Preventive Maintenance Schedule - Bunn Ultra-1 Service & Repair Manual

A common problem occurs when the proper preventive maintenance procedures are not followed. Failure to
perform these procedures may result in damaged equipment and may not be covered by warranty.
Please check the following items before assuming a refrigeration fault.
When the product does not freeze, there are several possibilities other than a failure in the refrigeration system.
The torque between the auger motor and the frozen product is contolled by the torque sensor board measur-
ing the distance between the pins on the coupler and shaft. When the distance between the pins reaches the
maximum allowable distance, the compressor shuts off. The machine thinks the product thickness has reach
the maximum and shuts off the compressor. The illustration below shows some of the other possible causes
for a false reading from the torque sensor board.
Proper inspection and preventive maintenance (including daily cleaning) will avoid expensive repairs and
costly down time.
A
B
C
D
E
DAMAGED/CORRODED AUGER SHAFT
DAMAGED/WORN BUSHINGS/SEALS
PREVENTIVE MAINTENANCE
NORMAL OPERATION
CHILL MODE
A. MOTOR SHAFT TORQUE SENSOR PIN
B. AUGER SHAFT TORQUE SENSOR PIN
C. TORSION SPRINGS
D. AUGER SHAFT
E. AUGER MOTOR COUPLING
POSSIBLE CAUSES FOR FALSE READINGS
WEAK TORSION SPRINGS
BENT TORQUE SENSOR PINS
DIRTY OR DAMAGED TORQUE SENSOR BOARD
ICE MODE
TOO MUCH KRYTOX GREASE
MISSING TORQUE SENSOR PINS
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