COMPRESSOR, WATER INLET SOLENOID VALVE, HOT GAS VALVE
NOTE: The length of the defrost cycle is
As shown it is possible to have a different length of the defrost cycle in connection with the different length of the second phase of the freezing cycle T2 relative to the ambient temperature situations; shorter when the ambient temperature is high and longer in colder ambients so to partially compensate the length of the freezing cycle, which is longer in high ambient temperatures and shorter in low ones.
H.Check, during the defrost cycle, that the incoming water flows correctly into the sump reservoir in order to refill it and that its surplus overflows through the overflow drain tube.
I.Check the texture of ice cubes just released. They have to be the right shape with a small depression of about
If the ice cubes require a correction to their shape, it is possible to modity the length of the timed freezing cycle by changing the DIP SWITCH keys setting as illustrated in table B.
It the ice cubes are shallow and cloudy, it is possible that the ice maker runs short of water during the freezing cycle second phase or, the quality of the supplied water requires the use of an appropriate water filter or conditioner or the installation of the optional water drain valve kit KWD.
J.To be sure of the correct operation of the ice level temperature sensor, located in one side of storage bin liner, during the defrost cycle place one shovel of ice cubes in contact with its probe for approx. 30
As the temperature of storage bin sensor reaches the value of +2˚C (35˚F), the ice level control transmits a signal to the microprocessor of the P.C. BOARD in order to stop the ice maker operation at the end of the defrost cycle with the simultaneous glowing of the 3rd RED LIGHT, to monitor the BIN FULL situation (Fig.6). Page 13
With no more ice cubes in touch with the ice level control the temperature of its probe progressively rises to reach + 4.5˚C (40˚F) and at this point the ice machine restarts to initiate a new freezing cycle with the simultaneous extinguishing of the 3rd RED LIGHT.
NOTE The
6.Principle of Operation
6.1How it works
In the cube ice makers the water used to make the ice is kept constantly in circulation by an electric water pump which primes it to the spray system nozzles from where it is diverted into the inverted mould cups of the evaporator. A small quantity of the sprayed water freezes into ice; the rest of it cascades by gravity into the sump assembly below for recirculation.
6.2Freezing Cycle
The hot gas refrigerant discharged out from the compressor reaches the condenser where, being cooled down, condenses into liquid. Flowing into the liquid line it passes through the drier filter, then it goes all the way through the capillary tube where, due to the heat exchanging action, it loses some of its heat content so that its pressure and temperature are lowered as well.
Next the refrigerant enters into the evaporator serpentine (which has a larger l.D. than the capillary) and starts to boil off; this reaction is emphasised by the heat transferred by the sprayed water.
The refrigerant then increases in volume and changes entirely into vapour.
The vapour refrigerant then passes through the suction accumulator (used to prevent any small amount of liquid refrigerant reaching the compressor) and through the suction line. In both the accumulator and the suction line it exchanges heat with the refrigerant flowing into the capillary tube (warmer), before being sucked into the compressor and recirculated as hot compressed refrigerant gas.
The freezing cycle is controlled by the evaporator temperature sensor (which has its probe in contact with the evaporator serpentine) which determines the length of the first and second portion of it and it is signalled by the glowing of the 6th RED LED.
The first portion length or time T1
NOTE If, after 15 minutes, the evaporator temperature has not yet reached the value of 0˚C (35˚F) (due to a partially or total shortage of refrigerant or to a too high condensing temperature, etc.) the sensor, through the P.C. BOARD, causes the unit to stop the operation with the simultaneous glowing of the SECOND RED WARNING LED (Fig. 7). Page 13. After having eliminated the source of the unit trip off, to restart the machine operation it is necessary first to rotate the program selector to the
The second portion length of freezing cycle or time T2
NOTE In case the time T2 gets longer than 45 minutes, the unit stops with the glowing of the second RED WARNING LED.
Also in this case, after having eliminated the source of the trip OFF to restart the machine it is necessary first to rotate the program selector to the RESET position then put it again on OPERATION or, switch OFF and ON the unit at power line Main Switch.
The third portion or time Ta (added time) of the freezing cycle is controlled by the electronic timer of P.C. BOARD. As the evaporator temperature reaches the value of
NOTE The activation of the timer (Time mode) of P.C. BOARD is signalled by the glowing of fourth RED LED located in the front of the P.C.
BOARD.
ATTENTION In case the length of the second portion of freezing cycle or time T2, lasts as long as between 35 and 45 minutes, the third portion or time Ta gets skipped by the P.C BOARD which puts the unit directly in the defrost or harvest cycle.
The length of the third portion of the freezing cycle (adjustable) is
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