Bunn Single Operating & Service Manual page 24

SERVICE (cont.)
ELECTRONIC CONTROL ASSEMBLY (cont.)
a.) 120 volts ac for two wire 120 volt models,
three wire 120/208 volt models and three wire
120/240 volt models after a delay of approximately
1 second.
b.) 200 to 240 volts ac for two wire 200 or 240 volt
models after a delay of approximately 1 second.
6. Disconnect the brewer from the power source.
If voltage was present as described, the liquid level
control system is operating properly, proceed to #7.
If voltage was not present as described, replace the
electronic control assembly (1) and temperature sen-
sor (8) in the tank lid.
NOTE - Each electronic control assembly is calibrated
to a temperature sensor. Both components MUST be
replaced as a set.
7. Reconnect the pink wire to terminal 5 of the elec-
tronic control assembly (1).
8. Remove the liquid level probe (7) from the tank
lid, and inspect it for mineral deposits. Replace it
if necessary. Keep the exposed ends of the probe
away from any metal surface of the dispenser.
9. With a voltmeter, check the voltage across ter-
minals 1 & 4 of the electronic control assembly
(1). Connect the brewer to the power source. The
indication must be:
a.)120 volts ac for two wire 120 volt models, three
wire 120/208 volt models and three wire 120/240
volt models after a delay of approximately 1 sec-
ond.
b.)200 to 240 volts ac for two wire 208 or 240 volt
models after a delay of approximately 1 second.
10. Touch the screw head end of the probe to the
brewer housing. The indication must be 0.
11. Move the probe away from the brewer housing.
The indication must again be:
a.)120 volts ac for two wire 120 volt models,
three wire 120/208 volt models and three wire
120/240 volt models after a delay of approximately
1 second.
b.)200 to 240 volts ac for two wire 200 or 240 volt
models after a delay of approximately 1 second.
12. Disconnect the brewer from the power source.
If voltage was present as described, reinstall the
probe, the sensing function of the system is operat-
ing properly.
If voltage was not present as described, check the pink
probe wire and the green ground wire for continuity
and/or replace the probe.
LIQUID LEVEL CONTROL OVERFLOWS
DRAIN CUP
(4)
RETRY
OVERFLOW
DRAIN CUP (4)
DISCONNECT PROBE
WIRE FROM PROBE (7)
SHORT PROBE WIRE
TO CHASSIS
RETRY
OVERFLOW
DRAIN CUP (4)
DISCONNECT WIRE
FROM
SOLENOID VALVE (12)
RETRY
OVERFLOW
REPLACE
CONTROL
ASSEMBLY (1)
Page 24
PROBLEM:
?
YES
NO NO
REPLACE PROBE (7)
?
YES
YES
REPLACE SOLENOID
VALVE (12)
?
NO
P831
27038 091900