Bunn SINGLE SHDBC Installation & Operating Manual page 33

TROUBLESHOOTING (cont.)
Problem
Water fl ows into tank continuously
with power applied to brewer.
Water will not heat or display shows
HEATING TIME TOO LONG
Possible Cause
1. Refi ll Probe or Sensitivity Set-
ting
2. Electronic Control Board
1. Limit Thermostat
CAUTION - Do not eliminate or
bypass limit thermostat. Use only
replacement part #23717.0001.
2. Tank Heaters
Page 33
Troubleshooting Procedures
Check the sensitivity setting. Refer
to the Refi ll function on page 20. 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.
Substitute a control board known to
be in good working order.
Remove power from the brewer.
Press reset button on limit ther-
mostat. Then check for continuity
through it.
Remove power from the brewer.
Check for continuity through the
tank heaters.
34025.1 082404