Diagnostic Chart - Bunn TWF-EZ Operating & Service Manual

Intermittent flashing of the READY indicator 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?)
Shorting pin on J6 connector of control board
not on correct set of pins (See page 7)
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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