Bunn TU3 service manual SERVICE cont, Dilution Solenoid Valve

Models: TU3

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DILUTION SOLENOID VALVE
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SERVICE (cont.)

DILUTION SOLENOID VALVE

P1277.40

FIG. 10 DILUTION SOLENOID VALVE

Location:

Viewing the brewer from the rear the dilution so- lenoid is mounted on the center of the solenoid mount- ing bracket which is secured to the trunk base.

Test Procedure:

1.Disconnect the brewer from the power source.

2.With a voltmeter, check the voltage across the white/blue and white/violet wires on the dilution solenoid terminals when the ON/OFF switch is in the ÒONÓ position and the start switch is momen- tarily placed in the lower position. Connect the brewer to the power source. After the approxi- mate setting on the delay dial, the indication must be:

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

b)240 volts ac for two wire 240 volt models.

c)100 volts ac for two wire 100 volt models, re- main for the approximate setting on the dilution dial, and then return to its previous indication.

3.Disconnect the brewer from the power supply.

If voltage is present as described, proceed to #4.

If voltage is not present as described, refer to the Wir- ing Diagrams and check the wiring harness.

4.Remove both wires from the coil and check for continuity across the coil terminals.

5.Check the solenoid valve for coil action. Connect the brewer to the power source, place the ON/OFF switch in the ÒONÓ position and momentarily place the start switch in the lower position and release. Listen carefully after the approximate setting on the delay dial in the vicinity of the solenoid valve for a ÒclickingÓ sound as the coil magnet attracts and after the approximate setting on the dilution dial, repels the plunger.

6.Disconnect the brewer from the power source.

If the sound is heard as described and water will not pass through the solenoid valve, there may be a block- age in the water line before or after the solenoid valve or, the solenoid valve may require inspection for wear, and removal of waterborne particles.

If the sound is not heard as described, replace the solenoid valve.

Removal and Replacement:

1.Remove all wires from the solenoid valves.

2.Turn off the water supply to the brewer.

3.Disconnect the water lines to and from the sole- noid valves.

4.Remove the two 8-32 keps nuts holding the mounting bracket to the trunk base.

5.Lift out the bracket.

6.Remove the two 10-32 slotted-head screws hold- ing the solenoid valve to the mounting bracket.

7.Securely install the new solenoid valve to the mounting bracket.

8.Attach the mounting bracket to the trunk base.

9.Securely fasten the water lines to and from the solenoid valves.

10.Refer to Fig. 11 when reconnecting the wires.

WHI/VIO to Dilution WHI/GRN to Solenoid

Brew Timer TL4

WHI/VIO to Brew Solenoid WHI/VIO to Brew Timer TL1

WHI/BLU to Dilution

Timer TL4

BREW

WHI/VIO to Dilution

SOLENOID

Solenoid

BRN/WHI to Selector

If continuity is present as described, reconnect the white/blue and white/violet wires and proceed to #5. If continuity is not present as described, replace the solenoid valve.

DILUTION Manual backgroundSwitch

SOLENOID

SWEETENER

SOLENOID (Optional)

FIG. 11 SOLENOID VALVE TERMINALS

P1278

10225 031804

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Bunn TU3 service manual SERVICE cont, Dilution Solenoid Valve