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(11) | EP 0 151 496 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Refrigeration system for a chilled product vending system |
| (57) A control circuit for cycling the evaporator fans on and off independently of the
operation of the compressor of the refrigeration system is described. The evaporator
fan is cycled on with the compressor and continues to run during the entire compressor
ON cycle. A first timer causes the evaporator fan to run for an additional delay period
following the cycling OFF of the compressor and the fans continue to blow air over
the evaporator coil until the temperature of the evaporator coil is sufficiently above
the freezing point of water (32°F, 0°C). The fans are then cycled off. A second cycling
timer is provided to intermittently cycle the evaporator fans on and off for predetermined
short intervals following the above-described delay period, and during the time when
the compressor is off. A third timer is provided to preclude freezing of the vended
products and/or the evaporator coil when a vending machine is disposed in a below
freazing environment. This timer is enabled when the thermostatic temperature switch
which controls the compressor opens, and will time out to cycle on the evaporator
fans for continuous operation for a predetermined period of time if the temperature
switch remains open in excess of a predetermined period of time. |