SERVICE (cont.)

TANK HEATER SWITCH

P1127.40

FIG. 14 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"(upper) 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)120V 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.

d)100 volts ac for 100 volt models.

4.Disconnect the brewer from the power source.

If voltage is present as described, proceed to #5.

If voltage is not present as described, refer to the Wiring Diagrams and check the brewer wiring har- ness.

5.Check for continuity between the black wire re- moved from the limit thermostat and the black insert on the terminal block. with the tank heater switch in the "ON" upper position. 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 sup- ply 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 spray- head 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.Gently reinstall the thermostat sensor and grom- met in the tank lid.

10.Remove the two #8-32 screws securing the tank assembly to the hood.

11.Lift tank and components out as an assembly and set aside for reassembly.

12.Disconnect the two black wires from the tank heater switch.

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Bunn CW-APS, CWT-TSR service manual Tank Heater Switch