Hoshizaki AMERICA 73183 - Manual (Page 28)

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10) Check that the components restart after defrost termination.
Refrigerator: DTh reaches 40 °F (4.4°C), Comp and ConFM (CM C1 (R)) energize. If
not, check DTh status. See "II.D.Thermistor Check." If DTh ohm reading is in proper
range, and Comp and ConFM do not energize, replace CM.
Freezer: DTh reaches 59°F (15°C). 3-min. later, Comp and ConFM (CM C1 (R)) and
EvapFM (CM F5 (Y)) energize. If not, check DTh status. See "II.D.Thermistor Check." If
DTh ohm reading is in proper range, and Comp, ConFM, or EvapFM do not energize,
replace CM. 12 min. after Comp, ConFM, and EvapFM energize, cabinet temperature
appears on CM. If components fail to start, replace CM.
Legend: CM–control module; Comp–compressor; ConFM–condenser fan motor;
CTh–cabinet thermistor; DH–defrost heater; DS–door switch; DTh–defrost
thermistor;
EvapFM–evaporator fan motors
D. Thermistor Check
The cabinet thermistor is used for cabinet temperature control and the defrost thermistor
is used for defrost cycle initiation and termination. Thermistor resistance varies
depending on temperature. The control module monitors the thermistors to control
system operation. No adjustment is required.
In the event the cabinet thermistor reading is out of range (E1 alarm), the compressor
operates on a fixed time basis of 5-min. on and 5-min. off.
In the event the refrigerator defrost thermistor reading is out of range (E2 alarm), defrost
initiation occurs every 4-hr. of cumulative compressor run time and terminates on
20-min. minimum defrost timer.
In the event the freezer defrost thermistor reading is out of range (E2 alarm), defrost
initiation occurs every 4-hr. of cumulative compressor run time and terminates based on
cabinet thermistor temperature.
To check thermistor resistance, follow the steps below.
1) Move the power switch to the "OFF" position, then unplug the appliance.
2) Remove the control box cover.
3) Disconnect and remove the thermistor in question.
4) Immerse the thermistor sensor portion in a glass containing ice and water for 2 to 3 min.
5) Check the resistance between the wires at the thermistor connector. Normal reading is
within 16.0 to 16.7 kΩ. If outside the normal reading, replace the thermistor.
6) Reconnect and replace the thermistor in its correct position. See "IV.B. Important Notes
for Component Replacement."
7) Plug the appliance back in. Move the power switch to the "ON" position.