John Wood Takagi - 240H-340H-540H - Manual (Page 46)

46
Page
Troubleshooting
Owner's Guide
Remote
Green
LED
Malfunction
description
Diagnosis
391 Two Times Air-fuel ratio rod
failure
• Check for connection/breakage of wires (Part #709)
and/or soot on the AFR rod. (Part #108)
441 Two Times Flow sensor failure
(Easy-Link System only)
• Check for connection/breakage of wires and/or
debris on the flow sensor impeller. (Part #402)
510 Six Times Abnormal main gas
solenoid valve
• Check for connection/breakage of wires (Part #708)
and/or burn marks on the computer board (Part #701).
551 Six Times Abnormal gas
solenoid valve
• Check for connection/breakage of wires (Part #708)
and/or burn marks on the computer board (Part #701).
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).
651 Four Times Flow adjustment
valve fault (Easy-
Link System only)
• Inspect the flow adjustment valve (Part #402), for
connection/breakage of wires, locked motor drive
due to scale buildup, and/or water leakage.
661 Four Times Bypass valve fault
(T-H3-DV / 540H
only)
• Inspect the bypass valve (Part #403), for connection/
breakage of wires, locked motor drive due to scale
buildup, and/or water leakage.
701 One Time Computer board
fault
• Check for connection/breakage of wires (Part #714).
711 One Time Gas solenoid valve
drive circuit failure
• Refer to 111 and 121 error code.
721 Six Times 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).
741 N/A Miscommunication
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.
751 N/A Miscommunication
between water
heater and
temperature
controller
• Inspect the connections between the water heater
and temperature controller.
• Check the power supply of the water heater.
761 N/A Miscommunication
in Easy-Link system
• Check if the connections between the parent unit
and the child units are correct. Refer to p. 26-29.
941 Five Times Abnormal exhaust
temperature
• Check if the set temperature is higher than 60 °C
(140 °F) and the system is Recirculation.
991 Five Times 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 #103), especially if the
water heater has been installed in a contaminated
area.