Takagi AT-D3U-IN User Manual

52 Page
Troubleshoong
Owner's Guide
Remote
Green
LED
Malfunction
description
Diagnosis
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 #714) 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).
651*
Four Flashes
Flow adjustment
valve fault (Only
Easy-Link & Multi-Unit
System)
 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 Flashes
Bypass valve fault
(510U model 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 Flash
Computer board fault  Check the outlet thermistor (Part #408) as it may need to
be cleaned.
 Check for connection/breakage of wires (Part #714).
711*
One Flash
Gas solenoid valve
drive circuit failure
 Refer to the 111 and 121 error codes.
721*
Six Flashes
False flame detection  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
 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 built-in controller
 Inspect the connections between the water heater and
built-in 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. 33.
 Verify that each unit has power and that its power switch
above the computer board is in the ON position.
991
Five Flashes
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.
 Check whether there is enough distance between the
exhaust and air intake terminals.
 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.
*These error codes will be cleared when water flow stops.

Takagi AT-D3U-IN Specifications

General

Brand	Takagi
Model	AT-D3U-IN
Category	Water Heater
Language	English