User Guide

42 Page
-Fault Analysis of Error Codes-
If the error code is displayed on the computer board of the water heater or remote controller, please
check the following. After checking, consult with the manufacturer.
Troubleshoong
Owner's Guide
Remote
Green
LED
Malfunction
description
Diagnosis
031
One Flash
Incorrect DIP switch
setting
 Check the DIP switch settings on the PCB (Part #701).
101
Five Flashes
Warning for the “991”
error code
 Check the gas type of the water heater.
 Check if there is any blockage in the intake air and/or
exhaust.
 Check to make sure that there is enough distance between
the concentric vent terminal and other exhaust vent
terminals.
 Check the altitude/elevation of area of where the water
heater is installed.
 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.
111*
Three Flashes
Ignition failure  Check if the Hi-limit switch (Part #412) is properly
functioning.
 Check for connection/breakage of wires (Part #413, 708,
709), burn marks on the computer board (Part #701), and/or
soot on the flame rod (Part #108).
 Check if there is a buzzing spark ignition sound coming
from the burner (Part #101) when the water heater
prepares for combustion.
 Listen for the double “clunk” sound coming from the gas
valve assembly (Part #102) when the water heater goes
into combustion.
 Check if there is leaking from heat exchanger (Part #401).
121*
Three Flashes
Loss of flame  Check if the Hi-limit switch (Part #412) is functioning
properly.
 Check for connection/breakage of wires (Part #413, 708,
709), burn marks on the computer board (Part #701),
and/or soot on the flame rod (Part #108).
 Check if there is leaking from heat exchanger (Part #401).
311*
Two Flashes
110C & 310C:
Outlet thermistor
failure
510C:
Heat exchanger
thermistor failure
 Check for connection/breakage of wires and/or debris on
thermistor (Part #407, 408, 411, 713).
321*
Two Flashes
Inlet thermistor failure
331*
Two Flashes
Outlet thermistor
failure
(510C model only)
391
Two Flashes
Air-fuel ratio rod failure  Check for connection/breakage of wires (Part #709) and/
or soot on the AFR rod (Part #108).
441
Two Flashes
Flow sensor failure
(Only Easy-Link &
Multi-Unit System)
 Check for connection/breakage of wires and/or debris on
the flow sensor impeller (Part #402).
510
Six Flashes
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 Flashes
Abnormal gas
solenoid valve
 Check for connection/breakage of wires (Part #708) and/
or burn marks on the computer board (Part #701).
611*
Four Flashes
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).