Service Handbook

Condensing Models: On-Demand Water Heater Service Handbook • 11
TROUBLESHOOTING
ERROR CODE GREEN LED ON
COMPUTER BOARD
SYMPTOM OR ISSUE TROUBLESHOOTING PROCEDURE
510 Six Flashes
Abnormal main OR
abnormal solenoid gas
valve
Abnormal Main/Solenoid
Gas Valve, p. 14.
551 Six Flashes Abnormal solenoid gas
valve
Abnormal Solenoid Gas Valve, p. 14.
611 Four Flashes Fan motor fault
Abnormal Fan Motor, p. 15.
701 One Flash Computer board fault
Proportional Gas Valve / Computer Board Fault,
p. 16.
711 One Flash
Gas solenoid valve drive
circuit failure
High Limit Switch / Overheat Cutoff Fuse Circuit is
Compromised, p. 16.
721 Six Flashes False flame detection
False Flame Detection, p. 16.
741 N/A
Miscommunication
between water heater
and remote controller
Remote Control Problem, p. 16.
751 N/A
Miscommunication
between water heater
and temperature
controller (Indoor model
only)
Temperature Controller Problem, p. 17.
941 Five Flashes
Abnormal exhaust
temperature (Indoor
model only)
Abnormal Exhaust Temperature, p. 17.
991 Five Flashes Imperfect
Combustion
Abnormal Combustion, p. 17.
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