13
closed water sYsteMs
Watersupply systems may,because of code requirements or such
conditionsashighline pressure,amongothers,have installeddevices
suchaspressurereducingvalves,checkvalves,andbackowpreventers.
Devices such as these cause the water system to be a closed system.
therMal eXpansIon
Aswaterisheated,itexpands(thermalexpansion).Inaclosedsystem
thevolumeofwaterwillgrowwhenitisheated.Asthevolumeofwater
growstherewillbe acorrespondingincreaseinwater pressuredue
tothermalexpansion.Thermalexpansioncancauseprematuretank
failure(leakage).Thistypeoffailureisnotcoveredunderthelimited
warranty.Thermalexpansioncanalsocauseintermittenttemperature-
pressurereliefvalveoperation:waterdischargedfromthevalvedueto
excessivepressurebuildup.Thisconditionisnotcoveredunderthe
limitedwarranty.Thetemperature-pressurereliefvalveisnotintended
fortheconstantreliefofthermalexpansion.
Aproperlysized 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.
Spraycan propellants, cleaning solvents, refrigerator and air
conditioningrefrigerants, swimming pool chemicals, calcium and
sodiumchloride(watersoftenersalt),waxes,andprocesschemicals
aretypicalcompoundswhicharepotentiallycorrosive.
Donotstoreproducts ofthissort neartheheater.Also,air whichis
broughtin 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
ofwaterheaterisduetoacorrosiveatmosphere.(Seelimitedwarranty
forcompletetermsandconditions).
water pIpInG
HOTTER WATER CAN SCALD:
Waterheatersareintendedtoproduce hotwater.Waterheatedtoa
temperaturewhichwill satisfyspace heating,clotheswashing, dish
washing,cleaningandothersanitizingneedscanscaldandpermanently
injureyouuponcontact.Somepeoplearemorelikelytobepermanently
injuredbyhotwaterthanothers.Theseincludetheelderly,children,the
physicallyordevelopmentallydisabled.Ifanyoneusinghotwatertsinto
oneofthesegroups orifthere isalocalcode orstatelaw requiringa
certaintemperaturewateratthehotwatertap,thenyoumusttakespecial
precautions.Inadditiontousingthelowestpossibletemperaturesetting
thatsatisesyourhot waterneeds,ameans suchasa *mixingvalve,
shallbeusedatthehotwatertapsusedbythesepeopleoratthewater
heater,seeFigure2.Valvesforreducingpointofusetemperatureby
mixingcoldandhotwaterarealsoavailable:
Consulta Qualied Installer or ServiceAgency. Follow manufacturer’s
instructionsfor installation of the valves. Before changing the factory
settingon the thermostat, read the “TemperatureRegulation” section in
this manual.
Thiswaterheatershall notbeconnectedto anyheatingsystemsor
component(s)usedwithanon-potablewaterheatingappliance.
Allpiping components connected to this unit for space heating
applicationsshallbesuitableforusewithpotablewater.
Toxicchemicals,suchasthoseusedforboilertreatmentshallnotbe
introduced into this system.
Whenthesystemrequireswaterforspaceheatingattemperatureshigher
thanrequiredfordomesticwaterpurposes,atemperingvalvemustbe
installed.PleaserefertoFigure2forsuggestedpipingarrangement.
InstallInG the new water heater