13
closed water sYsteMs
Watersupplysystems may, because of code requirements or such
conditionsashighlinepressure, amongothers,haveinstalleddevices
suchaspressurereducingvalves,checkvalves,andbackowpreventers.
Devicessuchasthesecausethewatersystemtobeaclosedsystem.
therMal eXpansIon
Aswaterisheated,itexpands(thermalexpansion).Inaclosedsystem
thevolumeofwaterwillgrowwhenitisheated.Asthevolumeofwater
growstherewillbea correspondingincreaseinwaterpressuredue
tothermalexpansion.Thermalexpansioncancauseprematuretank
failure(leakage).Thistypeoffailureisnotcoveredunderthelimited
warranty.Thermalexpansioncanalsocauseintermittenttemperature-
pressurereliefvalveoperation:waterdischargedfromthevalvedueto
excessivepressurebuildup.Thetemperature-pressurereliefvalveis
notintendedfortheconstantreliefofthermalexpansion.Thiscondition
isnotcoveredunderthelimitedwarranty.
Aproperlysized thermal expansion tank should be installed
onallclosed 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, cleaning solvents, refrigerator and air
conditioningrefrigerants,swimming pool chemicals, calcium and
sodiumchloride(watersoftenersalt),waxes,andprocesschemicals
aretypicalcompoundswhicharepotentiallycorrosive.
Donotstoreproducts ofthissortnearthe heater.Also,airwhichis
broughtincontact with the heater should not contain any of these
chemicals.Ifnecessary,uncontaminatedairshouldbeobtainedfrom
remoteoroutsidesources.Thelimitedwarrantyisvoidedwhenfailure
ofwaterheaterisduetoacorrosiveatmosphere.(Seelimitedwarranty
forcompletetermsandconditions).
water pIpInG
HOTTER WATER CAN SCALD:
Waterheatersareintendedtoproducehot water.Waterheatedtoa
temperaturewhichwill satisfyspaceheating,clothes washing,dish
washing,cleaningandothersanitizingneedscanscaldandpermanently
injureyouuponcontact.Somepeoplearemorelikelytobepermanently
injuredbyhotwaterthanothers.Theseincludetheelderly,children,the
physicallyordevelopmentallydisabled.Ifanyoneusinghotwatertsinto
oneofthesegroups orifthereisa localcodeorstatelaw requiringa
certaintemperaturewateratthehotwatertap,thenyoumusttakespecial
precautions.Inadditiontousingthelowestpossibletemperaturesetting
thatsatisesyourhotwater needs,ameanssuchas a*mixingvalve,
shouldbeusedatthehotwatertapsusedbythesepeopleoratthewater
heater,seeFigure2.Valvesforreducingpointofusetemperatureby
mixingcoldandhotwaterarealsoavailable:
ConsultaQualied Installer or Service Agency.Follow manufacturer ’s
instructionsforinstallation of the valves. Before changing the factory
settingonthe thermostat, read the “TemperatureRegulation” section in
thismanual.
Thiswaterheatershouldnotbeconnectedtoanyheatingsystemsor
component(s)usedwithanon-potablewaterheatingappliance.
Allpipingcomponents connected to this unit for space heating
applicationsshouldbesuitableforusewithpotablewater.
Toxicchemicals,suchasthoseusedforboilertreatmentshouldnotbe
introducedintothissystem.
Whenthesystem requires water for space heating at temperatures
higherthanrequiredfordomesticwaterpurposes,amixingvalvemustbe
installed.PleaserefertoFigure2forsuggestedpipingarrangement.
InstallInG the new water heater