Hoshizaki JWE-620UA-6B service manual Internal Booster Tank Thermistor Error H3, H4

g) Internal Booster Tank Thermistor Error (H3, H4)

•If the internal booster tank thermistor senses a temperature at or above 231°F (111°C) (2.4kΩ), the thermistor leads are considered shorted and the internal booster tank heaters de-energize, "H3" appears in the display, and the buzzer sounds.

•If the internal booster tank thermistor senses a temperature at or below -6°F (-21°C) (517kΩ), the thermistor leads are considered open and the internal booster tank heaters de-energize, "H4" appears in the display, and the buzzer sounds.

•After replacing the failed component, the alarm resets.

•See the chart below for possible causes and remedies. Note: When this error occurs, the auto fill cycle will not start.



Code

H 3 / H 4

Operation

Error

Thermistor senses abnormal temperature.Continues (internal booster tank heater off).

Item

Thermistor

Possible Cause

Connector not properly connected.

Remedy

Reconnect.

Open circuit (H4).

Replace.

Short circuit (H3).

Replace.

Defective.

Replace.

Control Board

Connector not properly connected.

Reconnect.

Defective.

Replace.

Note: See “III.E. Thermistor Check” and “IV.M. Removal and Replacement of Thermistor.”

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