Bunn Dual SH Installation And Operating Manual page 42

TROUBLESHOOTING (cont.)
Problem
Water flows into tank continuously
with power applied to brewer.
Water will not heat or display shows
HEATING TIME TOO LONG
Possible Cause
1. Refill Probe or Sensitivity Setting
2. Electronic Control Board
1. Limit Thermostat
CAUTION - Do not eliminate or by-
pass limit thermostat. Use only re-
placement part #23717.0001.
2. Tank Heaters
Page 42
Troubleshooting Procedures
Check the sensitivity setting. Refer
to the Refill function on page 28. If
the left three digit number is less
than the right number, the machine
"thinks" it is full and the refill valve
should be off. If the left number is
larger than the right, then the refill
valve will automatically be turned on
to fill 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 num-
ber changes from a high value when
water is NOT touching the refill probe
to a low value when water IS touch-
ing the probe. For best operation,
the right number should be set to a
value midway between these low
and high numbers. Before changing
the setting, confirm that the refill
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 thermo-
stat. Then check for continuity
through it.
Remove power from the brewer.
Check for continuity through the tank
heaters.
29877 091201