Thermistor Failure - U-Line U-3060DWRINT-00A User Manual & Service Manual

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.

THERMISTOR FAILURE

Zone Thermistors
If a zone thermistor in the unit fails the unit will continue
operate on a preset time interval "determined by mode"
(See Limp Mode Data Table). The unit will otherwise
operate normally.The error will be displayed on the main
display, "Self Test" and logged in "All Errors."
Limp Mode Data Table
Mode
Beverage/Drinks
Market/Fresh
Root
Pantry
Deli
Evaporator Thermistors
If an evaporator thermistor fails the unit will rely on a
preset defrost timer during defrost cycles. The unit will
otherwise operate normally. Evaporator thermistor errors
are hidden from the display and recorded in "All Errors"
and displayed in "Self Test" modes.
Ambient Thermistor
The ambient thermistor is mainly used for diagnostics. If
the thermistor fails, the unit will operate normally.
This unit has five thermistors. Thermistor one is located
along the right hand side wall in the top drawer. It is used
to maintain the operating temperature within that zone.
Thermistor two is located on the evaporator in the top
drawer. It is used for defrost.
ON OFF
10 45
10 45
5 90
10 45
10 45
Thermistor three is located along the right hand side wall
in the bottom drawer. It is used to maintain the operating
temperature within that zone.
Thermistor four is located on the evaporator in the bottom
drawer.
Thermistor five is located in the mechanical compartment
and monitors the ambient temperature within the
compartment. It is used mainly for diagnostics.
All five of the thermistors in the unit are identical. If a
thermistor is suspected of being defective it can be
OHMed out. In an ice water bath the thermistor should
OHM out at 16.1k OHMS +/-5%.
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 die electric grease to all
of our thermistor connections. Die electric grease will help
to keep thermistor connections clean and dry.
If you change a thermistor in the unit please re-apply die
electric grease to the connection. If you encounter a dirty
thermistor connection, you should replace the thermistor
and the thermistor harness.
Thermistor Resistance Data
Temp (F) Temp (C)
-40
-31
-22
-13
-4
5
14
23
32
66
Nominal Resistance
(OHMS)*
-40 169157
-35 121795
-30 88766
-25 65333
-20 48614
-15 36503
-10 27681
-5 21166
0 16330
Thermistor 1