Noritz GQ-C2857WS US User manual

SBB80JP-2
Rev. 01/17
Models : NRC98DV (GQ-C2857WS-FF US)
NRC98OD (GQ-C2857WS US)
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
FOR USE IN RESIDENTIAL OR MANUFACTURED HOME APPLICATIONS.
*SBB80JP*
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 - latest edition
and/or the Natural Gas and Propane Installation Code CSA B149.1 -
latest edition.
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.
CERTIFIED
R
Low NOx Approved
by SCAQMD
14 ng/J or 20 ppm
(Natural Gas Only)

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
[NRC98DV]
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 re-
sult in re or explosion, and personal injury
or death
Prohibited
[NRC98DV]
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20forfurtherinstructions.)
Be sure
to do.
Prohibited
[NRC98OD]
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 en-
close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
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.
Ex.ForNaturalGas
(NRC98DV (GQ-C2857WS-FF US))
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
[NRC98DV]
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
recreationalvehicleoronaboat.
Do not install this water heater
inamobilehomewhenusingSV
conversionkit(“-SV”conguration).
Prohibited
WARNING
Left side:
Min. 2" (50mm) 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
[NRC98DV]
Left side:
Min. 6" (150mm) Right side:
Min. 6" (150mm)
Upper:
Min. 36" (900mm)
[NRC98OD]
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!!

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 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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equipment
coolsbeforeperforming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.
Donotusecondensate,discharged
fromthedrainpipe,fordrinkingor
forconsumptionbyanimals.
Prohibited
[NRC98DV] [NRC98OD]

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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.( p.23) 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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, you’d turn the handle to
the left.

7
 ImportantSafetyInformation....................................................................... 2
Contents......................................................................................................... 7
 OverviewofCondensingTanklessGasWaterHeater.............................. 8
General Parts
Main Unit.................................................................................................... 9
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................................................................................... 21
 Troubleshooting........................................................................................... 24
 Follow-upService........................................................................................ 29
 Specications............................................................................................... 31
Contents

8
Cold water Cold water Gas Gas Hot water Hot water
Condensate
Combustion gas
About
400˚F (200˚C)
Exhaust Exhaust
About
120˚F (49˚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)
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.
2 gallons/hour (7.5 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, the low temperature
and high moisture content tends to produce
steam at the vent discharge terminal.
This is a normal occurrence.
Condensate
comes out from
here.
During combustion, white
steam may often be seen.
This is normal.

9
[NRC98DV (GQ-C2857WS-FF US)]
IndoorWallMounted,PowerVent/SealedModel
* Theaboveillustrationshowsanexampleofinstallation.
The exact installation conguration may be slightly different.
Main Unit
FrontCover
WaterSupplyValve
GeneralParts-1
IntakePipe
Flue Collar
Drain Pipe
Discharges the
condensate.
[NRC98OD (GQ-C2857WS US)]
OutdoorWallMounted,PowerVentedModel
ExhaustVent
GasSupplyValve
PressureReliefValve
WaterDrainValve
(with Water Filter)
(Inside Water Inlet)
(p.22)

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.:115°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.28)
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, do the following:
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. NRC98DV (GQ-C2857WS-FF US))

12
RemotecontrollerDisplay
Press the Power
On/OffButton.
How to Use
Setting and Using the Water Heater
Previous set
temperature
(Ex.: 120°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 in °C mode) 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
( )
If xtures incorporate mixing valves, set the temperature higher than usual.
*
For most residential applications, the recommended setting temperature is 120°F (50°C in °C mode) or less.
* Consult local codes for minimum operating temperatures.
(°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 46°C (115°F)
Shower, hot water supply, etc. High temperature
 46 47 48 50 55 60
 (115) (117) (118) (122) (131) (140)
The maximum output temperature
can be set using the remote
controller. (page 17)
When using °F mode:
When using °C mode:
*Initial factory setting is 115°F
 115 120 125 130 135 140
Shower, hot water supply, etc. High temperature
The maximum output temperature can be set using the remote controller. (page 17)
(°F:)
The temperature settings below are examples. The temperature setting
necessary depends on the usage, the length of piping and the time of year.
Note : An error code will be displayed when this water heater detects scale build-up in the heat exchanger.
The error code may be more frequently displayed when the unit is set to a high temperature. (125°F or higher)
Noritz recommends that water temperature is set as low as possible to prevent scale build-up in
the heat exchanger.

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:115°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:46°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: 115°F or 46°C (115°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) : )
115 120
Hot
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 : )
Hot
46 47 48
(115) (117) (118)

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))
115°F, 120°F, 125°F, 130°F,
135°F or 140°F.
(For Celsius (°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 -30°F (-35°C) for NRC98DV (GQ-C2857WS-
FF US) or -4°F (-20°C) for NRC98OD (GQ-C2857WS US).
- For models NRC98DV (GQ-C2857WS-FF US), 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.
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-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 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 -30°F (-35°C) for NRC98DV (GQ-C2857WS-FF US) or -4°F
(-20°C) for NRC98OD (GQ-C2857WS US).
- For models NRC98DV (GQ-C2857WS-FF US), 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

19
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
1. Close the gas valve.
2. Turn off ther power button.
3. 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.
Fixture
Do not touch with wet hands.
Drain Plugs
Each drain plug mignt not be visible
if insulation is installed around the
piping.
Preventing Damage from Freezing-2
To prevent damage from freezing, the water heater must be plugged into power at all times. If power is unplugged, drain the
water completely from the water heater. Then use an air compressor to remove all water from inside the unit's water piping.
It is recommended that Isolation Valves are installed on the water heater, otherwise the water connections will need to be
removed to drain the unit completely. Freeze damage due to not draining properly will not be covered under warranty.

20
Preventing Damage from Freezing-3
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.
4. Make sure that the area around the appliance is well ventilated; open a window or a door if necessary.
Then, operate the unit and verify that condensate is coming out of the drain pipe.
(During normal use of the water heater, condensate will begin to discharge from the drain pipe within 15
minutes of use. However, depending on the season and/or installation site conditions, it may take longer.)
* If water does not appear at the end of the drain line, a qualied service technician must clean the
condensate line.
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.
(By performing step 4 as described above, the condensate trap will automatically
ll itself with water.)
Be sure to do.
DANGER