Bunn SINGLE SHDBC Installation & Operating Manual page 32

TROUBLESHOOTING (cont.)
Problem
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.
Possible Cause
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
Page 32
Troubleshooting Procedure
Check the sensitivity setting. Refer
to the Refi ll function on page 28. 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 on page 25
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.
34025.1 082404