Bunn TB3 User Guide

Page 26

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.