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USER GUIDE
SAFETY • INSTALLATION & INTEGRATION • OPERATING INSTRUCTIONS • MAINTENANCE • SERVICE
Thermistors
Thermistors are used for various temperature readings.
Thermistors provide reliable temperature readings using a
resistance which varies based on surrounding
temperatures. If a faulty thermistor is suspected it may
be tested using an accurate ohmmeter.
Both thermistors in the unit are identical. If a thermistor is
suspected of being defective, the resistance can be
verified. Place the thermistor in an ice water bath, the
resistance should read 16.1k OHMs +/-5% on your meter.
Thermistor connections must be kept clean. A thermistor
connection that has become corroded can cause
resistance values from the thermistor to change as they
pass through a dirty connection to the board.
It is for that reason that we apply dielectric grease to all of
our thermistor connections. Dielectric grease will help to
keep thermistor connections clean and dry.
If you change a thermistor in the unit please re-apply
dielectric grease to the connection. If you encounter a
dirty thermistor connection, you should replace the
thermistor and the thermistor harness.
Thermistor error information can be found in the Control
Operations - Service section.
This unit has two thermistors.
Thermistor one (Zone):
Located along the right hand side wall. It is used to
maintain the operating temperature within that zone.
Thermistor two (Evaporator):
Located on the evaporator. It is used for defrost.
THERMISTOR FAILURE
Zone Thermistor
If the zone thermistor in the unit fails, the unit will
continue to cool in a backup mode (Self Preservation
Mode) to preserve the integrity of the contents. The unit
will otherwise operate normally.
1000 Series Self Preservation Mode:
The unit will cycle on for 10 minutes then off for 40
minutes.
Evaporator Thermistor
If the evaporator thermistor fails, the unit will rely on a
preset defrost timer during defrost cycles. The unit will
otherwise operate normally. Refer to defrost section.
Thermistor Resistance Data
Temp (F)
Temp (C)
-40
-40
-31
-35
-22
-30
-13
-25
-4
-20
5
-15
14
-10
23
-5
32
0
41
5
50
10
59
15
68
20
77
25
86
30
95
35
104
40
113
45
122
50
131
55
140
60
149
65
158
70
167
75
176
80
* (+/-5%)
u-line.com
Nominal Resistance
(OHMS)*
169157
121795
88766
65333
48614
36503
27681
21166
16330
12696
9951
7855
6246
5000
4029
3266
2665
2186
1803
1495
1247
1044
879
743
631
Thermistor 1
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Troubleshooting
