Bunn S, Operating & Service Manual

Page: 14 / 44

Page 14
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HI
SERVICE (cont.)
CONTROL THERMOSTAT
Location:
Models S & SA: The control thermostat is mounted
on a bracket inside the rear inspection cover on
the left side.
Models ST, STA, STF & STFA: The control ther-
mostat is located inside the front inspection
cover on the component mounting bracket.
Test Procedures:
1.
Disconnect the brewer from the power source.
2. Locate the blue wire on the control thermostat.
3. Check the voltage across the blue wire on the
control thermostat and the white insert on two
pole 100 or 120 volt terminal block or three pole
120/240 volt terminal blocks and the red insert
on two wire 200 volt or 240 volt terminal block
with a voltmeter. Connect the brewer to the
power source. The indication must be:
a) 120 volts ac for two wire 120 volt models and
three wire 120/240 volt models.
b) 200 to 240 volts ac for two wire 200 or 240 volt
models.
c) 100 volts ac for two wire 100 volt models.
4. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #5. If
voltage is not present as described, refer to the
Wiring
Diagrams and check the brewer wiring harness.
5. Locate the black wire on the control thermostat.
6. Gently remove the capillary bulb and grommet
from the tank.
7. Check the voltage across the black wire of the
control thermostat and the white insert on the
two pole 100 or 120 volt or three pole 120/240
volt terminal block and the red insert on the two
pole 200 volt or 240 volt terminal block with a
voltmeter when the control thermostat is turned
"ON" (Fully clockwise). Connect the brewer to the
power source. The indication must be:
a) 120 volts ac for two wire 120 volt models and
three wire 120/240 volt models.
b) 200 to 240 volts ac for two wire 200 volt or 240
volt models.
c) 100 volts ac for two wire 100 volt models.
8. Disconnect the brewer from the power source.
If voltage is present as described, reinstall the capillary
tube into the tank to the line 4.5" above the bulb, the
control thermostat is operating properly.
If voltage is not present as described, replace the
thermostat.
P1585
FIG. 2 CONTROL THERMOSTAT
29251 052500