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Merloni Full Sized - No Frost - Fridge Freezers     HOME
 

This manual covers a range of appliances. The following combinations are the First/First & Second Digits of the Model Nos covered.

bulletMT - Double Door - eg MTA332V
bulletMB - Combined - eg MBA3841C
bulletT - Double Door - eg TA3PXUK
bulletB - Combined - eg BE13PSUK
 
  No Frost with LCD Display No Frost with Standard Controls
Controls
Sensors
bulletFreezer Evaporator Sensor
bulletFreezer Air Sensor
bulletFridge Air Sensor
bulletFridge Door Switch (Magnetic Reed on PCB behind control panel)
bulletFreezer Evaporator Sensor
bulletFreezer Air Sensor
bulletFridge Air Sensor
bulletFridge 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
bulletCompressor
bulletFridge Lamps
bulletDefrost Heating Element
bulletFreezer Fan
bulletFridge Fan
bulletThermal Fuses
bulletCompressor
bulletFridge Lamps
bulletDefrost Heating Element
bulletFreezer Fan
bulletFridge Fan
bulletThermal Fuses
 
Diagnostics of Main Components
 
Compressor
 

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

bulletCompressor Protection - This prevents the compressor from switching on for 8 minutes from the time that it last switched off.
bulletAfter 4 hours of continuous running - The compressor will automatically cease running if this situation has occurred.
bulletPause 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
 
bulletElectronic PCB Management
bulletCompressor Control Circuit on PCB
bulletWiring Connections/Harnesses
bulletFaulty Compressor
bulletTemperature 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:

bulletThe 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.
bulletThe duration of last defrost cycle
bulletThe amount of door openings

End of Defrost:

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

 
Possible causes of any Defrost Heater Malfunctions
 
bulletElectronic PCB Management
bulletDefrost Heating Elements Control Circuit on PCB
bulletWiring Connections/Harnesses
bulletThermal Fuses
bulletHeating Elements
bulletBlocked Drain Hole
 
Testing
 
Use the Autotest procedure
 
Fridge Fan
 

The following situations will prevent the Fridge fan from operating.

bulletIf the fridge door is open even if the compressor is running
bulletAfter 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
bulletAfter a defrost cycle and when the compressor starts running the fan will not run until the evaporator coil reaches -17C. This is on top of the normal 5 minute delay.
 
Possible causes of any Fridge Fan Malfunctions
 
bulletElectronic PCB Management
bulletFridge Fan Control Circuit on PCB
bulletWiring Connections/Harnesses
bulletFridge Fan
 
Testing
 
Use the Autotest procedure
 
Freezer Fan
 

The following situations will prevent the Fridge fan from operating.

bulletIf the fridge door is open even if the compressor is running.
bulletAfter a defrost cycle and when the compressor starts running the fan will not run until the evaporator coil reaches -17C. This is on top of the normal 5 minute delay.
 
Possible causes of any Fridge Fan Malfunctions
 
bulletElectronic PCB Management
bulletFreezer Fan Control Circuit on PCB
bulletWiring Connections/Harnesses
bulletFreezer Fan
 
Testing
 
Use the Autotest procedure.
 
Fridge Lamps
 
bulletIf 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.
bulletIf 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
 
bulletElectronic PCB Management
bulletFridge Door Control Circuit on PCB
bulletLamp Control Circuit on PCB
bulletWiring Connections/Harnesses
bulletFridge Lamps
bulletPresence of magnet on the fridge door
 
Testing
 
Switch appliance on and open fridge door to check correct operation of lamps.
 
Thermal Fuses
 
bulletIf the temperature of the evaporator reaches 72C the thermal fuses will operate. This cut off all power to all heating elements.
bulletThermal 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
 
bulletWiring Connections/Harnesses
bulletThermal 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
 
bulletAll 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.
bulletIf 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
 
bulletElectronic PCB Management
bulletTemperature Monitoring Circuit on PCB
bulletTemperature Sensors
bulletWiring 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
 
bulletSwitch Appliance Off using On/Off Key
bulletPress & Hold the ECO key for more than 3 secs
 
LCD Display Controls Deactivation
 
bullet255s after activation
bulletSwitching the appliance Off by pressing the On/Off key
bulletDisconnecting power
 
 
Standard Controls Activation
 
bulletSwitch Appliance Off by rotating Freezer knob to the Off position
bulletPress & Hold the Super Freeze key for more than 3 secs
 
Standard Controls Deactivation
 
bullet255s after activation
bulletSwitching the appliance Off by rotating Freezer knob to the Off position
bulletDisconnecting power
 
 
Error Codes
 
 

 

 
 
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