E.At completion of the water filling phase (5 minutes) the unit passes automatically into the freezing cycle with the start up of:
COMPRESSOR WATER PUMP
FAN MOTOR (in air cooled version) controlled by the condensing temperature sensor located within the condenser fins (Fig.2). Page 20.
10.2 Operational Checks
F.Install, if necessary, the refrigerant service gauges on both the high side and low side Schräder valves to check the compressor head and suction pressures.
NOTE: On air cooled models, the condenser temperature sensor, which is located within the condenser fins, keep the head (condensing) pressure between 13,5 and 14,5 bars (190-205 psig).
In the water cooled models the discharge pressure is kept constant at the value of 14 bars (195 psig) by means of the water regulating valve located in the water supply line to the condenser.
In case of condenser clogging such to prevent the proper flow of the cooling air or fan motor out of operation, the condenser temperature rises and when it reaches 70°C (160°F) the condenser temperature sensor shuts-off the ice maker with the consequent light-up of the RED WARNING LIGHT (Fig.3). Page 20.
The same happen even for the water cooled version where the condenser probe is placed in contact with the refrigerant liquid line. When its temperature reaches 62°C (145°F) it trips-off automatically the machine.
After having diagnosed the reason of the rise in temperature and removed its cause, it is necessary to turn the head of the selector - always using an appropriate screwdriver - first on the RE-SETposition then return it on previous OPERATION position, thus to put the machine in condition to initiate a new freezing cycle.
The same can also be done by just switching OFF and ON the unit at main line switch.
In both cases the machine restarts with the usual 5 minutes water filling phase in order to provide enough water into the sump tank.
G.Check to see through the ice discharge opening that the spray systems are correctly seated and that the water jets uniformly reach the interior of the inverted mould cups; also make sure that the plastic curtain is hanging freely and there is no excessive water spillage through it.
H.The ice making process takes place thereby, with water sprayed into the moulds that gets gradually refrigerated by the heat exchange with the refrigerant flowing into the evaporator serpentine.
During the freezing process, when the evaporator temperature falls below an established value, the evaporator temperature sensor supplies a low voltage power signal to the electronic control device (P.C. BOARD) in order to activate an electronic timer. This one takes over the control of the freezing cycle up to the complete formation of the ice cubes (Fig.4) Page 20.
NOTE: The length of the entire freezing cycle if govened by the evaporator temperature sensor which has its probe placed in contact with the evaporator serpentine (Non adjustable) in combination with the electronic timer (Adjustable) incorporated in the P.C. BOARD. The timer adjustment is factory set in consideration of cooling version and ice cube size (Medium, Large).
It is possible, however, to modify the timed length of the freezing cycle, by changing the DIP SWITCH keys setting.
In Table B, Page 18 are shown the various time extensions of the freezing cycle second phase, in relation with the different DIP SWITCH settings.
I.After about 15-18 minutes from the beginning of the freezing cycle, in an hypothetic ambient temperature of 21°C, the defrost cycle takes place with the hot gas and the water inlet valves being simultaneously activated (Fig.5). Page 20. The electrical components in operation are:
COMPRESSOR
WATER INLET SOLENOID VALVE HOT GAS VALVE
and, if installed
WATER DRAIN SOLENOID VALVE
NOTE: The length of the defrost cycle is determined by the DIP SWITCH keys setting in conjunction with the ambient temperature sensor located just in front of the condenser. The length of defrost cycle can be adjusted by changing the combination setting of keys 5, 6 and 7 of DIP SWITCH as illustrated on Table C. Page 18.
As shown, per each individual key combination, it is possible to have a different length of the defrost cycle in relation to the different ambient temperature situations; shorter when the ambient temperature is high and longer in colder ambient’s to partially compensate for the length of the freezing cycle, which is longer in high ambient temperatures and shorter in low ones.
J.Check, during the defrost cycle, that the incoming water flows correctly into the sump reservoir in order to refill it and that the surplus overflows through the overflow drain tube.
K.Check the texture of ice cubes just released. They have to be in the right shape with a small depression of about 5-6mm in their crown. If not, wait for the completion of the second cycle before performing any adjustment.
If required, the length of the timed freezing cycle can be modified by changing the DIP SWITCH keys setting as illustrated in Table B Page 18.
If 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.
L.To be sure of the correct operation of ice level control device, place one hand between its sensing “eyes” to interrupt the light beam.
The RED LIGHT located in the front of the P.C. BOARD goes immediately OFF, and after 60 seconds, the unit stops with the simultaneous glowing of the 2nd YELLOW LIGHT to monitor the BIN FULL situation (Fig.6) Page 20.
Take the hand out from the ice level control sensors to allow the resumption of the light beam; the RED LIGHT, located in the front of the P.C. BOARD, will glow immediately.
After approximately 6 seconds the ice maker resumes its operation with the immediate glowing of the FOURTH YELLOW LIGHT indicating UNIT IN OPERATION and the extinguishing of the “BIN FULL” YELLOW LIGHT.
NOTE: The ICE LEVEL CONTROL (INFRARED SYSTEM) is independent from the temperature however, the reliability of its detection can be affected by external light radiation’s or by any sort of dirt and scale sediment which may deposit directly on the light source and on the receiver. To prevent any possible ice maker malfunction, due to negative affection of the light detector, it is advisable to locate the unit where it is not reached by any direct light beam or light radiation, also it is recommended to keep the bin door constantly closed and to follow the instructions for the periodical cleaning of the light sensor elements as detailed in the MAINTENANCE AND CLEANING PROCEDURES.
M.Remove, in installed, the refrigerant service gauges and re-fit the unit service panels previously removed.
