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MFI Series Electrical Sequence
Page 13
Electrical Sequence:
There are 7 indicator lights on the control board:
●WTR-OK: (Water OK) Green. Normal=Glowing. Glow when there is water in the reservoir.
●PWR-OK: (Power OK) Green. Normal=Glowing. Glows when the power board has power and is functional.
●Service: Red. Normally Off.
●Freeze: Red. Normally glowing when making ice.
●Bin Full: Red. Normally Off when making ice.
●LED1: White. Located next to the Control Board’s Compressor Relay. Normally glowing when making ice.
●LED2: White. Located next to the Control Board’s Auger Motor Relay. Normally glowing when making ice.
If the machine is switched OFF at the mode switch, but otherwise ready to go, switching the mode switch ON
does the following:
●The PWR-OK light glows.
●If there is water in the float reservoir, the WTR-OK light glows.
●After 10 seconds the Freeze, LED1 and LED3 lights glow and the machine starts up.
Start Up:
●The compressor relay and auger motor relay become energized, connecting power to the windings of the
auger motor and contactor coil.
●The contactor is energized, connecting power to the compressor, and the compressor starts.
●As ice is made it passes between the ice level sensors but because it is not a continuous stream it only
interrupts the sensor’s infrared beam momentarily. The bin full light remains off and the machine stays on
until ice builds up in the bin and blocks the path between the sensors for 6 seconds or longer. When that
occurs the bin full light glows and the machine shuts down.
Shut Down:
●The compressor relays opens, LED1 goes out.
●The compressor contactor opens.
●The auger motor stays on for 1 more minute, clearing out ice in the evaporator, and then
●The auger motor relay opens, LED3 goes out and the auger motor stops.
The compressor will not restart until 2 minutes or more have passed after last shutdown. If the path between
the ice level sensors remains clear for more than 10 seconds the ice machine will restart.
Control Board Protection Devices:
●When the water level in the reservoir falls below the water level sensor’s tip, the WTR-OK light goes out and
the machine shuts down. When water refills the reservoir the WTR-OK light glows and the machine starts up
again.
●If the auger drive motor currents becomes excessive the compressor and auger drive motor will be switched
OFF and the Service light will blink. The control board will restart the auger drive motor in 4 minutes. If
during the first 60 seconds after restart the auger motor current stays within limits, the compressor is
restarted and the machine returns to normal operation. If the auger motor’s current is excessive within 60
seconds after restart, the process will be repeated once more. If during that try the current is still excessive
the machine shuts down and must be manually reset. The Service light will then be glowing continuously.
To Reset:
●Switch power to the unit off and then back on.
Other Protection Devices:
●If the high pressure control cut out switch opens the machine will stop immediately. It will automatically
reset when the high pressure falls below its cut in point.
●If the low pressure control cut out switch opens the machine will stop immediately. It will automatically reset
when the pressure rises above its cut in point.
●The mode (ON-OFF) switch is the manual control for the complete machine, but it is not a service
disconnect.