Bunn TB3Q-LP - Manual (Page 13)

Page 13
SERVICE (cont.)
TANK HEATER
Location:
The tank heater is located inside the tank and
secured to the tank lid.
Test Procedures:
1. Disconnect the brewer from the power supply.
2. Turn on thermostat. Check the voltage across the
black and white wires on 120 volt models or the
black and red wires for 200 volt models and 230
volt models with a voltmeter. Connect the brewer
to the power source. The indication must be:
a) 120 volts ac for two wire 120 volt 20 amp
models .
b) 200 to 230 volts ac for two wire 200 or 230 volt
models.
3. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #4
If voltage is not present as described, refer to the Wir-
ing Diagrams and check wiring harness.
4. Disconnect the wires from the tank heater termi-
nals.
5. Check resistance value across tank heater terminals
and compare to chart.
If resistance is present as described, reconnect the
wires, the tank heater is ok.
FIG. 13-1 TANK HEATER
1680W-120V 7.9 - 9.2
1680W-100V 5.5 -6.4
1680W-230V 29.0 -33.7
TERMINAL TO SHEATH - INFINITE (OPEN)
HEATER RESISTANCE
If resistance is not present as described, replace the
tank heater.
NOTE- If any resistance is read between sheath and
either terminal, remove and inspect heater for
cracks in the sheath.
Removal and Replacement:
1. Disconnect the brewer from the power supply.
2. Disconnect the water supply from the brewer.
3. Disconnect the wires from the limit thermostat.
4. Disconnect the wires from the tank heater termi-
nals.
5. Remove sprayhead and the hex nut securing the
sprayhead tube to the hood. Set aside for reas-
sembly.
6. Remove the six #10 screws securing the tank lid
to the tank.
7. Remove the tank lid with limit thermostat, spray-
head tube and tank heater.
8 Remove the two hex nuts securing the tank heater
to the tank lid. Remove tank heater with gaskets
and discard.
9. Install new tank heater with gaskets on the tank
lid and secure with two hex nuts.
10. Install tank lid with limit thermostat, sprayhead
tube and tank heater using six #10 screws.
11. Secure sprayhead tube to hood using hex nut
removed in step 4.
12. Install sprayhead.
15. Reconnect the wires to the limit thermostat and
tank heater.
16. Reconnect the water and power supply.
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