Troubleshooting
Guide
18|
Page
ERROR
CODE
721
[510
(T
‐
D2)],
SIX
FLASHES/72
[110
(T
‐
KJR2),
310
(T
‐
K4)]
FALSE
FLAME
DETECTION
1)
First
and
foremost,
shut
off
all
gas
and
power
to
the
unit.
The
problem
could
be
the
flame
sensor,
but
if
it
isn’t,
this
is
a
very
dangerous
situation.
2)
Contact
the
Technical
Service
Department
for
further
assistance.
ERROR
CODE
741
[510
(T
‐
D2)],
74
[110
(T
‐
KJR2),
310
(T
‐
K4)]
MAIN
REMOTE
CONTROL
PROBLEM
This
error
code
only
occurs
when
there
is
a
miscommunication
between
the
temperature
remote
controller
and
the
water
heater.
1)
Check
that
all
wiring
is
properly
connected
to
the
remote.
2)
Verify
the
correct
model
of
remote
is
being
used
for
the
corresponding
tankless
model.
3)
Verify
that
only
a
remote
is
installed.
Multiple
remotes
will
result
in
this
error
code.
4)
If
you
disconnect
the
remote
from
the
heater
with
the
power
supply
on,
this
error
code
will
result.
Turn
off
power
before
disconnecting
the
remote
from
the
heater.
5)
Check
for
any
signs
of
power
surges.
ERROR
CODE
761
[510
(T
‐
D2)]
COMMUNICATION
FAILURE
1)
This
error
code
only
occurs
in
a
multiple
heater
setup,
where
there
is
a
miscommunication
between
master
and
slave
units
for
Easy
‐
Link
systems.
2)
This
error
code
will
only
be
displayed
on
the
master
heater.
3)
This
error
indicates
that
the
master
unit
has
lost
communication
with
the
indicated
heater.
4)
Verify
that
there
is
power
to
the
unit
that
has
lost
communication.
5)
See
the
Installation
Manual
for
proper
communication
cable
setup.
6)
Check
for
signs
of
power
surges.
ERROR
CODE
991
[510
(T
‐
D2)],
FIVE
FLASHES/99
[110
(T
‐
KJR2),
310
(T
‐
K4)]
ABNORMAL
COMBUSTION
1)
Refer
to
error
code
101.
2)
Contact
the
Technical
Service
Department
for
further
assistance
if
nothing
has
worked
so
far.
The
manifold
gas
pressure
may
need
adjustment.
3)
If
you
are
sure
that
the
problem
has
been
solved,
reset
the
computer
(p.
23).
