Electrolux SANTO 2941i Original operating manual

SERVICE INSTRUCTION
COLD
©AEG Hausgeräte GmbH Publ.-No.
Muggenhofer Straße 135 599 51 07 03
D-90429 Nürnberg
Germany EN
Fax [phone]
TSE-N
Edition: 02.01
LONGFRESH
MODELS
SANTO 2941i
SANTO 2902i
SANTO 2932i

AEG-Refrigeration 292 5209 68
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
1. General
The Santo 2941i longfresh has electronically controlled information displays and microproc-
essor controlled regulators for the refrigerator as well as for the 4-star freezer compartment.
A so-called longfresh compartment is integrated within the refrigerator of the appliance. In
addition, refrigerator and longfresh compartment are controlled via a magnetic valve.
Refrigerator compartment
longfresh compartment
4-star freezing compartment

AEG-Refrigeration 292 5209 69
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
2. Operation
2.1. Refrigerator and longfresh compartment
The refrigerator can be adjusted within a temperature range of +3 to +9oC (rated tempera-
ture). In contrast, the longfresh compartment has a fixed temperature setting of 2oC +2K. In
both longfresh shelves, air humidity can be set individually from about 40 to 90%.
Control lamp for Control lamp for Operation control lamp
refrigeration fan express cooling for refrigerator
Button Express Main switch Temp.contol LCD-temp.display
refrigeration cooling switch cooling/longfresh refrigerator refrigerator
fan compartment
2.1.1.Main switch
Switching on and off of the refrigerator and longfresh compartment is only possible with a pen
or similar (childproof safety switch).
Important: Do not disconnect from mains supply as logical on and off switching of
components is via electronic module.
2.1.2.Switch for refrigeration fan
When switching on, the appliance is automatically switched to operation with refrigeration fan
(control lamp on). The running fan increases cooling capacity and decreases thermal
stratification. Due to the energy-optimised 12V-DC motor, the refrigerator uses even less
energy when the fan is activated. If not required, the refrigeration fan can be switched off with
this button.

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Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
2.1.3.Express cooling
By pressing the button Express cooling, the temperature within the refrigerator is decreased
to its lowest value (+3oC). The fan is in constant operation (6 hours). After 6 hours, operation
reverts to normal. Both methods represent an extremely high cooling capacity. The longfresh
fan is running in fixed cycle operation.
2.2. Freezing compartment
The temperature for the freezing compartment can be adjusted between -14 to -28oC.
2.2.1.Main switch
As with the refrigerator, switching on and off of the freezing compartment is only possible with
a pen or similar (childproof safety switch).
Important: Do not disconnect from mains supply as logical on and off switching of
components is via electronic module.
2.2.2.Fast freeze button
- Pressing the fast freeze button activates the fast freeze function.
- Automatic reverting to normal operation after 48h, temperature limitation to -35oC!
- Manual reverting to fast freeze is possible at all times by pressing the fast freeze button
again.
Control lamp Control lamp
freezer fast freeze
LCD temp. display Temp. control Main switch Fast freeze
freezer freezer freezer switch

AEG-Refrigeration 292 5209 71
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
2.3. Temperature displays
The average refrigerator and the warmest freezer compartment temperatures are indicated
on the LCD display. During and after defrosting, the refrigeration temperature display is stored
and changes only when the temperature reaches normal levels again. 4 hours after the start
of defrosting, the actual temperature is displayed again.
Display range:
Refrigerator +19 to 0oC
Freezer 0 to -39oC
If the temperature falls outside these ranges, only lines are displayed; if the refrigeration
temperature falls below 0oC, then 0oC is constantly displayed.
As this is an integrated appliance, the background illumination of the temperature displays and
all LEDs are switched off when the refrigerator door is closed.
3. Warning controls
longfresh-temp.control lamp Freezer temperature control lamp
Cancel button acoustic signal refrigerator Cancelbuttonacousticsignalfreezer
3.1. Acoustic warning
The acoustic signal sounds if:
- one of the two doors is open longer than 30s (permanent signal). The signal can be
switched off by pressing the respective cancel button. The warning will sound again after
2 mins, if one door stays open.
- one or more sensor(s) is defective (short circuit). The intermittent signal can be switched
off by pressing the cancel button, an optical fault information is displayed on the
respective LCD window (see point 10).
- the temperature in relation to the set value rises excessively too much (values see point
3.2).
The intermittent acoustic temperature warning can be switched off by pressing the
respective cancel button and will sound again as soon as the door is next opened.

AEG-Refrigeration 292 5209 72
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
3.2. Optical warnings
The red LED alarm (temperature control lamp for refrigerator and freezer) flashes if
- the temperature in the longfresh compartment rises above 6oC
- the freezer temperature is
- at setting 1: warmer than -10.5oC
- at setting 2: warmer than -14.5oC
- at setting >2.75: warmer than -17.5oC
All LEDs and temperature displays are switched off when the door is closed (LCD display
without background illumination).
4. Defrosting
The refrigerator and the longfresh compartment are defrosted automatically. The freezer has
to be defrosted manually as this part is cooled statically (conventional freezer). Points 4.1 and
4.2 therefore only relate to the refrigerator and the longfresh compartment.
4.1. Normal defrosting
The longfresh compartment and the refrigerator are defrosted automatically after 12 h
compressor operation (= circa once per day).
Operation of electronic:
1. step: Pre-defrost (preparation of defrosting):
- prior to actual defrosting, the refrigerator temperatures are cooled to rated
temperature less 2K
2. step: Start of defrosting:
- thelongfreshcompartment is defrosted with a 10W-defrost heater (longfresh
compensation heater).
- the refrigerator is defrosted by self-generated heat
3. step: End of defrosting in longfresh compartment:
- when the temperature at the longfresh evaporator sensor has reached
+8oC.
4. step: End of defrosting in refrigerator:
- when the temperature at the refrigerator evaporator sensor has reached
+6oC and defrosting of longfresh compartment has been completed.

AEG-Refrigeration 292 5209 73
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
Defrosting of the refrigerator cannot be completed before defrosting of the longfresh
compartment is finished as the refrigerator is always defrosted at the same time the longfresh
compartment is defrosted.
4.2. Defrosting in continuous operation
Should the appliance for any reason switch to continuous operation (rise in ambient
temperature, faults in coolant system, overloading ...), then refrigerator and longfresh
compartment are defrosted after 10 h compressor operation, to avoid insufficient cooling due
to excessive ice build-up.
5. Refrigeration technology and automatic control technology - functional principles
5.1. Freezer
The Santo 2941io longfresh is equipped with a conventional 4-star freezing compartment.
This freezing compartment operates completely independent with respect to refrigeration and
control technology. The following description therefore relates mainly to the refrigerator and
longfresh compartment.
5.2. Refrigerator and longfresh compartment
The refrigerator incorporates a back panel evaporator, the longfresh compartment is
equipped with a U-evaporator (i.e. at the back and side).
5.2.1.Magnetic valve
By means of the magnetic valve, cooling can be directed optionally to the refrigerator and the
longfresh compartment or only to the longfresh compartment. Two types of valves are fitted
in series: the monostable Danfoss-3-way valve Type 0904 or the bistable Elbi-3-way valve.
If voltage is applied to the Danfoss-3-way valve, then the longfresh compartment only is
cooled. Switch-over of the Elbi-3-way valve is by voltage impulses.

AEG-Refrigeration 292 5209 74
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
5.2.2.Refrigeration technology
condenser
refrigeration evaporator
magnetic valve
compressor ` longfresh evaporator
5.2.3.Compressor control
The compressor is activated via the refrigeration fan or via the longfresh cooling fan.
Depending on the air sensor condition, the electronic activates the following functions:
a) Both cooling fans are warmer than the cut-in value:
- compressor ON
- magnetic valve without voltage, i.e. refrigerator and longfresh compartment are
cooling
b) The refrigeration fan is warmer than the cut-in value, the longfresh air sensor is between
ON- and OFF value:
- compressor ON
- magnetic valve without voltage, i.e. refrigerator and longfresh compartment are
cooling
- longfresh fan cycles, i.e. cooling performance in longfresh compartment is
reduced.

AEG-Refrigeration 292 5209 75
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
c) The refrigerator fan is cooler than the cut-in value, the longfresh fan is warmer than the cut-
in value:
- compressor ON
- voltage applied to the magnetic valve, i.e. only the longfresh compartment is being
cooled.
d) The refrigeration sensor is warmer than the cut-in value, the longfresh sensor is colder than
final rated value:
- compressor ON, i.e. no compartment is cooling until temperature on long-fresh air
sensor reaches cut-off value +0.5K in longfresh compartment.
It is possible that the longfresh compensation heating is switched on.
Only then:
- compressor ON
- magnetic valve without voltage, i.e. refrigerator and long-fresh compartment are cooled.
- longfresh fan cycles.
Note:
The refrigerator has first priority with regard to refrigeration technology and second priority
with regard to automatic control technology. The longfresh compartment on the other hand
has second priority with regard to refrigeration technology as the coolant flows from the
Rollbond-evaporator to the U-evaporator. With respect to automatic control technology
however, the longfresh compartment has top priority. If the thermal stress within the
refrigerator is already fairly high, then the cooling capacity of the longfresh compartment is
technologically reduced. This is however almost eliminated due to the cycling of the longfresh
fan or even by activating of the longfresh compensation heating (see also point 5.2.4).

AEG-Refrigeration 292 5209 76
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
5.2.4.Warm refrigerator temperature (fan regulation):
If the actual temperature of the refrigerator (= current temperature on refrigerator air sensor)
is higher by 5K than the cut-in value, then depending on the actual temperature of the
longfresh compartment (=current temperature on longfresh air sensor) the following functions
are progressively activated:
a) The actual temperature in the longfresh compartment is warmer by 0.5K than the cut-in
value.
- the refrigeration fan is switched parallel to the compressor.
b) The actual temperature of the longfresh compartment is colder than initial rated value.
- the refrigeration fan is switched parallel to the compressor
- the longfresh fan cycles
c) The actual temperature in the longfresh compartment is colder by 0.5K than the cut-off
value.
- the refrigeration fan is switched parallel to the compressor.
- the longfresh fan cycles
- voltage is applied to the longfresh compensation heating.
If the relevant actual temperature within the longfresh compartment is exceeded, then the
output of the respective function decreases. If the actual temperature within the refrigerator
reaches cut-in value +2K, the function ceases altogether.

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Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
red red white blue black
LED red
LED yellow
LED yellow
LED green
white red green
1/2
3/4/5/6
10/11
12/13
14/15/16
17/18
21/22
23/24 25/26 27/28
29/30
33/34
35/36
6. Components
The Santo 2941i contains 3 electronics, one operational PCB and one logical PCB as well as
a performance PCB.
6.1. Arrangement of terminal block of logical PCB (view from top):

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Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
6. Components
The Santo 2941i contains 3 electronics, one operational PCB and one logical PCB as well as
a performance PCB.
6.1. Refrigerator
6.1.1.Sensors
Two NTC-resistors are fitted within the refrigerator: one evaporator sensor and one air sensor.
The air sensor measures the actual temperature within the refrigerator and regulates the
compressor as well as the fan.
The evaporator sensor measures the evaporator temperature of the Rollbond-evaporator. It
is therefore responsible for ending the defrost process and for fault diagnosis.
Refrigeration evaporator sensor
(run in tube)
Refrigeration air sensor
6.1.2.Refrigeration fan
The refrigerator is equipped with a 12V energy-optimised DC-fan with the following advantages:
- even temperature distribution and
- increased cooling performance

AEG-Refrigeration 292 5209 79
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
6.2. longfresh compartment
6.2.1.Sensors
The longfresh compartment is also equipped with two NTC resistors, the longfresh evaporator
sensor and the longfresh air sensor. The longfresh air sensor measures again the actual
temperature, the longfresh evaporator temperature the evaporator temperature. The air
sensor is again responsible for controlling the compressor and fan, the evaporator sensor for
ending the defrost process and for fault diagnosis.
6.2.2.longfresh-fan
The longfresh compartment is equipped with a 230V shaded-pole motor with radial fan. During
normal operation, the longfresh-fan runs parallel to the compressor +10 min overrun. The
circulating air creates a layer of air around the longfresh shelves to ensure even temperature
distribution on the outside of the longfresh compartment. Without fan, very low parallel
temperatures would result which would lead to condensation or ice build-up.
In certain modes of operation such as
- warm refrigeration temperatures (see point 5.2.4) or
- fast cooling,
the longfresh fan within the refrigerator runs in cycling mode (1 min ON; 2 min OFF). The
cooling performance within the longfresh compartment is therefore reduced and compressor
run-time prolonged.
longfresh evaporator fensor tube
(run in tube)
longfresh fan
longfresh air sensor

AEG-Refrigeration 292 5209 80
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
6.2.3.Humidity filter
The air layer described under 6.2.2. together with the two integrated humidity filters enables
air humidity to be adjusted from about 40 to 90% as required and separately for the two
shelves.
Slide bar left - low air humidity; slide bar right - high air humidity.
slide bar upper shelf
slide bar lower shelf
6.2.4.longfresh compensation heater
The longfresh compensation heater (10W) is fitted directly underneath the U-evaporator. It
is integrated and therefore not replaceable!
The longfresh compensation heater serves two functions:
- shortening of defrost process in longfresh compartment (see point 4.1)
- supporting of automatic control and refrigeration technological functions.
(see point 5.2.3. and 5.2.4)
6.3. Magnetic valve
Two types of valves are fitted in series: the monostable Danfoss-3-way valve Type 0904 or
the bistable Elbi-3-way valve. If voltage is applied to the Danfoss-3-way valve, then the
longfresh compartment only is cooled. Switch-over of the Elbi-3-way is by voltage impulses.

AEG-Refrigeration 292 5209 81
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
6.4. Freezing compartment
The freezing compartment is fitted with a NTC-resistor, the freezer air sensor. The freezer air
sensor switches the compresser on and off and is responsible for activating warning signals.
Freezer air sensor
7. Low ambient temperature
In case of low ambient temperatures and ensuing long compressor down-times, the longfresh
fan is switched on for a period of 10 min every 30 min. This ensures even longfresh-
temperatures under these circumstances.

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VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
8.. Switch values and switching times
All switch values are stored in an EEPROM. The EEPROM is mounted onto an IC-plinth to
facilitate easy replacement. In special service cases therefore, the EEPROM could be fitted
later as a supplementary option without having to exchange the complete logical PCB.
Cut-in value for longfresh compartment: 1.1 oC
Cut-out value for longfresh compartment: 0.3 oC
Cut-in value for refrigerator on setting 1: 14.4 oC
Cut-in value for refrigerator on setting 4: 6.1 oC
Cut-off value for refrigerator on setting 1: 13.4 oC
Cut-off value for refrigerator on setting 4: 5.1 oC
Display offset for refrigerator on setting 1: -2.0 K
Display offset for refrigerator on setting 4: -3.0 K
Cut-in value for freezer on setting 1: -10.5 oC
Cut-in value for freezer on setting 4: -25.5 oC
Cut-off value for freezer on setting 1: -11.5 oC
Cut-off value for freezer on setting 4: -26.5 oC
Cut-in value for freezer on fast freeze mode: -34.0 oC
Cut-off value for freezer on fast freeze mode: -35.0 oC
Display offset for freezer: -3.0 K Constant!
Fast freeze time limit: 48 h

AEG-Refrigeration 292 5209 83
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
9. Self-test
During the self-test, sensors, compressor, fans, heater and electronic modules are automati-
cally checked for correct connection and performance. These values may be verified by
means of a Metra-tester. A diagnosed fault is recorded in code on the LCD display. This
significantly helps fault diagnosis for service.
9.1. Starting of self-test
The self-test is started
- when freezer is switched on
- when pressing cancel button of refrigerator and
- simultaneously switching-on refrigerator.
Pre-condition for the correct functioning is an uncooled appliance.
9.2. Procedure of self-test
1. Once switched on, the LCD-display shows dA for Danfoss magnetic valve or El for Elbi-
magnetic valve.
2. Press cancel button for refrigerator once:
CL for degree Celsius or FH for degree Fahrenheit is displayed.
3. Press cancel button for refrigerator once:
Start of automatic self-test. The cancel button for the refrigerator should now not be
pressed again inadvertently.
9.3. Automatic self-test
9.3.1.Step 1 (1 flashes in LCD display)
- refrigeration fan is switched on for 10s
- pause for 3s
- longfresh fan is switched on for 10s
- pause for 3s
- longfresh-compensation heater is activated for 10s
(power consumption ca. 43 mA)

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VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
One consuming device is omitted if the cancel button for the refrigerator is pressed. Due to
their low power consumption, the fans can only be checked manually. (The air current can be
heard and felt when the door is open and the door switch pressed).
9.3.2.Step 2 and 3 (a 2 or 3 flashes in LCD display)
These two steps automatically check
a) the sensors for cross-over
b) the two compressors for performance
c) the magnetic valve
d) the longfresh fan.
Step 2 longfresh compartment in sole operation (voltage applied to magnetic valve)
Step 3 longfresh compartment and freezer in operation (no voltage on magnetic valve)
Principle to a)
The evaporator sensors cool faster than the air sensors. It can therefore be checked whether
the sensors are crossed over.
Principle to b)
The compressors are switched on for a limited time only. The evaporator temperatures are
then checked before switching on and after switching off and the measurements compared
with pre-set minimum values.
Principle to c)
A defective magnetic valve (not switched) would result in cooling of the refrigeration
evaporator sensor as well (step 2).
Princple to d)
If the longfresh fan does not function correctly, the longfresh air sensor would not be cooled
sufficiently.
If, after completion of steps 2 and 3, no fault was found, the LCD displays a flashing 10 and
the compressor is switched off. Now the refrigerator door must be opened to initiate the next
test step. Any fault found is displayed in code (see point 10).

AEG-Refrigeration 292 5209 85
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
9.3.3.Step 4
This step automatically checks the electronics:
- all LEDs must be illuminated when the door is open
- internal refrigerator lamp must be on
- permanent acoustic warning signal
- the LCD displays a flashing 8 if all functions are correct
- the freezer display shows a blinking 88 if all functions are correct.
9.3.4.Step 5
This step checks the warning facilities of the freezer.
Procedure:
- open freezer door
- permanent acoustic warning signal
- close freezer door
- normal operation!
During the self-test, the LCD-displays show background illumination when the door is
closed.To test the electronic only, it is possible to switch straight to test-step 4 immediately
after the start of the self-test by pressing the cancel button of the refrigerator until the display
shows a flashing 10.
The functions
- fast cooling
- fast freeze and
- refrigerator fan
can be tested at any time via the LED control lamp by pressing the respective button.
The total self-test lasts about 20 min.

AEG-Refrigeration 292 5209 86
VH34-AUK 06.94
Santo 2941i longfresh E-Nr.: 621 370 121 (R12)
Santo 2902i longfresh E-Nr.: 621 371 022 (R134A)
10. Fault coding
The following fault codes are blinking in the LCD-display:
Code LCD Meaning possible cause of fault
SA KT longfresh air sensor defective sensor short circuit, sensor
disconnection/interruption
sb KT longfresh evaporator sensor sensor short circuit, sensor
defective disconnection/interruption
sc KT refrigerator air sensor defective sensor short circuit, sensor
disconnection/interruption
sd KT refrigerator evaporator sensor sensor short circuit, sensor
defective disconnection/interruption
SF GT freezer air sensor defective sensor short circuit, sensor
disconnection/interruption
FO KT EEPROM read error EEPROM not or incorrectly connected
F1 KT U-evaporator not cooled in sensors crossed, longfresh fan not
pre-set time period running, cooling system in longfresh
compartment blocked
F2 KT air in longfresh compartment sensors crossed, longfresh fan
not cooled in pre-set time not running, magnetic valve not
period switched
F3 KT U-evaporator too warm sensors crossed, appliance was not
compared to longfresh sufficiently warm prior to test
air temperature
F4 KT U-evaporator too warm sensors crossed, appliance was not
compared to refrigerator sufficiently warm prior to test, magnetic
air temperature valve not switched
F5 KT U-evaporator too warm sensors crossed, appliance was not
compared to refrigeration sufficiently warm prior to test,
evaporator temp. magnetic valve not switched
F6 KT longfresh-air temperature too sensors crossed, appliance was not
warm compared to refrigerator sufficiently warm prior to test,
air temperature magnetic valve not switched