Bunn C Series Service & Repair Manual page 11

SERVICE (cont.)
OPTIONAL ELECTRONIC THERMOSTAT (ERT):
The ERT is located inside the trunk on the upper left
side of the component bracket.
Test Procedures:
1. Disconnect the brewer from the power source.
2. Gently remove the temperature sensor and grom-
met from the tank.
3. Check voltage across the blue wire from limit
thermostat and the white wire at the terminal
block. Connect the brewer to the power source.
The indication must be: 120Vac.
If voltage is not present as described, refer to the wiring
diagrams and check the brewer wiring harness
If voltage is present as described, proceed to #4.
4. Disconnect the brewer from the power source.
5. With the temperature sensor and grommet still out
of the tank, check voltage across the black wire
to the heater and the white wire at the terminal
block. Connect the brewer to the power source.
The indication must be: 120Vac.
If voltage is not present as described, replace ERT.
If voltage is present as described, the ERT is function-
ing properly.
Removal and Replacement:
1. Disconnect the control thermostat wires.
2. Remove the temperature sensor by firmly pulling-
up on the metal sheath at the tank lid. This will
disengage the grommet from the tank lid.
3. Remove the one #8-32 screw securing the ERT to
the component bracket inside the trunk.
4. Slide the grommet to the top of the sheath.
5. Insert the temperature sensor 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.
6. Using the #8-32 screw, secure the ERT to the
component bracket inside the trunk.
7. For first type thermostat, refer to Wiring Diagrams
when reconnecting ERT wires.
8. Adjust the ERT as required.
First Type
Third Type
FIG 11-1 THERMOSTAT TERMINALS
NOTE: The ERT has a range of 170° - 210°F. Use care
not to set it too high or boiling could occur.
Page 11
Second Type
ERT
41711.1 052009