49
Page
Remote
Green
LED
Malfunction
description
Diagnosis
391*
Two Times
Air-fuel ratio rod
failure
•
Check for connection/breakage of wires (Part #708)
and/or soot on the AFR rod (Part #108).
510
Six Times
Abnormal main gas
solenoid valve
•
Check for connection/breakage of wires (Part #707)
and/or burn marks on the computer board (Part #701).
•
Check for signs of vent corrosion.
•
Check gas valve contacts and gas valve wire harness
connections for signs of rust or corrosion.
551
Six Times
Abnormal gas
solenoid valve
•
Check for connection/breakage of wires (Part #707)
and/or burn marks on the computer board (Part #701).
•
Check gas valve contacts and gas valve wire harness
connections for signs of rust or corrosion..
611*
Four Times Fan motor fault
•
Check for connection/breakage of wires, dust buildup
in the fan motor (Part #103) and/or burn marks on
the computer board (Part #701).
•
Check for frozen/corrosion of connectors (Part #103).
701*
One Time
Computer board fault
•
Check for connection/breakage of wires (Part #711).
711*
One Time
Gas solenoid valve
drive circuit failure
•
Refer to the 111 and 121 error codes.
721*
Six Times
False flame
detection
•
Check if there is leaking from heat exchanger (Part #401).
741
N/A
Miscommunication
between the water
heater and remote
controller
•
Check the model type of the remote controller.
•
Inspect the connections between the water heater
and remote controller.
•
Check the power supply of the water heater.
751
N/A
Miscommunication
between the water
heater and built-in
controller
(Indoor
model only)
•
Inspect the connections between the water heater
and temperature controller.
•
Check the power supply of the water heater.
941
Five Times
Abnormal exhaust
temperature
(Indoor
model only)
•
Check to see of the exhaust temperature is higher
than 149°F (65°C).
991
Five Times
Imperfect
combustion
•
Check if the gas type of the water heater matches
the gas supplied to it.
•
Inspect the environment around the water heater.
Determine how long the water heater has been
installed and match DIPswitches.
•
Check the altitude/elevation of the area of where
the water heater is installed.
•
Check if there is any blockage in the intake air and/
or exhaust.
•
If the water heater is installed as a direct-vent system,
check whether there is enough distance between the
intake air terminal and the exhaust terminal.
•
Check if there is grease and/or dirt in the burner (Part
#101) and the fan motor (Part #103), especially if the
water heater has been installed in a contaminated area
•
Check the DIP switches match gas type of the water
heater.
•
Check the manifold pressure at Max. and Min.
•
Check combustion chamber tube (part #117) to see
if it is clear and securely installed.
Troubleshooting
Owner's Guide
*
These error code will be clear when water flow stops.
