41
SERVICE (CONT.)
Temperature Probe
(Also known as Water Bath Thermistor)
FIG. 47 TEMPERATURE PROBE
Location:
The temperature probe is located on the top of the
tank assembly.
Purpose:
A thermistor (NTC) is a type of resistor which resis-
tance is dependent on temperature. The tempera-
ture sensor will become cool and embedded in the
ice block, the resis-tance will increase to the shut off
point of the software param-eter. When the water tem-
perature starts rising in temperature, the thermistor
resistance starts decreasing which tells the control
board to activate the refrigeration circuit.
Test Procedure:
Disconnect temperature probe from J9 on control
board and place the temperature sensor in a cup of
ice water for a few minutes before checking the re-
sistance across the two terminals of the temperature
probe while in the cup of ice water (32° F). The resis-
tance should be within 31280.00 to 34022.00 Ohms
@ 32° F.
If resistance is not to specification, replace the tem-
perature probe.
Removal and Replacement:
1. Disconnect the dispenser from the power source.
2. Remove the top rear cover.
3. Disconnect the two pin connector from the dis-
penser main wiring harness.
4. Remove the temperature probe by firmly pulling-
up on the tube at the tank lid. This will disengage
the grommet from the tank lid.
5. Slide a new grommet on to the new temperature
probe.
6. Insert the temperature probe through the hole
in the tank lid and press the grommet firmly and
evenly so that the groove in the grommet fits into
the tank lid.
7. Reconnect the two pin connector to the dispenser
main wiring harness.
FIG. 48 TEMPERATURE PROBE
ORN pin 1
WHI pin 2
TEMP RESISTANCE VOLTAGE
SHORTED 0 Ω 0VDC
32° F 31.2k - 34k Ω 3.3VDC
0.0° C
77° F 9.8k - 10.2k Ω 1.5VDC
25.0° C
OPEN INFINITE 5.0VDC
NOTE: ALL FIGURES LISTED ABOVE ARE APPROXIMATE.
55124 021418
To Next Page
Loading...