Hoshizaki REFRIGERATED PREP TABLE WITH RAISED RAIL 73168 - Manual (Page 31)

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5. Defrost Thermistor (cabinet) Malfunction Alarm (E8)
If the control board detects an open defrost thermistor, "E8" is displayed. When the
control board detects a shorted defrost thermistor, a 10-minute delay timer begins. After
the 10‑minute delay timer expires, "E8" is displayed. To bypass the 10‑minute delay
timer, move the power switch to the "OFF" position. Then, while pressing the rail "SET"
button, move the power switch to the "ON" position.
• If this alarm appears, first make sure that the thermistor is properly connected to the
control board.
• A shorted defrost thermistor is not detected by the control board during the 1st hour
after power is turned on. To bypass the 1-hour delay timer, move the power switch to
the "OFF" position. Then, while pressing the rail "SET" button, move the power switch
to the "ON" position.
Reset Options
The alarm automatically resets when one of the following conditions is met:
• The defrost thermistor is secured to the control board.
• The defrost thermistor is within normal operating range. For details, see "II.E. Thermistor
Check."
• A functioning defrost thermistor is installed.
Possible Causes
• Trouble with the defrost thermistor. For checkout procedure, see "II.E. Thermistor Check."
• Trouble with the control board reading the defrost thermistor.
E8 Alarm (short circuit) Reset
Under 10 min.
E8 (short circuit )
Detection Point
122°F (50°C)
Temperature
Display
E8
Blinking
E8 Alarm
(open circuit)
Reset
E8 Alarm Timer Start
E8 Alarm
Timer Start
Temperature Display
E8 Alarm (open circuit)
Detection Point
-67°F (-55°C)
E8
Blinking
10 min.
E8
Alarm
E8
Alarm
5a. Secondary Defrost Thermistor (Rail, not used)
The secondary defrost thermistor (located behind the wire cover) is not used for
operation of the unit. It is used for control board programming and should not be
removed. An "E8" alarm occurs when the secondary defrost thermistor is removed or
fails. For details, see "III.A.6. Defrost Thermistor (cabinet) Malfunction Alarm (E8)."