Installation Sheet

45 Page
Troubleshoong
Owner's Guide
*These error codes will be cleared when water flow stops.
Error
code
Malfunction
description
Diagnosis
611*
Fan motor fault  Check for connection/breakage of wires, dust buildup in the fan motor
(Part #416) and/or burn marks on the computer board (Part #701).
 Check for frozen/corrosion of connectors.
631
Abnormal external
pump
 Check whether the pump connected to center computer board works
properly.
651*
Flow adjustment valve
fault
 Inspect the flow adjustment valve for connection/breakage of wires,
locked motor drive due to scale buildup, and/or water leakage.
 Visual inspection of PCB: connection/breakage of wires and/or burn
marks on the computer board.
661*
Water control valve
fault
(Bypass function)
 Inspect the flow adjustment valve, for connection/breakage of wires,
locked motor drive due to scale buildup, and/or water leakage.
 Visual inspection of PCB: connection/breakage of wires and/or burn
marks on the computer board.
681
Abnormal external fan
motor
 Check whether the external fan motor connected to center computer
board works properly.
701*
Computer board fault
 Check for connection/breakage of wires and/or burn marks on the
computer board.
 Check the power supply of the water heater.
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 the heat exchanger (Part #401).
741
Miscommunication
between
water heater and
remote controller
 Check the model type of the remote controller.
 Inspect the connections between the water heater and remote con-
troller.
 Check the power supply of the water heater.
761
Miscommunication
in Easy-Link
System
 Check if the connections between the parent unit and the Child units
are correct. Refer to p. 28.
 Check that the power is on to all Child units.
991*
Imperfect
combustion
 Make sure that the gas type of the water heater matches the gas
supplied to it.
 Inspect the environment around the water heater. Determine how
long the unit has been 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 #416), especially if the water heater has been
installed in a contaminated area.
 Make sure that the DIP switches match the gas type of unit.
 Check the manifold pressure at Max. and Min.
 Check the proportional gas valve hose.