Limit Thermostat - Bunn TB3 Operating & Service Manual

SERVICE (cont.)

LIMIT THERMOSTAT

FIG. 12 LIMIT THERMOSTAT
Location:
The limit thermostat is located inside the hood on
the tank lid.
Test Procedure:
1. Disconnect the brewer from the power source and
remove the black wire from the limit thermostat.
2. With a voltmeter, check the voltage across the
black wire removed from the limit thermostat
and the white wire or red wire on the tank heater
terminal. Connect the brewer to the power source.
The indication must be:
a) 120 volts ac for two wire 120 volt models.
b) 230 volts ac for two wire 230 volt models.
c) 100 volts ac for two wire 100 volt models.
3. Disconnect the brewer from the power source.
If voltage is present as described, reconnect the black
wire and proceed to #4.
If voltage is not present as described, refer to the Wir-
ing Diagrams and check the wiring harness.
4. Remove the blue/black wire from the limit ther-
mostat.
5. With a voltmeter, check the voltage across the
exposed terminal of the limit thermostat and the
white wire from the power cord or the red wire
from the power connector. Connect the brewer to
the power source. The indication must be:
a) 120 volts ac for two wire 120 volt models.
b) 230 volts ac for two wire 230 volt models.
c) 100 volts ac for two wire 100 volt models.
6. Disconnect the brewer from the power source.
If voltage is present as described, reconnect the blue/
black wire to the limit thermostat. The limit thermostat
is operating properly.
If voltage is not present as described, replace the limit
thermostat.
Removal and Replacement
1. Remove both wires from the limit thermostat
terminals.
2. Carefully slide the limit thermostat out from under
P3040
the retaining clip.
3. Carefully slide the new limit thermostat into the
retaining clip.
4. Refer to Fig. 13 when reconnecting the wires.
FIG. 13 LIMIT THERMOSTAT TERMINALS
Page 22
BLU/BLK to
Control
Thermostat
BLK to Power Cord or
Power Connector
P1800
37235 050205