Noritz NRC661-DV User manual

SBB801H
Rev. 01/13
Models : NRC661-DV (For USA and Canada)
NRC661-OD (For USA only)
CONDENSING TANKLESS GAS WATER HEATER
Owner’s Guide
NORITZ America Corporation
-Donotstoreorusegasolineorotherammablevaporsandliquidsinthe
vicinityofthisoranyotherappliance.
-WHAT TO DO IF YOU SMELL GAS
•Donottrytolightanyappliance.
•Donottouchanyelectricalswitch;donotuseanyphoneinyourbuilding.
•Immediatelycallyourgassupplierfromaneighbor’sphone.Followthe
gassupplier’sinstructions.
•Ifyoucannotreachyourgassupplier,calltheredepartment.
-Installationandservicemustbeperformedbyaqualiedinstaller,service
agencyorthegassupplier.
If the information in this manual is not followed exactly, a re or explosion
may result causing property damage, personal injury, or death.
WARNING
Thank you for purchasing this Noritz Tankless Gas Water Heater.
Before using, please:
Read this manual completely for operation instructions.
Completely ll out the warranty registration card (included separately) and
mail the detachable portion to Noritz America Corporation.
Keep this manual (and the remainder of the warranty registration card) where
it can be found whenever necessary.
Installation must conform with local codes, or in the absence of local codes,
the National Fuel Gas Code, ANSI Z223.1/NFPA 54.
Noritz America reserves the right to discontinue, or change at any time, the
designs and/or specications of its products without notice.
FOR USE IN RESIDENTIAL APPLICATIONS.
CERTIFIED
R
*SBB801H*
Low NOx Approved
by SCAQMD
14 ng/J or 20 ppm
(Natural Gas Only)

2
Prohibited Don’t
touch.
Don’t
disassemble
the unit.
Don’t touch
with a wet
hand.
No ame.
High
Temperature.
To prevent damage to property and injury to the user, the icons shown below will be used to warn of
varying levels of danger.
Every indication is critical to the safe operation of the water heater and must be understood and observed.
Potential dangers from accidents during installation and use are divided into the following four
categories. Closely observe these warnings; they are critical to your safety.
Other icons
DANGER
WARNING
CAUTION
DANGER indicates an imminently hazardous situation which,
if not avoided, will result in death or serious injury.
WARNING indicates a potentially hazardous situation which, if not
avoided, could result in death or serious injury.
CAUTION indicates a potentially hazardous situation which, if not
avoided, may result in minor or moderate injury.
CAUTION used without the safety alert symbol indicates a potentially
hazardous situation which, if not avoided, may result in property damage.
CAUTION
Be sure
to do. Ground.
Electric
Shock.
DANGER
 Iconswarningofrisklevel
ImportantSafetyInformation-1
This is the safety alert symbol. It is used to alert you to potential personal injury hazards.
Obey all safety messages that follow this symbol to avoid possible injury or death.
Vaporsfromammableliquidswillexplodeandcatchrecausingdeathorsevereburns.
Do not use or store ammable products such as gasoline, solvents or
adhesives in the same room or area near the water heater.
Prohibited
Keepammableproducts:
1.Farawayfromthewater
 heater.
2.Inapprovedcontainers.
3.Tightlyclosed.
4.Outofchildren’sreach.
Vapors:
1.Cannotbeseen.
2.Vaporsareheavierthanair.
3.Goalongwayontheoor.
4.Canbecarriedfromotherrooms
tothemainburnerbyaircurrents.
HotWaterHeatertemperaturesover125°F(52°C)cancausesevereburnsinstantlyor
deathfromscalding.
Children, disabled and elderly are at the highest risk of being scalded.
Feel water temperature before bathing or showering.
Temperature limiting valves are available, ask professional person.
Prohibited
(Continued)

3
No ame.
(Continued)
WARNING
Be sure
to do.
Whenagasleakisnoticed:
1. Stopuseimmediately
2. Closethegasvalve
[NRC661-DV]
3. Openwindowsanddoors
Ifyoudetectabnormal
combustionorabnormalodors,
orduringanearthquake,tornado
orre:
1. Turnoffthehotwatersupply
2. Turnoffthepowertothewater
heater
3. Turnoffgasandwatersupply
valve
4. CallthenearestNoritzagent
Be sure
to do.
Do not allow anyone to change the water
temperaturewhilehotwaterisbeingused.
To prevent scalding, do not change the
water temperature to a higher setting.
Prohibited
A.Thiswaterheaterdoesnothave
apilot.Itisequippedwithan
ignitiondevicethatautomatically
lightstheburner.Donottryto
lighttheburnerbyhand.
B. BEFORE OPERATING smell all
aroundthewaterheaterareafor
evidenceofleakinggas.Besure
tosmellnexttotheoorbecause
somegasisheavierthanairand
willsettleontheoor.
WHATTODOIFYOUSMELLGAS.
• Do not try to light any
appliance.
• Do not touch any electrical
switch; do not use any phone
inyourbuilding.
• Immediately call your gas
supplierfromaneighbor’s
phone.Followthegassupplier’s
instructions.
• Ifyoucannotreachyourgas
supplier,calltheredepartment.
C. Useonlyyourhandtoturn
thegasvalveknob.Neveruse
tools.Iftheknobwillnotturnby
hand,don’ttrytorepairit.Call
aqualiedservicetechnician.
Force or attempted repair may
resultinareorexplosion.
D. Donotusethiswaterheaterif
anyparthasbeenunderwater.
lmmediatelycallaqualied
servicetechniciantoinspectthe
water heater and to replace any
damagedparts.
(Continued)
Prohibited
Checkthetemperature
oftherunninghotwater
beforeenteringthe
shower.
Checkthetemperature
beforesteppinginto
thebathtub.
High
Temperature.
ExplosionHazard;
Ifthetemperatureandpressurerelief
valveisdrippingorleaking,havea
qualiedservicetechnicianreplaceit.
Donotplugorremovethevalve.
Failure to follow these instructions can result
in fire or explosion, and personal injury or
death.
Prohibited
[NRC661-DV]
Do not use the water heater
iftheintake/exhaustpipeis
displaced,hasholes,is
cloggedoriscorroded.
Afterthewaterheaterhasbeenoutof
useforalongtimemakesurethatyou
llthecondensatetrapwithwater.
Thisistopreventdangerousexhaust
gasesfromenteringthebuilding.
Failuretollthecondensatetrapcould
resultinseverepersonalinjuryordeath.
(Refertopage21forfurtherinstructions.)
Be sure
to do.
Prohibited
[NRC661-OD]
DoNotInstallIndoors.
This will cause carbon
monoxide poisoning and
a potential re hazard. Indoor
Be sure
to do.
[Whensupplyingcombustionair
fromtheindoors]
Checkwhetherornottheair
supplyventisblockedwith
dust,trash,atowel,orthelike.
Blocking the opening may result
in incomplete combustion.
Towel
Air supply vent

4
Donotplacetheexhaustventterminal
inanindoorenvironmentbymeansof
adding walls and ceiling (Do not enclose
usingcorrugatedsheets,etc.)
Carbon monoxide poisoning or re may
occur as a result.
ImportantSafetyInformation-2
(Continued)
Ifthisunitwillbeinstalledinabeauty
salon or other location where hair
sprayoraerosolswillbeused,locate
the unit in a separate area that is
suppliedwithfreshairfromoutdoors.
Prohibited
Conrmthatthegasand
power supply indicated
ontheratingplate.
Ex.ForNaturalGas(NRC661-DV)
Installationandservicemustbe
performedbyaqualiedinstaller,
serviceagencyorthegassupplier.
Be sure
to do.
Be sure
to do.
(Continued)
Prohibited
Do not store or use gasoline or other
ammablevaporsandliquidsinthe
vicinityofthisoranyotherappliance.
Prohibited
Do not place or use a spray can near
thewaterheaterortheexhaustvent
terminal.
Do not use hair spray or spray
detergentinthevicinityofthe
heater.
Prohibited
Prohibited
[NRC661-DV]
Do not place outdoors
Rain may enter the unit or the
burner fire may be blown by
the wind, causing malfunction
or re as a result.
Prohibited
Outdoor
Leavetheproperclearancebetween
thewaterheaterandnearbyobjects
(trees,timber,boxeswithammable
materialsetc.).
Be sure
to do.
*Indicates suggested clearances for maintenance.
Donotplacecombustiblessuchas
laundry,newspapers,oilsetc.nearthe
heaterortheexhaustventterminal.
Prohibited
Donotusecombustiblechemicalssuch
asoil,gasoline,benzeneetc.inthenear
theheaterortheexhaustventterminal.
Prohibited
CarbonMonoxidePoisoningHazard.Do
notinstallthiswaterheaterinamobile
home,recreationvehicleoronaboat.
Prohibited
WARNING
Left side:
Min. 2" (50mm)
More 8" (200mm)** Right side:
Min. 2" (50mm)
Front:
Sug. 24" (600mm)*
Sug.3" (75mm)
from vent pipe*
Upper:
Min. 12" (300mm)
Exhaust vent
terminal
Exhaust vent
terminal
Unit
[NRC661-DV]
Left side:
Min. 6" (150mm) Right side:
Min. 6" (150mm)
Upper:
Min. 36" (900mm)
[NRC661-OD]
Unit
Front:
Sug. 24" (600mm)*
Be sure
to do.
[Whensupplyingcombustionair
fromtheindoors]
Checktheairsupplyopening
fordustorobstructions.
Clogged
air supply
opening!!
**In order to check a rating plate.
120,000
111,000
1.3 / 2.2
2.4"2.4"
1.3 / 2.2
115,700
107,000
120,000 BTU
15,000 BTU 133 4.0
1.0 2.4"
10.5"
505
ANSI Z21.10.3-2011/CSA 4.3-2011
15 150
2
NRC661-DV (eco TOUGH)

5
(Continued)
Do not allow small children to play
unsupervisedinthebathroom.
Donotallowsmallchildrentobathunsupervised.
Do not touch the power cord
withwethands.
Electric
Shock.
Don’t touch
with a wet
hand.
Prohibited
ContactNoritzbeforeusingwith
asolarpre-heater.
Contactaqualiedservice
technicianforanynecessary
repairs,serviceormaintenance.
ConsultthenearestNoritzagentif
the water heater location needs to
bechanged.
Don’t
disassemble
the unit.
Be sure
to do.
Be sure
to do.
CaliforniaProposition65listschemicalsubstances
knowntothestatetocausecancer,birthdefects,
death,seriousillnessorotherreproductiveharm.
Thisproductmaycontainsuchsubstances,
betheiroriginfromfuelcombustion(gas,oil)
orcomponentsoftheproductitself.
Thegasconversionkitshallbeinstalledbya
qualiedserviceagencyinaccordancewith
themanufacturer’sinstructionsandall
applicablecodesandrequirementsofthe
authorityhavingjurisdiction.
Theinformationintheinstructionsmustbe
followedtominimizetheriskofreor
explosionortopreventpropertydamage,
personalinjury,ordeath.Thequalied
serviceagencyisresponsiblefortheproper
installationofthiskit.Theinstallationisnot
properandcompleteuntiltheoperationof
theconvertedapplianceischeckedas
speciedinthemanufacturer’sinstructions
suppliedwiththekit.
CAUTION
Be sure to electrically ground the
unit.
Keeppowercordfreeofdust.
Ground.
Be sure
to do.
Donotusethewaterheaterfor
otherthanhotwatersupply,shower
andbath.
Prohibited
Prohibited
Donotcoverthewaterheaterand
theexhaustventterminal,store
trashordebrisnearit,orinanyway
blocktheowoffreshairtotheunit.
Donotturnoffthewaterheater
whilesomeoneisbathing.
Prohibited
Donotuseabrokenormodiedpowercord.
Donotbind,bendorstretchpowercords.
Donotscratch,modify,orsubjectthemto
impactorforce.
Donottouchtheexhaustventpipe
andexhaustventterminalduringor
immediatelyafteroperationofthe
waterheater.
Do not install in locations where
excessivedustordebriswillbe
intheair.
Prohibited
Don’t
touch.
Prohibited
Be sure
to do.
Topreventburnsorscalding,turnoffthe
powerbuttonandwaituntiltheunitcools
beforeperformingmaintenance.
Donotusecondensate,discharged
fromthedrainpipe,fordrinkingor
forconsumptionbyanimals.
Prohibited
[NRC661-DV] [NRC661-OD]

6
ImportantSafetyInformation-3
CAUTION
Donotdrinkwaterthathasbeeninsidethe
unitforanextendedperiodoftime.Donot
drinktherstuseofhotwaterfromtheunit
inthemorning.
Cleanthelteronthewaterinletas
frequentlyasrequiredbythequalityof
yourlocalwater.
Keeptheareaaroundtheunitclean.
If boxes, weeds, cobwebs, cockroaches etc. are in
the vicinity of the unit, damage or re can result.
Donotinstalltheunitwheretheexhaustwill
blowonwallsorwindows.
Problemsresultingfromscaleformationare
notcoveredbythewarranty.
Thisunitisonlyapprovedforinstallationup
to4500ft.(1350m)abovesealevel.
For installations at higher elevations, contact Noritz
America for Instructions.
Checkignitionduringuseandextinction
afteruse.
Ifthewatersupplyisinexcessof12grains
pergallon(200mg/L)ofhardness,acidic
orotherwiseimpure,treatthewaterwith
approvedmethodsinordertoensurefull
warrantycoverage.
Preventingdamagefromfreezing( p.19)
Damage can occur from frozen water within the
device and pipes even in warm environments.
Be sure to read below for appropriate measures.
Repairs for damage caused by freezing are not
covered by the warranty.
Takenecessarymeasurestopreventfreezing
ofwaterandleakageofgaswhenleavingthe
unitunusedforlongperiodsoftime.( p.20)
Donotusepartsotherthanthosespeciedfor
thisunit.
Ifitissnowing,checktheexhaustvent
terminalforblockage.
Donotdisassembletheremotecontroller.
Donotusebenzene,oilorfatdetergentsto
cleantheremotecontroller.
This may cause deformation.
Donotgettheremotecontrollerwet.
Although it is water resistant, too much water can
cause damage.
Donotsplashwaterontheremotecontroller.
Donotexposetheremotecontrollertosteam.
Do not locate the remote controller near stoves or
ovens, this may cause damage or failure.
Do not run water through the unit when unit
isnoton.
When discharging hot water, make sure the unit is ON.
If water is run through the unit with the unit
OFF, water may condense inside the unit and cause
incomplete combustion or damage to the internal
electrical components.
For single-handle xtures or valves, discharge water
setting the handle completely to the water side.

7
 ImportantSafetyInformation....................................................................... 2
Contents......................................................................................................... 7
 OverviewofCondensingTanklessGasWaterHeater.............................. 8
Unit Components.......................................................................................... 9
Display Window............................................................................................ 10
Initial Operation............................................................................................ 11
How to Use (Not using the remote controller)
Using the Water Heater............................................................................. 12
How to Use (Using the optional remote controller)
Remote Controller..................................................................................... 13
Setting and Using the Water Heater........................................................ 14
Flow Meter Alarm...................................................................................... 16
Muting the Remote Controller.................................................................. 18
 AdjustingtheMaximumOutputTemperature........................................ 18
 PreventingDamagefromFreezing............................................................. 19
Regular Maintenance................................................................................... 22
 Troubleshooting........................................................................................... 25
 Follow-upService........................................................................................ 30
 Specications............................................................................................... 32
Contents

8
Thecondensingtanklessgaswater
heaterdischargescondensate.
When heat from the exhaust gas is collected within
the secondary heat exchanger, condensation occurs
from moisture in the exhaust gas and the resulting
water is discharged from the drain pipe (approx.
0.8 gallons/hour (3 liters/hour) maximum). It is not a
water leak. Do not plug or block the drain line as it
must always be allowed to freely ow.
Note : The condensate discharged is acidic with a pH
level of approximately 2-3.
A condensate neutralizer may be required by
local code prior to disposal.
Drain pipe
(Installation example)
OverviewofCondensingTanklessGasWaterHeater
This water heater is a high efciency, fully condensing appliance. Unlike a traditional tankless water
heater, a condensing type captures heat from the exhaust gas and uses it to preheat the incoming
cold water as it passes through the secondary heat exchanger as illustrated below.
Thecondensingtanklessgas
water heater tends to show
whitesteam.
After the exhaust gas passes through the
secondary heat exchanger, it becomes low in
temperature and moisture rich which tends to
produce steam at the vent discharge terminal.
This is a normal occurrence.
Condensate comes
out from here.
Cold water Cold water Gas Gas Hot water Hot water
Condensate
Combustiongas
About
400˚F(200˚C)
Exhaust Exhaust
About
140˚F(60˚C)
Conventional
type
Condensing
TanklessGas
Water Heater
Water is heated
usingtheexhaust
gaswhichisabout
400˚F(200˚C)
.
Primary heat exchanger
Primary heat exchanger
Secondary heat exchanger
condensate trap
Combustiongas
About
400˚F(200˚C)
About
400˚F(200˚C)
During combustion, white
steam may often be seen.
This is normal.

9
[NRC661-DV]
IndoorWallMounted,PowerVent/SealedModel
* Theaboveillustrationshowsanexampleofinstallation.
The exact installation conguration may be slightly different.
Unit
FrontCover
WaterSupplyValve
Unit Components
IntakePipe
Flue Collar
Drain Pipe
Discharges the
condensate.
[NRC661-OD]
OutdoorWallMounted,PowerVentedModel
ExhaustVent
PressureReliefValve
WaterDrainValve
(with Water Filter)
(Inside Water Inlet)
(p.23)
Displayed during
power "ON" or
combustion. (p.10)
Two or three digit-
number is displayed
when a failure occurs.
(p.25)
Display Window
GasSupplyValve

10
The display window allows you to view the status
of unit or error codes.
Display Window
When other indication will appear, please refer to troubleshooting. ( p.25)
(Ex.NRC661-DV)
(Display Window)
Whenthegasburnerison.
Whenthegasburnerison,set
temperature's is
displayedforoneminute.
Whenhotwaterows.
Ifthereisaproblemwiththeunit,anumerical
errorcodewillash.(p.25)
When unit is initially plugged into power,
set temperature's is displayed for approx. three minutes.
(When the gas burner is off, and cold water ows.)
After one minute passed from turn on hot water, the outside edge of
the three digit display will rotate in a circular pattern.
On
(Ex.: error cord 11)

11
Initial Operation
Before the rst use of your water heater, make the following preparations.
Follow steps 1 through 4.
1Open the water supply valve.
Open a hot water xture to conrm that
water is available, and then close the
xture again.
3Open the gas supply valve.
Hot water xture
2
Plug into power.
CLOSED
4
OPEN
Donottouchwithwethands.
(Ex. NRC661-DV)
Please check the following when you use the water heater for the rst time after the installation.
Usually, the hot water is supplied by opening the hot water if gas, water, and electric power are
supplied (if there is a remote controller, it should be turned ON).

12
Checkthatelectrical
powerisconnected.
Turnonhotwater.
Mixfordesired
temperature.
Turnoffthehot
water.
The factory temperature setting is 120°F. Mix with
cold water with a mixing valve or at the xture for
desired temperature.
Topreventscalding.
How to Use (Not using the remote controller)
Using the Water Heater
If you want to the temperature to be changed to 135°F or 140°F, contact the installer or Noritz.
DANGER
High Temperature
HotWaterHeatertemperaturesover125°F(52°C)cancause
severeburnsinstantlyordeathfromscalding.
•
Children, disabled and elderly are at the highest risk of being scalded.
Feel water temperature before bathing or showering.
Temperature limiting valves are available, ask professional person.
(Ex.NRC661-DV)
(Display Window)
(Display Window)
Set temperature is displayed.
* When unit is initially plugged
into power.
Hot water
Indicates the burner is on. The outside edge of
the 3 digit display will rotate in a circular pattern.
Hot water
Cold water
STOP
Indicates the burner is off.
The electrical power does not need to
be disconnected between uses.
* How to check the set temperature.
If the power supply is set to "OFF",
and then set to "ON", the temperature
of supplied hot water is displayed.
Indicates the burner is on

13
OptionalRemoteController(RC-7651M)
For setting the hot
water temperature,
the ow meter alarm,
and other settings.
PowerOn/OffButton
For turning electrical
power to the unit on
and off.
Flow Meter Alarm Set Button
For setting the ow
meter alarm.
(p.16-17)
Setting Buttons
* Before use, remove the protective sheet from the remote controller surface.
Temperature Setting
(Ex.:110°F)
Flow Meter Setting
The display will ash
after hitting the ow
meter alarm set button.
(p.16)
Error Code
When this indicator is lit,
the hot water temperature
can be set. (p.14)
Ifyouwanttochangethetemperatureofsuppliedhotwaterfrequentlyoryouwanttoset
theamountofhotwatertoaccumulatethehotwater,thisremotecontrollerisuseful.
A number will ash if
a failure occurs.
(p.25)
Priority Indicator
Burner On Indicator
When burning, the
indicator is lit.
( p.14and17)
Note: Initial factory setting is set to display in °F and gallons.
To adjust the display to °C and liters, refer to the Installation Manual.
How to Use (Using the optional remote controller)
Remote Controller
Whatisactuallydisplayeddependsonhowthewaterheaterisset.

14
How to Use (Using the optional remote controller)
Setting and Using the Water Heater
PressthePowerOn/
OffButton.
The temperature will be
displayed on the remote
control thermostat.
Settemperature.
(
Alwayscheckthetemperature
settingbeforeuse.)
Turnonhotwater.
Turnoffthehot
water.
Hot
Cold
On
Previous set temperature
(Ex.: 110°F)
On
(°F:)
The temperature settings below are examples. The temperature setting
necessary depends on the usage, the length of piping and the time of year.
*Initial factory setting is 110°F
If xtures incorporate mixing valves, set the temperature higher than usual.
*
For most residential applications, the recommended setting temperature is 120°F / 50°C (122°F) or less.
* Consult local codes for minimum operating temperatures.
 100 105 110 115 120 125 130 135 140
Shower, hot water supply, etc.
Washing
dishes, etc.
High temperature
The maximum output temperature can be
set using the remote controller. ( p.18)
(°C (°F):)
The temperature settings below are examples. The temperature setting
necessary depends on the usage, the length of piping and the time of year.
*Initial factory setting is 40°C (104°F)
Shower, hot water supply, etc.
Washing
dishes, etc.
High
temperature
 37 38 39 40 41 42 43 44 45 46 47 48 50 55 60
(99)  (100) (102) (104) (106) (108) (109) (111) (113) (115) (117) (118) (122) (131) (140)
The maximum output temperature
can be set using the remote
controller. ( p.18)
When using °F mode:
When using °C mode:
Check the indicator lights.
Water temperature
On
Off

15
Remote controller Display
High Temperature
Topreventscalding:
Flashes for 10 sec
DANGER
HotWaterHeatertemperaturesover125°F(52°C)cancause
severeburnsinstantlyordeathfromscalding.
• Children, disabled and elderly are at the highest risk of being scalded.
Feel water temperature before bathing or showering.
Temperature limiting valves are available, ask professional person.
• When setting the unit to 125°F / 55°C (131°F) or higher, the
temperature display will ash for
10 seconds and emit a tone as
a high temperature warning.
• Take caution when using the unit again after setting to 125°F
(52°C) or higher. Always check the set temperature before use.
• Do not allow anyone to change the water temperature while hot
water is running.

16
How to Use (Using the optional remote controller)
Flow Meter Alarm
Plug the bath drain.
(Starting with the power off)
Press the Power
On/Off Button.
Set temperature.
(Always check the temperature
setting before use. )
Adjust ow meter alarm setting.
Turn on hot water.
Turn off the hot
water when the
alarm sounds.
Check the indicator lights.
Water temperature
Previous set temperature
(example:110°F)
On
The temperature will be
displayed on the remote
control thermostat.
When the display
setting is in Celsius.
When the display
setting is in Fahrenheit.
On On
Previous set temperature
(example:40°C)
Hot
Cold
Check the indicator lights.
Water temperature
Press the ow meter alarm set button (the setting will
ash on the display) and adjust with the setting buttons.
Increase
Decrease
Choose the ow meter alarm setting from the following options:
10 - 60 gallon (40 - 240L) (In 5 gallon (20L) intervals), 70 gallon (260L),
80 gallon (300L), 90 gallon (340L), 100 gallon (380L) , 990 gallon.
Note:
The alarm will not sound if it is set for 990 gallon.
Flow meter setting
will be ashing
(ex. 45 gallon)
* The level can only be adjusted
while the indicator is ashing.
* After ten seconds, the remote
will again display the temperature.
Flow meter setting
will be ashing
(ex. 180L)
The a alarm will sound
when the set level has been
reached. Stop the water.
Note: The alarm will not sound
if it is set for 990 gallon.
On
Off
On
Off
Preparation
To set the ow meter alarm:

17
An alarm will sound for ten
seconds when the ow
reaches the set level.
The water will continue to run unless
it is manually turned off.
If the ow meter alarm is being used to indicate when a tub is full:
• If any hot water is being used besides what is going into the tub, the alarm will sound
before the tub is full.
•
If there was water in the tub before the ll began, or if the water is not shut off manually
when the alarm sounds, the tub may overow.
• If there was water in the tub before the ll began, the temperature in the tub after it is full
may be different from the temperature setting.
* Initial factory setting: 110°F or 40°C (104°F)
Water Temperature
The temperatures settings below are only examples. The
temperature setting necessary will depend on the usage,
the length of piping and the time of year.
(°C (°F) : )
Warmer HotWarm
37 38 39 40 41 42 43 44 45 46 47 48
(99) (100) (102) (104) (106) (108) (109) (111) (113) (115) (117) (118)
100 105 110 115 120
Warmer HotWarm
The temperatures settings below are only examples. The
temperature setting necessary will depend on the usage,
the length of piping and the time of year.
(°F : )

18
How to Use (Using the optional remote controller)
Adjusting the Maximum Output Temperature
The remote controller will emit a sound when any button is pushed. This sound can be muted if it is desired.
How to Use (Using the optional remote controller)
Muting the Remote Controller
* Initial factory setting is with sound
• The ow meter alarm cannot be muted.
• The high temperature warning tone when setting the unit to 125°F / 55°C (131°F) or higher will
not emit a sound when muted.
Hold the Power On/
Off Button for ve
seconds.
Sound
Muted
No sound
after 5 sec. Tone sounds
after 5 sec.
Turn off the Power
On/Off Button.
Press and hold the ow
meter alarm set button
until a sound is heard
(2 sec.).
Change the temperature
using the setting
buttons.
Set the Power button to ON when
continuing to use the unit as is.
Otherwise, let the unit sit for 30 sec.
Off
Tone sounds
after 2 sec.
The upper limit of the hot-water supply
temperature can be changed to
(For Fahrenheit (°F))
100°F, 105°F, 110°F, 115°F, 120°F, 125°F, 130°F,
135°F or 140°F.
(For Celsius (°C))
37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C,
45°C, 46°C, 47°C, 48°C, 50°C, 55°C or 60°C.
Up
Down

19
* Damage can occur from frozen water within the device and pipes even in warm environments.
Be sure to read below for appropriate measures.
* Repairs for damage caused by freezing are not covered by the warranty.
Freezing cannot be prevented when the power plug is unplugged. Do not remove the power
plug from the wall outlet.
Freezing will be prevented regardless of whether the operation switch is ON or OFF.
Take the measures below for extremely cold temperatures*. <Only using the remote controller>
Outside temperature including wind chill factor less than -30°F (-35°C) for NRC661-DV or -4°F (-20°C)
for NRC661-OD.
- For models NRC661-DV, when supplying combustion air from the indoors, the room temperature must be
greater than 32°F (0°C) to prevent freezing and the room inside must not have negative pressure.
This method can protect not only the heater, but also the water supply, water piping and mixing valves.
1. Turn off the Power On/Off Button.
2. Close the gas supply valve.
3. Open a hot water xture, and keep a small stream of hot water
running. (0.1 gallon (400cc)/minute or about 0.2" (4mm) thick.)
* If there is a mixing valve, set it to the highest level.
4. The ow may become unstable from time to time.
Check the ow 30 minutes later.
* In general, it is not advisable to run water through the unit when
it is OFF (p. 6), but in this case freeze prevention is more important.
* Remember to set mixing valves and xtures to their original levels before using the unit again
to prevent scalding.
* If there is still a risk that the unit will freeze, drain the unit as shown on the next page.
Preventing Damage from Freezing-1
Freezing is prevented within the device automatically by the freeze-prevention heater.
If water will not ow because it is frozen
1. Close the gas and water valves.
2. Turn off the power button.
3. Open the water supply valve from time to time to check whether water is running.
4. When the water is owing again, check for water leaks from the unit and piping before using.
If the heater or the piping is frozen, do not use the heater or it may get damaged.
CAUTION
* In normal operation, freezing is prevented within the device automatically unless the outside
temperature without wind is below -30°F (-35°C) for NRC661-DV or -4°F (-20°C) for NRC661-OD.
- For models NRC661-DV, when supplying combustion air from the indoors, the room temperature must be
greater than 32°F (0°C) to prevent freezing and the room inside must not have negative pressure.
* The freeze prevention heaters will not prevent the plumbing external to the unit from freezing.
Protect this plumbing with insulation, heat tape or electric heaters, solenoids, or pipe covers.
If there remains a freezing risk, contact the nearest Noritz agent.
0.2" (4mm)
thick
Hot Water Fixture

20
If the water heater will not be used for a long period of time,
drain the water.
Drain the water as follows:
To avoid burns, wait until the unit cools down before draining the water.
The appliance will remain hot after it is turned off.
High Temperature
CAUTION
1. Close the gas valve.
2. <Not using the remote controller>
Fully open one of the hot water xtures.
<Using the remote controller>
Turn off the power button.
3. <Not using the remote controller>
Turn off the power supply after 2 minutes or more pass from operation of 2.
<Using the remote controller>
Turn off the power supply.
4. Close the water supply valve.
5. Fully open all hot water xtures.
6. Turn the drain plug to the left to open, and then remove.
7. Check that the water is completely drained, close all the
drain plugs and the hot water xtures after 10 minutes
or more pass from operation of 6.
Drain water into a bucket to prevent water damage.
Do not touch with wet hands.
Fixture
Fixture
Do not touch with wet hands.
Drain Plugs
Each drain plug might not be
visible if insulation is installed
around the piping.
(Ex. NRC661-DV)
Preventing Damage from Freezing-2