Bunn TB3 Coffeemaker User Manual


 
Page 26
SERVICE (cont.)
SWEETNER SOLENOID VALVE
FIG. 20 SWEETNER SOLENOID VALVE
P3298
FIG. 21 SOLENOID VALVE TERMINALS
P2843
37235 050205
WHI/VIO to Brew Solenoid
WHI/VIO to Brew Timer TL1
BRN/WHI to Selector
Switch
Location:
Viewing the brewer from the front, the sweetener
solenoid is mounted on the right side of the solenoid
mounting bracket which is secured to the bottom base
housing.
Test Procedure:
1. Disconnect the brewer from the power source.
2. With a voltmeter, check the voltage across the
brown/white and white/violet wires on the sweet-
ener solenoid terminals when the UNSWEET/OFF/
SWEET switch is in the “SWEET” position and the
start switch is momentarily placed in the lower
position. Connect the brewer to the power source.
After the approximate setting on the delay dial, 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,
remain 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. If continuity
is present as described, reconnect the brown/white
and white/violet wires and proceed to #5.
If continuity is not present as described, replace the
solenoid valve.
5. Check the solenoid valve for coil action. Con-
nect the brewer to the power source, place the
UNSWEET/OFF/SWEET switch in the “SWEET”
position and momentarily place the start switch
in the lower position and release. At the start of
a brew cycle, listen carefully in the vicinity of the
solenoid valve for a “clicking” sound as the coil
magnet attracts and at the end of the brew cycle
when the plunger is released.
6. Disconnect the brewer from the power source.
If the sound is heard as described and sweetener
will not pass through the solenoid valve, there may
be a blockage in the sweetener line before or after
the solenoid valve or, the solenoid valve may require
inspection for wear, and removal of 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 sweetener 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
solenoid bracket to the mounting bracket.
5. Lift out the valve and 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 solenoid valve and bracket to the
mounting bracket.
9. Securely fasten the sweetener and water lines to
and from the solenoid valves.
10. Refer to Fig. 19 when reconnecting the wires.