Timing Chart; [A] Principle Of Operation; [B] Protectors - Hoshizaki FM-170AFE Service Manual

4. TIMING CHART

[a] PRINCIPLE OF OPERATION

When the Operation Switch is moved to the "ON" position, water is supplied through the
Control Water Valve. This cycle continues until the Reservoir is full and the Float Switch
signals to close the Water Valve. The Gear Motor will then start in 1 second and the Compressor
in 60 seconds. This starts the normal icemaking process.
During normal operation, the icemaker will stop only when the Ice Storage Bin is full and the
Bin Control activates. This will automatically reset to resume normal operation.
Float Switch
Control Water Valve
Bin Control Switch
Gear Motor
Fan Motor
Compressor

[b] PROTECTORS

1) Pressure Switch
If the Pressure Switch activates, the Gear Motor, Fan Motor and Compressor stop
simultaneously in 0.25 sec. When the switch resets at the correct pressure, the icemaker
starts the icemaking process in the same way as startup. (See "[a] PRINCIPLE OF
OPERATION.")
Although the Pressure Switch will automatically reset, the Compressor will stop for at least 5
minutes for protection in case the head pressure rises to activate the Pressure Switch again.
If this happens, the icemaker will start and stop repeatedly without making ice until the cause
of head pressure rise is removed.
2) Motor Protector (GM)
When the Protector activates, the Gear Motor, Fan Motor and Compressor stop simultaneously
in 0.25 sec. The Protector has to be manually reset. Check and resolve the cause of the
Protector tripping before pressing the Reset.
POWER ON
UPPER
LOWER
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
1sec 90sec
60sec 150sec
Fig. 6
21
BIN FULL
1sec
60sec