Service Diagnosis - Scotsman MDT2C12 User Manual

SERVICE DIAGNOSIS

SYMPTOM
Unit will not run
No LED lights
6th Yellow LED glows
5th Yellow LED glows
2nd LED glows
3rd Yellow LED blinks
3rd Yellow LED glows
Compressor cycles intermittently
Low ice production
Will not dispense
POSSIBLE CAUSE
Blown fuse in P.C. Board
Master switch in OFF position
Inoperative P.C. Board
Loose electrical connections
Inoperative or dirty ice level control
Shortage or too soft water
High head pressure
Too high evap. temperature
Shortage or lack of refrigerant
Gear motor tends to run on reverse
Too low gear motor rotating speed
No rotation of gear motor
Gear motor starts and stops
Low voltage
Non-condensable gas in system
Compressor starting device with loose
wires
Capillary tube partially restricted
Moisture in the system
Low water level in the freezer
Shortage of refrigerant
Pitted or stained auger surface
Dispense motor open
No power to dispense motor
Control board does not work
Open harness
Defective sensor
May 2002
Page 19
SUGGESTED CORRECTION
Replace fuse & check for cause of blown
fuse
Turn switch to ON position
Replace P.C. Board
Check wiring
Replace or clean ice level control
See remedies for shortage of water or
install a mineral salt metering device
Dirty condenser. Clean
Inoperative fan motor. Replace
Check and charge refrigerant system
Check gear motor capacitor
Check rotor bearings, freezer bearings and
interior of freezer for scores. Replace
whatever is worn or damaged.
Check for power to drive motor (16 A
fuses)
Check for stator winding
Check for correct operation of drive after a
while motor magnetic sensor
Check for correct magnetic capacity of
magnetic cylinder
Check circuit for overloading
Check voltage at the supply to the
building. If low, contact the power
company
Purge the system
Check for loose wires in starting device
Blow charge, add new gas & drier, after
evacuating system with vacuum pump
Same as above
Adjust to approx 20mm below ice spout
Check for leaks & recharge
Clean or replace auger
Check windings
Check harness connections from
touch free sensors to control board &
from board to motor
Trace harness from touch free
sensors to PC board, jump the two
center pins, the dispense motor
should turn. If not replace the board
Check the harness for continuity, if
any wire is open, replace the harness
If the above does not prove to be a
problem, replace the sensors
MDT2