Bunn STFA User Manual

Page of 44
Page 18
SOLENOID VALVE (Models ST, STA, STF & STFA)
Location:
The  solenoid  valve  is  located  inside  the  front
inspection panel on the center lower part of the com-
ponent mounting bracket.
Test Procedures:
1.
Disconnect the brewer from the power source.
2.
Disconnect the wires (FIG. 9) from the solenoid
valve. With the "ON/OFF" switch in the "ON" upper
position press the start switch.
3.
Check the voltage across the two wires with a
voltmeter.  Connect  the  brewer  to  the  power
source. The indication must be:
a) 120 volts ac for two wire 120 volt models and
three wire 120/240 volt models.
b) 200 to 240 volts ac for two wire 200 or 240 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.
5.
Check  for  continuity  across  the  solenoid  valve
coil terminals.
If  continuity  is  present  as  described,  reconnect  the
wires (FIG. 9) to the solenoid.
If continuity is not present as described, replace the
solenoid valve.
SERVICE (cont.)
P1587
P1588
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.
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
blockage 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 the wires from the solenoid valve.
2.
Turn-off the water supply to the brewer.
3.
Disconnect the water lines to and from the sole-
noid valve.
4.
Remove the two #8-32 screws securing the so-
lenoid  mounting  bracket  to  the  component
bracket. Remove solenoid bracket and solenoid
valve as an assembly.
5.
Remove the two #10-32 screws and lockwashers
securing  the  solenoid  valve  to  the  solenoid
bracket.
6.
Using two #10-32 screws and lockwashers in-
stall new  solenoid valve on solenoid mounting
bracket.
7.
Using  two  #8-32  screws  install  solenoid  valve
and bracket to the component bracket.
8.
Securely fasten the water lines to and from the
solenoid valve.
9.
Refer to FIG. 9 when reconnecting the wires.
FIG. 8 SOLENOID
FIG. 9 SOLENOID TERMINALS
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