A.O. Smith 197835-001 Water Heater User Manual


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13
CLOSED WATER SYSTEMS
Watersupplysystemsmay,becauseofcoderequirementsorsuch
conditionsashighlinepressure,amongothers,haveinstalleddevices
suchaspressurereducingvalves,checkvalves,andbackowpreventers.
Devicessuchasthesecausethewatersystemtobeaclosedsystem.
THERMAL EXPANSION
Aswaterisheated,itexpands(thermalexpansion).Inaclosedsystem
thevolumeofwaterwillgrowwhenitisheated.Asthevolumeofwater
growstherewillbeacorrespondingincreaseinwaterpressuredue
tothermalexpansion.Thermalexpansioncancauseprematuretank
failure(leakage).Thistypeoffailureisnotcoveredunderthelimited
warranty.Thermalexpansioncanalsocauseintermittenttemperature-
pressurereliefvalveoperation:waterdischargedfromthevalvedueto
excessivepressurebuildup.Thetemperature-pressurereliefvalveis
notintendedfortheconstantreliefofthermalexpansion.Thiscondition
isnotcoveredunderthelimitedwarranty.
Aproperly sizedthermalexpansiontankshould be installed
onallclosedsystemstocontroltheharmfuleffectsofthermal
expansion..
FIGURE 10.
NOTE: To protect against untimely corrosion of hot and cold
water ttings, it is strongly recommended that di-electric unions
or couplings be installed on this water heater when connected
to copper pipe, see Figure 2 also.
CHEMICAL VAPOR CORROSION
CORROSION OF THE FLUEWAYS AND VENT SYSTEM MAY OCCUR IF
AIR FOR COMBUSTION CONTAINS CERTAIN CHEMICAL VAPORS. SUCH
CORROSION MAY RESULT IN FAILURE AND RISK OF ASPHYXIATION.
Spraycanpropellants,cleaningsolvents,refrigeratorandair
conditioningrefrigerants,swimmingpoolchemicals,calciumand
sodiumchloride(watersoftenersalt),waxes,andprocesschemicals
aretypicalcompoundswhicharepotentiallycorrosive.
Donotstoreproductsofthissortneartheheater.Also,airwhichis
broughtincontactwiththeheatershouldnotcontainanyofthese
chemicals.Ifnecessary,uncontaminatedairshouldbeobtainedfrom
remoteoroutsidesources.Thelimitedwarrantyisvoidedwhenfailure
ofwaterheaterisduetoacorrosiveatmosphere.(Seelimitedwarranty
forcompletetermsandconditions).
WATER PIPING
HOTTER WATER CAN SCALD:
Waterheatersareintendedtoproducehotwater.Waterheatedtoa
temperaturewhichwillsatisfyspaceheating,clotheswashing,dish
washing,cleaningandothersanitizingneedscanscaldandpermanently
injureyouuponcontact.Somepeoplearemorelikelytobepermanently
injuredbyhotwaterthanothers.Theseincludetheelderly,children,the
physicallyordevelopmentallydisabled.Ifanyoneusinghotwatertsinto
oneofthesegroupsorifthereisalocalcodeorstatelawrequiringa
certaintemperaturewateratthehotwatertap,thenyoumusttakespecial
precautions.Inadditiontousingthelowestpossibletemperaturesetting
thatsatisesyourhotwaterneeds,ameanssuchasa*mixingvalve,
shouldbeusedatthehotwatertapsusedbythesepeopleoratthewater
heater,seeFigure2.Valvesforreducingpointofusetemperatureby
mixingcoldandhotwaterarealsoavailable:
ConsultaQualiedInstallerorServiceAgency.Followmanufacturer’s
instructionsforinstallationofthevalves.Beforechangingthefactory
settingonthethermostat,readthe“TemperatureRegulation”sectionin
thismanual.
Thiswaterheatershouldnotbeconnectedtoanyheatingsystemsor
component(s)usedwithanon-potablewaterheatingappliance.
Allpipingcomponentsconnectedtothisunitforspaceheating
applicationsshouldbesuitableforusewithpotablewater.
Toxicchemicals,suchasthoseusedforboilertreatmentshouldnotbe
introducedintothissystem.
Whenthesystemrequireswaterforspaceheatingattemperatures
higherthanrequiredfordomesticwaterpurposes,amixingvalvemustbe
installed.PleaserefertoFigure2forsuggestedpipingarrangement.
INSTALLING THE NEW WATER HEATER
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