Bunn TB3 User Guide
Page 16
SERVICE (cont.)
BREW SOLENOID VALVE
4
2
3
1
M
M
IN
UT
ES
M
IN
UT
ES
DE
LA
Y
DE
LA
Y
D
IL
UT
IO
N
BU
NN
-O
-M
AT
IC
P/
N
33
55
5
3
6
4
7
5
6
6
7
8
FIG. 2 BREW SOLENOID VALVE
P3040
Location:
Viewing the brewer from the rear the brew sole-
noid valve is mounted on the left side of the mounting
bracket.
bracket.
Test Procedures:
1. Disconnect the brewer from the power source.
2. Disconnect the white/violet and white/green wires
1. Disconnect the brewer from the power source.
2. Disconnect the white/violet and white/green wires
from the solenoid valve. With the ON/OFF switch
in the "ON" upper position press the start switch.
in the "ON" upper position press the start switch.
3. With a voltmeter, check the voltage across the
white/violet and white/green wires. Connect the
brewer to the power source. The indication must
be:
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 Wiring
Diagrams and check brewer wiring harness.
If voltage is not present as described, refer to Wiring
Diagrams and check brewer wiring harness.
5. Check for continuity across the solenoid valve coil
terminals.
If continuity is present as described, reconnect the
white/violet from the ON/OFF switch and white/green
wire from the brew timer.
white/violet from the ON/OFF switch and white/green
wire from the brew timer.
If continuity is not present as described, replace the
solenoid valve.
solenoid valve.
6. Check the solenoid valve for coil action. Connect
the brewer to the power source. With ON/OFF
switch in the "ON" upper position press start switch
and listen carefully in the vicinity of the solenoid
valve for a "clicking" sound as the coil magnet
attracts.
switch in the "ON" upper position press start switch
and listen carefully in the vicinity of the solenoid
valve for a "clicking" sound as the coil magnet
attracts.
7. 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 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.
pass through the solenoid valve, there may be a block-
age in the water line before 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 solenoid valves.
2. Turn off the water supply to the brewer.
3. Disconnect the water lines to and from the sole-
1. Remove all wires from 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 brewer base.
5. Lift out the bracket.
6. Remove the two #10-32 slotted-head screws hold-
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 brewer base.
9. Securely fasten the water lines to and from the
9. Securely fasten the water lines to and from the
solenoid valves.
10. Refer to the Fig.3 when reconnecting the wires
FIG.3 SOLENOID VALVE TERMINALS
P1278
BREW
SOLENOID
SOLENOID
DILUTION
SOLENOID
SOLENOID
WHI/VIO to Dilution
Solenoid
Solenoid
WHI/GRN to
Brew Timer TL4
Brew Timer TL4
WHI/VIO to Brew Solenoid
WHI/VIO to Brew Timer TL1
WHI/VIO to Brew Timer TL1
WHI/BLU to Dilution
Timer TL4
Timer TL4
37235 080204