If
the
error
code
is
indicated
on
the
3
‐
digit
7
‐
Seg
LED
on
the
PCB
(Part
#701)
of
the
water
heater
(and/or
the
remote
controller),
refer
to
Section
B
.
<<
It
takes
long
time
to
get
hot
water
at
the
fixtures
>>
・
The
time
it
takes
to
deliver
hot
water
from
the
water
heater
to
your
fixtures
depends
on
the
length
of
piping
between
the
two.
The
longer
the
distance
or
the
bigger
the
pipes,
the
longer
it
will
take
to
get
hot
water.
・
If
you
would
like
to
receive
hot
water
to
your
fixtures
quicker,
you
may
want
to
consider
a
hot
water
recirculation
system.
<<
The
water
is
not
hot
enough
or
turns
cold
and
stays
cold
>>
・
Compare
the
flow
and
temperature.
Refer
to
the
“Output
temperature
chart”
of
the
installation
manual.
・
Check
cross
plumbing
between
cold
water
lines
and
hot
water
lines.
・
Check
if
the
gas
supply
valve
fully
open,
the
gas
line
sized
properly
and
the
gas
supplies
pressure
enough.
Refer
to
the
“Gas
supply
and
gas
pipe
sizing”
of
the
installation
manual.
・
Check
the
set
temperature,
and
change
the
dipswitch
setting.
Refer
to
Section
D
.
・
Refer
to
“Water
circuit”
in
this
section.
<<The
water
is
too
hot>>
・
Check
the
set
temperature,
lower
setting
temperature.
<<The
hot
water
is
not
available
when
a
fixture
is
opened>>
・
Refer
to
the
“Power
supply
circuit
”
and
“Water
circuit”
in
this
section.
<<Fluctuation
in
hot
water
temperature>>
・
Check
if
the
filter
on
the
cold
water
inlet
cleaned.
(Part
#409)
・
Check
if
the
gas
line
sized
properly
and
the
supply
gas
pressure
sufficient.
・
Check
for
cross
connection
between
cold
water
lines
and
hot
water
lines.
・
Refer
to
“Water
circuit”
in
this
section.
<<Unit
does
not
ignite
when
water
goes
through
the
water
heater>>
・
Refer
to
the
“Power
supply
circuit
”
and
“Water
circuit”
in
this
section.
・
If
you
use
the
remote
controller,
turn
the
power
button
on
and
then
the
green
LED
will
lit.
・
Check
if
the
filter
on
the
cold
water
inlet
cleaned.
(Part
#409)
B.
Error
codes
031:
Incorrect
dipswitch
setting
・
Check
the
dipswitch
settings
on
the
PCB.
Refer
to
Section
D
.
101:
Warning
for
the
“991”
error
code
・
Check
the
gas
type
of
the
water
heater.
If
it’s
wrong
gas
type
model,
replace
the
water
heater
to
correct
one.
・
Check
if
there
is
any
blockage
(For
example,
Damper
sticking,
Vent
Flaps
installed
on
the
terminator,
Snow
build
up
around
terminator,
Installed
in
a
closet
(No
ventilation
or
lack
of
combustion
air))
in
the
intake
air
and/or
exhaust.
Refer
to
the
“Vent
termination
clearances”
of
the
installation
manual.
・
If
the
water
heater
is
installed
as
a
direct
‐
vent
system,
check
whether
there
are
enough
distance
between
the
intake
air
terminal
and
the
exhaust
terminal.
Refer
to
the
“Vent
termination
clearances”
of
the
installation
manual.
・
Check
if
the
total
vent
length
doesn’t
exceed
50
ft
and
the
#
of
elbows
is
less
than
5Ea.
・
Check
the
altitude/elevation
of
area
of
where
the
water
heater
installed.
Refer
to
the
“High
‐
altitude
function”
of
the
Section
D
.
And
change
the
dipswitch
settings.
・
Check
if
there
is
grease
and/or
dirt
in
the
burner
(Part
#101),
and
the
fan
motor
(Part
#114),
especially
if
the
water
heater
has
been
installed
in
a
contaminated
area.
・
Check
if
there
is
dust
and
lint
in
heat
exchanger.
・
Check
the
manifold
pressure
of
the
water
heater.
Refer
to
installation
manual.
111:
Ignition
failure
1.
Check
gas
supply
and
inlet
gas
pressure.
2.
Check
if
the
Hi
‐
limit
switch
(Part
#432)
is
properly
functioning.
3.
Check
for
connection/breakage
of
wires
(Part
#110,
404,
704,
705,
710,
719),
burn
marks
on
the
computer
board
(Part
#701),
and/or
soot
on
the
flame
rod
(Part
#106).
And
then
if
O.H.C.F
(Part
#008
and/or
#404)
is
breakage,
Consult
the
manufacturer.
4.
Check
if
there
is
a
buzzing
spark
ignition
sound
coming
from
the
burner
(Part
#101)
when
water
heater
prepares
for
combustion.
5.
Listen
for
the
double
“clunk”
sound
coming
from
the
gas
valves
assembly
(Part
#118)
when
water
heater
goes
into
combustion.
6.
(Only
no
sparking
and/or
kick
sound)
Check
voltage
on
each
wire
to
gas
valves
assembly
(Part
#118)
and/or
the
igniter
(Part
#123).
Refer
to
the
“Appendix
A”
in
Section
C
.
*No
sparking
sound
>>>>>
Refer
to
the
#1
at
“Appendix
A”
in
Section
C
.
*No
kick
sound
>>>>>
Refer
to
the
#2
at
“Appendix
A”
in
Section
C
.
7.
Check
if
there
is
leaking
from
heat
exchanger
(Part
#401
or
456)
8.
Check
if
there
is
dust
and
lint
in
nozzles
of
the
manifold
(Part
#118).
9.
Check
current
on
the
flame
rod
(Part
#106).
Refer
to
the
#3
at
“Appendix
A”
in
Section
C
.
121:
Loss
of
flame
1.
Check
gas
supply
and
inlet
gas
pressure.
2.
Check
if
the
Hi
‐
limit
switch
(Part
#432)
is
properly
functioning.
3.
Check
for
connection/breakage
of
wires
(Part
#110,
404,
704,
705,
710,
719),
burn
marks
on
the
computer
board
(Part
#701),
and/or
soot
on
the
flame
rod
(Part
#106).
And
then
if
O.H.C.F
(Part
#008
and/or
#404)
is
breakage,
Consult
the
manufacturer
.
4.
Check
if
there
is
leakage
from
heat
exchanger
(Part
#401
or
456).
5.
Check
if
there
is
dust
and
lint
in
nozzles
of
the
manifold
(Part
#118).
6.
Check
current
on
the
flame
rod
(Part
#106).
Refer
to
the
#3
at
“Appendix
A”
in
Section
C
.
311,321,331,341*:
Disconnected/short
‐
circuited
thermistor
・
Check
for
connection/breakage
of
wires
and/or
debris
on
thermistor
(Part
#422,
433,
418,
706,
707,721).
・
Check
thermistor
resistance.
Refer
to
the
“Appendix
D”
in
Section
C
.
391:
Air
‐
fuel
Ratio
Rod
failure
・
Check
for
connection/breakage
of
wires
(Part
#710)
and/or
soot
on
the
AFR
rod.
(Part
#106).
M
M
a
a
i
i
n
n
t
t
e
e
n
n
a
a
n
n
c
c
e
e
s
s
h
h
e
e
e
e
t
t
7
7
3
3
W
W
0
0
0
0
3
3
A.
Troubleshooting
C.
Wiring
Diagram
and
check
point
of
the
Water
heater
<Right
bank
of
dipswitches>
441:
Flow
Sensor
failure
(Only
Easy
‐
Link
system)
・
Check
for
connection/breakage
of
wires
and/or
debris
on
impeller
(Part
#429,
708).
510,551:
Abnormal
Main
and
Gas
Solenoid
Valve
・
Check
for
connection/breakage
of
wires
(Part
#705)
and/or
burn
marks
on
the
computer
board
(Part
#701).
・
Reset
power
supply
of
the
water
heater.
・
Check
voltage
on
the
each
valve
on
the
gas
valves
assembly
(Part
#118).
Refer
to
the
“Appendix
C”
in
Section
C
.
611,621*:
Fan
motor
and
Exhaust
Fan
motor
fault
・
Check
for
connection/breakage
of
wires,
dust
buildup
in
the
fan
motor/Exhaust
fan
motor
(Part
#114,124)
and/or
burn
marks
on
the
computer
board
(Part
#701).
・
Check
for
frozen/corrosion
of
connectors
of
the
fan
motor
(Part
#114,124).
・
Check
voltage
between
blue
wire
and
each
wire
of
the
fan
motor
(Part
#114,124)
during
operation.
Refer
to
the
“Appendix
B”
in
Section
C
.
631:
Abnormal
External
Pump
・
Check
whether
the
pump
connected
to
PCB
(Part
#701)
works
properly.
651,661:
Water
control
valve
fault
(Only
Easy
‐
Link
system)
・
Check
the
water
control
valve
(Part
#423),
connection/breakage
of
wires
(Part
#423),
motor
drive
locked
due
to
scale
buildup,
and/or
water
leakage.
・
Check
voltage
between
black
wire
and
red
wire.
Refer
to
the
“Appendix
F”
in
Section
C
.
701:
Computer
board
fault
・
Check
for
connection/breakage
of
wires
(Part
#708)
and/or
burn
marks
on
the
computer
board
(Part
#701).
711:
Hi
‐
limit
switch
trip/
Gas
solenoid
valve
drive
circuit
failure
・
Check
connection/breakage
of
wires
(Part
#705)
and/or
burn
marks
on
the
computer
board
(Part
#701).
721:
False
flame
detection
1.
Clean
the
flame
rod
(Part
#106).
2.
For
indoor
models,
check
if
condensate
drain
is
installed
on
the
vent
collar
of
the
water
heater.
3.
Check
if
there
is
leaking
from
heat
exchanger
(Part
#401
or
456).
741:
Miscommunication
between
water
heater
and
remote
controller
1.
Check
the
model
type
of
the
remote
controller.
Model
name
9007603005
(TM
‐
RE30)
is
the
correct
one.
2.
Inspect
for
the
connections
between
the
water
heater
and
remote
controller.
Refer
to
“Remote
controller
connections”
section
in
the
Installation
manual.
3.
Check
the
power
supply
of
the
water
heater.
4.
If
this
error
code
appears
only
the
3
‐
digit
7
‐
Seg
LED
on
the
PCB
(Part
#701),
check
the
voltage
on
the
remote
controller
terminal
on
the
PCB.
Refer
to
the
“Appendix
E”
in
Section
C
.
5.
If
this
error
code
appears
only
remote
controller,
replace
the
PCB
(Part
#701).
6.
If
this
error
code
appears
both
the
PCB
(Part
#701)
and
the
remote
controller,
replace
the
remote
controller.
761:
Miscommunication
between
Parent
unit
and
Child
units
for
Easy
‐
link
system
(Only
520H
models)
・
Check
if
connection
between
the
parent
unit
and
the
child
units
are
correct.
Refer
to
“Easy
‐
Link
system”
section
in
the
Installation
manual.
941*:
Abnormal
exhaust
temperature
(Only
520H
and
320H
Direct
Vent
Indoor)
・
Check
if
the
set
temperature
is
higher
than
140°F
(60°C)
and
the
system
is
Recirculation.
・
Check
exhaust
thermistor
resistance.
Refer
to
the
“Appendix
D”
in
Section
C
.
991:
Imperfect
combustion
・
Refer
to
the
“Error
code
101”
in
this
section.
<<The
fan
motor
still
spinning
after
operation
has
stopped>>
・
This
is
normal.
After
operation
has
stopped,
the
fan
motor
keeps
running
for
35
seconds
in
order
to
re
‐
ignite
quickly,
as
well
as
purge
all
the
exhaust
gas
out
of
the
flue.
<<Abnormal
sound
from
water
heater>>
・
An
abnormal
sound
from
the
water
heaters
is
caused
by
not
enough
air
supply
or
wrong
installations.
The
water
heater
needs
more
combustion
air.
Refer
to
the
“Error
101”
in
the
Section
B
.
<<Power
supply
circuit>>
1.
If
the
remote
controller
installed,
press
the
“ON/OFF”
button
of
the
remote
controller,
and
make
sure
that
the
green
LED
on
the
“ON/OFF”
button
of
the
remote
controller
is
lit.
Restart
the
water
heater.
2.
Check
if
that
the
3
‐
digit
7
‐
Seg
LED
on
the
PCB
(Part
#701)
of
the
water
heater
is
lit.
If
so,
the
power
supply
circuit
of
the
water
heater
is
under
normal
condition.
Next,
refer
to
the
“Water
circuit”
in
this
section.
3.
Check
the
fuse
on
the
surge
box
(Part
#715),
and
if
it
has
a
brown
spot,
need
to
replace
it.
4.
Check
the
power
supply,
and
make
sure
that
the
water
heater
has
120
VAC.
5.
If
the
3
‐
digit
7
‐
Seg
LED
on
the
PCB
(Part
#701)
isn’t
lit,
some
electrical
parts
can
be
broken.
Consult
the
manufacturer
.
<<Water
circuit>>
1.
If
you
set
the
remote
controller,
turn
the
power
button
on
and
then
the
green
LED
will
lit.
2.
Open
all
hot
water
faucets,
and
make
sure
that
there
is
enough
water
flow.
This
water
heater
needs
at
least
0.5
GPM
water
flow
to
operate.
3.
Check
for
reverse
connection
and
cross
connection.
4.
Check
if
the
filter
on
the
cold
water
inlet
cleaned.
(Part
#409)
5.
Check
if
there
is
no
debris
or
obstruction
on
the
fixtures.
6.
Check
if
water
ways
in
the
water
heater
are
frozen.
If
so,
unfreeze
them.
And
refer
to
installation
manual
to
protect
your
water
heater
from
freeze.
7.
Check
if
the
inlet
water
pressure
is
higher
than
40
psi.
And
if
it’s
lower
than
40
psi,
need
to
increase
the
pressure.
8.
Check
for
connections
and
breakage
of
wires
(Part
#423,
429).
9.
Check
if
the
motor
drive
of
the
water
control
valve
(Part
#423)
is
locked
due
to
scale
buildup,
and/or
water
leakage,
Consult
the
manufacturer.
<Left
bank
of
dipswitches>
Left
bank
Right
bank
Appendix
D
(For
error
code:
311,
321,
331,
341
and
941)
・
Mixing
thermistor
(Find
the
marking
of
No.113
on
the
connector)
Check
point
“E1”
・
Output
thermistor
(Find
the
marking
of
No.12
on
the
connector)
Check
point
“E2”
・
Inlet
thermistor
(Find
the
marking
of
No.42
on
the
connector)
Check
point
“E3”
Check
resistance
between
black
wire
and
black
wire.
Temperature
°F
50
59
68
77
86
95
°C
10
15
20
25
30
35
Resistance
k
Ω
15.4
12.6
10.3
8.5
7.0
5.9
・
Exhaust
thermistor
(Find
the
marking
of
No.52
on
the
connector)
Check
point
“K1”
Check
resistance
between
white
wire
and
white
wire.
Temperature
°F
50
59
68
77
86
95
°C
10
15
20
25
30
35
Resistance
k
Ω
19.5
15.9
13.0
10.7
8.9
7.4
All
check
points
are
normal?
Yes
>>
Replace
the
PCB.
(Part
#701)
No
>>
Replace
the
wrong
thermistor.
(Part
#422,
433,
418,
706)
Appendix
E
(For
error
code:
741)
Refer
check
point
“F”
on
the
wiring
diagram
above.
Check
voltage
on
the
remote
controller
terminal
on
the
PCB.
(Normal:
11
to
25
VDC)
This
check
point
is
normal?
Yes
>>
Replace
the
remote
controller.
No
>>
Replace
the
PCB.
(Part
#701)
Appendix
C
(For
error
code:
510
and
551)
Refer
check
point
“C”
in
the
diagram
to
the
left
and
followings.
Check
voltage
on
the
each
valve
on
the
gas
valves
assembly.
・
Between
blue
wire
and
light
blue
wire
(#3).
(Normal:
78
to
100
VDC)
・
Between
blue
wire
and
green
wire
(#9).
(Normal:
78
to
100
VDC)
・
Between
blue
wire
and
orange
wire
(#53).
(Normal:
78
to
100
VDC)
・
Between
blue
wire
and
red
wire
(#73).
(Normal:
78
to
100
VDC)
All
check
points
are
normal?
Yes
>>
Replace
the
gas
valves
assembly.
(Part
#118)
No
>>
Replace
the
PCB.
(Part
#701)
Appendix
B
(For
error
code
611
and 621)
Refer
check
point
“G1”
&
“G2”
in
the
diagram
to
the
left
and
followings.
・
Check
voltage
between
red
wire
and
blue
wire.
(Normal:
110
to
160
VDC)
・
Check
voltage
between
yellow
wire
and
blue
wire.
(Normal:
13
to
17
VDC)
・
Check
voltage
between
orange
wire
and
blue
wire
(Normal:
2.0
to
6.5
VDC)
All
check
points
are
normal?
Yes
>>
Replace
the
fan
motor
and
Exhaust
fan
motor.
(Part
#114&124)
No
>>
Replace
the
PCB.
(Part
#701)
Appendix
F
(For
error
code:
651
and
661)
Refer
check
point
“J”
on
the
wiring
diagram
above.
Check
voltage
between
blue
wire
and
brown
wire.
(Normal:
13
to
16
VDC)
This
check
point
is
normal?
Yes
>>
Replace
the
Water
control
valve.
(Part
#423)
No
>>
Replace
the
PCB.
(Part
#701)
Appendix
A
(For
error
code
111)
Check
these
points
during
ignition
stage.
#
1.
Refer
check
point
“B2”
on
the
wiring
diagram
above.
Check
voltage
between
purple
wires.
(Normal:
90
to
110
VAC)
This
Check
point
is
normal?
Yes
>>
Replace
the
igniter
(Part
#123)
No
>>
Go
to
Next
#
2.
Refer
check
point
“C”
and
“H1”
on
the
wiring
diagram
above.
Check
the
voltage
bellows.
C:
Between
blue
wire
and
light
blue
wire
(#3).
(Normal:
78
to
100
VDC)
C:
Between
blue
wire
and
orange
wire
(#53).
(Normal:
78
to
100
VDC)
H1:
Check
the
voltage
between
white
wire
and
red
wire.
(Normal:
1
to
15
VDC)
These
check
points
are
normal?
Yes
>>
Replace
the
gas
valves
assembly.
(Part
#118)
No
>>
Replace
the
PCB.
(Part
#701)
#
3.
Check
current
thought
the
orange
flame
rod
wire
(Part
#710).
(Normal:
more
than
1
μ
A)
This
check
point
is
normal
during
operation?
Yes
>>
Replace
the
PCB.
(Part
#701)
No
>>
Replace
the
flame
rod.
(Part
#106)
D.
Dipswitch
Settings
on
the
computer
board
of
the
water
heater
Change
the
dipswitch settings
when
the
power
supply
is
turning
off.
The
dark
square
is
the
direction
the
dipswitch
should
be
set
to.
DEFAULT
is
the
factory
setting.
FM
speed
is
increased
automatically.
The
Gas
Type
and
Model
Type
dipswitch
should
already
be
properly
preset
from
the
factory.
*The
341,
621
and
941
error
codes
are
applied
to
the
520H
and
320H
Direct
Vent
Indoor
model
only.
BK: BLACK
R: RED
W: WHITE
G: GREEN
BL: BLUE
O: ORANGE
Y: YELLOW
P: PURPLE
BR:BROWN
LB:LIGHT BLUE
Single
unit
is
the
same
as
the
child
unit.
N O
N O
1
2
3
4
5
6
7
8
9
1
0
1
2
3
4
5
6
7
8
9
1
0
Propane
Natural
Gas
Gas
type
Easy
‐
Link
system
N O
N O
1
2
3
4
5
6
7
8
9
1
0
1
2
3
4
5
6
7
8
9
1
0
DEFAULT
Parent
Unit
Child
Unit
J
J
T
T
H
H
2
2
1
2
3
4
5
6
7
8
N O
9
1
0
1
2
3
4
5
6
7
8
N O
9
1
0
1
2
3
4
5
6
7
8
N O
9
1
0
High
‐
altitude
function
FM++
(4,000
to
5,000
ft)
DEFAULT
(0
to
2,500
ft)
Over
5,000
ft:
Consult
the
manufacturer
FM+
(2,500
to
4,000
ft)
Inlet
thermistor
Mixing
thermistor
Output
thermistor
B K
B K
B K
Air-fuel
ratio rod
Ground
Flame rod
MV
SV3
SV1
SV2
B K
B K
B K
O.H.C.F
B L
B L
B L
B L
Y
G
O
B L
L B
O
R
G
Parent
W
W
B K
B K
B L
B L
R
R
Re mo te c on tr ol le r
1
234
56
OF
F
7
8
1
234
56
OF
F
7
8
2
1
W
Y
O
R
Gas
Propor-
tional
Valve
W
R
W
R
B K
R
W
Flow
Sensor
B K
W
R
Hi-limit switch
for exhaust
Exhaust
thermistor
W
W
W
R
YG
W
BK
BR
R
O
Y
G
W
BK
BL
Water
Control
valve
Igniter
rod
I G
P
P
P
P
BK
BK
G
B K
W
Trans-
former
Ground
B R
B R
120
VAC
G
Ground
B K
W
W
B K
B L
B R
Surge
box
W
BK
BL
W
Y
O
R
BL
W
9
10
9
10
B L
B L
H i - l i m i t
s w i t c h
O.H.C.F
B L
B L
520H / 320H Direct
Vent Indoor Only
M A X b u t t o n
M I N b u t t o n
I n c r e a s e b u t t o n
E r r o r c a l l b u t t o n
D e c r e a s e b u t t o n
A l a r m
p o r t
P u m p p o r t
B u r n i n g l a m p
7 S e g L E D
N u m b e r d i s p l a y b u t t o n
L e f t b a n k
o f d i p s w i t c h e s
R i g h t b a n k
o f d i p s w i t c h e s
Fan motor for
exhaust
Fan
motor
Heaters
Freeze protection
thermostat
520H / 320H Direct
Vent Indoor Only
J
I
9007603005
(TM
‐
RE30)
D2
D1
K1
B1
B2
G2
G1
A
A1
A2
C1
C2
F
C
E2
H2
H1
E3
K2
E1
N O
N O
1
2
3
4
5
6
7
8
9
1
0
1
2
3
4
5
6
7
8
9
1
0
Model
type
520H Outdoor
and
320H
Outdoor
520H Direct
Vent
Indoor
and
320H
Direct
Vent
Indoor
