Bunn TU3Q service manual Control Thermostat

Models: TU3Q

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SERVICE (cont.)

CONTROL THERMOSTAT

FIG. 8 CONTROL THERMOSTAT

P2200.50

 

Location:

The control thermostat is located inside hood on the right side.

Test Procedures:

1.Disconnect the brewer from the power source.

2.Locate the blue/black wire on the control thermo- stat.

3.With a voltmeter, check the voltage across the blue/ black wire on the control thermostat and the white wire on the tank heater for 100 volt and 120 volt two wire models or red wire on the tank heater for 230 volt two wire models. Connect the brewer to the power source. The indication must be:

a)120 volts ac for two wire 120 volt models.

b)230 volts ac for two wire 230 volt models.

c)100 volts ac for two wire 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 wir- ing diagrams and check the brewer wiring harness.

5.Locate the black wire on the control thermostat.

6.Gently remove the capillary bulb and grommet from the tank.

7.With a voltmeter, check the voltage across the black wire of the control thermostat and the white wire on the tank heater for 100 volt and 120 volt two wire models or red wire on the tank heater for 230 volt two wire models when the control ther- mostat is turned fully clockwise. Connect the

brewer to the power source. The indication must be:

a)120 volts ac for two wire 120 volt models.

b)230 volts ac for two wire 230 volt models.

c)100 volts ac for two wire 100 volt models.

8.Disconnect the brewer from the power source.

If voltage is present as described, reinstall the capil- lary tube into the tank to the line 5.5" above the bulb, the control thermostat is operating properly.

If voltage is not present as described, replace the ther- mostat.

Removal and Replacement:

1.Remove both wires from the control thermostat terminals.

2.Remove the thermostat capillary bulb by firmly pulling up on the capillary tube at the tank lid. This will disengage the grommet from the tank lid.

3.Remove the #8-32 screw holding the control ther- mostat to its bracket.

4.Slide the grommet to the line 5.5" 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 a vertical position.

NOTE: The capillary tube must be clear of any elec- trical termination and not kinked.

7.Fasten the new control thermostat to its bracket.

8.Refer to Fig. 9 when reconnecting the wires.

9.Adjust the control thermostat as required.

 

 

BLK to

 

OFF

Tank Heater (100/120V)

NNUB

 

 

 

 

Thermal Fuse (230V)

BLU/BLK to Limit

Thermostat

P2090.80

FIG. 9 CONTROL THERMOSTAT TERMINALS

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10288 110503

 

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Bunn TU3Q service manual Control Thermostat