Williamson GWI-127 User manual

Brand: Williamson

Model: GWI-127

Category: Water heaters & boilers

Type: User manual

This manual is also suitable for

G W I

Boiler Manual

Series 2

Gas-Fired Water Boilers

Part Number 550-142-785/0812

This manual must only be used by a qualiﬁed heating installer/service technician. Failure to comply could result in

severe personal injury, death or substantial property damage.

 When calling or writing about the boiler— Please have:  •  boiler model number from the boiler rating label  and

•CPnumberfromtheboilerjacket.YoumaylisttheCPnumberinthespaceprovidedonthe“Installationandservice

certicate”foundonpage 21.

Hazards that will or can cause minor personal

injury or property damage.

Special instructions on installation, operation or

maintenance that are important but not related to

personal injury or property damage.

INSTALLER —Readallinstructionsbeforein-

stalling. Read page 2 ﬁrst. Follow all instructions

in proper order to prevent personal injury or death.

• Considerpipingandinstallationwhendetermining

boiler location.

• Anyclaimsfordamageorshortageinshipment

must be ﬁled immediately against the transporta-

tion company by the consignee.

USER — Please read the following. Failure to

comply could result in severe personal injury,

death or substantial property damage.

• This manual is for use only by your qualiﬁed

heating installer/service technician.

• PleaseseetheUser’sInformationManualforyour

reference.

• Have the boiler serviced by a qualied service

technician, at least annually.

Hazards that will cause severe personal injury,

death or substantial property damage.

Hazards that can cause severe personal injury,

death or substantial property damage.

Hazard deﬁnitions

Contents Page

1 Prepare boiler location .......................................................2

2 Prepare boiler .....................................................................6

3 Vent installation ..................................................................7

4 Installwaterpiping ............................................................13

5 Installgaspiping ...............................................................16

6 Field wiring .......................................................................17

7 Start-up ............................................................................18

8 Checkoutprocedure .........................................................20

9 DepartmentofEnergyCompliance .................................. 21

9a Sequenceofoperation .....................................................22

10 Operating instructions ......................................................26

11 Service and maintenance .................................................27

12 Troubleshooting ................................................................31

13 Replacement parts ........................................................... 41

14 Dimensions .......................................................................46

15 Ratings .............................................................................47

2Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Installations must follow these codes:

• Local,state,provincial,andnationalcodes,laws,regulations

and ordinances.

• NationalFuelGasCode,ANSIZ223.1–latestedition.

• StandardforControlsandSafetyDevicesforAutomatically

FiredBoilers,ANSI/ASMECSD-1,whenrequired.

• NationalElectricalCode.

• ForCanadaonly:B149.1orB149.2InstallationCode,CSA

C22.1CanadianElectricalCodePart1andanylocalcodes.

Certiﬁcation

 TheGWIboilergasmanifoldandcontrolsmetsafe

lightingandotherperformancecriteriawhenboiler

underwent tests specied in ANSI Z21.13–latest

edition.

Before locating the boiler:

❏ Checkfornearbyconnectionto:

• Systemwaterpiping

• Ventingconnections

• Gassupplypiping

• Electricalpower

❏ Checkareaaroundboiler.Removeanycombustiblematerials,

gasolineandotherammableliquids.

 Failuretokeepboilerareaclearandfreeofcom-

bustible materials, gasoline and other ﬂammable

liquids and vapors can result in severe personal

injury, death or substantial property damage.

❏ Boiler must be installed so that gas control system components

areprotectedfromdrippingorsprayingwaterorrainduring

operation or service.

❏ Ifnewboilerwillreplaceexistingboiler,checkforandcorrect

system problems, such as:

1. Systemleakscausingoxygencorrosionorsectioncracks

fromhardwaterdeposits.

2. Incorrectly-sizedexpansiontank.

3. Lackofantifreeze(whenrequired)inboilerwatercausing

systemandboilertofreezeandleak.

Failure to adhere to the guidelines below can

result in severe personal injury, death or sub-

stantial property damage.

When servicing boiler —

1. To avoid electric shock, disconnect electrical supply

beforeperformingmaintenance.

2. Toavoidsevereburns,allowboilertocoolbeforeper-

formingmaintenance.

Boiler operation —

3. Donotblockowofcombustionorventilationairtoboiler.

4. Shouldoverheatingoccurorgassupplyfailtoshutoff,do

notturnoffordisconnectelectricalsupplytocirculator.

Instead,shutoffthegassupplyatalocationexternalto

the appliance.

5. Donotusethisboilerifanyparthasbeenunderwater.

Immediatelycallaqualiedservicetechniciantoinspect

theboilerandtoreplaceanypartofthecontrolsystem

and any gas control that has been under water.

Boiler water —

6. DO NOT use petroleum-based cleaning or sealing com-

pounds in boiler system. Water seal deterioration will oc-

cur,causingleakagebetweenboilersections,circulator

anges,diaphragmtanksorothersystemcomponents.

This can result in substantial property damage.

7. DO NOT use“homemade cures” or“boiler patent

medicines”. Serious damage to boiler, personnel and/

or property may result.

8. Continualfreshmakeupwaterwillreduceboilerlife.Min-

eralbuildupinsectionsreducesheattransfer,overheats

castiron,andcausessectionfailure.Additionofoxygen

and other gases can cause internal corrosion. Leaks

in boiler or piping must be repaired at once to prevent

makeupwater.

9. Donotaddcoldwatertohotboiler.Thermalshockcan

causesectionstocrack.

Glycol — potential ﬁre hazard —

Allglycolisammablewhenexposedtohightemperatures.If

glycol is allowed to accumulate in or around the boiler or any

otherpotentialignitionsource,arecandevelop.Inorderto

prevent potential severe personal injury, death or substantial

propertydamagefromreand/orstructuraldamage:

• Never store glycol of any kind near the boiler or any

potential ignition source.

• Monitorandinspectthesystemandboilerregularlyfor

leakage.Repairanyleaksimmediatelytopreventpos-

sibleaccumulationofglycol.

• Neveruse automotiveantifreezeor ethyleneglycol in

thesystem.Usingtheseglycolscanleadtohazardous

leakageofglycolintheboilersystem.

1 Prepare boiler locationRead this ﬁrst!

Codes & checklist

The boiler contains ceramic ﬁber and ﬁber-

glassmaterials.Usecarewhenhandlingthese

materials per instructions on page 48ofthis

manual. Failure to comply could result in severe

personal injury.

Part Number 550-142-785/0812

Service clearances

1. Provideminimumclearancesforcleaningandservicingthe

boilerandforaccesstocontrolsandcomponentsaslistedin

the table below:

2. Provideatleastscrewdriverclearancetojacketfrontpanel

screws for removal of front panel for inspection and minor

service.Ifunabletoprovideatleastscrewdriverclearance,

installunionsandshutoffvalvesinsystemsoboilercanbe

movedforservicing.

Small space installations

1. When the boiler is located in a closet or small space, provide

clearances no less than those shown in Figure 1. The clear-

ancesarerequiredto anysurface,whethercombustibleor

non-combustible.

Table 1 Minimum foundation size

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Service clearances: Minimum

Top (for cleaning ﬂueways) 35”

Front (for access to controls and components) 18”

Back 7”

Leftside (for cleaning and servicing) 24”

Right side 7”

Boiler

model

Minimum

foundation

length

Minimum

foundation

width

GWI-047 25” 12”

GWI-063 25” 12”

GWI-095 25” 15”

GWI-127 25” 18”

GWI-158 25” 21”

GWI-190 25” 24”

Minimum clearance to combustible materials

1. Hotwaterpipesmustbeatleast½”fromcombustiblematerial.

2. Single-wallventpipemustbeatleast2inchesfromcombus-

tible material.

3. TypeBdouble-wallmetalventpipe—seeventmanufacturer’s

recommendationforclearancestocombustiblematerial.

Figure 1 Minimum clearances

Flooring and foundation

Flooring

TheGWIboilerisapprovedforinstallationoncombustibleooring,

but must never be installed on carpeting.

 Donotinstallboileroncarpetingeveniffoundation

is used. Fire can result, causing severe personal

injury, death or substantial property damage.

Foundation

1. Provideasolidbrickorminimum2-inchthickconcretefounda-

tionpadifanyofthefollowingistrue:

• oorcanbecomeooded.

• theboilermountingareaisnotlevel.

2. See Table 1forminimumfoundationdimensions.

Residential garage installations

Takethefollowingspecialprecautionswheninstallingtheboilerin

aresidentialgarage,perANSIZ223.1,paragraph5.1.9:

• Mounttheboileraminimumof18 inches above the ﬂoorof

the garage to assure the burner and ignition devices will be

no less than 18 inches above the ﬂoor.

• Locateorprotect the boiler so it cannot be damaged by a

moving vehicle.

1 Prepare boiler location continued

Clearances

4Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

1 Prepare boiler location continued

 Failuretofollowallinstructionscanresultinuegas

spillageandcarbonmonoxideemissions,causing

severe personal injury or death.

When removing boiler from existing common vent system:

Atthetimeofremovalofanexistingboiler,thefollowingsteps

shall be followed with each appliance remaining connected to

the common venting system placed in operation, while the other

appliances remaining connected to the common venting system

are not in operation.

a. Seal any unused openings in the common venting system.

b. Visuallyinspecttheventingsystemforpropersizeandhori-

zontalpitchanddeterminethereisnoblockageorrestriction,

leakage,corrosionorotherdeciencieswhichcouldcausean

unsafecondition.

c. Testventsystem—Insofarasispractical,closeallbuilding

doors and windows and all doors between the space in which

the appliances remaining connected to the common venting

system are located and other spaces of the building.Turn

on clothes dryers and any appliance not connected to the

commonventingsystem.Turnonanyexhaustfans,suchas

rangehoodsandbathroomexhausts,sotheywilloperateat

maximumspeed.Donotoperateasummerexhaustfan.Close

ﬁreplace dampers.

d. Place in operation the appliance being inspected. Follow the

lighting/operatinginstructions.Adjustthermostatsoappliance

will operate continuously.

e. Testforspillageatdrafthoodreliefopeningafter5minutesof

mainburneroperation.Usetheameofamatchorcandle.

f. Afterithasbeendeterminedthateachapplianceremaining

connected to the common venting system properly vents when

testedasoutlinedabove,returndoors,windows,exhaustfans,

ﬁreplace dampers, and any other gas-burning appliance to

theirpreviousconditionsofuse.

Any improper operation of common venting system should be

corrected so the installation conforms with the National Fuel

GasCode,ANSIZ223.1–latestedition.Correctbyresizingto

approach the minimum size as determined using the appropriate

tablesinPart11ofthatcode.Canadianinstallationsmustcomply

withB149.1orB149.2InstallationCode.

Chimney draft vent requirements

1. Venting must be installed according to Part 7, Venting of

Equipment,ofNationalFuelGasCode,ANSIZ223.1-latest

editionandapplicablebuildingcodes.Canadianinstallations

mustcomplywithB149.1orB149.2InstallationCodes.

2. Chimneyorventtermination:

• Achimney,oranyventotherthanaTypeBventwithlisted

ventcap,mustextendatleast3feetabovethehighest

pointwhereitpassesthrougharoofofabuilding,andat

least2feethigherthananyportionofabuildingwithina

horizontaldistanceof10feet.

• TypeBventswithlistedcapsmayterminateasinFigure2

ifnocloserthan8feetfromaverticalwallorsimilarob-

struction.

• Otherwise,Type B ventsmustterminate at least2 feet

abovetheroofpenetrationandatleast2feethigherthan

anyportionofabuildingwithin10feet.

3. Alinedchimneyispreferredandmustbeusedwhenrequired

by local, state, provincial and national codes, laws, regulations

and ordinances. Vitreous tile linings with joints that prevent

retentionofmoistureandliningsmadeofnoncorrosivemateri-

alsarebest.Adviceforueconnectionsandchimneylinings

canbeobtainedfromlocalgasutility.TypeBdouble-wallmetal

vent pipe or single-wall vent pipe may be used as a liner.

4. Cold masonrychimneys,alsoknownas outside chimneys,

typicallyhaveoneormorewallsexposedtooutsideair.

When any atmospheric gas-ﬁred boiler with automatic vent

damperisventedthroughthistypeofchimney,thepotential

existsforcondensationtooccur.Condensationcandamage

amasonrychimney.Manufacturerrecommendsthefollowing

to prevent possible damage.

a. Linechimneywithcorrosion-resistantmetallinersuchas

AL29-4C®single-wallstainlesssteelorB-vent.Sizeliner

perNationalFuelGasCodeANSIZ223.1–latestedition.

b. Provide drain trap to remove any condensate.

5. Where two or more gas appliances vent into a common chim-

neyorvent,equivalentareashouldbeatleastequaltoareaof

ventoutletonlargestapplianceplus50percentofventoutlet

areaofadditionalappliance.

Direct exhaust venting (Category III) — DO NOT

COMMON venttheGWIinadirectexhaustsystem

(CategoryIII).Connectingmorethanoneappliance

toadirectexhaustsystemwillcauseuegasspill-

ageorappliancemalfunction,resultinginpossible

severe personal injury, death or substantial property

damage.

 Inspect existing chimney before installing boiler.

Failure to clean or replace perforated pipe or tile

lining will cause severe personal injury or death.

Vent system

 GWI boilers can be either chimney draft vented

or direct-exhaust vented. See pages 7 to 12 for

detailed installation instructions.

 Ifyouareremovinganexistingboilerfromashared

ventingsystemandthenewGWIboilerwillnotshare

theventsystem(allowedonlywhenchimneydraft

venting),youmusttesteachremainingappliance

individuallytoverifytheventsystemstilloperates

adequately.Followguidelinesbelow.

Figure 2 Terminations with Type B vent tted with listed

cap, provided vent is at least 8 feet from any

vertical wall or similar obstruction.

Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Products to avoid

Spray cans containing chloro/ﬂuorocarbons

Permanent wave solutions

Chlorinatedwaxes/cleaners

Chlorine-basedswimmingpoolchemicals

Calciumchlorideusedforthawing

Sodiumchlorideusedforwatersoftening

Refrigerantleaks

Paint or varnish removers

Hydrochloric acid/muriatic acid

Cementsandglues

Antistaticfabricsoftenersusedinclothesdryers

Chlorine-typebleaches,detergents,andcleaningsolvents

foundinhouseholdlaundryrooms

Adhesivesusedtofastenbuildingproductsandothersimilar

products

Areas likely to have contaminants

Dry cleaning/laundry areas and establishments

Swimming pools

Metalfabricationplants

Beauty shops

Refrigerationrepairshops

Photo processing plants

Autobodyshops

Plasticmanufacturingplants

Furniture reﬁnishing areas and establishments

New building construction

Remodeling areas

Garageswithworkshops

Table 2 Corrosive contaminants and likely locations

 To prevent potential of severe personal injury or

death, check for products or areas listed below

beforeinstallingboiler.Ifanyofthesecontaminants

arefound:

• removecontaminantspermanently.

— OR —

• isolateboilerandprovideoutsidecombustion air.

Seenational,provincialorlocalcodes forfurther

information.

Pleasereviewthefollowinginformationonpotentialcombustion

air contamination problems.

See Table 2forproductsandareaswhichmaycausecontami-

nated combustion air.

Air contamination Air openings

1 Prepare boiler location continued

CombustionairandventilationopeningsmustcomplywithSec-

tion 5.3,“Air for Combustion andVentilation”, of National Fuel

GasCodeANSIZ223.1–latestedition,orapplicablelocalbuilding

codes.CanadianinstallationsmustcomplywithB149.1orB149.2

InstallationCodes.

Seetablebelowforminimumcombustion/ventilationairopening

sizes.Whereopeningsarerequired,providetwo(2)openings—

onewithin12inchesoftheceiling,theotherwithin12inchesof

the ﬂoor, as shown in the table illustrations.

 Provideadequatecombustionandventilationairto

assurepropercombustionandreducetheriskof

severe personal injury, death or substantial property

damage caused by ﬂue gas spillage and carbon

monoxideemissions.

6Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Location Natural gas Propane gas

U. S.

Sea level –

2,000 ft over

2,000 ft Sea level –

2,000 ft over

2,000 ft

2.00 mm (Note1) 1.30 mm (Note1)

Canada

Sea level –

2,000 ft 2,000 –

4,500 Sea level –

2,000 ft 2,000 –

4,500

2.00 mm 1.90 mm 1.30 mm 1.20 mm

Note1: ForU.S.elevationsabove2,000feet,contactyourlocalsupplierfor

details.

1 Prepare boiler location continued

Exhaust fans and air movers

The appliance space must never be under a negative pressure.

Always provide air openings sized not only to the dimensions

requiredfortheringrateof allappliances,butalsoto handle

theairmovementrateoftheexhaustfansorairmoversusingair

fromthebuildingorspace.

Air openings continued

2 Prepare boiler

Place boiler/crate near position

1. Leaveboilerincrateandonpalletuntilinstallationsiteisready.

2. Moveentirecrateandpalletnexttoselectedlocation.

3. Removecrate.Leaveboileronpallet.

4. Removeboilerfrompalletasfollows:

a. Tiltleftsideofboilerupandplaceaboardunderleftlegs.

b. Tilt boiler the other way and place a board under right legs.

c. Slideboilerbackwardsoffpalletandintoposition.

 Donotdropboilerorbumpjacketonoororpallet.

Damage to boiler can result.

5. Checklevel.

a. Shimlegs,ifnecessary.

b. Do not alter legs.

Placement and setup

Motorized air dampers

Iftheairopeningsarettedwithmotorizeddampers,electrically

interlockthedamperto:

• Preventtheboilerfromringifthedamperisnotfullyopen.

• Shuttheboilerdownshouldthedampercloseduringboiler

operation.

Toaccomplishthisinterlock,wireanisolated contact(provingthe

damperopen)inserieswiththethermostatinputto the boiler.

Theboilerwillnotstartifthiscontactisopen,andwillshutdown

should it open during operation.

The boiler contains ceramic ﬁber and ﬁberglass

materials.Usecarewhenhandlingthesematerials

per instructions on page 48ofthismanual.Failure

to comply could result in severe personal injury.

Inspect oriﬁces and burners

1. Removefrontjacketdoor.Removebaseaccesspanel(See

Figure 25, item 4, page 42).

2. Checkforcorrectly-sizedmanifoldorices. SeeTable 3for

sizing.(Theoricesizeisstampedontheoricespudbarrel.)

 Correctly-sized manifold orices must be used.

Failure to do so will result in severe personal injury,

death or substantial property damage.

3. Levelandstraightenburners.

Burners must be properly seated in slots in burner

restwiththeiropeningsfacingup.Mainburnerori-

cesmustinjectdowncenterofburner.Failureto

properly seat burners will result in severe personal

injury, death or substantial property damage.

4. Reinstall access panel.

Do not operate boiler without access panel secured

in place. Failure to comply could cause momentary

amerolloutonignitionofmainame,resultingin

possible ﬁre or personal injury hazard.

Table 3 Manifold orice sizing

Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Perform hydrostatic pressure test

Pressure test boiler before attaching water or gas piping or

electricalsupply(exceptasnotedbelow).

Prepare boiler for test

1. Removetheshippingnipple(fromGWIsupplytapping)and

removetheboilerreliefvalve.Temporarilyplugthereliefvalve

tapping with a ¾” NPT pipe plug.

2. Remove1¼”nipple,reducingteeand drainvalvefromac-

cessorybag.Installinboilerreturnconnectionasshownon

in Figure 27, item 3, page 44.Installcirculatoroneitherthe

return or supply.

3. Remove 1¼” nipple, 1¼” tee, bushing and pressure/tempera-

turegaugefromaccessorybag.Pipetoboilersupplyconnec-

tion as shown in Figure 27, item 2, page 44.(Usepipedope

sparingly.)

4. Connectahosetoboilerdrainvalve,theotherendconnected

toafreshwatersupply.Makesurehosecanalsobeusedto

drainboileraftertest.

5. Connectanippleandshutoffvalvetosystemsupplyconnec-

tion on the 1¼” tee. This valve will be used to bleed air during

thell.(Valveandnipplearenotincludedwithboiler.)

6. Connectanippleandshutoffvalvetosystemreturnconnec-

tion(atcirculatorangeifcirculatorinstalledonreturn).This

valvewillbeusedtobleedairduringthell.(Valveandnipple

arenotincludedwithboiler.)

Fill and pressure test

1. Opentheshutoffvalvesyouinstalledonsupplyandreturn

connections.

Pressure test

2. Slowlyopenboilerdrainvalveandfreshwatersupplytoll

boiler with water.

3. Whenwaterowsfromshutoffvalves,closeboilerdrainvalve.

4. Closeshutoffvalves.

5. Slowlyreopenboilerdrainvalveuntiltestpressureofnotmore

than 45 psi is reached on the pressure/temperature gauge.

6. Testatnomorethan45psifornomorethan10minutes.

 Donotleaveboilerunattended.Acoldwaterllcould

expandandcauseexcessivepressure,resultingin

severe personal injury, death or substantial property

damage.

7. Make sure constant gauge pressure has been maintained

throughouttest.Checkforleaks.Repairiffound.

 Leaksmustberepairedatonce.Failuretodoso

can damage boiler, resulting in substantial property

damage.

Do not use petroleum-based cleaning or sealing

compounds in boiler system. Severe damage to

boiler will occur, resulting in substantial property

damage.

Drain and remove ﬁttings

1. Disconnectllwaterhosefromwatersource.

2. Drain boiler at drain valve or out hose, whichever provides

bestaccesstodrain.Removehoseafterdrainingifusedto

drain boiler.

3. Removenipplesandvalvesunlesstheywillremainforusein

the system piping.

4. Removeplugfromreliefvalvetapping.Seepage13toreplace

reliefvalve.

3 Vent installation

TheGWIboilercanbeventedusingoneofthefollowingmethods:

 Useonlytheventmaterialsandmethodsoutlined

inthismanual.Useofanyothermaterialsormeth-

odscouldresultinventfailureoruegasleakage,

causing severe personal injury, death or substantial

property damage.

Chimney draft venting

—Usesthenaturaldraftprovidedbyaverticalventorchimney.

Whenventedusingchimneydraftventing,GWIboilersarerated

asCategoryIappliances(nopressureinventanduegastem-

peraturehotenoughtoavoidexcessiveventcondensation).See

followingsectionforinstallationprocedures.

Chimneydraftinstallationsuse:

a. Ventconnector(singleordoublewall)sizedtoeliminatepositive

pressure in vent system. Diameter increases immediately at

boiler. See Figure 3, page 8forconnectorsizing.

b. Double-wallmetalvent(B-vent)orchimneywithlinerapproved

bytheNationalFuelGasCode,ANSIZ223.1–latestedition,

orinCanadaB149.1orB149.2InstallationCode.

Direct exhaust — vertical or sidewall

— Vent pipe is pressurized and terminated vertically through the

rooforthroughasidewall.Whenventedasdirectexhaust,GWI

boilersareratedasCategoryIIIappliance(positivepressurein

theventanduegastemperaturehotenoughtoavoidexcessive

ventcondensation).

Youmustuseonlytheventmaterialslistedinthismanual.See

pages 8 through 12 forinstallationprocedures.

Directexhaustinstallationsuse:

a. Vent materials speciﬁed in this manual.

b. Ventterminationthroughoutsidewall,rooforunusedchimney.

(Tightchimneyareaswillmakeventjointconstructionvery

difcult.)

GWI venting options

2 Prepare boiler continued

8Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

3 Vent installation continued

Chimney draft venting

 Inspect existing chimney before installing boiler.

Failuretocleanorreplaceperforatepipeorlining

will cause severe personal injury or death.

Vent sizing given in Figure 3 is only a general

guideline. The vent connector and chimney must

be designed, sized and constructed in compliance

with all applicable codes. Failure to correctly size

and install the vent system could result in severe

personal injury, death or substantial property dam-

age.

See page 4foradditionalrequirementswhenchim-

neydraftventing.

1. Usedoublewallmetalvent(B-vent)orchimneywithlineras

requiredbytheNationalFuelGasCode,ANSIZ223.1–latest

edition,orinCanada,B149.1orB149.2InstallationCode.

2. Topreventdowndrafts,chimneyshouldextendatleast3feet

abovethehighestpointwhereitpassesthrougharoofand

atleast2feethigherthananyportionofabuildingwithina

horizontaldistanceof10feet.

3. Toventwithanotherappliance,seeNationalFuelGasCode,

ANSIZ223.1–latesteditionorinCanadaB149.2orB149.2

InstallationCode

4. Donotconnectbreechingtoanyportionofamechanicaldraft

system that can operate under positive pressure.

5. Maintainminimum2”clearancefromcombustiblematerials

to vent pipe.

6. Do not use chimney with an open ﬁreplace.

7. Make horizontal runs as short as possible. Long runs can

cause condensation.

8. When longer runs are used, support pipe with appropriate

hangers.

9. Topreventblockage,donotventintobottomofchimney.

10.Ventpipemustnotgobeyondinsidewallofchimney.

11. Vent passing through ﬂoors or ceilings must be ﬁrestopped.

12. See Figure 3 to connect boiler to venting system.

Figure 3 Chimney draft venting installation

Part Number 550-142-785/0812

Table 4 Maximum vent length

Max.vent length

(feet)

Total number of 90° elbows

(Notes 1 & 2)

1 2 3 4 5 6

GWI-047 to GWI-158 55 48 41 34 27 20

GWI-190 35 28 21 14 7 --

Notes:

1. Do not include termination ﬁtting when counting total number of elbows.

2. One (1) 90° elbow is equivalent to two (2) 45° elbows.

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Direct exhaust venting

Obtain vent system components

1. ThefollowingspecialgasventsystemscomplywithUL-1738

andULC-S636standardsandarecertiedbyCSAastheonly

systemssuitableforusewithGWIboilers(all3”diameter):

• Heat-Fab,Inc.Saf-TVent®

• Flex-LInternational,Inc.StaR-34

• Z-Flex®,Inc.Z-VentII

• ProTechSystemsFasNSeal™

 Useonlytheventstarterofthesamemanufacturer

astheventcomponents.Donotmixcomponents

fromdifferentsystems.Theventsystemcouldfail,

causing ﬂue gas spillage, resulting in severe per-

sonal injury or death.

2. Selectverticalorsidewallventingdependingonjobrequire-

ments.

3. RefertoTable4formaximumventrunlengthsandnumberof

elbows.DonotexceeddatainTable 4.

4. SelectventcomponentsfromseparateGWI Vent Component

Supplement.Allcomponents,includingtheventstarter,must

beofthesameventmanufacturer.Donotmixcomponents.

1. Select a vent pipe manufacturer from separate GWI Vent

Component Supplement and obtain all vent components

needed, based on boiler location and venting method.

2. Youmustusetheventstarter(seebelow)madebytheventpipe

manufacturer.SeeGWI Vent Component Supplementfor

partnumberofeachcomponent,listedbyventmanufacturer.

 Useonlytheventstarterofthesamemanufacturer

astheventcomponents.Donotmixcomponents

fromdifferentsystems.Theventsystemcouldfail,

causing ﬂue gas spillage, resulting in severe per-

sonal injury or death.

3. Follow all applicable national, state, local or provincial codes

whenventingtheGWIboiler.

4. Connectventstartertoblowerhousingoutletasshownbelow.

a. Donotmixcomponentsfromdifferentventmanufacturers.

b. Maintainminimum2”clearancefromcombustiblematerials

to vent pipe.

c. Seal with sealant specied by vent pipe manufacturer,

using 3/8”bead(notrequiredforFasNSeal™).

d. Tighten strap at band clamp screw until strap is snug

around blower housing.

3 Vent installation continued

10 Part Number 550-142-785/0812

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Series 2 Gas-Fired Water Boilers – Boiler Manual

Direct exhaust venting continued

1. Locatetheboilerandventpenetrationthroughthewallsoall

requirementsonthispageandinFigures 4 and 5 will be met.

Alsofollowventmanufacturer’sinstructions.

2. Gaseswillformwhiteplumeinwinter.Plumecouldobstruct

window view.

3. Prevailing winds could cause freezing of condensate and

water/icebuilduponventtermination,building,plantsorroof.

Icebuilduponventterminationcancause boiler shutdown

andbuildingfreeze-up.

4. Windsover31mphcancausenuisanceboilershutdownif

boilerissidewallvented.Thiscouldresultinlossofheatto

building,causingfreeze-up.

5. Locateorguardventterminationtopreventcondensatefrom

damagingexteriorsurfaces.

6. Locatetheventterminationwellawayfromtrees,shrubs,and

decorative items.

7. Locateorguardventtopreventaccidentalcontactbypeople

or pets.

8. Do not terminate vent in window well, stairwell, alcove, court-

yard, or other recessed areas.

9. Do not wrap or insulate vent pipe or ﬁttings.

10.Donotterminateventaboveanydoororwindow.Condensate

canfreeze,causingiceformations.

11. Do not connect:

• Anyotherappliancetoventpipe.

• Multipleboilerstoacommonventpipe.

12.Canadianinstallations—SeeB149.1orB149.2Installation

Code.Terminateventnolessthan6feetfromanothercom-

bustionairinlet,3feetfromanyotherbuildingopening,and

3feetfromanygasserviceregulator.

13. See Figures 4 and 5, showing that the vent must terminate:

• atleast7feetabovepublicwalkway.

• 3feetaboveanyforcedairintakewithin10feet.

• morethan4feetbelowortosideofalldoorsorwindows.

• morethan1footabovegradeoranticipatedsnowline.

14. Vent must also terminate:

• atleast6feetawayfromadjacentwalls.

• nocloserthan5feetbelowroofoverhang.

• atleast4feethorizontally(andinnocaseaboveorbelow

unless a 4 foot horizontal distance is maintained) from

electricmeters,gasmeters,regulators,reliefvalves,and

otherequipment.

15. Site conditions may dictate greater clearances.

16.Donotextendexposedventpipeoutsideofbuilding.Conden-

satecouldfreezeandblockventpipe.

 Agasventextendingthroughanexteriorwallshall

not terminate adjacent to the wall or below building

extensionssuchaseaves,overhangs,balconiesor

decks.Failuretocomplycouldresultinsevereper-

sonal injury, death or substantial property damage.

Vent termination location

Follow instructions on this page when determining

ventlocationtoavoidpossibilityofseverepersonal

injury, death or substantial property damage.

Figure 4 Maintain minimum clearances from public

walkways and building air openings

Figure 5 Maintain minimum clearances from doors,

windows and snow line

3 Vent installation continued

Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Direct exhaust venting continued

1. Donotmixtypesormanufacturersofventmaterials.

 Useonlytheventstarterofthesamemanufacturer

astheventcomponents.Donotmixcomponents

fromdifferentsystems.Theventsystemcouldfail,

causing ﬂue gas spillage, resulting in severe per-

sonal injury or death.

2. Clean all joints beforesealing. See ventmanufacturer’s in-

structionsforcleaningandsealingjoints.Usetheirspecied

sealant. Do not use screws.

3. Installventpipewithseamsontopofventhorizontalruns.

Followrequirementsonpage 10forventterminationlocation.

4. Maintainminimum2”clearancefromcombustiblematerials

to vent pipe.

5. Vertical venting — See Figure 6.Followventmanufacturer’s

instructionsforventingthroughroof.

• Vent pipe must extend through roof ashing, jacket or

thimble.

• Vent may pass through oor, inside wall or concealed

space when installed according to vent manufacturer’s

instructions.

Sidewall venting — See Figures 7 and 8. Vent must terminate

atleastonefootaboveanticipatedsnowline.Vent mustbe

terminated only with:

• Elbowwithintegralscreen.

• Elbowandterminationcouplingwithscreen(notavailable

forStaR-34).

6. Donotsealventpipe(slipconnectorforSaf-TVent)toinside

or outside plate.

7. Ifpassingthroughnoncombustiblewall,provideholediam-

eterlargeenoughtoinserttheventpipe(slipconnectorfor

Saf-TVent).

8. Installhorizontaldrainteeascloseaspossibletoboiler,in

ﬁrst horizontal run. See Figure 7.

9. Do not exceed the maximum vent system length given in

Table 4, page 9.

 Condensatedrainline—useonlysiliconetubing

ratedforatleast400°Ffortherst18”ofconden-

sate drain line, then other non-metallic tubing may

beused.Usinganyothermaterialcouldcauseue

gasleakage,potentiallyresultinginseverepersonal

injury, death or substantial property damage.

On some installations, the condensate drain ﬁtting

may be omitted, provided:

• Ventmanufacturershowsthisoptionintheirinstruc-

tions.

• Ventisslopedtowardterminationasshownindotted

lines in Figure 7.

• Theventisinstalledperboilermanufacturer’sand

ventmanufacturer’sinstructions.

Condensatedrippagefromsuchventsmayaccumulateonthe

groundbelow.Considertrafcintheareatoavoidhazarddueto

ice accumulation.

Installing direct exhaust vent and termination

3 Vent installation continued

Figure 6 Vertical direct exhaust installation Figure 7 Direct exhaust through side wall

12 Part Number 550-142-785/0812

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Series 2 Gas-Fired Water Boilers – Boiler Manual

 Usinganyterminationotherthanoneofthoseshown

could cause nuisance outages and loss of heat,

resulting in substantial property damage.

Direct exhaust venting continued

Figure 8 Sidewall vent termination options and

installation requirements

3 Vent installation continued

Part Number 550-142-785/0812

Table 6 Water pipe size (based on 20 °F rise)

General

Boiler

model

number

system From

system

GWI-047 ¾” ¾”

GWI-063 1” 1”

GWI-095 1” 1”

GWI-127 1” 1”

GWI-158 1 ¼” 1 ¼”

GWI-190 1 ¼” 1 ¼”

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

IfinstallationistocomplywithASMEorCanadianrequirements,

anadditionalhightemperaturelimitisneeded.Installcontrolin

supply piping between boiler and isolation valve. Set second

controltominimum20°Fabovesetpointofrstcontrol.Maximum

allowablesetpointis240°F.Seepage 24 and 25forwiring.

Alowwatercutoffdeviceisrequiredwhenboilerisinstalledabove

radiation level or by certain state or local codes or insurance

companies.Uselowwatercutoffdesignedforwaterinstallations.

Electrodeprobe-typeisrecommended. Purchaseandinstallin

tee in supply piping above boiler.

Usebackowcheckvalveincoldwatersupplyifrequiredby

local codes.

See Figure 9(diaphragm-typeorbladder-typeexpansiontank)

orFigure10(closed-typeexpansiontank)onpage 14, and Table

6, for near-boiler and single-zone systems designed for return

wateratleast130°F.

See page 13formultiple-zonepiping.

See page 14forboilersusedwithrefrigerationsystems.

Near-boiler piping

Relief valve

Installreliefvalveverticallyin¾”tappingonsideofboiler.See

thetagattachedtothereliefvalveformanufacturer’sinstructions.

To avoid water damage or scalding due to valve

operation, discharge line must be connected to re-

liefvalveoutletandruntoasafeplaceofdisposal.

Terminate the discharge line to eliminate possibility

ofsevereburnsshouldthevalvedischarge.

• Dischargelinemustbeasshortaspossibleandbe

the same size as the valve discharge connection

throughout its entire length.

• Dischargelinemustpitchdownwardfromthevalve

and terminate at least 6” above the ﬂoor drain where

any discharge will be clearly visible.

• Thedischargelineshallterminateplain,notthread-

ed,withamaterialserviceablefortemperaturesof

375°Forgreater.

• Donotpipethedischargetoanyplacewherefreez-

ing could occur.

• Noshutoffvalveshallbeinstalledbetweentherelief

valve and boiler, or in the discharge line. Do not plug

or place any obstruction in the discharge line.

• Failuretocomplywiththeaboveguidelinescould

resultinfailureofthereliefvalvetooperate,result-

inginpossibilityofseverepersonalinjury,deathor

substantial property damage.

• Testtheoperationofthevalveafterllingandpres-

surizingsystembyliftingthelever.Makesurethe

valvedischargesfreely.Ifthevalvefailstooperate

correctly,replaceitwithanewreliefvalve.

Circulator

The circulator is shipped loose (wiring pre-attached to boiler)

to allow you to locate it either in the return or supply piping, as

desired. See page 14foratypicalinstallation.Pipetheexpansion

tanktothesuctionsideofthecirculatorwheneverpossible.Install

anairseparatorinthesupplypiping.Connecttheexpansiontank

totheairseparatoronlyiftheseparatorisonthesuctionsideof

thecirculator.Alwaysinstallthesystemllconnectionatthesame

pointastheexpansiontankconnectiontothesystem.Figures 4

and 5 show typical near-boiler piping connections.

Expansion tank

Diaphragm- or bladder-type expansion tank — Figure 9,

page 14

1. Ensure expansion tank size will handle boiler and system

watervolumeandtemperature.Tankmustbelocatedinboiler

returnpipingasclosetoboileraspossible,beforeinletside

ofcirculator.Seetankmanufacturer’sinstructionsfordetails.

2. Installanautomaticairventasshown.

Closed-type expansion tank — Figure 10, page 14

1. Ensureexpansiontanksizewillhandleboilerandsystemwater

volumeandtemperature.Seetankmanufacturer’sinstructions

fordetails.

2. Connecttankto½”NPTtappinglocatedbehindsupplyoutlet,

using ½” NPT piping. Pitch any horizontal piping up towards

tank1inchper5feetofpiping.

 Undersizedexpansiontanks cause system water

tobelostfromreliefvalveandmakeupwatertobe

addedthroughllvalve.Eventualsectionfailurecan

result.

Water piping — multiple zone systems

Installsystempipingusingeithercirculatorzoningorzonevalve

zoning.Installexpansiontankonsuctionsideofsystempump.

Alwaysconnectllline only at the expansiontank—neverat

another point in the system.

DO NOT connect directly from 3-wire zone

valves to the T-T terminals on the boiler.

When using 3-wire zone valves, install an isolation

relay.Connectthezonevalveendswitchwiresto

theisolationrelaycoil.Connecttheisolationrelay

contact across the boiler T-T terminals. Failure to

comply can result in damage to boiler components

or cause unreliable operation, resulting in severe

property damage.

4 Install water piping4 Install water piping

14 Part Number 550-142-785/0812

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Series 2 Gas-Fired Water Boilers – Boiler Manual

Water piping — refrigeration systems

Prevent chilled water from entering boiler

Installboilersothatchilledmediumispipedinparallelwiththe

heatingboiler.Useappropriatevalvestopreventchilledmedium

from entering boiler.  See Figure 11 for typical installation of

balancingvalveandcheckvalve.

Figure 9 Diaphragm- or bladder-type expansion tank:

Piping to single-zone system using

diaphragm-type or bladder-type expansion

tank. See Table 6, page 13, for piping sizes.

Figure 10 Closed-type expansion tank: Piping to single-

zone system using closed-type expansion

tank. See Table 6, page 13, for piping sizes.

Figure 11 Piping refrigeration systems

 Installboilersothatchilledmediumispipedinpar-

allelwithheatingboiler.Useappropriatevalvesto

preventchilledmediumfromenteringboiler.Consult

AHRIInstallationandPipingGuides.

 If boiler is connected to heating coils located in

air handling units where they can be exposed to

refrigeratedair,useowcontrolvalvesorotherau-

tomatic means to prevent gravity circulation during

coolingcycle.Circulationofcoldwaterthroughthe

boilercouldresultindamagetotheheatexchanger,

causing possible severe personal injury, death or

substantial property damage.

 Ifsystemincludesradiantheatingcircuits,provide

piping and controls to regulate the temperature sup-

plying the radiant circuits. Failure to comply could

result in substantial property damage.

 UseFigure9orFigure10onlyforsystemsdesigned

forreturn waterat least130°F.Forsystemswith

low return water temperature, such as converted

gravity systems and radiant heating systems, install

bypasspiping(seepage 15)toprotectboileragainst

condensation. Failure to prevent low return water

temperaturetotheboilercouldcausecorrosionof

the boiler sections or burners, resulting in severe

personal injury, death or substantial property dam-

age.

4 Install water piping continued

Part Number 550-142-785/0812

4 Install water piping continued

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Figure 12 System bypass piping in boiler loop with

separate system circulator, using primary/

secondary piping

Figure 13 Boiler bypass piping — use only for high

water content systems — DO NOT use for

radiant panel systems

Near-boiler piping continued

 Installallcomponentsspeciedaboveandadjustvalvesasdescribedtopreventlowtemperatureintheboiler.Failureto

preventlowwatertemperatureintheboilercouldcausecorrosionoftheboilersectionsorburners,resultinginsevere

personal injury, death or substantial property damage.

System bypass method

1. Apply bypass piping of Figure 12 to high water content

systems,radiantpanelsystemsoranysystemthatislikely

to operate with low return water temperature for extended

periods.

2. Thebypassarrangementshownprotectstheboilerfromdam-

age caused by condensate corrosion due to low return water

temperatureandprotectslowtemperaturesystemsfromtoo

high a supply temperature.

3. Adjustthebypassvalvesasindicatedbelow.

Adjust Bypass valves 1 and 2 as follows:

1. Startwithvalve2fullyclosed,valve1fullyopen.

2. Slowlyopenvalve2whileclosingvalve1.Adjustthevalves

untiltheboilerpressure/temperaturegaugereads160°For

higher.Asyouopenthevalves,pauselongenoughtoallow

temperaturestoleveloff.Ittakesawhilefortheboilerwater

temperature to rise as the ﬂow changes.

3. Bypass valve 2 allows hot boiler outlet water to blend with

colder return water, raising the supply temperature to the boiler.

Bypass valve 1 balances the pressure drop through valve 2.

4. Thepurposeofthispipingistoraisethereturnwatertem-

peraturetotheboilerenoughtopreventcondensationofue

gases.

Boiler bypass method

1. ApplybypasspipingofFigure 13 to high water content sys-

tems, such as converted gravity systems.

2. Thebypassarrangementshownprotectstheboilerfromdam-

age caused by condensate corrosion due to low return water

temperature.Thismethoddoesnotprovideprotectionfrom

high temperature water being supplied to the system.

3. DO NOT apply this piping to radiant panel systems.

4. Adjustthebypassvalvesasindicatedbelow.

Adjust Bypass valves 1 and 2 as follows:

1. Startwithvalve1fullyclosed,valve2fullyopen.

2. Slowlyopenvalve1whileclosingvalve2.Adjustthevalves

until the boiler pressure/temperature gauge reads approxi-

mately60°Fhigherthanthesystemtemperaturegauge.As

you open the valves, pause long enough to allow temperatures

toleveloff.Ittakesawhilefortheboilerwatertemperatureto

rise as the ﬂow changes.

3. Bypass valve 1 controls system ﬂow rate. Bypass valve 2

controls ﬂow through the boiler.

4. Thepurposeofthispipingistocause ahighenoughtem-

perature rise in the boiler that the average temperature will

bewarmenoughtopreventcondensationofuegases.

16 Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Figure 14 Gas supply pipingTable 7 Pipe capacity for 0.60 specic gravity natural gas

Connecting gas supply piping to boiler

1. RemovejacketfrontpanelandseeFigure 14 to pipe gas to

boiler.

a. Installdriplegatinletofgasconnectiontoboiler.Where

localutilityrequiresdriplegtobeextendedtotheoor,

useappropriatelengthofnipplebetweencapandtee.

b. Installgroundjointunionforservicing,whenrequired.

c. Installmanualshutoffvalveingassupplypipingoutside

boilerjacketwhenrequiredbylocalcodesorutilityrequire-

ments.

d. InCanada—Whenusingmanualmainshutoffvalve,it

must be identiﬁed by the installer.

2. Support piping with hangers, not by boiler or its accessories.

3. Purgeallairfromgassupplypiping.

4. Beforeplacingboiler in operation,checkboiler and its gas

connectionforleaks.

a. Close manual main shutoff valve during any pressure

testing at less than 13” w.c.

b. Disconnectboilerandgasvalvefromgassupplypiping

during any pressure testing greater than 13” w.c.

 Donotcheckforgasleakswithanopename—Use

bubbletest.Failuretousebubbletestorcheckfor

gasleakscancauseseverepersonalinjury,death

or substantial property damage.

5. Usepipedopecompatiblewithpropanegases.Applysparingly

onlytomalethreadsofpipejointssothatpipedopedoesnot

blockgasow.

5 Install gas piping

Failure to apply pipe dope as described in this

manual can result in severe personal injury, death

or substantial property damage.

Natural Gas:

1. SeeTable7forpipelengthanddiameter.Baseonratedboiler

input(divideby1,000toobtaincubicfeetperhour).Table 7

isonlyforgaswithspecicgravity0.60,withapressuredrop

throughthegaspipingof0.30”w.c.Foradditionalgaspipe

sizinginformation,seeANSIZ223.1(B149.1orB149.2for

Canadianinstallations).

2. Inletpressurerequiredatgasvalveinlet:

• Maximum:13”w.c.

• Minimum:5”w.c.

• Manifoldgaspressure:3.5”w.c.

3. Install100%lockupgaspressureregulatorinsupplylineif

inletpressureexceeds13”w.c.Adjustfor13”w.c.maximum.

Propane Gas:

1. Contactgassuppliertosizepipes,tanksand100%lockup

gas pressure regulator.

2. Adjustpropanesupplyregulatorprovidedbygassupplierfor

13”w.c.maximumpressure.

3. Inletpressurerequiredatgasvalveinlet:

• Maximum:13”w.c.

• Minimum:11”w.c.

• Manifoldgaspressure:10”w.c.

Gas pipe

length

(feet)

Capacity of pipe for pipe size of:

(Capacity in cubic feet gas per hour)

½” ¾” 1” 1¼” 1½”

10 132 278 520 1050 1600

20 92 190 350 730 1100

30 73 152 285 590 860

40 63 130 245 500 760

50 56 115 215 440 670

75 45 93 175 360 545

100 38 79 150 305 460

150 31 64 120 250 380

Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Foryoursafety,turnoffelectricalpowersupplyat

serviceentrancepanelbeforemakinganyelectrical

connectionstoavoidpossibleelectricshockhazard.

Failure to do so can cause severe personal injury

or death.

 WiringmustbeN.E.C.Class1.

 If rollout thermal fuse element wire as supplied

withboilermustbereplaced,type200°Cwireor

equivalentmustbeused.Ifotheroriginalwiringas

supplied with boiler must be replaced, use only type

105°Cwireorequivalent.

 Boilermustbeelectricallygroundedasrequiredby

NationalElectricalCodeANSI/NFPA70-latestedition.

Electrical installation must comply with:

1. NationalElectricalCodeandanyothernational,state,provin-

cial or local codes or regulations.

2. InCanada,CSAC22.1CanadianElectricalCodePart1,and

any local codes.

Wiring connections

Boiler is shipped with controls completely wired. See wiring dia-

gram on page 24 and 25fordetails.Circulatorisshippedloose,

butwiringharnessispre-attachedtotheboiler.Connectwiresin

circulatorjunctionbox.

Thermostat

1. Connectthermostatasshownonwiringdiagramonboiler.

2. Installoninsidewallawayfrominuencesofdrafts,hotorcold

waterpipes,lightingxtures,television,sunraysorreplaces.

3. If thermostat has a heat anticipator, set heat anticipator in

thermostattomatchpowerrequirementsofequipmentcon-

nectedtoit.Ifconnecteddirectlytoboiler,seeWiringdiagrams,

6 Field wiring

page 24 and 25,foranticipatorsetting.Forotherdevices,see

manufacturer’sspecications.Wiringdiagramonboilergives

settingforcontrolmoduleandgasvalve.Alsoseeinstructions

with thermostat.

DHW (if used)

ConnectDHWaquastatasshowninwiringbelow.Economy

functionisn’tutilizedwithDHWinput.

R & C Connections (if used)

24Vacleadsshouldbeusedforpowerstealingthermostatsonly!

Junction box (furnished)

1. Connect120VACpowerwiring(Figure 15).

2. Fuseddisconnectorserviceswitch(15amp.recommended)

maybemountedonthisbox.Forthoseinstallationswithlocal

codeswhichprohibitinstallationoffuseddisconnectorservice

switchonboiler,installa2x4coverplateontheboilerjunction

boxandmounttheserviceswitchremotelyasrequiredbythe

code.

Wiring multiple zones

Seezonevalvemanufacturer’sliteratureforwiringandapplication.

Aseparatetransformerisrequiredtopowerzonevalves.Zoning

withcirculatorsrequiresarelayforeachcirculator.

DO NOT connect directly from 3-wire zone

valves to the T-T terminals on the boiler.

When using 3-wire zone valves, install an isolation

relay.Connectthezonevalveendswitchwiresto

theisolationrelaycoil.Connecttheisolationrelay

contact across the boiler T-T terminals. Failure to

comply can result in damage to boiler components

or cause unreliable operation, resulting in severe

property damage.

Figure 15 Field wiring connections — service switch, DHW (if used) and thermostat (or end switch) provided by installer

18 Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Check for gas leaks

 Beforestartingtheboiler,andduringinitialopera-

tion,smellneartheoorandaroundtheboilerfor

gas odorant or any unusual odor. Do not proceed

withstart-upifthereisanyindicationofagasleak.

Repairanyleakatonce.

 Propaneboilersonly—Yourpropanesuppliermixes

anodorantwiththepropanetomakeitspresence

detectable.Insomeinstances,theodorantcanfade

and the gas may no longer have an odor.

• Propanegascanaccumulateatoorlevel.Smell

neartheoorforthegasodorantoranyunusual

odor.Ifyoususpectaleak,donotattempttolight

the pilot.

• Usecautionwhenattemptingtolightthepropane

pilot.Thisshouldbedoneby aqualiedservice

technician,particularlyifpilotoutagesarecommon.

• Periodicallychecktheodorantlevelofyourgas.

• Inspectboilerandsystematleastyearlytomake

sureallgaspipingisleak-tight.

• Consultyourpropanesupplierregardinginstallation

ofagasleakdetector.Therearesomeproductson

themarketintendedforthispurpose.Y

oursupplier

may be able to suggest an appropriate device.

Determine if water treatment is needed

Do not use petroleum-based cleaning or sealing

compounds in boiler system. Severe damage to

boiler will occur, resulting in substantial property

damage.

 Eliminateallsystemleaks.Continualfreshmakeup

waterwillreduceboilerlife.Mineralscanbuildup

insections,reducingheattransfer,overheatingcast

iron,andcausingsectionfailure.

Verify water chemistry

Consultlocalwatertreatmentcompaniesforunusuallyhardwater

areas(above7grainshardness)orlowpHwaterconditions(below

7.0).BoilerwaterpHof7.0to8.5isrecommended.

Freeze protection (when used)

Useantifreezemadeespeciallyforhydronicsystems.Inhibited

propylene glycol is recommended.

Do not use ethylene glycol, automotive or undiluted

antifreeze. Severe personal injury or death can

result.

1. Determine antifreeze quantityaccordingtosystemwater

content. Boiler water content is listed on page 47. Remember

toincludeexpansiontankwatercontent.

2. Followantifreezemanufacturer’sinstructions.

3. A50%solutionofpropyleneglycol/waterprovidesmaximum

protectiontoabout-30°F.

4. Localcodesmayrequirebackowpreventeroractualdiscon-

nectfromcitywatersupply.

5. Whenusingantifreezeinasystemwithautomaticll,installa

watermetertomonitorwatermakeup.Glycolwillleakbefore

thewaterbeginstoleak,causingglycolleveltodrop.Added

waterwilldilutetheantifreeze,reducingthefreezeprotection

level.

Preparation

Fill the system with water

1. Closemanualandautomaticairventsandboilerdraincock.

2. Fill to correct system pressure. Correct pressure will vary

witheachapplication.T

ypical coldwater llpressurefor a

residential system is 12 psi.

3. Purgeairfromsystem:

a. Connectahosetopurgevalveorvalves,ifinstalled.Route

hose to an area where water can drain and be seen.

b. Close the boiler or system isolation valve between the

purge valve and ﬁll connection to the system.

c. Closezoneisolationvalves.

d. Openquick-llvalveoncoldwatermakeupline.

e. Open purge valve.

f. Onezoneatatime,opentheisolationvalves.Allowwater

to run through the zone, pushing out the air. Run until no

noticeable air ow is present. Close the zone isolation

valvesandproceedwiththenextzone.Followthisproce-

dure until all zones are purged.

g. Closethequick-llwatervalveandpurgevalveandremove

the hose. Open all isolation valves. Watch that system

pressure rises to correct cold-ﬁll pressure.

h. Afterthesystemhasoperatedforawhile,eliminateany

residual air by using the manual air vents located through-

out the system.

i. Ifpurgevalvesarenotinstalledinsystem,openmanualair

vents in system one at a time, beginning with lowest ﬂoor.

Closeventwhenwatersquirtsout.Repeatwithremaining

vents.

4. Open automaticairvent (diaphragm-type orbladder-type

expansiontanksystemsonly)oneturn.

5. Open other vents:

a. Starting on the lowest ﬂoor, open air vents one at a time

untilwatersquirtsout.

b. Repeat with remaining vents.

6. Reﬁll to correct pressure.

Inspect system water piping

Afterllingthe boiler and systemwithwater, inspectallpiping

throughoutthesystemfor leaks. Iffound, repairimmediately.

Repeatthisinspectionaftertheboilerhasbeenstartedandthe

system has heated up.

 Leaksmustberepairedatonce.Failuretodosocan

damage the boiler, resulting in substantial property

damage.

Do not use petroleum-based cleaning or sealing

compounds in boiler system. Severe damage to

boiler will occur, resulting in substantial property

damage.

Inspect base insulation

Checktomakesureinsulationissecureagainstallfoursidesof

thebase.Ifinsulationisdamagedordisplaced,donotoperate

boiler. Replace or reposition insulation.

Failure to replace damaged insulation or reposition

insulation can result in a ﬁre hazard, causing severe

personal injury, death or substantial property dam-

age.

The boiler contains ceramic ﬁber and ﬁberglass

materials.Usecarewhenhandlingthesematerials

perinstructionsonpage48ofthismanual.Failure

to comply could result in severe personal injury.

7 Start-up

Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

Operate boiler

DO NOT proceed with boiler operation unless boiler

and system have been ﬁlled with water and all in-

structionsandproceduresofpreviousmanualsec-

tions have been completed. Failure to do so could

result in severe personal injury, death or substantial

propertydamage.Beforestartingtheboiler...

• ReadmanualSections 9 and 10andthe“Operating

instructions”, page 26.

• Verifytheboilerandsystemarefullofwater.

• VerifytheStart-up“Preparation”proceduresofthis

section have been completed.

Adjust boiler control settings

BOILER OPERATING TEMPERATURE

With power turned on, control module receives a signal from

the temperature sensor and displays boiler temperature. The

control knob labeled BOILER TEMP is used to adjust the

operating temperature setpoint, turning clockwise to increase

temperature setting and counterclockwise to decrease. When the

knob is turned to adjust temperature the display will brighten to

indicate adjustment mode. After temperature is set to desired

value, display will dim after approximately 5 seconds to indicate

measurement mode.

ADJUST BOILER OPERATING TEMPERATURE TO

DESIRED SETPOINT

BOILER ECONOMY SETTING

To comply with Department of Energy regulations, the control

module circulates available hot water before turning on the boiler

to attempt to satisfy a call for heat. While attempting to satisfy

the heat demand, the control module also monitors the boiler

temperature changes via the temperature sensor and determines

whether or not the available hot water will satisfy the demand,

adjusting the time delay to turn on the boiler until it determines

that additional heat will be needed. The knob labeled ECONOMY

ADJUST provides an adjustment between maximize (MAX) and

minimize (MIN) the delay. The maximum (MAX) adjustment

position should be used to maximize energy savings. Turning the

knob counterclockwise decreases the delay time and should only

be used in the event that the heated space becomes uncomfortable.

ADJUST ECONOMY TO DESIRED POSITION

(MAX IS THE PREFERRED SETTING)

IMPORTANT

In accordance with Section 325 (f) (3) of the Energy Policy

and Conservation Act, this boiler is equipped with a feature

that saves energy by reducing the boiler water temperature

as the heating load decreases. This feature is equipped with

an override which is provided primarily to permit the use of

an external energy management system that serves the same

function.

7 Start-up continued

THIS OVERRIDE MUST NOT BE USED UNLESS AT LEAST

ONE OF THE FOLLOWING CONDITIONS IS TRUE:

• An external energy management system is installed that

reduces the boiler water temperature as the heating load

decreases.

• This boiler is part of a modular or multiple boiler system

having a total input of 300,000 BTU/hr or greater.

• This boiler is equipped with a tankless coil.

Start the boiler

Followthe“Operatinginstructions”,page 26.

Ifboilerfailstostart,see“Ifboilerdoesn’tstart...Checkfor:”

on this page.

Check system and boiler

 Eliminateallsystemleaks.Continualfreshmakeup

waterwillreduceboilerlife.Mineralscanbuildup

insections,reducingheattransfer,overheatingcast

iron,andcausingsectionfailure.

 Ifyoudiscoverevidenceofanygasleak,shutdown

theboileratonce.Findtheleaksourcewithbubble

test and repair immediately. Do not start boiler again

until corrected. Failure to comply could result in se-

vere personal injury, death or substantial property

damage.

Do not use petroleum-based cleaning or sealing

compounds in boiler system. Severe damage to

boiler will occur, resulting in substantial property

damage.

1. Checksystempipingforleaks.Iffound,shutdownboilerand

repair immediately.

2. Ventairfromsystemusingmanualvents.Airinthesystemwill

interferewithcirculationandcauseheatdistributionproblems

and noise.

3. Inspectventsystemthoroughlyforsignsofdeteriorationfrom

corrosion,physicaldamageorsagging.Verifythatmasonry

chimney liners are in good condition, with no obstructions,

and there are no openings into the chimney.

4. Checkaroundtheboilerforgasodorfollowingtheprocedure

ofpage 16ofthismanual.

5. Verifyoperationusingproceduresbelow.Perform“Checkout

procedure” on pages 20 and 21andllinthe“Installationand

service certiﬁcate”.

If boiler doesn’t start . . . Check for:

1. Looseconnections,blownfuseorserviceswitchoff?

2. Highlimitswitchsetbelowboilerwatertemperature?

3. Thermostatsetbelowroomtemperature?

4. Gasnotturnedonatmeterorboiler?

5. Incominggaspressurelessthan:

 5”w.c.fornaturalgas?11”w.c.forpropanegas?

6. Ifnoneoftheabovecorrectstheproblem,see“Troubleshoot-

ing”, page 31ofthismanual.

20 Part Number 550-142-785/0812

GWI

Series 2 Gas-Fired Water Boilers – Boiler Manual

❏ Boilerandheatdistributionunitslledwithwater?

❏ Automaticairvent,ifused,openonefullturn?

❏ Airpurgedfromsystem?

❏ Airpurgedfromgaspiping?Pipingcheckedforleaks?

❏ Correctly-sized manifold orices installed? See Table 3,

page 6tochecksizeandfueltype.

 Correctly sized manifold orices must be used.

Failure to do so will cause severe personal injury,

death or substantial property damage.

❏ Followed“Operatinginstructions”onboilerorinmanual,page

26forproperstart-up?

❏ Properburnerameobserved?See“Verifyoperation”,manual

Section 7.

❏ Test temperature limit — While burners are operating, turn

BoilerTempadjustmentknobcounterclockwiseuntildisplay

reading is below actual boiler water temperature. Burners

should go off while circulator continues to operate.Turn

BoilerTempadjustmentknobclockwiseuntildisplayread-

ingisaboveboilerwatertemperatureandignitionsequence

should resume.

❏ Test additional eld-installed controls — If boiler hasalow

water cutoff, additional high limit or other controls, test for

operation as outlined by manufacturer. Burners should be

operatingandshouldgooffwhencontrolsaretested.When

controls are restored, burners should reignite.

❏ Testignitionsystemsafetydevice:

a. Connectmanometertooutletsideofgasvalve.Startboiler,

allowingfornormalstart-upcycletooccurandmainburn-

erstoignite.Withmainburnerson,manuallyshutoffgas

supplyatmanualmainshutoffgasvalve.Burnersshould

gooff.Openmanualmainshutoffgasvalve.Manometer

should conﬁrm there is no gas ﬂow. Pilot will relight, ﬂame

sensing element will sense pilot ﬂame and main burners

reignite.

❏ Setlimitcontrol(s)tosystemtemperaturerequirements.Adjust

balancing valves and controls to provide design temperature

to system.

❏ SetEconomymode,fullyclockwise.

❏ For multiple zones, adjust ﬂow so it is about the same in each zone.

❏ Verifythermostatheatanticipator(ifavailable)setproperly?

See wiring diagram label on boiler or in manual, page 24 and

25.

❏ Cycleboilerwiththermostat—Raisetohighestsettingand

verify boiler goes through normal start-up cycle. Lower to

lowestsettingandverifyboilergoesoff.

❏ CycleDHWAquastatifused.

❏ Measurenaturalgasinput:

a. Operate boiler 10 minutes.

b. Turnoffotherappliances.

c. Atnaturalgasmeter,measuretime(inseconds)required

touseonecubicfootofgas.

d. Calculategasinput:

3600 x 1000

number of seconds from step c

= Btuh

e. Btuhcalculatedshouldapproximateinputratingonboiler

8 Checkout procedure

Check burner ﬂame — Pilot burner

Proper pilot ﬂame (see Figure 16):

1. Blue ﬂame.

2. Innerconeengulngpilotamesensor.

3. Pilot ﬂame sensor glowing cherry red.

Improper pilot ﬂame:

1. Overred — Large ame lifting or blowing past pilot ame

sensor.

2. Underred—Smallame.Innerconenotengulngpilotame

sensor.

3. Lackofprimaryair—Yellowametip.

Figure 17 Typical main burner ame

Verify operation

Figure 16 Typical pilot burner ame

4. Incorrectlyheatedpilotamesensor.

Check burner ﬂames — Main burner

Proper main burner ﬂame (see Figure 17):

1. Yellow-orangestreaksmayappear(causedbydust).

Improper main burner ﬂame:

1. Overred—Largeames.

2. Underred—Smallames.

3. Lackofprimaryair—Yellowtippingonames(sootingwill

occur).

7 Start-up continued

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Williamson GWI-127 User manual

Brand: Williamson

Model: GWI-127

Category: Water heaters & boilers

Type: User manual

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