Service manual
COLD
5. OPERATION
5.1 NORMAL
When the thermostat knob is on (OFF) position it means that:
the compressor is off;
all Leds are off;
the electronic board is powered ( 220-240V 50Hz ! ! ! ).
Warning: the electronic board is powered with a 220-240V 50Hz voltage even if the thermostat
knob is on (OFF) position. Therefore, disconnect the appliance from the electric power before
operating with the electronic board.
By rotating clockwise the thermostat knob the green LED switches ON.
In FROST-FREE chest freezer, the humidity inside the freezer compartments accumulates on the
evaporator battery, thanks to the air circulation, thus preventing the formation of frost on food.
During normal operation time the electronic board powers the compressor and the fan circuits.
The operation time which corresponds to the interval between the following defrosting lasts about 14 hours
with normal opening of the door ( it can last up to 71 hours if the door is never opened !).
5.2 NORMAL OPERATION WITH FIRST SWITCHING ON OR POWER FAILURE
In case of fault when the appliance is switched on for the first time or in case of a power failure, one of the
two conditions described below occurs:
1. If the internal temperature is higher or the same as the cut-in temperature of the thermostat (CUT-IN),
when the power is restored, the electronic board activates the compressor and the fan till the set
temperature is reached and after 5 hours the electronic board activates the defrosting procedure.
2. If the internal temperature is lower than the cut-in temperature of the thermostat (CUT-IN), when the
power is restored, the compressor functions in thermostatic conditions and after 5 hours the electronic
board starts the defrosting procedure.
The electronic board activates, anyway,
the defrosting procedure after 5 hours in case of both the first
switching on and a power failure
.
Warning
: if you turn the thermostat knob anti-clockwise till the zero position (OFF), all the counters will be
reset (apart from those necessary to the manual defrosting procedure) and once the thermostat knob has
been turned clockwise in ON position, the compressor will operate in thermostatic conditions.
5.3 DEFROSTING
All the humidity in the compartment accumulates on the evaporator, which is the coldest part of the
compartment; periodically. Every about 14 hours minimum with normal door openings (till 71 hours if the
door is never opened!), it is necessary to defrost the ice which forms on the battery. Therefore the
electronic board disconnects the circuit that powers the compressor and the fan and, after checking for the
defrosting heater, it powers the defrosting heater for about 20 minutes minimum.
In case the defrosting
heater is interrupted or its connector is disconnected, green and yellow LEDs flashing alternately
and the defrosting heater lasts 1 hour.
The heat generated by the defrosting heater does not affect the temperature of the freezer compartment or
the temperature of the food packages, since the whole thermal energy is consumed in the defrosting
process of the ice on the evaporator.
After 20 minutes, the board detects every minute the signal of the defrosting process in order to determine
the intervention of the defrosting cut-out switch.
When the defrosting cut-out switch intervenes, the electronic control switches on the compressor and the
fan again with a 5 minute delay.
If for any reason, the defrosting cut-out switch does not intervene and the temperature of the battery rises
up to +40 °C, the defrosting heater will be switched off by the safety thermal switch.
FROST FREE CHEST FREEZER with ERF1050
electronic
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