Weil-McLain SlimFit Commercial Condensing Gas Boiler User manual

Brand: Weil-McLain

Model: SlimFit Commercial Condensing Gas Boiler

Type: User manual

Weil-McLain SlimFit Commercial Condensing Gas Boiler offers high efficiency and reliable performance for commercial heating applications. Its advanced condensing technology reduces operating costs by capturing and reusing heat from exhaust gases. The boiler features a compact design, making it suitable for space-constrained installations. With its ability to common vent up to eight boilers, it provides flexible venting options. The boiler also ensures safety through negative pressure maintenance in the vent system and the use of carbon monoxide detectors.

Part No. SF-E009-A/0516

Application Guide

for

Common Venting SlimFit 550-750 Series 3 Boilers

Hazard denitions

e following dened terms are used throughout these Instructions to bring attention to the presence of hazards of

various risk levels or to important information concerning the life of the product.

Indicates presence of hazards that can cause severe personal injury, death or substantial property damage.

Indicates special instructions on installation, operation or maintenance that are important but not related

to personal injury or property damage.

Common Venting methods and requirements for SlimFit Boilers (SF 550 and SF 750 Series 3)

The SlimFit boiler can be common vented when the following requirements are met.

• CommonventingoftheSlimFitboilercanonlybedoneinaCategoryIIventsystem.Allrequire-

ments for the SlimFitboilertobeventedinaCategoryIIcongurationmustbemetasstatedinthe

SlimFit Boiler Manual or all subsequent addendas.

• SlimFit boilers can only be common vented with other SlimFit Boilers.

• ThemaximumnumberofSlimFit boilers to be common vented together is eight.

• TheVentsystemforaCategoryIISlimFit boiler is considered a Designed / Engineered vent system

and should be designed by a professional using accepted engineering practices.

• VerticalVentonly.

• Combustionairmustcomefromtheboilerroom.SeeDirectExhaust–CombustionAiropening

requirements in SlimFitVentCategoryIIAddendum.

• Mustincreaseventingto6”or8”usinga8”to6”bellreduceratboilerventadapterforCategoryII

VentConnection.

• TheVentSystemshouldbedesignedsothatthepressureintheverticalventpipeisbetweenthe

ranges provided in the Table 1, page 2, during all operating conditions (i.e., High Fire through Low

Fire,prepurge,postpurgeandignition).Ifanegativepressurecannotbeguaranteedatprepurgeand

post purge, a backﬂow preventer is required on each boiler’s vent.

To prevent backﬂow through boiler, negative pressure must be maintained in vent system at all

times including prepurge and post purge cycles.

• Fluegastemperatureshouldnotexceed210°F;theboilerwillshutdownandrecycleifitdoes.The

uegastemperatureshouldtypicallybewithin20°Fofthereturnwatertemperatureoftheboiler.If

there is the potential for a wide variation in return water temperatures, the lowest possible tempera-

ture should be used for any calculations.

- continued on next page

Series 3

Models 550 and 750 MBH

Commercial Condensing

Gas-ﬁred water boilers

SlimFit

™

Series 3

gas-fired water boiler — Application Guide

Part number SF-E009-A/0516

- continued

• Stack/VentFlowRateforeachindividualboilermodelislistedinthetablebelow.Thisowrateis

basedontheunitrunningat9.25%CO

andthemaximumuegastemperatureof210°F.

The values can vary depending on the location of the installation and operating conditions.

• Acarbonmonoxidedetector(s)isrequiredintheboilerroomforSlimFitboilersinstalledinaCat-

egoryIIconguration.Thecarbonmonoxidedetectormustbewiredonthesameelectricalcircuitas

theboiler.Checkyourlocalcodesforanyadditionalrequirementsofcarbonmonoxidedetectors.

ImproperInstallationofaCategoryIIventsystemresultinginpositivepressureintheventsystemcan

resultinuegasspillageandcarbonmonoxideemissions,causingseverepersonalinjuryordeath.

Weil-McLainrecommendstheuseofaVariableSpeedChimneyFan/Powerventertoensurethatthe

appropriatenegativepressureismaintainedforCategoryIIventing.Thisisrecommendedbecause,asa

resultoftheboiler’sefciency,theexhaustgastemperaturescanbequitelowresultinginlessnaturaldraft.

AowprovingswitchshouldbewiredintotheProofofClosurejumpercircuitontheboilercontrol.See

the boiler manual for additional information. The use of this device should be considered in any Engi-

neeredVentsystem.

 Weil-McLainrecommendstheuseofaDoubleActingBarometricDamperorModulatingDampertoen-

suretheappropriatenegativepressurerangeiskeptforCategoryIIventing.Theuseofthisdeviceshould

beconsideredinanyEngineeredVentsystem.

 Whenusingadamperofanykind,itisrecommendedtouseathermalspillswitchtodetectanyexhaust

owintotheboilerroom.VerifythetemperaturerangeonthethermalspillswitchisadequatefortheFlue

gas temperature from the

SlimFit boiler. The use and set-point of this shall be determined by the system

designer.TheAutoresetinputontheBoiler’scontrolcanbeusedtowireinthethermalspillswitch.

The thermal spill switch should shut down all boilers connected to the common ﬂue. Each boiler must be

wired to its own set of dry contacts activated by the spill switch.

 Increasingthenegativepressureintheventpipewillslightlyincreasetheringrateatlowre,thusreduc-

ingtheboiler’struemodulationrange.Considerthisfactorduringsystemdesign.

Code Compliance

Venting/Combustionairpiping–Installationsmustprovideprovisionsforcombustionand

ventilationairinaccordancewiththesection“VentingofEquipment”,oftheNationalFuelGasCode,

ANSIZ223.1/NFPA54,or“VentingSystemsandAirSupplyforappliances”oftheNaturalGasand

PropaneInstallationCode,CAN/CSAB149.1,orapplicableprovisionsofthelocalbuildingcodes.

TABLE 1 Rating & Vent Data

Boiler

Model

Input

Btuh

Stack / Vent

ow rate

scfm

Negative Pressure to be

maintained at

Vent Connection of the boiler

Inches w.c.

SlimFit Vent

Adapter

required for

Category II

SF 550 550,000 128 -0.001 to -0.100 6”- 8”

SF 750 750,000 175 -0.001 to -0.100 6”- 8”

SlimFit

™

Series 3

gas-fired water boiler — Application Guide

Part number SF-E009-A/0516

Thegurebelowrepresentsageneralcommonventingapproach.TheVentsystemforaCategoryIISlimFit

boiler is considered a Designed / Engineered vent system and should be designed by a professional using

accepted engineering practices.

Figure 1 Common vent

Part Number SF-E009-A/0516

Weil-McLain

500 Blaine Street

Michigan City, IN 46360-2388

http://www.weil-mclain.com

SlimFit

™

Series 3

gas-fired water boiler — Application Guide

Weil-McLain SlimFit Commercial Condensing Gas Boiler User manual

Weil-McLain SlimFit Commercial Condensing Gas Boiler User manual

Weil-McLain SlimFit Commercial Condensing Gas Boiler User manual

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