13
CLOSED WATER SYSTEMS
Watersupplysystemsmay,becauseofcoderequirementsorsuch
conditionsashighlinepressure,amongothers,haveinstalleddevices
suchaspressurereducingvalves,checkvalves,andbackowpreventers.
Devices such as these cause the water system to be a closed system.
THERMAL EXPANSION
Aswaterisheated,itexpands(thermalexpansion).Inaclosedsystem
thevolumeofwaterwillgrowwhenitisheated.Asthevolumeofwater
growstherewillbeacorrespondingincreaseinwaterpressuredue
tothermalexpansion.Thermalexpansioncancauseprematuretank
failure(leakage).Thistypeoffailureisnotcoveredunderthelimited
warranty.Thermalexpansioncanalsocauseintermittenttemperature-
pressurereliefvalveoperation:waterdischargedfromthevalvedueto
excessivepressurebuildup.Thisconditionisnotcoveredunderthe
limitedwarranty.Thetemperature-pressurereliefvalveisnotintended
fortheconstantreliefofthermalexpansion.
Aproperly sizedthermalexpansiontankshould 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.
Spraycanpropellants,cleaningsolvents,refrigeratorandair
conditioningrefrigerants,swimmingpoolchemicals,calciumand
sodiumchloride(watersoftenersalt),waxes,andprocesschemicals
aretypicalcompoundswhicharepotentiallycorrosive.
Donotstoreproductsofthissortneartheheater.Also,airwhichis
broughtincontactwiththeheatershouldnotcontainanyofthese
chemicals. If necessary, uncontaminated air should be obtained from
remote or outside sources. The limited warranty is voided when failure
ofwaterheaterisduetoacorrosiveatmosphere.(Seelimitedwarranty
forcompletetermsandconditions).
WATER PIPING
HOTTER WATER CAN SCALD:
Waterheatersareintendedtoproducehotwater.Waterheatedtoa
temperaturewhichwillsatisfyspaceheating,clotheswashing,dish
washing,cleaningandothersanitizingneedscanscaldandpermanently
injureyouuponcontact.Somepeoplearemorelikelytobepermanently
injuredbyhotwaterthanothers.Theseincludetheelderly,children,the
physicallyordevelopmentallydisabled.Ifanyoneusinghotwatertsinto
oneofthesegroupsorifthereisalocalcodeorstatelawrequiringa
certaintemperaturewateratthehotwatertap,thenyoumusttakespecial
precautions.Inadditiontousingthelowestpossibletemperaturesetting
thatsatisesyourhotwaterneeds,ameanssuchasa*mixingvalve,
shallbeusedatthehotwatertapsusedbythesepeopleoratthewater
heater,seeFigure2.Valvesforreducingpointofusetemperatureby
mixingcoldandhotwaterarealsoavailable:
ConsultaQualiedInstallerorServiceAgency.Followmanufacturer’s
instructionsforinstallationofthevalves.Beforechangingthefactory
settingonthethermostat,readthe“TemperatureRegulation”sectionin
this manual.
Thiswaterheatershallnotbeconnectedtoanyheatingsystemsor
component(s)usedwithanon-potablewaterheatingappliance.
Allpipingcomponentsconnectedtothisunitforspaceheating
applicationsshallbesuitableforusewithpotablewater.
Toxicchemicals,suchasthoseusedforboilertreatmentshallnotbe
introduced into this system.
Whenthesystemrequireswaterforspaceheatingattemperatureshigher
thanrequiredfordomesticwaterpurposes,atemperingvalvemustbe
installed.PleaserefertoFigure2forsuggestedpipingarrangement.
INSTALLING THE NEW WATER HEATER