Service instruction Cold AEG 5 18 C C COOLMATIC C C FROSTMATIC SANTO electronic Table of contents SERVICE INSTRUCTION ELECTRONIC CONTROL FLEC 2.3 General 2 1 THE PANEL 2 2 FUNCTIONS 3 3 CABINET START-UP 7 4 TEMPERATURE SENSORS 8 5 SPECIAL FUNCTIONS 11 6 CHANGING THE CIRCUIT BOARD and 12 CHANGING THE SENSOR HOLDER, refrigerator/air 13 Appendix 1 14 DISPLAYS IN THE SIGN WINDOW 14 Refrigerator and freezer with electronic control FLEC 2.3 Publication number 599 511 018
SERVICE INSTRUCTION ELECTRONIC CONTROL FLEC General The factory in Mariestad is introducing a new assortment of electronically controlled refrigerators and freezers. Electronics control and display the temperature in the freezer and refrigerator respectively. The control panel for the new electronic control has a slightly different appearance depending on the design model. However the electronics themselves are the same. Below is the panel for AEG with numeric display shown.! NOTE! Circuit boards and wiring (including sensor wiring) have a voltage of 230 V. a c d e f h i j k l AEG 5 18 C C COOLMATIC C C FROSTMATIC SANTO electronic b g 1 THE PANEL a) Refrigerator switch (off/on) b) Refrigerator thermometer c) Temperature selector / thermostat (refrigerator) d) Fast cooling lamp - illuminates yellow when fast cooling e) Fast cooling button, COOLMATIC f) Freezer switch (off/on) g) Freezer thermometer h) Temperature selector / thermostat (freezer) i) Freezing lamp - Illuminates yellow when freezing j) Freezing button, FROSTMATIC k) Warning lamp flashes when door alarm and when the temperature is too high. l) Reset button for sound alarm. 2
2 FUNCTIONS a c d e f h i j k l AEG 5 18 C C COOLMATIC C C FROSTMATIC SANTO electronic b g Switches for refrigerator and freezer respectively (a, f) a - refrigerator f - freezer - The refrigerator and the freezer can be started and stopped separately by the switches a) and f). - Switch off the freezer by pressing the button (f) for appr. 3 seconds. The time delay prevents switching off the cabinet by mistake, during for example cleaning. During switch off a countdown sequense 3, 2, 1, is shown on the display. - Press the button (f) again to start the freezer. Temperature selector / Thermostat (c, h) c - the refrigerator can be set between +2 and +8 C, and H (=Holiday) h - the freezer can be set between -15 and -24 C - Press the temperature selector to set the required temperature, press the left button + for warmer press the right button - for colder. - The first time any of the buttons are pressed the thermometer shows in flashing figures the previously required temperature. Now you can begin to set the required temperature by pressing + or -. The set temperature is always displayed by flashing light. After 5 seconds the flashing stops and the thermometer displays the temperature of the cabinet again. This feature allows you to check the setting by pressing the buttons + or - once without changing the set value. When you start a cabinet at room temperature select the required temperature as stated above. When the set point has been flashing for 5 seconds the freezer and refrigerator thermometer displays the actual temperature. See section Start-up of cabinets The temperature setting H is a Holiday setting giving a temperature of +15 C. When restarting the cabinet after off the temperature does not need to be reset. The electronic control will automatically set it to the previously set temperature. 3
Door switch The traditional switch has been removed and replaced by a Reed element on the circuit card and a foamed in magnet in the in the middle of the end cap of the upper frame of the upper door. (see figure). Reed-element Function test Test the Reed element by moving a loose magnet below the center of the front panel. If the light in the cabinet turns off it is OK. Magnet Refrigerator thermometer (b) The refrigerator thermometer displays temperatures between 0 C and +39 C. - When colder than 0 C - flashes. Lower or higher temperatures than -35 C or+39 C are indicated as sensor failure. The thermometer displays a steady light: - when the thermometer shows the cabinet temperature The thermometer flashes: - while the temperature is being set by the temperature selector - when colder than 0 C - flashes The thermometer shows or - if the temperature gauge has stopped working The thermometer shows the average temperature in the refrigerator. The cabinet temperature varies depending on the type of cabinet. Generally it is coldest on the shelf under the drip slot and warmest at the top of the cabinet. In order to avoid heavy fluctuations around the set point a temperature window of +/-2 C has been allowed around this set value. At temperatures within this window the set point is displayed. At temperatures outside the window the actual value is displayed. The thermometer has a maximum changing speed of 1 C every 10th minute in cold as well as warm direction. It is essential that no warm articles are placed close to the two sensors in the refrigerator since faulty displays and/or faulty operations cycles might then occur. 4
The freezer thermometer (g) The freezer thermometer shows temperatures between -35 C and +39 C. Lower or higher temperatures than -35 C or +39 C are indicated as sensor failure. The thermometer shows a steady light: - when the thermometer shows the cabinet temperature. The thermometer flashes: - while the temperature is being set by the temperature selector - at temperature alarm The thermometer shows - if the temperature gauge has stopped working a c d e f h i j k l AEG 5 18 C C COOLMATIC C C FROSTMATIC SANTO electronic b g The freezer thermometer shows the temperature of the warmest part of the freezer. This means that other temperatures in the cabinet (which can be measured with an ordinary thermometer) always are lower than the temperature shown on the thermometer. The warmest part in the freezer varies depending on the type of the cabinet, but it is generally at the top in the front part of the freezer to the door sealing. The difference in temperature between that measured in the middle of the cabinet (not measured directly against the evaporator) and the warmest part of the freezer may vary between 3and 7 C. In order to avoid heavy fluctuations around the set point a temperature window of +/-2 C has been allowed around this set value. At temperatures within this window the set point is displayed. At temperatures outside the window the actual value is displayed. The thermometer has a maximum changing speed of 1 C every 10th minute in cold and 1 C every 20th minute in warm direction. It is essential that no warm articles are placed close to the two sensors in the freezer since faulty displays and/or faulty operations cycles might then occur. Temperature alarm, freezer (k) The alarm is activated when the warmest part in the freezer (= the indicated temperature) reaches 11 C. The red warning light (k) flashes and the acoustic alarm sounds intermittently. The temperature is displayed on the thermometer with flashing figures. You can switch the acoustic alarm off by pressing the general reset button (l). When the acoustic alarm has been turned off the thermometer shows the temperature with a steady light. The red warning lamp continues to flash as long as the cabinet temperature remains -11 C or higher. When the cabinet has turned cold again and the red warning lamp turns off. If the cabinet automatically reaches a temperature below the alarm level -11 C but the alarm has not been reset by the button (l) (f.i. after a short power failure and nobody was at home) the 5
acoustic alarm will reset itself. However the thermometer will in such cases show the temperature of the cabinet with a flashing light and the warning lamp will also flash. This is due to the fact that the electronic circuit has a memory function. After one push on the reset button the thermometer will during 5 seconds show the highest temperature reached in the freezer and the red warning lamp will turn off. Temperature alarm, refrigerator (k) The alarm is activated when the warmest part in the refrigerator (= the indicated temperature) reaches +11 C. The red warning light (k) flashes and the acoustic alarm sounds intermittently. You can switch the acoustic alarm off by pressing the general reset button (l). The red warning lamp continues to flash as long as the cabinet temperature remains +11 C or higher. When the cabinet has turned cold again the red warning lamp turns off. Door alarm (K) The warning light starts to flash and the acoustic alarm sounds when: - the refrigerator door has remained open for approximately 5 minutes. - the freezer door has remained open for approximately 80 seconds. Turn the acoustic signal off by pressing the reset button (l). The red warning lamp turns off when the door is closed. If the door is not closed a new alarm will start after approx. 5 minutes (refrigerator) and approx. 80 seconds (freezer). Freezing/FROSTMATIC (j) When the freezing button (j) is pressed the compressor starts to work continuously and the yellow lamp (i) is lit. The freezing function is automatically interrupted after appr. 52 hours and the yellow lamp turns off. The freezing process may also be interrupted early by pressing the freezing button again. The freezer compressor has minimum deceleration time of 20 minutes. At worst it thus may take 20 minutes before the compressor will start after freezing has been turned on. Fast cooling, COOLMATIC (e) When the button for fast cooling (e) is pressed the thermostat is automatically switched to +2 C and the yellow lamp (d) is lit. The fast cooling is automatically interrupted after appr. 6 hours and the yellow lamp turns off. The fast cooling process may also be interrupted early by pressing the fast cooling button again. To set the refrigerator in fast cooling position is equal to setting +2 C manually. Reset button for alarm (l) The reset button (l) is used to switch the acoustic alarm off when there is a door opening alarm and/or temperature alarm. This button is also used to switch the warning lamp off and to show the highest temperature after an alarm (see sections Alarm and Cabinet start-up ). 6
3 CABINET START-UP a c d e f h i j k l AEG 5 18 C C COOLMATIC C C FROSTMATIC SANTO electronic The refrigerator and the freezer can be used independently. Start 1) Press the switch buttons (a), (f) to start the refrigerator and the freezer respectively. 2) When the cabinet has been started the refrigerator - and the freezer thermometer displays the actual temperature. 3) Since the cabinet is warm the warning lamp flashes and the acoustic alarm sounds. Pressing once on the reset button resets the acoustic alarm. The warning lamp continues to flash until the freezer temperature is below -11 C and the refrigerator temperature is below +11 C. Setting of Temperature The temperatures are set by the temperature selectors (c) and (h) - press the left button + for warmer and press the right button - for colder temperatures. During setting the figures in the thermometer flash. Flashing ends soon after the last pressing of the button. When the cabinet has been turned-off and is to be restarted the temperature does not have to be reset. The electronic circuit will automatically reset to the previously set temperature. Switch off b When the complete cabinet is to be switched off: - Switch off each respective part using the buttons (a) for the refrigerator and (f) for the freezer. - Remove the plug from the socket. When only the refrigerator or the freezer are to be switched off: - Switch off with button (a) for the refrigerator and (f) for the freezer respectively. In order not to switch off the cabinet by mistake each respective switch must be pressed during appr. 3 seconds. g! NOTE! The cabinet is considered charged until the plug has been removed from the socket. 7
4 TEMPERATURE SENSORS The cabinet contains temperature sensors, NTC, for temperature reading. Refrigerator/freezers has three sensors; one inside the freezer and two in the refrigerator. The two sensors in the refrigerator are located in the evaporator, and in the air resp. Refrigerators contains two sensors and freezers one sensor. The sensors are keyed and fit in only one way in the contact housing of the circuit card. The keys are shown below. Freezer Brown Fridge, air White Fridge evaporator Black The characteristics of the sensors are shown below: Resistance Temperature for NTC sensor 100000 90000 80000 70000 60000 50000 40000 30000 20000 10000 0-40 -30-20 -10 0 10 20 30 40 Resistance [ohm] Temperature [ C] 8
TEMPERATURE SENSORS when foamed-in evaporator The cabinet uses temperature sensors, NTC, for measuring the temperature. Fridge/freezers has three sensors; one in the freezer and two in the refrigerator. The two sensors in the refrigerator are placed in foamed-in tubes accessible from the back of the cabinet. The small diameter tube leads to the evaporator and the large diameter tube leads to the air sensor of the fridge. The evaporator sensor has a mark showing how far it should be into the tube to be correctly assembled. The foamed sensors have different sensor bulbs (temperature sensors) with different diameters (see figure blow). The freezer sensor is not foamed-in. All sensors are keyed and will only fit one way in the connector housing on the circuit card. New with foamed sensors is also that they do not have different cable colors due to a new supplier (both are gray /white) but they have the article number hot stamped. For sensors not foamed-in the colors are kept. Keying of the sensors is shown in figure below. Fridge, air luft 5 mm bulb Fridge evaporator 4 mm bulb Freezer Brown 9 mm bulb Sensor characteristics are shown below: 100000 90000 80000 70000 60000 50000 40000 30000 20000 10000 0-40 -30-20 -10 0 10 20 30 40! NOTE! It is of utmost importance that the cable inlets for the sensors are absolutely tight. Poor sealing cause heat from the condensor to be conducted to the sensors. This will influence the control and display of the thermometers. 9
Sensor failure Should any of the sensors be defective (resistance value too high or too low, short circuit or interruption) each compressor will be on for about 30 minutes and off for about 45 minutes. At sensor failure the thermometers show: Refrigerator (air sensor defective): Lower part of the thermometer shows: Refrigerator (evaporator sensor defective): Upper part of the thermometer shows. Freezer (freezer sensor defective): Lower part of the thermometer shows: At extreme temperatures the alarm levels may be released even if the sensors are intact. Therefore, failure codes at temperatures above +39 C and below -35 C should be ignored. 10
5 SPECIAL FUNCTIONS Test program The electronics makes it possible to run a test program. This can be useful after f.i. a service card change. Run the test program by: 1) Remove the plug from the socket and insert it again 2) Simultaneously pressing the buttons for higher temperature setting (freezer) and freezing respectively. Keep pressing them for about five seconds. Now the test program starts which means that: - All segments are lit on the thermometer display. - All indicator lamps are lit. If the upper door is opened (also valid for cabinets with one door) the warning light is turned off. - If the lower door is opened (two-door cabinets) the freezing light(s) turn off. - When any of the buttons is pressed the summer sounds and the thermometer display window shows actual sensor temperature on the cooling plate. The test program is automatically interrupted after appr. 1 minute and the cabinet returns to normal setting. The test program can also be interrupted by switching the cabinet off and on or by simultaneously pressing the buttons for higher temperature setting (freezer) and freezing respectively and keeping them pressed for approx. five seconds. Changing the temperature area of the freezer If the customer experiences excessive deviations between measured and displayed temperatures the service technician can move the entire temperature area to a display 3 C colder. This can be done as follows: Press the reset button (l) and the freezing button (j) simultaneously and keep them pressed for five seconds. After five seconds the summer sounds with a long signal which confirms that the display has been moved. To return to normal display again, press the buttons (l) and (j) simultaneously for 5 seconds. Now the summer sounds with a short signal. Note! The display will not change immediately to a colder display. Instead the temperature inside the cabinet is successively changed to appr. 3 C warmer. 11
6 CHANGING THE CIRCUIT BOARD AND SENSOR HOLDERS When changing the circuit card the entire component holder cpl with the circuit card should always be replaced. Please note that the component holders cpl are coded for return (see list below) and should be returned to the factory in their original packaging with the service order attached. Component holder cpl 242 50 01-01 Combi cabinet, normally insulated, 3 freezer boxes Component holder cpl 242 50 01-02 Combi cabinet, normally insulated, 4 freezer boxes Component holder cpl 242 50 01-03 Combi cabinet, max insulated Working order when changing circuit card: Open the control panel as follows... 1. Loosen the door from down and up. Unscrew the pivot pin. 2. Loosen the front panel by way of the three snap fixings at the upper side of the panel. 3. Pull out the panel front and the component box. 4. Loosen wiring and sensors to make it possible to pull out the front and circuit card. 1 3 2 5. Loosen the component box by carefully bending the front part while simultaneously snapping the box from its fixings by pulling the front upwards. 6. It is now possible to replace the circuit card. In front off the display card there is a plastic film protecting the electronics against ESD (electrostatic discharge). The plastic film has two cut-outs at each side, suitable to the support ribs at the upper side of the component boxes outside. -Hang the plastic film on the support ribs and then carefully press the component box and the front together. -Check that the buttons work properly after the assembly. 12
CHANGING THE SENSOR HOLDER, refrigerator/air The figure shows the sensor at refrigerators. At combined fridge/freezers the sensor are almost equal placed but are shorter (see text). 1 Carefully pull out the sensor holder along the cabinet until it has come loose from the snap fixing. 2 Turn out the holder and it is all done. 3 The sensor is at different places on refrigerators and combined fridge/freezers. In refrigerators the sensor goes out through the whole holder on the back off the cabinet while the sensor in combi cabinets goes in the guide (not the whole way through the sensor holder) foamed in at the holder. It is different sensor holders for refrigerators and combis. Sensor holders in refrigerator is at the cabinets right side, while it is at the left side in the combi cabinets. Assembly is at reversed order. CHANGING SENSOR, refrigerator/evaporator and air, foamed sensor The figure shows the evaporator sensor to be removed/installed from the back. Fridge section in combined cabinet With foamed evaporator, (seen from the back) Remove/install the air sensor in the same way as earlier but install it in the wider tube and make sure it is pushed all the way through the tube and enters the refrigerator. Then install the sensor holder for fridge/air, see above, and push any surplus cable back into the tube and seal the drilled hole with some sealing compound. Sensor channel in evaporator for evaporator sensor Foamed evaporator Evaporator sensor (4mm) Evaporator sensor is pushed into the narrow tube Mark for how far the bulb shall be inserted Foamed sensor tube for evaporator Foamed sensor tube for fridge (air) Drilled hole in sheath for installing sensors 13
Appendix 1 DISPLAYS IN THE SIGN WINDOW Refrigerator 0 - +39 steady light: Displays the average temperature in the refrigerator. 2-8 - H flashing: Displayed during temperature setting. Disappears 5 seconds after temperature setting is complete. - flashing: Displayed if the temperature in the refrigerator is below 0 C steady light: Sensor failure on air sensor. steady light: Sensor failure on evaporator sensor. Freezer +39 - -35 steady light: Displays the highest temperature in the freezer. -15-24 flashing: Displayed during temperature setting. Disappears 5 seconds after temperature setting is complete. +39-35 flashing: Displayed if the temperature in the freezer has been above -11 C and it has automatically returned to a lower temperature. +39-11 steady light: Displays the highest temperature in the cabinet after a power failure (showed during 5 seconds while pressing the reset button. The warning lamp simultaneously turns off). steady light: Sensor failure in the freezer. 14