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 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