MDT5N25 & MDT5N40
ELECTRICAL SEQUENCE
Refer the wiring diagram as needed.
The “Power” light on the board glows whenever there is power to the machine (and the master switch is ON).
If the machine is switched off at the master switch, but is otherwise ready to go, switching the master switch to ON does the following:
The bin empty and power lights on the circuit board glow.
There is a 15 second delay
If there is enough water in the reservoir, the circuit board will allow the machine to start up.
Start up consists of:
The compressor contactor coil receives power from the circuit board.
The contactor is energized, connecting power to the compressor, and the compressor starts.
The auger motor receives power from the circuit board and starts.
As ice goes past the ice level sensors, the bin empty light will stay on and the machine will continue to run, unless the ice stays between the sensors for more than 15 seconds (bin full). At that point, the bin empty light goes out, and the machine shuts down.
Other reasons for shut down:
Low water level (as sensed by the thermistor in the reservoir).
Shut Down consists of:
The compressor contactor opens
The compressor stops
The auger motor is run by the circuit board for 2 more minutes, clearing out ice in the evaporator, and then
The auger motor no longer receives power from the circuit board, and the auger motor stops.
After a 6 minute delay, If the ice level sensor is clear (bin empty) for more than 15 seconds, the machine will start up again.
Another purpose of the circuit board is to turn the machine off if there is not enough water in the machine.
When the water level in the reservoir falls below the tip of the water level sensor, the machine will “shut down”
After a 6 minute delay, if the water refills the reservoir, the machine will start up again.
Separate from the circuit board:
If the high pressure control (cut out switch) opens, the compressor will stop immediately (through the contactor ). It must be manually reset.
The master switch is the manual control for the complete machine, but it is not a service disconnect.
Ice Vending
When a user places a container in front of the Touch Free ice sensor and below the ice delivery chute, the circuit board connects power to the bin drive motor and ice is dispensed for as long as the container is present. If the user does not remove the container, ice will be dispensed for 60 seconds and then stop.
When a user places a container in front of the Touch Free water sensor, and below the water spout, the circuit board connects power to the water solenoid valve and water is dispensed. If the user does not remove the container water will be dispensed for 90 seconds and then stop.
Splash panel cleaning:
A switch, located next to the water spout, may be pushed to disable the
Splash Panel
Cleaning or
Touch Free
Disable Switch
May 2001
Page 13
