Tank Heater - Bunn OT Installation & Operating Manual

SERVICE (cont.)

Tank Heater

FIG. 26 TANK HEATER
Location:
The tank heater is located on the tank lid, FIG. 26.
Test Procedure:
1. Check the voltage across the black and white
or red wires on the tank heater with a voltmeter
when the control thermostat is turned "ON" (fully
clockwise). Connect the brewer to the power
source. The indication must be:
a) 120 volts ac for two wire 120 volt models.
b) 200 or 240 volts ac for two wire 200 volt or
240 volt models and three wire 120/240 volt
models.
c) 100 volts ac for two wire 100 volt models.
2. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #3.
If voltage is not present as described, refer to the Wir-
ing Diagrams and check the brewer wiring harness.
3. Check for continuity across the terminals of the
tank heater.
If continuity is present as described, reconnect the
wires, the tank heater is operating properly.
If continuity is not present as described, replace the
tank heater.
NOTE - If the tank heater remains unable to heat,
remove and inspect the heater for cracks in the
sheath.
Removal and Replacement:
1. Remove the wires to the tank heater and limit
thermostat terminals.
2. Gently pull the thermostat tube with grommet out
of the tank lid.
3. Remove the sprayhead and sprayhead nut from
the panel on the bottom of the hood.
4. Disconnect the air vent tube from the fitting above
the sprayhead panel.
5. On units with faucet, disconnect the inlet and
outlet tubes from the faucet coil fittings.
6. Loosen the eight 8-32 nuts on the tank lid and
remove the tank lid.
7. Remove the two nuts from the tank heater fit-
tings.
8. Remove the tank heater.
9. Install the new tank heater with new sealing wash-
ers on the underside of the tank lid.
10. Securely tighten the nuts to be certain of a wa-
P1698
tertight seal.
11. Reinstall the tank lid and tighten the eight nuts.
12. Reconnect the air vent tube to the fitting above
the sprayhead panel.
13. Reconnect the inlet and outlet tubes to the faucet
coil fittings on units with faucet.
14. Reinstall the sprayhead tube nut and spray-
head.
15. Reinstall the thermostat into the tank lid.
16. Refer to FIG. 27 when reconnecting the wires.
WHI (Models OT15 & 20) to Terminal Block
RED (Models OT35 & RT35) to Terminal Block
BLK to Control Thermostat
FIG. 27 TANK HEATER WIRING
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