Bunn Dual TF DBC - Manual (Page 46)

Page 46
Troubleshooting Procedure
TROUBLESHOOTING (cont.)
Problem Possible Cause
Check the sensitivity setting. Refer
to the Refi ll function. If the left
three digit number is less than the
right number, the machine “thinks”
it is full and the refi ll valve should
be off. If the left number is larger
than the right, then the refi ll valve
will automatically be turned on to
fi ll the tank. The right number is
the threshold setting and can be
adjusted to compensate for extreme
water conditions: very pure, low
conductance water requires a higher
setting, while high mineral content,
high conductance water requires
a lower setting. Note that the left
number changes from a high value
when water is NOT touching the refi ll
probe to a low value when water IS
touching the probe. For best opera-
tion, the right number should be set
to a value midway between these low
and high numbers. Before changing
the setting, confi rm that the refi ll
probe is free of scale buildup and
the connection to it is secure.
Test the Refi ll valve. Refer to Testing
Individual Components.
When this condition occurs, the
brewer will display OVERFLOW CUP
FULL. EMPTY CUP. The reason for
overfi lling could be a defective refi ll
valve, an incorrect sensitivity setting,
(see above) or boiling.
Substitute a control board known to
be in good working order.
Foreign material lodged in valve,
holding it in open state.
3. Refi ll Probe or Sensitivity Set-
ting
4. Refi ll Valve
5. Overfl ow Protection Switch
6. Electronic Control Board
1. Refi ll valve
Automatic refi ll will not operate or
display shows FILL TIME TOO LONG
(cont.)
Water fl ows into tank continuously
with power removed from brewer.
35058.1 071205