Water Treatment
▲The illustration is an example. Please check with the actual water heater about the position of piping, and form.
City Water Supply
Pressure
Relief
Va
lv
e
Hot Water to Fixtures
Shutoff Valve
Drain
Cold to W
ater
Heater
Optional Sediment
Filter
Water T
reatment Device
Shutoff Valve
NORITZ
Condensing
Ta
nkless Gas
Water Heater
Water T
reatment System
T
ype of W
ater
Hardness Level
Tr
eatment Device*
Flush Frequency**
Soft
0-1 gpg
1-3 gpg
(0-17 mg/L)
None
None
Slightly Hard
(17-51 mg/L)
None
None
Moderately
Hard
Hard
3-7 gpg
(51-120 mg/L)
H2Flow or
ScaleShield
H2Flow or
ScaleShield
Once a
Ye
ar*** or
Flashing the error code****
Once a
Ye
ar*** or
Flashing the error code****
Once a
Ye
ar*** or
Flashing the error code****
Once a
Ye
ar*** or
Flashing the error code****
7-10 gpg
(120-171 mg/L)
Ve
ry Hard
10-12 gpg
(120-200 mg/L)
H2Flow or
Wa
ter Softener
H2Flow or
Wa
ter Softener
Extremely
Hard
> 12 gpg
(> 200 mg/L)
*
When selecting a treatment device, you must
consult with the device’s spec sheet and
installation manual for guidelines and limitations.
Not all water supplies are compatible -
a water test may be required.
**
Install Noritz Isolation
Va
lves to allow for flushing.
***Flushing is required if a water treatment
device is not installed.
**** The error code
"
" will be flashing in the
Display Window.
= 1, 2, 3, 4, F
# = 1, 2, 3, 4, 5, 6, 7, 8, 9, A, b, C, d, E, F
Residential Use
Tr
eatment Guidelines
If
this
water
heater
will
be
installed
in
an
application
where
the
supply
water
is
hard,
the
water
must
be
treated
with
either
the
Noritz
H2Flow
or
ScaleShield
or
a
water
softene
r
.
Refer
to
the
below
tables
for
sugg
e
s
te
d
treatment an
d
mai
ntenan
c
e mea
sures
t
o
be ta
k
en ba
s
e
d
o
n t
h
e
w
ater
hardn
e
ss
l
e
v
e
l.
I
f
t
his
w
ater
he
ater
will
be
ins
t
alled
i
n an
applic
at
io
n
wher
e t
h
e
supply
w
ater
is
hard,
S
cal
e B
uild-up
ma
y
caus
e
damag
e t
o
t
h
e Heat
Exchang
er
.
In t
his
c
a
s
e
,
t
his
w
ater
he
ater
d
ete
c
t
s
S
cal
e B
uild-up
i
n t
h
e Heat
E
xchange
r an
d
t
he
n t
h
e
erro
r
cod
e "
"
*
will
fl
a
sh
i
n t
h
e D
ispl
a
y
W
indow.
W
he
n t
h
e
erro
r
cod
e "
"
*
is
displayed,
t
h
e Heat E
xchange
r
needs
t
o
be
flushed
t
o
preve
nt
damag
e
fro
m S
cal
e B
uild-up.
Re
f
er t
o
t
h
e
"
P
r
ocedu
re
fo
r
flushi
n
g
t
h
e Heat E
xchange
r"
o
r
co
nta
c
t
Nori
t
z
Amer
ic
a
fo
r
mo
re
i
n
form
at
io
n
.
(http://support.noritz.com/ or 866-766-7489)
Damage
to
the
water
heater
as
a
result
of
the
items
below
is
not
covered
by
the
Noritz
America
Limited
Warrant
y.
•
W
ater in excess of 12 gpg (200mg/L) of hardness
•
Poor water quality (See the
W
ater Quality List on .)
•
The
water
heater
has
displayed
a "
"
error
code
indicating
Scale
Build-up,
but
the
heat
exchanger
has not been flushed.
Note:
Water
sof
tener
s
ma
y
be
regul
ate
d
b
y
t
h
e
local
w
ater
jurisdic
t
io
n
,
consul
t
wi
t
h
t
h
e man
uf
a
c
t
ure
r
fo
r
cod
e
,
sizing,
an
d
ins
t
all
at
io
n
guidelines
; t
h
e
below
diagra
m
is
fo
r re
ferenc
e
only.
Fo
r
mor
e
i
n
form
at
io
n
abou
t H2
Flow
an
d
S
cal
eS
hield,
co
nta
c
t
Nori
t
z
A
meric
a at
h
tt
p://suppo
rt
.nori
t
z.co
m
/
o
r
866-766-7489.
* = 1, 2, 3, 4, F
#
= 1, 2, 3, 4, 5, 6, 7, 8, 9,
A, b, C, d, E, F
73
Summary of Contents for NRC661-DV
Page 17: ...NR501 OD NR662 OD Thermistor Cold Water Thermistor Hot Water Gas Proportioning Valve 17...
Page 19: ...19 5 Operation Flow Chart Water heating Shutdown procedure Ignition operation NR501 OD...
Page 20: ...Water heating Shutdown procedure Ignition operation 20 NR662 OD...
Page 71: ...located 71...