service manual refrigeration - McCulloch Spares, Parts & Accessories

service manual refrigeration - McCulloch Spares, Parts & Accessories
SERVICE MANUAL
REFRIGERATION
© ELECTROLUX ZANUSSI S.p.A.
VIA GIARDINI CATTANEO, 3
I - 33170 PORDENONE (ITALY)
Fax (0434) 394096
Publication no.
599 34 81-93
010601
ITZ/SERVICE/AA
NOFROST
UNDERCOUNTER
FREEZERS
NOFROST UNDERCOUNTER FREEZERS
2/20
CONTENTS
1. INTRODUCTION....................................................................................................................................... 4
2. REFRIGERATION CIRCUIT ...................................................................................................................... 5
3. ELECTRIC WIRING .................................................................................................................................. 6
3.1 ELECTROMECHANIC VERSION................................................................................................................... 6
3.2 ELECTRONIC VERSION ............................................................................................................................. 7
4. FUNCTIONAL DIAGRAM.......................................................................................................................... 8
4.1 ELECTROMECHANIC VERSION ................................................................................................................... 8
4.2 ELECTRONIC VERSION ............................................................................................................................. 9
5. OPERATION .......................................................................................................................................... 10
5.1 NORMAL........................................................................................................................................... 10
5.2 DEFROSTING................................................................................................................................... 11
6. COMPONENTS ...................................................................................................................................... 12
6.1 CONTRO PANEL : .................................................................................................................................. 12
6.2 FREEZER COMPARTMENT : ..................................................................................................................... 12
6.3 COMPRESSOR COMPARTMENT:............................................................................................................... 13
7. ACCESSIBILITY..................................................................................................................................... 15
7.1. ACCESSIBILITY TO CONTROL PANEL............................................................................................. 15
7.2. ACCESSIBILITY TO FREEZER COMPARTMENT.............................................................................. 17
8. TROUBLESHOOTING ............................................................................................................................ 19
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1. INTRODUCTION
This manual describes the NOFROST UNDERCOUNTER FREEZERS models.
The basic model is a 80 litre freezer produced in two versions with:
- electromechanic control
- electronic control
NOFROST UNDERCOUNTERS consists of a single freezer compartment.
The cold, produced by the evaporator battery in the freezer compartment, is then distributed by the fan located
over the battery.
FREEZER COMPARTMENT
The fan makes the cold air circulate in the compartment: it enters by nozzle 1 and comes out of nozzle 2 passing
through the evaporator battery. The thermostat bulb ( for the electromechanic version ) or the sensor ( for the
electronic version ) are located inside (pos. A) and detect the air temperature in the compartment.
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2. REFRIGERATION CIRCUIT
Legend :
1. compressor
1. condensator
2. filter
3. capillary
4. heat exchanger
5. battery evaporator
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3. ELECTRIC WIRING
3.1 electromechanic version
( check the specific diagram for each model ! )
Legend :
1.
3.
5.
7.
9.
24.
25.
26.
27.
28.
junction box
frezeer compressor junction box
overload cut-out
freezer thermostat
defrosting heater
battery fan
timer
safety thermal switch (+ 40 °C)
defrosting cut-out switch (+ 10 °C)
running capacitor
NOFROST UNDERCOUNTER FREEZERS
a.
b.
c.
d.
e.
yellow-green
brown
blue
white
black
6/20
3.2 electronic version
( check the specific diagram for each model ! )
Legend :
1.
3.
5.
9.
24.
25.
26.
27.
28.
41.
junction box
freezer compressor junction box
overload cut-out
defrosting heater
battery fan
timer
safety thermal switch (+ 40 °C)
defrosting cut-out switch (+ 10 °C)
running capacitor
electronic board
NOFROST UNDERCOUNTER FREEZERS
a.
b.
c.
d.
e.
f.
yellow-green
brown
blue
white
black
grey
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4. FUNCTIONAL DIAGRAM
4.1 electromechanic version
( check the specific diagram for each model ! )
Legend :
1.
3.
5.
7.
9.
24.
25.
26.
27.
28.
junction box
freezer compressor junction box
overload cut-out
freezer thermostat
defrosting heater
battery evaporator
timer
safety thermal switch (+ 40 °C)
defrosting cut-out switch (+ 10 °C)
running capacitor
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4.2 electronic version
( check the specific diagram for each model ! )
Legend :
1.
3.
5.
9.
24.
25.
26.
27.
28.
41.
junction box
freezer compressor junction box
overload cut-out
defrosting heater
battery fan
timer
safety thermal switch (+ 40 °C)
defrosting cut-out switch (+ 10 °C)
running capacitor
electronic board
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5. OPERATION
5.1 NORMAL
In NOFROST refrigerators, thanks to the air circulation, the humidity inside the freezer compartment
accumulates on the evaporator battery, thus avoiding the formation of frost on food.
During the normal operation time the timer cam closes 3-4 contacts thus powering the compressor and fan
circuit. The operation time lasts about 18.5 hours.
The arrows in the picture show the current path.
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5.2 DEFROSTING
The ice on the battery must be removed regularly, therefore after about 18.5 hours of operation, the timer (25)
switches from 3-4contact to 3-2contact, disconnecting the compressor and the fan and switching on the
defrosting heater (9)
After about 42 minutes of defrosting, the timer switches to 3-4 contact again, switching the compressor and the
fan on and disconnecting the heater.
If the battery temperature reaches +10°C in less than 42 minutes, the heater is switched off by the defrosting
cut-out switch (26). If, for any reason, it does not switch on and the battery temperature reaches +40°C, the
heater will be switched off by the safety thermal switch (27).
The arrows in the picture show the current path.
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6. COMPONENTS
6.1 Contro panel :
- SUPER A pilot lamp;
- ON/OFF B pilot lamp;
- thermostat knob T;
- push-button SUPER S
fixed positions in the electromechanic version
(hidden if OFF, in sight if ON)
by impulse timed exclusion
(about 48 hours) in the electronic version; in case
of first ignition or of power failure, SUPER
sets automatically for about 5 hours;
6.2 Freezer compartment :
- fan D;
- couple of thermal overload cut-outs E
- evaporator battery F
- defrosting heater G ( 151 W – 381 Ω )
- conveyor K
- side hooks L
TYPE OF THERMAL
OVERLOAD CUT-OUT
DEFROSTING
SAFETY
OPERATION TEMPERATURE
OPENING
CLOSURE
+ 10 °C
- 1 °C
+ 40 °C
+ 30 °C
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6.3 Compressor compartment:
At the back of the appliance there is the timer H;
by using a screwdriver it is possible to rotate the shaft
cam manually, only clockwise, to switch the 3-4 and
3-2 contacts switch.
TIME “A”
19 h 12 ‘
TIME “B”
42 ‘
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By rotating the timer shaft clockwise with a screwdriver, you can hear two snaps that indicate the contacts
st
closure. As you can see in the picture (the position of the snaps is merely indicative), between the 1 snap and
nd
nd
st
the 2 snap the run is minimum, between the 2 and the 1 snap the run is longer:
Warning :
nd
-
In order to test the appliance during “normal” operation, you need to rotate the timer cam till the 2
as to close 3-4 contact;
snap so
-
In order to test the appliance during “defrosting” operation, you need to rotate the timer cam till the 1 snap
so as to close 3-2 contact.
st
Rubber valves
The defrosting water is drained outside by means of a special silicon rubber valve inserted into the conveyor
drain. Its structure enables the defrosting water to exit easily, while during the cooling phase, because of the
eddy inside the compartment, the valve closes thus avoiding the external humid air to be ducted in.
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7. ACCESSIBILITY
7.1. ACCESSIBILITY TO CONTROL PANEL
To access the control panel it is necessary to unscrew the two screws that fix the top to the hinges, then push
the top forward in order to uncouple the hooks from the mushroom screws.
Inside the top there is the controls support with the thermostat (or the electronic board), the thermostat knob and
the SUPER push-button.
The thermostat capillary (or the electronic sensor)
enters the compartment by hole U .
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Characteristics of NTC sensor:
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7.2. ACCESSIBILITY TO FREEZER COMPARTMENT
To access the components of the freezer compartment
remove the protection I by unscrewing the 5 screws.
Evaporator battery
The evaporator battery F is hooked to
the conveyor K
by means of two side clips L
and three hooks N located at the bottom,
removable with a screwdriver.
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Defrosting heater
The defrosting heater G is inserted into the
aluminium wings of the battery; to replace it, it is
necessary to open the hooks N at the bottom of
the conveyor with a screwdriver and extract the
heater from the battery wings paying attention not
to deform them.
Thermal overload cut-outs
The two +10°C e +40°C overload cut-outs are
connected together in a single component E and
are not available as single spare part.
They are fixed to the conveyor with two screws.
The conveyor
The conveyor for the defrosting heater is fitted to
the bottom of the compartment with two clips; to
remove the conveyor it is necessary to push down
the two clips.
The fan
The fan is fixed with two screws.
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8. TROUBLESHOOTING
WARNING !
Unplug the appliance before operating.
Discharged circuit :
In case of refrigerating gas leakage, the troubleshooting must be carried out not only in the traditional weldings,
but also in the junctions with LOKRING ring of the battery-capillary R and battery-return hose S hoses.
Excessive ice on the battery :
If the rubber valve remains open, the humid air outside the freezer compartment penetrates inside and
accumulates too much ice on the battery. The valve remains open if there are foreign bodies or if it looses
elasticity, therefore, in the first case the foreign bodies must be removed, while in the latter the rubber valve must
be replaced.
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No defrosting :
If no defrosting cycle occurs, the possible causes might be:
Sequence
n°
1
POSSIBLE CAUSES
The defrosting heater is
interrupted
2
One or both thermal
overload cut-out switches
are open
3
Timer blocked or faulty
HOW TO CHECK
CORECTIVE ACTION
Disconnect the heater connector
and check with the tester the
correct heater value to the
connector clamps
Freeze the battery then unplug
the appliance, disconnect the
connector of thermal overload cutouts and check with a tester their
electrical continuity to the
connector clamps
Unplug the appliance, position the
thermostat knob on ON, then
access the timer box and
measure the electrical continuity
with a tester:
a) between clamp 1 of timer and
the line clamp of the feeding
plug;
b) between the clamp 3 of timer
and the clamp of the feeding
clamp neutral wire
If the heater value is not about
380 Ω, replace the interrupted
heater
If the heater value is ∞ Ω
(infinite=open circuit), replace
the thermal overload cut-outs,
while if the heater value is 0 Ω
then check sequence n° 3
If the heater values of [ a) and
b) ] are 0 Ω then replace the
timer
For the electronic version there is no switch before the timer therefore, when the appliance is connected to the
supply mains, the timer is always supplied but it does not action anything if the electronic thermostat is OFF.
Faulty sensor :
If the sensor is faulty the electronic board is set so as the appliance operates with some pre-set programme
cycles:
30 minutes compressor ON
45 minutes compressor OFF
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