SHIELD Combustion SystemTM - Lochinvar

SHIELD Combustion System TMProviding Safety Through Advanced TechnologyChanges to the American National StandardsInstitute (ANSI) construction standard forresidential gas-fired water heaters becameeffective on July 1, 2003. The standardrequires combustion technology to resist theignition of flammable vapors outside the waterheater. Lochinvar is pleased to introduce itsShield Combustion System, designed withpatented technology to meet the ANSIrequirements. This new technology provides thehigh efficiency, long service life,maintenance free operation andlow NOx emissions, which youhave come to expect fromLochinvar gas-fired residentialwater heaters.Key ComponentsThe key component of theShield Combustion System isthe Lock-Shield flamearrestor plate. The flamearrestor plate is made from304L stainless steel and isprecisely designed andmanufactured with 18,000geometrically engineered airlouvers. The air louvers areoriented to increase the velocityof the air entering the combustionchamber, preventing ignitedflammable vapors from travelingbackward out of the chamberand outside the water heater.The thermal switch, locatedin the combustion chamber, iscalibrated to detect the increasedheat created when flammablevapors are ignited and will shutdown the gas supply to the pilotand main burner. The thermalswitch will also shut down theburner and pilot if lint, dustor oil accumulates in sufficientquantities to restrict airflowthrough the arrestor plate.How it worksWhen the water heater is firing under normalconditions, combustion air is drawn into thewater heater through slots in the outer jacket.The air is then pulled through slots around thebottom of the combustion chamber. Next the airtravels up through louvers in the Lock-Shieldflame arrestor plate where its velocity is increasedand its direction altered. Once the air enters thecombustion chamber it mixes with the gas supplyand is efficiently burned,transferring heat into the water.What HappensIf a flammable vapor spilloccurs in the vicinity of thewater heater, where traceamounts of vapors are present,the vapors will be harmlesslyignited by the burner or pilotflame. If significant quantitiesof flammable vapors are pulledinto the combustion chamber,the velocity of air through theflame arrestor plate preventsthe flame from travelingbackward and igniting theflammable vapors outsidethe water heater.Lochinvar ConfidenceYou can rest assured that theLochinvar Shield CombustionSystem will provide years ofsafe, efficient and dependableservice. The system hasundergone extensive fieldtesting, as well as life cycletesting in an independentlaboratory.

SHIELD Combustion System TMLock-Shield Flame Arrestor PlateDesigned and manufactured withengineering precision, the air louversare oriented to increase air velocityand trap flammable vapors in thecombustion chamber. And the 304Lstainless steel construction providesresistance to impact,heat, crackingand corrosion.Proven Low NOx BurnerProvides efficient, clean combustionwith low NOx emissions that meet theair quality standards of California andTexas. It is the same proven designthat has been used for years to allowoff-the-shelf replacement.Piezo IgniterProvides simple push buttonignition of the pilot flame.Standard ThermocoupleStandard thermocoupleallows for quick, off-theshelf replacement.Corrosion ResistantCombustion ChamberChamber design changesthe air flow directionto prevent build-up oflint and dust and reducemaintenance requirements.Pedestal BaseCorrosion resistant base sits flat on thefloor eliminating the need for legs.Resettable Thermal SwitchThis reliable bimetallic thermal switch shuts down the burnerand pilot operation in the event of flammable vapor ignitionin the combustion chamber. It also provides protectionagainst lint, dust and oil buildup by shutting down the unitwhen it detects significant air restriction.Sight GlassProvides an unobstructed viewinto the combustion chamberto allow for observation of theburner and pilot flames.