45
Page
Troubleshooting
Owner's Guide
110 (T-KJr2) and
310 (T-K4)
510
(T-D2)
Malfunction
description
Diagnosis
Red
LED
Remote Remote
7 Seg LED
Two
Times
39
391
Air-fuel ratio
rod failure
•
Check for connection/breakage of wires (Part #709) and/
or soot on the AFR rod (Part #108).
N/A
N/A
441
Flow sensor
failure (Easy-Link
System only)
•
Check for connection/breakage of wires and/or debris on
the flow sensor impeller (Part #402, 717).
Six Times
51
510
Abnormal gas
solenoid valve
•
Check for connection/breakage of wires (Part #708) and/
or burn marks on the computer board (Part #701).
Six Times
55
N/A
Abnormal main
gas valve
•
Check for connection/breakage of wires (Part #708) and/
or burn marks on the computer board (Part #701).
Four
Times
61
611
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).
N/A
N/A
651
Flow adjustment
valve fault (Easy-
Link System only)
•
Inspect the flow adjustment valve (Part #402), for
connection/breakage of wires (Part #718), locked motor
drive due to scale buildup, and/or water leakage.
One Time
70
701
Computer board
fault
•
Check for connection/breakage of wires (Part #714) and/
or burn marks on the computer board (Part #701).
•
Check the power supply of the water heater.
Six Times
72
721
False flame
detection
•
For indoor models, check if condensate drain is installed
on the vent collar of the water heater.
•
Check if there is leaking from heat exchanger (Part #401).
N/A
74
741
Miscommuni-
cation between
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.
N/A
N/A
761
Miscommuni-
cation in Easy-
Link System
•
Check if the connections between the parent unit and the
child units are correct. Refer to p. 24-27
.
Five Times
99
991
Imperfect
combustion
•
Check the gas type of the water heater.
•
Inspect the environment around the water heater.
Determine how long the unit has been installed.
•
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 #104), especially if the
water heater has been installed in a contaminated area.