Hoshizaki rh1-aac Manual Suplementar
16
C. Thermistors
Thermistors (semiconductors) are used for cabinet temperature control and defrost
termination. The resistance varies depending on temperature. No adjustment is required.
If necessary, check for resistance between thermistor leads and visually check the
thermistor mounting.
termination. The resistance varies depending on temperature. No adjustment is required.
If necessary, check for resistance between thermistor leads and visually check the
thermistor mounting.
1. Cabinet Thermistor (SEN1: white and black leads)
This temperature reading can be identified by looking at the temperature shown on the
display. However, in some cases the display may be reading "dEF". In this case turn the
unit to the "OFF" position. Next press the up arrow button while turning the unit "ON" with
the toggle switch. This will by-pass the initial defrost cycle and allows the display to show
the cabinet thermistor reading. This temperature should correspond closely with the
actual cabinet temperature.
display. However, in some cases the display may be reading "dEF". In this case turn the
unit to the "OFF" position. Next press the up arrow button while turning the unit "ON" with
the toggle switch. This will by-pass the initial defrost cycle and allows the display to show
the cabinet thermistor reading. This temperature should correspond closely with the
actual cabinet temperature.
2. Defrost Thermistor (SEN2: black and red leads)
This temperature reading can be found by entering the service menu. To access this
menu, press and hold the "°F" and down arrow buttons. Once released, "dIF" is displayed
and you have access to the menu. To advance to the next display, press the "°F" button.
Press "°F" until "SEn" is displayed. Press "°F" one more time and this reading should be
the evaporator coil temperature.
menu, press and hold the "°F" and down arrow buttons. Once released, "dIF" is displayed
and you have access to the menu. To advance to the next display, press the "°F" button.
Press "°F" until "SEn" is displayed. Press "°F" one more time and this reading should be
the evaporator coil temperature.
Note: This thermistor is mounted in the evaporator; therefore, when the machine is in
the freeze cycle you will see temperatures that correspond to actual evaporator
temperature.
temperature.
3. Thermistor Check Procedure
1) Unplug the unit from the electrical outlet and disconnect thermistor leads on the control
module.
) Remove the thermistor.
3) Immerse the thermistor sensor portion in a glass containing ice water for or 3 minutes.
4) Check for a resistance between thermistor leads. Replace the thermistor if it exceeds
3) Immerse the thermistor sensor portion in a glass containing ice water for or 3 minutes.
4) Check for a resistance between thermistor leads. Replace the thermistor if it exceeds
the normal reading. See "IV.I. Removal and Replacement of Thermistors."
Temperature Resistance Ω
°F
°C
0
-17.8
704
10
-1.
713
3
0.0
81
50
10.0
880
70
1.1
961
90
3.
1,046