11
WATER PIPING
WATER (POTABLE) HEATING AND SPACE HEATING
Thiswaterheatershallnotbeconnectedtoanyheatingsystems
orcomponent(s)usedwithanon-potablewaterheatingappliance.
Allpipingcomponentsconnectedtothisunitforspaceheating
applicationsshallbesuitableforusewithpotablewater.
Toxicchemicals,suchasthoseusedforboilertreatmentshallnot
beintroducedintothissystem.
Whenthesystemrequireswaterforspaceheatingattemperatures
higherthanrequiredfordomesticwaterpurposes,amixingvalve
mustbeinstalled.PleaserefertoFigure6forsuggestedpiping
arrangement.
Thesewaterheaterscannotbeusedinspaceheatingapplications
only.
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,andbackflowpreventers.Devicessuchasthesecause
thewatersystemtobeaclosedsystem.
THERMAL EXPANSION
Aswaterisheated,itexpands(thermalexpansion).Inaclosed
systemthevolumeofwaterwillgrowwhenitisheated.Asthe
volumeofwatergrowstherewillbeacorrespondingincreasein
water pressure due to thermal expansion. Thermal expansion
cancauseprematuretankfailure(leakage).Thistypeoffailure
is not covered under the limited warranty. Thermal expansion
canalsocauseintermittentTemperature-PressureReliefValve
operation: water discharged from the valve due to excessive
pressurebuildup.Thisconditionisnotcoveredunderthelimited
warranty.TheTemperature-PressureReliefValveisnotintended
fortheconstantreliefofthermalexpansion.
A properly sized thermal expansion tank must be installed on
all closed systems to control the harmful effects of thermal
expansion.Contactalocalplumbingservicetechniciantohave
athermalexpansiontankinstalled.
FIGURE 7.
NOTE: To protect against untimely corrosion of hot and cold
waterttings,itisstronglyrecommendedthatdi-electricunions
orcouplingsbeinstalledonthiswaterheaterwhenconnectedto
copperpipe.
Figure7showsthetypicalattachmentofthewaterpipingtothe
water heater.
TEMPERATURE-PRESSURE RELIEF VALVE
Explosion Hazard
Temperature-Pressure Relief Valve
must comply with ANSI Z21.22-
CSA 4.4 and ASME code.
Properly sized temperature-
pressure relief valve must be
installed in opening provided.
Can result in overheating and
excessive tank pressure.
Can cause serious injury or death.
Thiswaterheaterisprovidedwithaproperlyrated/sizedand
certifiedcombinationTemperature-PressureReliefValve(T&P
valve)bythemanufacturer.Thevalveiscertifiedbyanationally
recognizedtestinglaboratorythatmaintainsperiodicinspection
ofproductionoflistedequipmentofmaterialsasmeetingthe
requirementsforReliefValvesforHotWaterSupplySystems,
ANSIZ21.22•CSA4.4,andthecoderequirementsofASME.
Ifreplaced,thenewT&Pvalvemustmeettherequirements
oflocalcodes,butnotlessthanacombinationTemperature-
PressureReliefValverated/sizedandcertifiedasindicatedin
theaboveparagraph.Thenewvalvemustbemarkedwitha
maximumsetpressurenottoexceedthemarkedhydrostatic
workingpressureofthewaterheater(150psi=1,035kPa)
andadischargecapacitynotlessthanthewaterheaterBtu/
hr or kW input rate as shown on the water heater’s model
ratinglabel.