Bunn C Series Service & Repair Manual page 10

SERVICE
This section provides procedures for testing and
replacing various major components used in this
brewer should service become necessary. Refer to
Troubleshooting for assistance in determining the
cause of any problem.
WARNING - Inspection, testing, and repair of electri-
cal equipment should be performed only by qualified
service personnel. The brewer should be unplugged
when servicing, except when electrical tests are re-
quired and the test procedure specifically states to
plug-in the brewer.
COMPONENT ACCESS
WARNING - Disconnect the brewer from the power
source before the removal of any panel or the replace-
ment of any component.
All components are accessible by the removal of
the top cover, front inspection panel, warmer plate(s)
and rear utility cover (Twins only).
CONTROL THERMOSTAT
FIG. 10-1 CONTROL THERMOSTAT
Location:
The control thermostat 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. Disconnect the leads from control thermostat.
3. Gently remove the capillary bulb and grommet
from the tank.
4. Check for continuity across the thermostat termi-
nals. The indication must be:
a) Continuity with knob rotated fully clockwise.
b) No continuity with knob rotated fully counter-
clockwise. NOTE: First style does not have the ON/
OFF feature, simply check continuity.
If continuity is not present as described, replace control
thermostat.
If continuity is present as described, refer to the wiring
diagrams and check the brewer wiring harness.
Removal and Replacement:
1. Disconnect the control thermostat wires.
2. Remove the thermostat capillary bulb by firmly
pulling up on the capillary at the tank lid. This will
disengage the grommet from the tank lid.
3. Remove the one #8-32 screw securing the control
thermostat to the component bracket inside the
trunk.
4. Slide the grommet to the line 4.5" above the bulb
on the new capillary tube.
5. Insert the capillary bulb 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. Carefully bend the capillary tube so that the tube
and bulb inside the tank are in the vertical posi-
tion.
NOTE - The capillary tube must be clear of any electri-
cal termination and not kinked.
7. Using #8-32 screw(s), secure the control thermo-
stat to the component bracket inside the trunk.
8. For first type thermostat, refer to Wiring Diagrams
when reconnecting thermostat wires.
9. Adjust the control thermostat as required.
NOTE: First type will only turn approximately one
turn. Clockwise to the stopper is approximately
180° F, maximum counterclockwise to stopper is
approximately 200° F.
Later types will be approximately 200° F when
turned maximum clockwise. Turning it counter-
clockwise until it clicks will turn off (open con-
tacts).
Page 10
41711.1 052009