for a period of 3 secs to prevent any warm air that has entered the compartment from travelling down to the freezer compartment
	After a defrost cycle and when the compressor starts running the fan will not run until the evaporator coil reaches -17°C. This is on top of the normal 5 minute delay.

Possible causes of any Fridge Fan Malfunctions

	Electronic PCB Management
	Fridge Fan Control Circuit on PCB
	Wiring Connections/Harnesses
	Fridge Fan

Testing Use the Autotest procedure Freezer Fan

The following situations will prevent the Fridge fan from operating.

	If the fridge door is open even if the compressor is running.
	After a defrost cycle and when the compressor starts running the fan will not run until the evaporator coil reaches -17°C. This is on top of the normal 5 minute delay.

Possible causes of any Fridge Fan Malfunctions

	Electronic PCB Management
	Freezer Fan Control Circuit on PCB
	Wiring Connections/Harnesses
	Freezer Fan

Testing Use the Autotest procedure. Fridge Lamps

	If the fridge door is left open for a period of greater than 2 mins the lamps will start to operate intermittently, switching on & off at regular intervals.
	If the fridge door is left open for a period of greater than 7 mins then the frequency of flashing will increase.

Possible causes of any Fridge Lamp Malfunctions

	Electronic PCB Management
	Fridge Door Control Circuit on PCB
	Lamp Control Circuit on PCB
	Wiring Connections/Harnesses
	Fridge Lamps
	Presence of magnet on the fridge door

Testing Switch appliance on and open fridge door to check correct operation of lamps. Thermal Fuses

	If the temperature of the evaporator reaches 72°C the thermal fuses will operate. This cut off all power to all heating elements.
	Thermal Fuses cannot be reset and therefore have to be replaced before the appliance will start to operate as normal

Possible causes of any Thermal Fuse Malfunctions

	Wiring Connections/Harnesses
	Thermal Fuses

Testing Using the Autotest procedure to force all the elements on will confirm that the thermal fuses are closed circuit. Although, it should be noted, that if the heating elements do not operate it does not mean that the thermal fuses are open circuit. See section on Defrost Heating Element. Temperature Sensors

	All temperature sensors operate by using resistance values to control the required temperatures in each compartment. The Electronic PCB measures the resisitance values of the sensors.
	If any of temperature sensors malfunction the appliance will still operate and no fault will be indicated to the user. The Electronic PCB uses a timed thermostat run to continue running the appliance this also includes a defrost cycle which again is a timed operation.

Possible causes of any Temperature Sensor Malfunctions

	Electronic PCB Management
	Temperature Monitoring Circuit on PCB
	Temperature Sensors
	Wiring Connections/Harnesses

Testing Any faulty temperature sensors will be displayed using the Autotest procedure. Please note that none temperature sensors can be replaced.

Autotest Procedure LCD Display Controls Activation

	Switch Appliance Off using On/Off Key
	Press & Hold the ECO key for more than 3 secs

LCD Display Controls Deactivation

	255’s after activation
	Switching the appliance Off by pressing the On/Off key
	Disconnecting power

Standard Controls Activation

	Switch Appliance Off by rotating Freezer knob to the Off position
	Press & Hold the Super Freeze key for more than 3 secs

Standard Controls Deactivation

	255’s after activation
	Switching the appliance Off by rotating Freezer knob to the Off position
	Disconnecting power

Error Codes