Bunn CDBC Operating & Service Manual page 21

The bank of temperature indicators indicates that a fault exists. Count the number of flashes between pauses and
use this chart as a guide to investigating the fault.
FLASHES CAUSE
1 Dry Plug - In Fault -
Sheath of temperature probe dry for 10 minutes after power-up
2 Low Tank Level Fault -
Level probe dry for 7 minutes after fill valve is energized
3 Low Water Temperature Fault -
Sensor in tank is calling for heat for 30 minutes or more
4 Tank Sensor Disagreement -
Level probe detects water, but dry plug-in probe dry
5 Temp Sensor Out-of-Range - High
6 Temp Sensor Out-of-Range - Low
DIAGNOSTICS
THINGS TO CHECK
Water Pressure (Is water shut "OFF")
Temperature probe wiring
Fill valve wiring, function, & strainer
Green wire between tank and circuit board
Water pressure (Is water shut "OFF")
Level probe wiring
Temperature probe wiring
Fill valve wiring, function, & strainer
Tank heater wiring & function
Temperature probe wiring
Temperature probe wiring
Level probe wiring
Green wire between tank and circuit board
Sensor not connected to circuit board
Sensor wires shorted together or to chassis
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