Tank Heater Switch - Bunn C Series Service & Repair Manual

SERVICE (cont.)

TANK HEATER SWITCH

FIG 18-1 TANK HEATER SWITCH
Location:
The tank heater switch is located on the rear of
the brewer on the upper left side of the trunk.
Test Procedure:
1. Disconnect the brewer from the power source.
2. Disconnect the black wire from the limit thermo-
stat.
3. With the tank heater switch in the "ON" position
and with a voltmeter, check the voltage between
the black wire removed from the limit thermostat
and the white wire or red wire on the tank heater.
Connect the brewer to the power source. The
indication must be:
a) 120 volts ac on two wire 120 volt models.
b) 240 volts ac on three wire 120/240 volt mod-
els.
c) 200 to 240 volts ac on 200 volt or 240 volt
models.
4. Disconnect the brewer from the power source.
If voltage is not present as described, proceed to
#5.
If voltage is present as described, the switch is work-
ing properly.
5. With the tank heater switch in the "ON" upper posi-
tion, check for continuity between the black wire
removed from the limit thermostat and the black
insert on the terminal block. Continuity should
not be present in the "OFF" lower position.
If continuity is present as described, the tank heater
switch is operating properly.
If continuity is not present as described, replace the
tank heater switch.
Removal and Replacement:
1. Shut off and disconnect the incoming water supply
to the brewer.
2. On automatic brewers gently remove the fill tube
from back of fill basin.
3. Remove the tank inlet fitting securing fill basin the
tank lid. Remove fill basin and gasket. Set all three
parts aside for reassembly.
4. On brewers with faucets, disconnect the water
supply to coil assembly and remove the tube from
the tank to the faucet.
5. Remove sprayhead and hex nut securing sprayhead
tube to the hood. Set aside for reassembly.
6. Disconnect the wires on the limit thermostat and
the tank heater and the control thermostat (early
models).
7. Gently pull the thermostat sensor and grommet
from the tank lid.
8. Insert a tube to the bottom of the tank and syphon
ALL of the water out.
9. Remove the two #8-32 screws securing the tank
assembly to the hood.
10. Lift tank and components out as an assembly and
set aside for reassembly.
11. Disconnect the two black wires from the tank heater
switch.
12. Remove the plastic facenut, hex facenut and the
switch indicator/guard bracket that secures tank
heater switch to the rear of the brewer. Remove
switch and discard.
13. Insert new tank heater switch through the hole in
the upper left rear of the trunk and secure with
switch indicator/guard bracket, hex facenut and
plastic facenut.
14. Reconnect the two black wires to the tank heater
switch terminals.
Page 18
41711.1 052009