Installation Sheet

44 Page
-Fault Analysis of Error Codes-
If the error code is displayed on the computer board of the water heater or the controller, please check
the following. After checking, consult with the manufacturer.
Troubleshoong
Owner's Guide
Error
code
Malfunction
description
Diagnosis
031
Incorrect DIP
switch setting
 Check the DIP switches settings on the PCB (Part #701).
101
Warning for the
“991” error code
 Check the gas type of the water heater matches the gas supplied to it.
 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.
 Check the DIP switches match gas type of unit.
 Check the manifold pressure at Max. and Min.
 Check the proportional gas valve hose.
111*
Ignition failure  Check if the Hi-limit switch (Part #403) is properly functioning.
 Check for connection/breakage of wires, burn marks on the computer
board (Part #701), and/or soot on the flame rod (Part #103).
 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 gas valve assembly
(Part#114) when the water heater goes into combustion.
 Check if there is leaking from the heat exchanger (Part #401).
 Check that the gas is turned on.
 Check the gas supply.
121*
Loss of flame  Check if the Hi-limit switch (Part #403) is functioning properly.
 Check for connection/breakage of wires, burn marks on the computer
board (Part #701), and/or soot on the flame rod (Part #103).
 Check if there is leaking from the heat exchanger (Part #401).
 Check gas supply
311*
Outlet thermistor
failure
 Check for connection/breakage of wires and/or debris on thermistor.
 Check the resistance.
321*
Inlet thermistor
failure
331*
Mixing thermistor
failure
391*
Air-fuel ratio rod
failure
• Check for connection/breakage of wires and/or soot on the AFR rod.
441*
Flow sensor
failure (Easy-Link
System only)
 Check for connection/breakage of wires and/or debris on the flow sensor
impeller.
 Check that the water isolation valves are open.
 Check inlet water filter for debris.
510
Abnormal main
gas valve
 Check for connection/breakage of wires and/or burn marks on the com-
puter board.
 Check for signs of vent corrosion.
 Check gas valve contacts and gas valve wire harness connections for signs
of rust or corrosion.
551
Abnormal gas
solenoid valve
 Check for connection/breakage of wires and/or burn marks on the com-
puter board.
 Check gas valve contacts and gas valve wire harness connections for signs
of rust or corrosion.
*These error codes will be cleared when water flow stops.