Noritz proTOUGH NR981-OD User manual

SBA8893
Rev. 01/12
Models : NR981-OD
NR981-DVC
NR981-SV
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.
When applicable, installation must conform with the Manufactured Home
Construction and Safety Standard, Title 24 CFR, Part 3280 or the Canadian
Standard CAN/CSA-Z240 MH Mobile Homes, Series M86.
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 OR MANUFACTURED HOME APPLICATIONS.
CERTIFIED
R
Low NOx Approved
by SCAQMD
14 ng/J or 20 ppm
(Natural Gas Only)
*SBA8893*

2
Prohibited Don’t
touch.
Don’t
disassemble
the equipment.
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.
[NR981-DVC,NR981-SV]
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)
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
Prohibited
[NR981-OD]
DoNotInstallIndoors.
This will cause carbon
monoxide poisoning and
a potential re hazard. Indoor
Prohibited
[NR981-DVC,NR981-SV]
Do not use the water
heateriftheexhaust
pipeisdisplaced,
hasholes,isclogged
oriscorroded.
[NR981-SV]
Checkwhetherornottheair
inletlteriscloggedwith
dust,trashorthelike.
Clogging the opening may
result in incomplete combustion.
Be sure
to do.
Air inlet filter

4
Donotplacetheunitor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
Be sure the gas/power
supplied matches the
gasontheratingplate.
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
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
Unit
Left side:
Min. 6" (150mm)
Right side:
Min. 6" (150mm)
Upper:
Min. 36" (900mm)
Front:
Sug. 24" (600mm)*
Unit
Ex.ForNaturalGas(NR981-OD)
[NR981-DVC,NR981-SV]
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
Left side:
Min. 2" (50mm) Right side:
Min. 2" (50mm)
Front:
Sug. 24" (600mm)*
Sug. 3" (75mm)
from vent pipe*
Upper: Min.
12" (300mm)
[NR981-OD]
[NR981-DVC,NR981-SV]
Exhaust vent
terminal
Exhaust vent
terminal [NR981-SV]
Checktheairsupplyopening
fordustorobstructions.
Be sure
to do.
Clogged
air supply
opening!!

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.
Donotdisassemble,repair,or
modifytheproductbyyourself.
Otherwise, an unexpected accident or failure
may occur as a result.
ConsultthenearestNoritzagentif
the water heater location needs to
bechanged.
Don’t
disassemble
the equipment.
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.
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orthe
exhaustventterminalandconcentric
pipe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equipmentcoolsbeforeper-
formingmaintenance.
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.
[NR981-OD] [NR981-SV]
[NR981-DVC]

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.( p.21)
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equipment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.18)
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.19)
Donotusepartsotherthanthosespecied
forthisequipment.
Ifitissnowing,checktheairinlet,exhaust
ventand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.
Forpreventingunexpectedcarbonmonoxide
poisoning,itisrecommendedtoattachaCo
sensor(commercially-availableproduct).(The
waterheaterdoesnotstopautomatically.)

7
 ImportantSafetyInformation....................................................................... 2
Contents......................................................................................................... 7
General Parts
Main Unit.................................................................................................... 8
Remote Controller.................................................................................... 10
Initial Operation............................................................................................ 11
How to Use
Setting and Using the Water Heater........................................................ 12
Flow Meter Alarm...................................................................................... 14
Muting the Remote Controller.................................................................. 16
 AdjustingtheMaximumOutputTemperature........................................ 17
 PreventingDamagefromFreezing............................................................. 18
Regular Maintenance................................................................................... 20
 Troubleshooting........................................................................................... 23
 Follow-upService........................................................................................ 28
 Specications............................................................................................... 30
Contents

8
Main Unit
General Parts-1
NR981-OD
(OutdoorWallMounted,PowerVentedModel)
Air Inlet
GasSupplyValve
PressureReliefValve
ExhaustVent
FrontCover
WaterDrainValve
(withWaterFilter)
(Inside Water Inlet)
(p.21)
NR981-SV
(IndoorWallMounted,PowerVentedModel)
Flue Collar
FrontCover
Air Inlet Filter
WaterSupplyValve
GasSupplyValve
PressureReliefValve
WaterSupplyValve
WaterDrainValve(withWaterFilter)
(Inside Water Inlet) ( p.21)

9
* Theaboveillustrationshowsanexampleofinstallation.
The exact installation conguration may be slightly different.
NR981-DVC
(IndoorWallMounted,PowerVent/SealedModel)
FrontCover
WaterSupplyValve
GasSupplyValve
WaterDrainValve
(withWaterFilter)
(Inside Water Inlet)
(p.21)
PressureReliefValve
Operation Panel
Concentric Pipe
In this Owner’s Guide, this
panel will be referred to as
the “Remote Controller”.
Main Unit

10
RemoteController(RC-7651M)
For setting the hot
water temperature,
the ow meter alarm,
and other settings.
PowerOn/OffButton
For turning the
heater on and off.
Flow Meter Alarm Set Button
For setting the ow
meter alarm.
( p.14-15)
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.15)
Error Code
When this indicator is lit,
the hot water temperature
can be set. ( p.12)
Whatisactuallydisplayeddependsonhowthewaterheaterisset.
A number will ash if
a failure occurs.
( p.27)
PriorityIndicator
Burner On Indicator
When burning, the
indicator is lit.
( p.13and15)
Note: As shipped from the factory, the remote controller is set to display in °F and gallons.
To adjust the display to °C and liters, refer to the Installation Manual.
General Parts-2

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
Turn on the power.
CLOSED
4
OPEN
Donottouchwithwethands.
(Ex. NR981-OD)

12
RemotecontrollerDisplay
Press the Power
On/OffButton.
How to Use
Setting and Using the Water Heater
Previous set
temperature
(Ex.: 110°F)
The temperature will be
displayed on the remote
control thermostat.
1
2(Starting with the Power Off)
On
On
High Temperature
Topreventscalding:
Flashes for 10 sec
1
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.

13
4
3Turn on hot
water.
2
Settemperature.
Turnoffthehot
water.
Alwayscheckthe
temperature setting
beforeuse.
Hot
Cold
Check the indicator lights.
Water temperature
On Off
(°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.17)
(°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.17)
When using °F mode:
When using °C mode:
( )

14
How to Use
Flow Meter Alarm
3
2,3
1
2
Set temperature.
Press the Power
On/Off Button
Plug the bath drain.
Preparation
(Starting with the power off)
Always check
temperature setting
before use.
Hot
Cold
On
The temperature will be displayed
on the remote control thermostat.
Previous set temperature (example:110°F)
On Check the indicator lights.
Water temperature
1
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.
On Check the indicator lights.
Water temperature
Previous set temperature (example:40°C)
When the display setting is in Celsius. When the display
setting is in Fahrenheit.
( )

15
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.
5Turn off the hot
water when the
alarm sounds.
4Turn on hot
water.
3Adjust ow meter
alarm setting.
To set the ow meter alarm:
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.
Note: The alarm will not sound
if it is set for 990 gallon.
On
Flow meter setting will be ashing
(ex. 45 gallon)
Off
The alarm will sound when
the set level has been
reached. Stop the water.
* The level can only be adjusted
while the indicator is ashing.
* After ten seconds, the remote
will again display the temperature.
On
Flow meter setting will be ashing (ex. 180L)
Off
* 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 : )

16
The remote controller will emit a sound
when any button is pushed. This sound
can be muted if it is desired.
1
How to Use
Muting the Remote Controller
* Initial factory setting is with sound
Sound
Muted
No sound
after 5 sec.
1Hold the Power On/Off
Button for ve seconds.
Tone sounds
after 5 sec.
• 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.

17
How to Use
Adjusting the Maximum Output Temperature
2
3
1
3
Change the
temperature using
the setting buttons.
Press and hold the ow
meter alarm set button until
a sound is heard (2 sec.).
Up
Down
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.
2
Turn off the
power.
Off
1
Set the Power button to ON when continuing to use
the unit as is. Otherwise, let the unit sit for 30 sec.
4
Tone sounds
after 2 sec.

18
*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*.
Outside temperature including wind chill factor less than -4°F (-20°C) for NR981-OD or -30°F (-35°C)
for NR981-DVC or NR981-SV.
- For model NR981-SV, 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.
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.
* When linking multiple units, discharge water equivalent to
(0.1 gallon (400cc)/minute per unit.)
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
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 equipment 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 -4°F (-20°C) for NR981-OD or -30°F (-35°C) for NR981-DVC or NR981-SV .
- For model NR981-SV, 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

19
Drain Plugs
Each drain plug
mignt not be visible
if insulation is
installed around
the piping.
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 equipment cools down
before draining the water. The appliance will remain
hot after it is turned off.
High Temperature
CAUTION
Fully open all hot water xtures.
4Open all drain plugs and drain the water out of
the unit.
1
Close the water supply
valve.
6
Close the gas valve and disconnect
the electrical power supplied to the unit.
2
3Fully open all
hot water xtures.
Fixture
Drainage Using the Remote Controller
2(1) Turn the power on/off button “On”.
(2) Turn and leave open
the hot water xtures
for more than 2 minutes
and close.
* If multiple units are being used,
drain two minutes for each unit.
* An 11 Error Code may appear on
the remote controller.
This is not a malfunction of the unit.
Do not turn Power ON/OFF Button OFF.
Manual Draining
Close the water supply
valve and disconnect
the electrical power
supplied to the unit.
3
4
5When the water is completely drained, replace
all drain plugs and close the hot water xtures.
5Open all drain plugs and drain the
water out of the unit.
6
Close the gas valve.
1
When the water is completely drained,
replace all drain plugs and close the
hot water xtures.
Fixture
Fixture
(Ex. 120°F)
Do not touch with wet hands.
Do not touch with wet hands.
Drain water into a bucket to prevent water damage.
(1) Turn the power on/off
button “off”.
(2)
Press the ow meter alarm set
button for about two seconds
until the alarm sounds.
The maximum hot water
temperature will ash.
(3) Press the ow meter alarm
set button again.
(4) Press the setting button
marked “ “.
The display
will change from "oF" to "on"
after the button is pushed.
Turning the Unit Back On
1. Check that all drain plugs are inserted.
2. Check that all hot water xtures are closed.
3. Follow the procedure on p.11 “Initial operation”, steps 1 through 4.

20
Periodic Maintenance
Wipe the outside surface with a wet cloth, then dry the surface. Use a neutral detergent to clean any stains.
• Do not use benzene, oil or fatty detergents to clean the remote controller;
deformation may occur.
• The remote controller is water resistant but not water proof. Keep it as dry as possible.
Regular Maintenance-1
Periodic Inspection
Equipment
Remote Controller
Wipe the surface with a wet cloth.
Be sure to do.
To prevent burns or scalding, turn off the power button and wait until the
equipment cools before performing maintenance.
CAUTION
Check
For laundry, newspaper,
timber, oil, spray cans
and other combustible
materials. near the heater
or the exhaust vent
terminal.
For abnormal sounds
during operation.
For abnormalities in
external appearance,
discoloration or aws.
For water leaks from the
equipment and piping.
For dust and soot in
the exhaust vent or the
exhaust vent terminal.
Check
Check Check
Check
For proper operation of
pressure relief valve.
Check
(Ex. NR981-OD)