A/O Smith Gas Water Heater Service Handbook

7/30/2019 A/O Smith Gas Water Heater Service Handbook

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CommerCial / residential gas water heater

sc hk

PRINTED IN THE U.S.A. 0410 318556-000

serviCing should only be performed by a Qualified serviCe agent

500 Tennessee Watz Parkwa

Ashand Cit, TN 37015

for models:

btX 100, gdhe 50

series 120 & 121installation Considerations - pre serviCeCheCKs - water heater ConstruCtion -

operation & serviCe - troubleshooting


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3/72

1

table of Contents

TAblE Of CONTENTS .......................................................................... 1

INTRODUCTION .................................................................................... 2

Qalicatis ..................................................................................... 2

Service Warig ................................................................................ 2

Service Remier..............................................................................2

Tls Reqire................................................................................... 2

INSTAllATION CONSIDERATIONS ............... ................ ............... ....... 3Istrcti Maal .............................................................................3

Clse Water Sstems ...................................................................... 3

Thermal Epasi............................................................................ 3

Air Reqiremets............................................................................... 3

Ctamiate Air............................................................................... 3

Vetig............................................................................................... 4

Geeral Vetig Ifrmati ....................................................... 4

Maimm Eqivalet Legth Reqiremets ............................... 4

Itake Air Cecti .................................................................. 5

Electrical Reqiremets..................................................................... 6

Grig a Plarit ............................................................... 6

Pwer Sppl Test ...................................................................... 6

Istallati Check List........................................................................ 7

FEATuRES And CoMPonEnTS ......................................................... 8

Frt & Back Views ........................................................................... 8

Tp View ............................................................................................ 9

Cmbsti Blwer & Brer Assembl............................................ 9

OPERATION AND SERvICE ............................................................... 10

Hw It Wrks ................................................................................... 10

Cmbsti Blwer..........................................................................11

Brer Assembl .............................................................................12

Cmbsti Blwer a Brer Remval .......................................14

Flame Sesr.................................................................................. 18

Flame Sesig operati ......................................................... 18

Flame Sesig Crret Test...................................................... 19

Igiter............................................................................................... 20

Igiter Crret Test....................................................................20

venturi ................ ................ ............... ................ ............... ............... 22

Gas vae ................ ................ ............... ................ ............... .......... 23

Gas Valve Vltage Tests............................................................ 23

Gas Valve Remval...................................................................24

Gas Pressure ................................................................................... 25

Gas Pressure Test ............... ................ ................ ............... ....... 26

Gas Flw Test ........................................................................... 27

Pressre Switches ........................................................................... 28

Cstrcti & operati..........................................................28

Ctrl Sstem Mitrig........................................................ 29

Pressre Switch Tests ..................................................................... 31

Ctiit Test drig Stab .................................................31

Ctiit Test drig operati .............................................. 32

Pressre Test drig operati ................................................32

Temperatre Prbe .......................................................................... 35

Temperatre Sesr Test ..........................................................35

ECo Ctiit Test .................................................................. 36

Ctrl Sstem Harware ......................................................... 37

uIM (user Iterface Mle) ............................................... 37

CCB (Cetral Ctrl Bar) .............................................. 39

CCB Cver Remval A Replacemet ............................. 40

CCB Circit Bar Lat ................................................... 41

CCB Cecti Ieticati ........................................... 42

Wirig diagram .......................................................................... 44

ConTRoL SySTEM oPERATIon ................................................ 45

Oeriew .................................................................................... 45

Ctrl Sstem Featres .................................................... 45

Cmmercial A Resietial Mels .................................. 46

Ctrl Sstem navigati.................................................. 46

user Ipt Btts .............................................................. 46

desktp Scree................................................................... 46

Stats Ics ........................................................................ 47

operatig States ................................................................. 48

Ctrl Sstem Mes .............................................................. 48

Temperatres ...................................................................... 49

Heater Status ...................................................................... 50

displa Settigs .................................................................. 51

Heater Ifrmati .............................................................. 51

Current faut ....................................................................... 52

Falt Histr ........................................................................ 52

Falt occrrece................................................................. 52

Restre Factr defalts .................................................... 52

Service Ctact Ifrmati................................................ 53

Seqece of operati............................................................. 54

Seqece of operati Flw Chart .......................................... 55

TROUblESHOOTING ................................................................... 56

Rgh Startig/Rgh operati........................................ 56nt Egh Ht Water........................................................ 56

Heater Stats Me ............................................................ 56

Thigs T Check Befre Servicig ...................................... 56

Resettig The Ctrl Sstem ............................................ 56

Ctrl Sstem urespsive ................................................... 57

uIM (LCd) Is Blak ............................................................. 57

uIM Is Iperable................................................................ 57

Falt Messages ......................................................................... 58

AC Reersed ....................................................................... 58

Temp Prbe ope ............................................................... 58

Temp Prbe Shrt ............................................................... 58

Flame Sesr Shrt ............................................................ 59

Flame detect Errr.............................................................. 59

Eerg Ct ot (ECo) ........................................................ 60

Blcke Air Itake ............................................................... 61

Blcke Ehast ................................................................. 62

Blwer Prver Failre.......................................................... 62

Blwer Prver ope............................................................ 63

Lw Igiter Crret.............................................................. 64

Igiti Failre..................................................................... 65

Cmmicati Failre ....................................................... 66


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2 Servicig shl l be perfrme b a Qalie Service Aget

This Service Maal cvers the water heater Mel a Series mbers liste the frt cver l. Theistrctis a illstratis ctaie i this maal will prvie with trbleshtig prceres t

verif prper perati a iagse a repair cmm service prblems.

QualifiCations

Qualified installer or serviCe agenCy

Istallati a service f this water heater reqires abilit eqivalet t that f a Qalie Agec (as eeb AnSI belw) i the el ivlve. Istallati skills sch as plmbig, air sppl, vetig, gas sppl aelectrical sppl are reqire i aiti t electrical testig skills whe perfrmig service.

ansi Z223.1 2006 sc. 3.3.83: Qalie Agec - A iivial, rm, crprati r cmpa that eitheri pers r thrgh a represetative is egage i a is respsible fr (a) the istallati, testig r

replacemet f gas pipig r (b) the cecti, istallati, testig, repair r servicig f appliaces aeqipmet; that is eperiece i sch wrk; that is familiar with all precatis reqire; a that hascmplie with all the reqiremets f the athrit havig jrisicti.

serviCe warning

If are t qalie (as ee b AnSI abve) a licese r certie as reqire b the athrit

havig jrisicti t perfrm a give task t attempt t perfrm a f the prceres escribe ithis maal. If t ersta the istrctis give i this maal t attempt t perfrm aprceres tlie i this maal.

serviCe reminder

Whe perfrmig a trbleshtig step tlie i this maal alwas csier the wirig a cectrsbetwee cmpets. Perfrm a clse visal ispecti f all wirig a cectrs t a frm a givecmpet befre replacemet. Esre wires were strippe befre beig crimpe i a wire cectr, esre

wires are crimpe tightl i their cectrs, esre cecti pis i sckets a plgs are t amager wr, esre plgs a sckets are matig prperl a prviig g ctact.

Failre t perfrm this critical step r failig t perfrm this step thrghl fte reslts i eeless wtime, ecessar parts replacemet, a cstmer issatisfacti.

tools reQuired

Istrcti Maal that came with the water heater.

All tls cmm t istallati a service f cmmercial water heaters sch as ha tls, trch, pipewreches etc.

Lg (8-10) T hale 1/8 ich he (alle ke) wrech fr Cmbsti Blwer remval a istallati.

He (Alle) wrech sizes: 5/32, 1/8, 1/4 a 5/16" - fr Brer, a 24 Vlt Gas Valve remval a

istallati.

Tw igital mameters: Rage -20.00 t +20.00" W.C. Reslti - 0.01" W.C. Recmme uEI melEM200 r eqivalet. Reqire t test pressre switch perfrmace. Als se t measre sppl amaifl gas pressres.

digital Mlti Meter; Fielpiece HS36, Flke 187, uEI dL289 r eqivalet capable f measrig:

AC/dC Vltage.

ohms.

dC micr amps (A) - ame sesig crret, see Flame Sesig Crret Test page 19.

AC amp meter- recmme uEI mel dL289 r eqivalet.

120 VAC plg i tlet tester, see Figre 2 page 6

introduCtion


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3Servicig shl l be perfrme b a Qalie Service Aget

installation Considerations

This secti f the Service Maal cvers sme f the critical istallati reqiremets that, whe verlkefte reslt i peratial prblems, w time a eeless parts replacemet. Csts t crrect istallati

errrs are t cvere er the limite warrat. Esre all istallati reqiremets a istrctisctaie i the Istrcti Maal that came with the water heater have bee fllwe prir t perfrmiga service prceres.

instruCtion manualHave a cp f the Istrcti Maal that came with the water heater ha fr the mel a seriesmber beig service. Istallati ifrmati give i this Service Maal is t a cmplete istallatiistrcti. Istallati ifrmati give i this maal has a limite fcs as it applies t servicig the water

heater. This Service Maal es t replace r spersee the Istrcti Maal that came with the wateheater. Alwas refer t the Istrcti Maal fr cmplete istallati istrctis. If the Istrcti Maais t ha cpies ca be btaie frm the mafactrers web site r b callig the techical spprtphe mber shw the back cver f this maal.

Closed water systemsWater sppl sstems ma, becase f ce reqiremets r sch citis as high lie pressre, amgthers, have istalle evices sch as pressre recig valves, check valves, a back w preveters

devices sch as these case the water sstem t be a clse sstem.

thermal eXpansionAs water is heate, it epas (thermal epasi). I a clse sstem the vlme f water will grw wheit is heate. As the vlme f water grws there will be a crrespig icrease i water pressre e t

thermal epasi. Thermal epasi ca case prematre tak failre (leakage). This tpe f failre is cvere er the limite warrat. Thermal epasi ca als case itermittet Temperatre-PressreRelief Valve perati: water ischarge frm the valve e t ecessive pressre bil p. This citiis t cvere er the limite warrat. The Temperatre-Pressre Relief Valve is t itee fr the

cstat relief f thermal epasi.

A prperl size thermal epasi tak mst be istalle all clse sstems t ctrl the harmfl effects

f thermal epasi. Ctact a lcal plmbig service agec t have a thermal epasi tak istalle.

air reQuirementsCarefll review the reqiremets fr cmbsti a vetilati air i the Istrcti Maal that came

with the water heater. Failre t meet these reqiremets whe the water heater is istalle r verlkigtheir imprtace whe servicig the water heater fte reslts i eeless w time, ecessar partsreplacemet, a cstmer issatisfacti.

A iaeqate sppl f air fr cmbsti a vetilati fte cases peratial prblems. A lack cmbsti a vetilati air ca create a egative ambiet air pressre i the istalle space which calea t imprper cmbsti a peratial prblems with pressre switches.

Contaminated airCmbsti air that is ctamiate ca greatl imiish the life spa f the water heater a water heatercmpets sch as Igiters a Brers. Prpellats f aersl spras, beat shp spplies, water sfteerchemicals a chemicals se i r cleaig prcesses that are preset i the cmbsti, vetilati r

ambiet air ca case sch amage.

Vaprs frm vlatile cmps sch as slvets, cleaers, chlrie base chemicals a refrigerats iaiti t beig highl ammable i ma cases, ca als react t frm highl crrsive sbstaces sch ashrchlric aci isie the cmbsti chamber. The reslts ca be hazars a case prct failre.

If the water heater is istalle i beat shps, barber shps r laries with r cleaig eqipmet, it isimperative the water heater be istalle i a direct Vet cgrati s that air fr cmbsti is eriveirectl frm the tr atmsphere thrgh a seale itake air pipe. See the vetig istallati secti

i the Istrcti Maal that came with the water heater fr mre ifrmati direct Vet istallatis.


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venting

This secti f the Service Maal is t a cmplete vetig istallati istrcti. Refer t the IstrctiMaal that came with the water heater; esre the vetig has bee istalle per all Istrcti Maal

reqiremets. Csts t crrect istallati errrs are t cvere er the limite warrat.

general venting information

The water heaters cvere i this maal are peratiall eqivalet t Categr IV appliaces a ma beistalle i either a Pwer Vet r direct Vet cgrati.

C iv acCategr IV appliaces perate with a psitive vet (ehast) static pressre a with vet gas temperatres

lw egh t prce cesate i the vet pipig.

Pwer Vent Cnguratin

Pwer Vet cgratis erive all cmbsti air frm the rm where the are istalle a ischarge alle gases t the tr atmsphere thrgh a seale vet (ehast) pipe. Pwer vet cgratis havee vet pipe cecte t the water heater which ca be termiate i a vertical r hriztal arragemet.

Direct Vent Cnguratin

direct Vet cgratis erive all cmbsti air irectl frm the tr atmsphere thrgh a sealeitake air pipe a ischarge all e gases t the tr atmsphere thrgh a seale vet (ehast) pipe.

direct Vet cgratis have tw pipes cecte t the water heater, e vet pipe a e itake airpipe. direct Vet cgratis ca als be termiate i a vertical r hriztal arragemet.

maXimum eQuivalent length reQuirements

The the itake air a/r vet pipe fr the water heaters cvere ithis maal ca be istalle sig 2 ich r 3 ich pipe epeig the verall eqivalet legth" f each pipe. Eqivalet legths

are calclate b aig the ttal liear feet f istalle pipe t theaccmlate eqivalet legth f all el istalle elbws.

Each 2 ich r 3 ich 90 elbw istalle is eqivalet t 5 liearfeet f pipe. 45 elbws are eqivalet t 2.5 liear feet f pipe.

o direct Vet istallatis the itake air a/r vet pipe are calclate separatel a each pipe's ttaleqivalet legth mst t ecee the maimm eqivalet legth reqiremets state i the IstrctiMaal that came with the water heater, see Table 1 belw.

table 1

Number f 90 Ebws

Instaed

2 ic p 3 ic p

Maximum Feet (Meters) Maximum Feet (Meters)

oe (1) 40 feet (12.2 meters) 120 feet (36.6 meters)

Tw (1) 35 feet (10.7 meters) 115 feet (35.0 meters)

Three (3) 30 feet (9.1 meters) 110 feet (33.5 meters)

Fr (4) 25 feet (7.6 meters) 105 feet (32.0 meters)

Five (5) 20 feet (6.1 meters) 100 feet (30.5 meters)Si (6) 15 feet (4.6 meters) 95 feet (29.0 meters)

Tw 45 elbws are eqivalet t e 90 elbw.

pipe siZe reQuirements

Esre the crrect size pipe has bee se fr the legth f itake air a/r vet pipig istalle. 2 ich pipe

ma be se p t 40 eqivalet feet with e 90 elbw istalle, if the istallati reqires mre eqivaletfeet f itake air a/r vet pipe, 3 ich pipe mst be se p t the maimm shw i Table 1 abve.

maXimum elbow reQuirements

The maimm mber f 90 elbws allwe fr the vet pipe is si (6). o direct Vet istallatis themaimm mber f 90 elbws allwe fr the itake air pipe is si (6), see Table 1 abve.

2

3

= 5 linear feet of pipe

= 5 linear feet of pipe


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faCtory supplied/installed fittings

Factr spplie vet a itake air termiatis a factr istalle ttigs the water heater are tfactre i t the vet a itake air pipe eqivalet feet calclatis. The itake air cecti ttig a

ehast elbw (vet cecti) are factr istalle ttigs, see Figre 1 belw a Figre 3 page 8.

intaKe air ConneCtion

The itake air cecti has a scree a a hse barb istalle at the factr, see Figre 1 belw.

The itake air cecti scree is istalle t prevet ebris frm eterig the Cmbsti Blwer a/r

Brer. This scree is left i place whe the water heater is istalle i a Pwer Vet cgrati bt msbe remve befre cectig the itake air pipig direct Vet istallatis. oce the itake air pipe isistalle the scree, if t remve, wl be hie frm view a ma becme clgge with ebris ver

time. This ca case pr cmbsti a Blocked Air Intake falt citis a Ctrl Sstem lck tsEsre this scree has bee remve all direct Vet istallatis if eperiecig Blocked Air Intake falcitis.

The hse barb is istalle the itake air cecti t cect the Blcke Itake Air switch sesig tbeThe itake air cecti is factr istalle s that the hse barb is at apprimatel a 115 agle whe

viewe frm the e. Esre the hse barb is t riete a lwer tha 115 as this will allw water frmcesate r sw beig raw isie the itake air pipig direct Vet istallatis t ll the BlckeItake Air switch sesig tbe. If water es eter the Blcke Itake Air switch sesig tbe it will amagethe switch a case Blocked Air Intake falt citis a Ctrl Sstem lck ts. Esre this hse

barb is prperl riete whe eperiecig Blocked Air Intake falt citis. Agles betwee 90 a115 are acceptable. If ecessar lse the hse clamp the itake air cecti elbw a rtate theitake air cecti ttig t ajst the agle prperl as shw i Figre 1 belw.

HOSE BARB

ANGLED

BETWEEN

90 AND 115

HOSE BARB FITTING FOR

BLOCKED INTAKE AIR

SWITCH SENSING TUBE

COMBUSTION BLOWER

INTAKE AIR CONNECTION

24 VOLT

GAS VALVE

INTAKE AIR

CONNECTION

INTAKE AIR

CONNECTION ELBOW

INTAKE AIR

CONNECTION

SCREEN MUST

BE REMOVED

ON DIRECT VENT

INSTALLATIONS

Figure 1

Service Ntes:

Plastic ebris left the eges f itake air pipe sectis after cttig mst be remve direct Vet

istallatis. These ebris ca cllect isie a clg the Brer which ca case pr cmbsti,

stig, rgh startig, rgh perati a Ignition Failure falt citis a Ctrl Sstem lckts. The Brer is a raial esig that ca trap ebris, see Figre 5 page 9.

Eceeig the eqivalet legth limitatis fr the vet pipig will case Blocked Exhaustfalt

citis a Ctrl Sstem lck ts.

Eceeig the eqivalet legth limitatis fr the itake air pipig will case Blocked Air Intake faltcitis a Ctrl Sstem lck ts.

Eceeig the maimm mber f elbws allwe fr the itake air a/r vet pipig will als case

Blocked Air Intake and Blocked Exhaustfalt citis a Ctrl Sstem lck ts.

usig smaller itake air a/r vet pipe tha reqire fr the istalle eqivalet legth will als caseBlocked Air Intake and Blocked Exhaustfalt citis a Ctrl Sstem lck ts.


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eleCtriCal reQuirements

The water heaters cvere i this maal reqire a 120 VAC (Vlts Alteratig Crret) 1 (Sigle Phase)pwer sppl. The maimm AC amperage is apprimatel 5.2 FLA (fll la amps) rig the Igiter Warm

up peratig state. Resietial mels are factr eqippe with a 3 prg appliace cr that plgs it astaar 120 VAC wall tlet. Cmmercial mels are t eqippe with a appliace cr; a appliacecr r har wirig will have t be el istalle, see Cmmercial A Resietial Mels page 46.

grounding and polarity

The water heaters cvere i this maal must be prperl gre a the plarit f the pwer spplmust be crrect.Crrect plarit wirig fr a staar 120 VAC resietial wall tlet is shw i Figre 2belw, te the wwar rietati f the gr cecti scket.

The ht a etral wires frm the pwer sppl mst cect t the black (ht) a white (etral) wiresrespectivel isie the 120 VAC jcti b the water heater, see Figre 4 page 9 fr jcti blcati. The gr wire frm the pwer sppl mst cect t the gree wire isie the 120 VAC jcti

b the water heater.

A "Reverse Plarit" citi ccrs whe the ht a etral wires are cecte i reverse frm what

is shw i Figre 2. If the pwer sppl plarit is reverse it will caseAC Reversedfalt citis aCtrl Sstem lck ts. If the water heater is t gre prperl it will case Ignition Failure faltcitis a Ctrl Sstem lck ts, see Flame Sesr page 18 a the Pwer Sppl Test belw.

HOT(typically black)

NEUTRAL(typically white)

GROUND(typically green)

120 VOLTS

120 VOLTS

0 VOLTS

120 VAC POWER SUPPLY POLARITY CORRECT WIRING

120 VAC WALL OUTLET

PLUG IN OUTLET TESTER

NEUTRAL HOT

GROUND

Figure 2

power supply testPrper grig a plarit ca be verie with a AC vlt meter b takig three vltage reaigs at thewall tlet beig se r the pwer sppl wirig isie the water heater's 120 VAC jcti b. Iepesiveplg i tlet testers, available at mst hme ceters a harware stres, ca be se t qickl verif

prper grig a crrect plarit at a 120 VAC wall tlet, see Figre 2 abve.

Check fr AC vtage between:

1. Ht & netral - shl be apprimatel 120 VAC.

2. Ht & Gr - shl be apprimatel 120 VAC.

3. netral & Gr - shl be apprimatel 0 VAC.


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installation CheCK list

The list belw represets sme f the mst critical istallati reqiremets that, whe verlke, fte reslti peratial prblems, w time a eeless parts replacemet. Befre perfrmig a trbleshtig

prceres se the list belw t check fr istallati errrs. Csts t crrect istallati errrs are tcvere er the limite warrat. Esre all istallati reqiremets a istrctis ctaie i theIstrcti Maal that came with the water heater have bee bserve a fllwe.

See Trbleshtig page 56 fr service prceres relatig t the falt citis metie belw.

1. The vet (ehast) pipe mst t be cmbie r cecte t a ther appliaces vet sstem rchime.

2. The itake air pipe mst t be cmbie r cecte t a ther appliaces itake air pipig.

3. The water heaters cvere i this maal are cesig appliaces. Cesate will frm i the vetpipe rig rmal perati, cesate ca als frm i the itake air pipig i certai circmstacesEsre the itake air a/r vet pipig is t istalle i a maer that will allw water t be trappe

i the pipig. This will lea t Blocked Exhausta/rBlocked Air Intake falt citis a CtrSstem lck ts.

4. Esre the itake air a/r vet pipig is the crrect size fr the istalle legth. See the vetigreqiremets secti i the Istrcti Maal that came with the water heater. usig smaller pipe thais reqire will lea t Blocked Exhausta/rBlocked Air Intake falt citis a Ctrl Sstem

lck ts.5. Esre the itake air a/r vet pipig are withi the maimm eqivalet legths reqire i the

Istrcti Maal that came with the water heater. Eceeig the maimm legth r mber f elbws

allwe will als lea t Blocked Exhausta/rBlocked Air Intake falt citis a Ctrl Sstemlck ts.

6. Esre there is a water trap frme i the cesate rai tbe/lie cecte t the ehast elbw the water heater a that the cesate rai is wig freel. Cesate rai blckage will casethe ehast elbw t ll with water a lea t Blocked Exhaustfalt citis a Ctrl Sstem

lck ts.

7. Esre the vet a itake air termiatis have aeqate clearaces frm each ther a the termiatis

f ther appliaces. Failre t maitai aeqate clearaces ca case the recirclati f e gases

betwee the vet a itake air pipig. Recirclati f e gases will case pr cmbsti, stig,igiti failre, rgh starts, rgh perati, prematre failre f the heat echager a icig f thecmbsti air itake rig severe cl weather.

8. direct vet termiatis beig istalle i ea air spaces sch as alles, atrims, a isie crers

ca als case the recirclati f e gases betwee the vet a itake air pipig. T prevet therecirclati f e gases, maitai as mch istace as pssible betwee the itake air a vettermiatis.

9. Esre the screes i the factr spplie termiatis are secrel istalle t prevet blckage i theitake air a/r vet pipig.

10. o direct Vet istallatis esre the scree at the itake air cecti the water heater wasremve befre the itake air pipig was cecte, see Itake Air Cecti page 5.

11. Esre the pwer sppl cectis t the water heater are plarit crrect. use a 120 VAC hsehltlet tester t verif crrect plarit a gr at a tlet the water heater is plgge it. Reverse

plarit (etral a ht wires reverse) will case theAC Reversedfalt citi a Ctrl Sstemlck t.

12. Esre the water heater a the Brer are prperl gre. The water heater Ctrl Sstem reqiresa aeqate earth gr fr ame sesig (vericati), see Flame Sesig operati page 18Iaeqate grig t the water heater a/r the Brer will case the Ignition Failure falt citia Ctrl Sstem lck t. See Electrical Reqiremets page 6 a Figre 10 page 13.


10/72


features and Components

front & baCK views

HEATING LOOP

RETURN LINECONNECTION

3/4 INCH NPT

DRAIN VALVE

TEMPERATURE

PRESSURERELIEF VALVE

FRONT VIEW BACK VIEW

EXHAUST ELBOW(2 INCH PVC VENT

CONNECTION)

CONDENSATEDRAIN CONNECTION

BLOCKED EXHAUSTSWITCH SENSING TUBE

HEATING LOOPSUPPLY LINE

CONNECTION

3/4 INCH NPT

2 INCH PVC

INTAKE AIRCONNECTION

TOP COVER

ON / OFF SWITCH

UIM(user interface module)

CONTROL INTERFACECOVER.

TEMPERATUREPROBE - LOCATED

BEHIND CONTROLINTERFACE COVER

TANK GLASSING

PLUG COVER.USED FOR

MANUFACTURINGPURPOSES ONLY.

DO NOT REMOVEGLASSING PLUG

FOR ANY SERVICEOR MAINTENANCE.

COVER MAY BEREMOVED IF LEAK

IS SUSPECTED.

Figure 3


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top view

BLOWER

PROVER

SWITCH

CCB ENCLOSURE

(central control board)

3/4 INCH NPT

WATER OUTLET

WITH OUTLET

ANODE ROD

3/4 INCH NPT

WATER INLET

BLOCKED

EXHAUST

SWITCH

TEMPERATUREPRESSURE

RELIEF VALVE

BURNER

SIGHT GLASS

FRONT

1/2 INCH

SUPPLY GAS

CONNECTION

BLOCKED

INTAKE AIR

SWITCH

COMBUSTION

BLOWER

2 INCH PVC

INTAKE AIR

CONNECTION

2 INCH PVC

VENT CONNECTION

JUNCTIONBOX - 120 VAC

POWER SUPPLY

CONNECTIONS

SECOND

ANODE ROD

Figure 4

Combustion blower & burner assembly

COMBUSTION

BLOWER

EXPLODED VIEW

GASKET(SILICONE)

BLOWER

DISCHARGE

ORIFICE

GASKET

(FIBER)

BURNER SIGHT

GLASS AND

WIRING HARNESS

COVER PLATE

GASKET (SILICONE)

GASKET

GASKET (FIBER)

GASKET (FIBER)

BURNER SIGHT GLASS

BURNER

ADAPTER

BURNER ADAPTER

WIRING HARNESS.

IGNITER/FLAME

SENSOR

IGNITER

BURNER

BURNER FLANGE

(FLOATING FLANGE)

FLAME

SENSOR

GAS VALVE

VENTURI ASSEMBLY

INTAKE AIR

ELBOW

ASSEMBLED VIEW

Figure 5


12/72


OPERATION AND SERvICE

how it worKs

This secti f the maal will cver perati, cmm service prceres a water heater cstrcti.The water heater cvere i this maal has a helical shape cil heat echager that is sbmerge ithe strage tak. These water heaters se a tp mte w re raial esig Brer. This is a frce

raft brer; ht brig gases are frce thrgh the heat echager er pressre a eit thrgh theehast/vet cecti lcate at the bttm f the water heater.

Startig at the tp air a fel gas are raw i b the Cmbsti Blwer a Vetri, see CmbstiBlwer page 11aVetri page 22. Fle gases a are frce thrgh the helical shape heat echagerb the Cmbsti Blwer a t thrgh the ehast/vet tlet, see Figre 6 belw.

BLOWER/BURNER

GAS VALVE

ASSEMBLY

COMBUSTION

AIR INTAKE

CONNECTION

HELICAL SHAPE

HEAT EXCHANGER

ARROWS SHOW

PATH OF FLUE

GASES THROUGH

THE HEAT

EXCHANGER

EXHAUST/VENT

OUTLET

INTERNAL VIEW

Figure 6


13/72


Combustion blower

The Cmbsti Blwer is a assembl that icles the blwer hsig, blwer mtr a a electricspee ctrl. The Cmbsti Blwer is ctrlle b the CCB (Cetral Ctrl Bar), see Ctrl Sstem

Harware page 37.

The CCB ses 120 VAC frm the J2 scket the CCB circit bar t a 3 pi wirig scket the blweassembl, see CCB Circit Bar Lat page 41 a Figre 7 belw. The CCB als ses a PWM (PlseWith Mlati) sigal frm the J13 scket t a 5 pi wirig scket the assembl. The PWM sigal isa electric istrcti t start, stp a ctrl blwer spee.

The Cmbsti Blwer rs at higher spees rig the Pre/Pst Prge peratig states a rs at alwer spee rig the Igiter Warm up peratig state, see Table 6 page 48 fr a list f peratig states

The Igiter Stats ic is isplae the Ctrl Sstem LCd rig the Igiter Warm up peratig statesee Table 5 page 47.

sc n:

The 5 pi PWM sigal plg MuST remai plgge i t the 5 pi scket the blwer assembl at all timesdiscectig this plg will case the Cmbsti Blwer t r at maimm spee ctisl. This ma

case rgh starts, rgh perati a/r the Ignition Failure falt citi a Ctrl Sstem lck tIf the electric spee ctrl is fctiig prperl Cmbsti Blwer spee shl ticeabl recerig the Igiter Warm up peratig state. If blwer spee recti es t ccr rig the Igiter Warm

up peratig state esre the 5 pi plg frm the CCB is secrel plgge it the matchig 5 pi scket the blwer assembl a that the J13 plg is secrel plgge it the J13 scket the CCB circit barPerfrm a clse visal ispecti f the pis isie the plgs a sckets at the Cmbsti Blwer a theCCB, replace a wr r amage wirig haresses as ecessar.

BLOWER MOTOR

AND ELECTRONIC

SPEED CONTROL

COMBUSTION BLOWER ASSEMBLY

BLOWER

HOUSING

3 PIN

WIRING

SOCKET

5 PIN

WIRING

SOCKET

Figure 7


14/72


burner assembly

The Brer is a raial esig brer with a steel ber jacket the ter srface a is part f a larger BrerAssembl. Figre 8 a Figre 9 belw shw sie views f the cmplete Brer Assembl remve frm

the water heater with ke cmpets ietie. See the eple view f the Cmbsti Blwer & BrerAssembl page 9 als.

BURNER ADAPTER

WIRING HARNESS

IGNITER/FLAME

SENSOR

BLOWER

FLANGE

BURNER

ADAPTER

BURNER

FLANGE &

GASKET

BURNER

BURNER ASSEMBLY

RIGHT SIDE VIEW

FLAME

SENSOR

Figure 8

BURNER ADAPTER

WIRING HARNESS

IGNITER/FLAME

SENSOR

BLOWER

FLANGE

BURNER

ADAPTER

BURNER

FLANGE &

GASKET

BURNER

BURNER ASSEMBLYLEFT SIDE VIEW

IGNITER

Figure 9


15/72


BURNER GROUND

WIRE

BURNER

ADAPTER

BLOWER FLANGE WITH BLOWER

DISCHARGE ORIFICE IN PLACE

BURNER ADAPTER

WIRING HARNESS

IGNITER/FLAME SENSOR

Figure 10

BURNER SIGHT

GLASS

BURNER ADAPTER

WIRING HARNESS

IGNITER/FLAME

SENSOR

BLOWER

DISCHARGE

ORIFICE

BLOWER FLANGE WITH

ORIFICE REMOVED

Figure 11

BLOWER

DISCHARGE

ORIFICE

BLOWER

FLANGE

WIRING

HARNESS

GROMMETBURNER

ADAPTER

BURNER ADAPTER

WIRING HARNESS

IGNITER/FLAME

SENSOR

Figure 12


16/72


Combustion blower and burner removal

The Cmbsti Blwer a Brer Assembl mst be remve t ispect the Brer a t service the FlameSesr a Igiter. This secti will prvie istrctis hw t remve a ispect these cmpets.

Service Ntes:

There are fr 1/8 ich he hea machie screws that hl the Cmbsti Blwer t the BlwerFlage the Brer Aapter. There are fr 1/2 ich threae sts a ts that hl the Brer

Aapter t the Heat Echager Flage tp f the water heater strage tak. There are fr 5/16 ich

he hea machie screws that hl the Brer t the Brer Aapter. All three f these cectis have gaskets. The Cmbsti Blwer gasket is a rage silice

gasket place betwee the Cmbsti Blwer tlet a the Blwer Flage tp f the BrerAapter. There is a white ber gasket betwee the Brer Aapter a the Heat Echager Flage tp f the water heater. There is als a white ber gasket betwee the Brer a the Brer Aapter.

See the eple view f the Cmbsti Blwer & Brer Assembl page 9 a Figre 13 belw.

Befre remvig the Cmbsti Blwer a/r Brer Assembl esre there are ew gaskets ha fr all these cectis. Call the tll free phe mber the back cver f this maal t rerthese parts. Have the cmplete Mel, Series a Serial mber (lcate the water heater's ratig

label) fr the water heater beig service ha befre callig.

d t place a screws, sts, ts, parts r tls tp f the water heater whe remvig theCmbsti Blwer a/r Brer Assembl. Place these a a ther lse bjects i a safe lcatirig these prcere. Small parts a tls ca easil fall w it the heat echager rig these

prceres a ma be etremel ifclt r t retrieve. See Figre 6 page 10.

Esre the Brer gr wire is secre prperl whe ishe. The Brer mst be gre fr thectrl sstem t prve ame. Failre t gr the Brer prperl will case a Ignition Failure faltciti a Ctrl Sstem lck t, see Flame Sesig operati page 18.

ORANGE SILICONE GASKET BETWEEN THE COMBUSTION

BLOWER AND THE BLOWER FLANGE ON THE BURNER ADAPTER

WHITE FIBER GASKET BETWEEN THE BURNER ADAPTER AND THE

THE HEAT EXCHANGER FLANGE ON TOP OF THE STORAGE TANK

Figure 13

Combustion blower removal

1. If the water heater is i a heatig ccle lwer the operatig Set Pit t e the ccle, see Temperatres

page 49.

2. Tr ff pwer t the water heater at the water heater's /ff switch.

3. Tr ff the circit breaker that serves the water heater r plg the water heater appliace cr frmthe 120 VAC wall tlet if s eqippe.

4. discect the 3 pi plg frm the Cmbsti Blwer assembl, see Figre 7 page 11.

5. discect the 5 pi plg frm the Cmbsti Blwer assembl, see Figre 7 page 11.


17/72


6. discect the 24 Vlt pwer wires t the 24 Vlt Gas Valve at the tw spae cectrs i the wirigharess t the valve, see Figre 14 belw.

7. discect the Blwer Prver switch sesig tbe frm the Cmbsti Blwer tlet sesig prt, seeFigre 14 belw.

8. Tr ff the sppl gas t the water heater at the mai gas shtff valve servig the water heater.

9. discect the sppl gas lie t the water heater at the water heater's 24 Vlt Gas Valve.

10. If the water heater has bee istalle i a direct Vet cgrati, iscect the itake air pipe at the

itake air cecti the water heater, see Figre 14 belw.11. Lse the hse clamp clsest t the Vetri the Itake Air Elbw a remve the Itake Air Elbw

a Itake Air Cecti ttig as assemble it, see Figre 14 belw.

12. usig a small scket wrech with a 1/8 ich he attachmet r a lg (8-10) T hale 1/8 ich he (alle

ke) wrech remve the fr he hea machie screws that hl the Cmbsti Blwer t the BrerAapter, see Figre 15 page 16.

13. Lift the Cmbsti Blwer p a ff f the Brer Aapter, see Figre 15 page 16.

14. Remve the rage silice gasket.

15. Esre the Blwer discharge orice is preset a seate prperl tp f the Brer Aapter, see

Figre 10 page 13.

16. See the Service ntes belw fr aitial ifrmati.Combustion blower installation

17. T re-istall the Cmbsti Blwer fllw the steps fr remval i reverse rer.

18. Istall a ew rage silice gasket betwee the Cmbsti Blwer a the Brer Aapter.

19. d t vertighte the Cmbsti Blwer he hea screws rig istallati, trqe shl beapprimatel 3 ft lbs.

20. Restre pwer t the water heater a r it thrgh at least e cmplete heatig ccle befre leavigt esre it is peratig prperl.

INTAKE AIR CONNECTION FITTING

VENTURI

COMBUSTION BLOWER ASSEMBLY TOP VIEW

HOSE

CLAMP

INTAKE AIR

ELBOW

COMBUSTION BLOWEROUTLET SENSING PORT

24 VOLT GAS VALVE

WIRING HARNESS

SPADE CONNECTORS

SUPPLY GAS CONNECTION

24 VOLT GAS VALVE

COMBUSTION

BLOWER

Figure 14


18/72


Figure 15

burner assembly removal

1. Fllw the istrctis t remve the Cmbsti Blwer begiig page 14.

2. Remve the Blwer discharge orice frm the tp f the Brer Aapter.

3. uplg the Brer Aapter wirig haress; three male/female spae cectis fr the Igiter a

Flame Sesr behi the CCB eclsre, see Figre 10 page 13.

4. usig a scket wrech with a 1/2 ich eep well scket remve the fr 1/2 ich ts frm the sts

hlig the Brer Aapter i place, see Figre 16 page 17 a Figre 17 page 17.

5. Slie the Brer gr wire eelet cectr p a ff f the 1/2 ich st it is secre t. This gr

wire mst be pt back i place whe reistallig the Brer Assembl, see Figre 16 page 17.6. Esre there are t a lse parts, tls, screws r bjects f a ki tp f the water heater

befre remvig the Brer Assembl. If a lse bjects preset stre them i a ifferet lcati.

7. Carefll lift the Brer Assembl straight p a t f the water heater's heat echager peig, see

Figre 17 page 17.

8. Ispect the Flame Sesr a its ceramic islatr fr cracks a wear. Replace the Flame Sesr if itshws a sig f amage r ecessive wear, see Figre 19 page 19.

9. Esre the Flame Sesr is t tchig the Brer srface, the gap shl be apprimatel 1/2 ich.

10. Esre the Flame Sesr mtig screw is tight.

11.Alwas clea the ame sesr with ltra e steel wl while the Brer Assembl is t. d t se a

harsh abrasives sch as sa paper t clea the Flame Sesr.12. Ispect the Brer Aapter wirig haress a wirig haress grmmet, replace the wrig haress if it

shws a sig f ecessive wear r amage, see Figre 8 page 12 a Figre 12 page 13.

13. Ispect the Igiter. Replace the Igiter if it shws a sig f amage r ecessive wear.

14. Esre the Igiter mtig screw is tight.

15. Remve the fr 5/16 ich he hea machie screws hlig the Brer t the Brer Aapter aremve the Brer frm the Brer Aapter. See Figre 5 page 9.

16. Ispect the Brer. Esre there are t a ebris isie the Brer, see the Service ntes page 5.Replace the Brer if it is amage r clgge with ebris.


19/72


burner assembly installation

17. T re-istall the Brer Assembl fllw the steps fr remval i reverse rer.

18. Istall a ew white ber gasket betwee the Brer Aapter a the Heat Echager Flage tp the water heater. Istall a ew white ber gasket betwee the Brer a the Brer Aapter als. SeeFigre 5 page 9.

19. d t vertighte the 5/16 ich he hea machie screws hlig the Brer t the Brer Aapter rthe 1/2 ich ts that hl the Brer Aapter t the Heat Echager Flage tp f the water heater

strage tak.

20. Restre pwer t the water heater a r it thrgh at least e cmplete heatig ccle befre leavigt esre it is peratig prperl.

FOUR 1/2 INCH

NUTS AND STUDS

BURNER

GROUND

WIRE

BURNER SIGHT GLASS

WIRING HARNESS COVER

PLATE AND GASKET.

TWO PHILLIPS HEAD

SCREWS HOLD COVER

PLATE AND GASKET IN

PLACE.

Figure 16

Figure 17


20/72


flame sensor

Igiti f the Brer is ctrlle electricall. The priciple f perati fr electric igiti relies ame sesig crret t prve the fel gas wig t the Brer has bee igite a is brig safel.

Flame sesig reqires crrect pwer sppl plarit a a aeqate earth gr t the water heater's

Brer, see Electrical Reqiremets a the Pwer Sppl Test page 6. See Figre 16 page 17 fr theBrer gr wire lcati.

flame sensing operation

The Flame Sesr is a metal (cctr) r mte i a ceramic islatr. The Ctrl Sstem applies a AC vltage t the Flame Sesr thrgh a sigle wire.

The brer ame will cct a small amt f electrical crret.

The burnermust be gre fr crret t w frm the Flame Sesr t the Brer.

drig igiti the brer ame mst make cmplete a ctis ctact with the Flame Sesr.

As the AC vltage ws frm the Flame Sesr thrgh the brer ame t the (gre) Brer theAC vltage is "rectie" a becmes a dC vltage.

The crret wig betwee the Flame Sesr a Brer is dC micr amp crret epresse as: A.

Flame sesig crret ca be measre with a dC micr amp test meter, see Tls Reqire page 2.

IGNITER

BURNER

FLAME

BURNER(MUST BE GROUNDED)

CERAMIC INSULATOR

FLAME SENSOR

METAL CONDUCTOR

CONTROL SYSTEM

APPLIES AC VOLTAGETO FLAME SENSOR

AC VOLTAGE FLOWS FROM THE FLAME

SENSOR TO THE BURNER. THE BURNER

MUST BE GROUNDED FOR CURRENT TOFLOW. DURING THIS PROCESS THE AC

VOLTAGE IS RECTIFIED AND BECOMES

A DC VOLTAGE. DC MICRO AMP CURRENT

THEN FLOWS BETWEEN THE FLAME SENSOR

AND THE BURNER.

GAP BETWEEN THE FLAME SENSOR AND THE

BURNER SHOULD BE APPROXIMATELY 1/2 INCH

Figure 18

minimum flame sensing Current

T prve brer ame rig the Igiti Vericati state the Ctrl Sstem mitrs ame sesigcrret; the dC micr amp (A) crret wig thrgh the Flame Sesr. The Ctrl Sstem mst sese amiimm amt f crret t prve ame. The miimm ame sesig crret is 1.0 A. If ame sesigcrret es t reach 1.0 A rig igiti r falls belw this amt rig a heatig ccle the Ctrl

Sstem will immeiatel e-eergize the 24 Vlt Gas Valve.

After 3 faile trials fr igiti the Ctrl Sstem will lck t a ispla Ignition Failure (falt citi)

the LCd. If ame sesig crret rps belw 1.0 A rig a heatig ccle the Ctrl Sstem will e-eergize the 24 Vlt Gas Valve a eter the Iter-Prge peratig state, see operatig States page 48.

After the Iter-Prge peratig state the Ctrl Sstem will tr fr igiti agai if a call fr heat is still active,see the Seqece of operati page 54.


21/72


flame sensing Current test

drig the heatig ccle the ame sesig crret is rmall betwee 8.0 A a 12.0 A with a cleaFlame Sesr. over time the Flame Sesr will accmlate crrsi (rst) a this will rece ame sesig

crret. With heavier se, mre heatig ccles/greater la, crrsi will ccr mre qickl.

Measrig ame sesig crret reqires a test meter with a dC micr amp

fcti, see Tls Reqire page 2. The meters selectr is set t dC micramps. The tw test leas frm the meter are place i series with the ame sesigcircit. This ca be e at the spae (male/female) wirig cectrs behi the

CCB eclsre r at the J4 spae cecti the CCB circit bar. See Figre19 belw a the CCB Circit Bar Lat page 41.

T measre ame sesig crret tr ff pwer t the water heater a cectthe test meter fllwig e f the tw meths shw i Figre 19. Restre pwea esre a call fr heat is active - whe the Ctrl Sstem eergizes the 24 VlGas Valve the meter will measre ame sesig crret rig rmal perati.

FLAME SENSOR

CERAMIC INSULATOR

FLAME SENSING TEST BEHIND

THE CCB ENCLOSURE

FLAME SENSING TEST INSIDE

THE CCB ENCLOSURE

CCB J4 FLAME SENSOR

CONNECTION

IGNITER/FLAME SENSOR

WIRING HARNESS FROM CCB

WIRE FROM

FLAME SENSOR

WIRE FROM

FLAME SENSOR

Figure 19

Service Ntes:

The Flame Sesr wire behi the CCB is e f three wires i a haress that als serves the Igiter.Esre have ietie the crrect wire befre perfrmig a ame sesig test t prevet amage tthe test meter. A female spae cectr is se at the e f the wrig haress frm the CCB fr the

Flame Sesr, tw male cectrs are se fr the Igiter.

The mst cmm case fIgnition Failure lck t is a crre Flame Sesr. Rst/crrsiwill accmlate the Flame Sesr ver time. The Flame Sesr shl be ispecte a cleaeatime the measre ame sesig crret is belw 8 A r the Brer has bee remve. Clea

the Flame Sesr with ltra e steel wl. do noT se a carse abrasive material sch as sapaper. Ispect the ceramic islatr the Flame Sesr fr cracks, replace the Flame Sesr if itis amage. The Cmbsti Blwer a Brer mst be remve t access the Flame Sesr, seeCmbsti Blwer a Brer Remval page 14.

A pe ame sesig circit case b iscecte r lse cectrs ca als case igitifailre. Check the spae cectr behi the CCB eclsre a check all wirig a wirigcectis betwee the Flame Sesr a the J4 cectr CCB circit bar, see CCB CircitBar Lat page 41.

The Brer t beig gre will case Ignition Failure - see Electrical Reqiremets page 6 a

Figre 16 page 17. Esre the water heater a the Brer are prperl gre.


22/72


igniter

The water heaters cvere b this maal se a ht srface igiter (HSI). The Igiter is mae f a ceramiccmpsite material, see Figre 20 belw. The Ctrl Sstem pwers the Igiter (120 VAC) frm the J5

Scket the CCB. The Ctrl Sstem mitrs amperage thrgh the Igiter t esre it is ht egh tigite the fel gas wig t the Brer rig igiti. The amt f Igiter amperage is prprtial t itsheat tpt; the higher the amperage is, the higher the srface temperatre f the Igiter will be.

Figure 20

The Ctrl Sstem is prgramme t verif a miimm f 0.5 AC amps rig the Igiter Warm up peratigstate, see operatig States page 48. If the crret es t reach 0.5 amps rig warm p the Ctrl

Sstem will lck t a ispla Low Igniter Current falt citi the LCd. See the Seqece ofoperati page 54.

Igiters are wearig parts, ver time ht srface igiters will wear t a mst be replace as the will lger geerate egh heat t case igiti. The life f the Igiter is irectl tie t sage; the mberf heatig ccles. Csier rasig the differetial settig t rece the mber f heatig ccles if freqet

Igiter failre ccrs, see operatig Set Pit A differetial Ajstmet page 49.

With age a wear the resistace f the Igiter, measre i hms, will rise. As the resistace rises the

electrical crret wig thrgh the Igiter ecreases a s es the Igiter's srface temperatre. newIgiters will geerall measre betwee 90 a 120 hms at 77 F (25 C). The acceptable resistace fr aIgiter shl be less tha 200 hms. Measrig resistace is a sefl test t verif if the Igiter is lgerwrkig at all; IE: if the measre resistace is a pe circit, iite hms, the Igiter mst be replace.

Hwever, the resistace f the Igiter varies with temperatre a with the test meter beig se. Becasef these variables the mst reliable el test is t measre crret rig the Igiter Warm up peratig statet verif Igiter crret is abve the Ctrl Sstem's reqire miimm f 0.5 AC amps.

igniter Current test

1. usig a clamp stle amp meter, clamp the jaws f the amp meter ar e f the tw Igiter wires at

the J5 Scket the CCB r behi the CCB eclsre where the wirig haress frm the CCB cectst the Brer Aapter wirig haress. See CCB Cver Remval A Replacemet page 40, CCB CircitBar Lat page 41 a Figre 21 page 21.

2. Esre a call fr heat is active, raise the operatig Set Pit r mp water at a earb tre.

3. Esre the desktp Scree is visible the Ctrl Sstem's LCd, see desktp Scree page 46.

4. Recr Igiter amperage rig the Igiter Warm up peratig state. The Cmbsti Blwer spee willticeabl rece jst befre the Igiter is eergize a a aimate lightig blt Stats Ic appears the desktp Scree, see Stats Ics page 47.

5. If the Igiter crret is less tha 0.5 r zer amps, check all wrig a cectis betwee the J5Scket the CCB a the Brer Aapter wirig haress behi the CCB. Tr ff pwer a check the

resistace t the Igiter at the tw Igiter wires frm the Brer Aapter wirig haress behi the CCB.Esre the tw Igiter wires are se fr this test, the Igiter wires frm the Brer Aapter will bth be"female" spae cectrs. If it is a pe circit, iite resistace, remve the Cmbsti Blwer aBrer Assembl t ispect the Igiter a the Brer Aapter wirig haress. Replace the Igiter a/

r Brer Aapter wirig haress if ecessar. See Cmbsti Blwer a Brer Remval page 14.


23/72


IGNITER CURRENT TEST AT J5 SOCKET ON CCB

IGNITER CURRENT TEST BEHIND CCB ENCLOSURE

Figure 21

Service Ntes:

The aimate lightig blt Stats Ic is visible the LCd desktp Scree rig the Igiter warm p

peratig state. See desktp Scree page 46 a Stats Ics page 47. As a visal crmati that miimm Igiter crret is preset the Ctrl Sstem will ispla a checkmark et t the lightig blt ic the desktp Scree rig the Igiter Warm up peratig state.

Esre the wirig a cectis betwee the J5 Scket the CCB a the Brer Aapter are tbrke, piche r iscecte.

Esre there is apprimatel 120 VAC at the J5 Scket the CCB rig Igiter Warm up.

It is a g practice t check igiter crret whe a service r maiteace is beig perfrme.Igiter crret will be apprimatel 0.60 t 0.70 AC amps whe the Igiter is ew. Becase ht srface

igiters are wearig parts the ca case itermittet igiti failre with age a wear. Replacig theIgiter whe crret is lwer tha 0.55 AC amps is a g prevetive maiteace prcere that caprevet lss f ht water a cstmer issatisfacti.


24/72


venturi

A Vetri is mte the ilet f the Cmbsti Blwer. All cmbsti air ws thrgh the Vetri. Thetlet f the 24 Vlt Gas Valve cects irectl t the sie f the Vetri. Fel gas ws frm the tlet f

the 24 Vlt Gas Valve it the sie f the Vetri irectl.

Isie the Vetri there is a ce shape restrictr that cstricts the air passage t the Cmbsti Blwerilet. As air eters the cstricti pit its velcit icreases. A pressre rp ccrs at this pit acreates a egative pressre i the cavit betwee the ce shape restrictr a the Vetri hsig. Thisegative pressre plls gas frm the tlet f the 24 Vlt Gas Valve it the Cmbsti Blwer where it is

mie with cmbsti air a the spplie t the Brer. See Figre 22 belw.

This gas fee sstem es t prce a tpical maifl gas pressre t the Brer. The maifl (ffset)

gas pressre, gas pressre t the Brer, is ver lw. See Gas Pressre page 25.

Negative Pressure

Negative Pressure

Velocity Increases

At Constriction Point

Pressure Drops

GA

S

VAL

VE

Combustion Air

VENTURI

VENTURI INLET

GAS INLET24 VOLT GAS VALVE

BLOWER

BLOWER

SUPPLY GAS

BURNER

Figure 22


25/72


gas valve

The 24 Vlt Gas Valve these water heaters is dC vltage valve. The CCB ses 24 VAC t the valve athe AC vltage is rectie it a dC vltage b electrics ctaie isie the plg e f the 24 Vlt Gas

Valve wirig haress, see Figre 23 belw.

VENTURI

24 VOLT GAS VALVE ASSEMBLY TOP VIEW

24 VAC FROM THE J6 SOCKET

ON THE CCB CONNECTS TO

THESE TWO SPADE TERMINALS

AT THE END OF THE 24 VOLT

GAS VALVE WIRING HARNESS.

SUPPLY GAS CONNECTION

24 VOLT GAS VALVE

PLUG RETAINING

SCREW

24 VOLT GAS VALVE

WIRING HARNESS

24 VOLT GAS VALVE WIRING

HARNESS PLUG. 24 VAC

FROM CCB IS RECTIFIED TO

24 VDC BY ELECTRONICS

INSIDE THE PLUG END.

COMBUSTION

BLOWER

Figure 23

gas valve voltage tests

1. Check fr 24 VAC spplie t the 24 Vlt Gas Valve at pis 2 a 15 f the J6 Plg the CCB, see

CCB Cver Remval A Replacemet page 40 a CCB Circit Bar Lat page 41. usig a"AC" vlt meter isert the tw test prbes it pis 2 a 15 f the J6 Plg the CCB rig theIgiti Vericati r Heatig peratig states, see Figre 24 belw. 24 VAC shl be preset. The

aimate gas valve Stats Ic is isplae the Ctrl Sstem LCd rig these peratig states

See operatig States page 48 a desktp Scree page 46.2. Check fr 24 VdC at the plg e f the 24 Vlt Gas Valve wirig haress rig the Igiti Vericati

peratig state. Lse the retaiig screw fr the 24 Vlt Gas Valve wirig haress plg a iscecthe plg, see Figre 23 abve. La the plg e psie w a at srface. usig a "dC" vlt meteisert the tw test prbes it the tw tsie plg sckets, see Figre 24 belw. 24 VdC shl be

preset.

AC VOLTAGE TEST DC VOLTAGE TEST

Figure 24


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gas valve removal

The tlet f the 24 Vlt Gas Valve is cecte b age irectl t the sie f the Vetri a is secre bthree - 5/32 he hea screws. A gas rice with gasket is tte it the gas valves tlet age, see Figre

25 a Figre 26 belw. The 24 Vlt Gas Valve mst be remve t ispect the gas rice. Esre there isa ew gasket ha befre remvig the valve. Call the tll free phe mber the back cver f thismaal t rer parts. Have the cmplete Mel, Series a Serial mber (lcate the water heater'sratig label) fr the water heater beig service ha befre callig.


page 49.


3. Lse the retaiig screw fr the wirig haress plg the valve a iscect the plg, see Figre23 page 23.


5. discect the sppl gas lie t the water heater at the water heater's 24 Vlt Gas Valve.

6. If the water heater has bee istalle i a direct Vet cgrati, iscect the itake air pipe at theitake air cecti the water heater.

7. Lse the hse clamp clsest t the Vetri the Itake Air Elbw a remve the Itake Air Elbwa Itake Air Cecti ttig as assemble it, see Figre 14 page 15.

8. Remve 3 gas valve mtig screws - 5/32 he hea machie screws, see Figre 25 belw.

9. Carefll lift 24 Vlt Gas Valve b ff f the Vetri.

10. Fllw these steps i reverse rer t reistall the 24 Vlt Gas Valve.

11. R the water heater thrgh a cmplete heatig ccle befre leavig t esre it is peratig prperl.

24 VOLT GAS VALVE

VENTURI

5/32 INCH

HEX WRENCH

GAS ORIFICE

& GASKET

Figure 25

GAS ORIFICE

GAS ORIFICE SIZES

NATURAL GAS: 0.191

PROPANE GAS: 0.162

GASKET

Figure 26


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gas pressure

The water heater cvere i this Service Maal is rate at 100,000 Bt/hr ipt. It is certie fr elevatisp t 10,100 feet (3,078 meters). Fr higher elevatis call the tll free spprt phe mber shw the

back cver f this maal fr techical assistace.

table 2

MAnIFoLd oFFSET PRESSuRE MInIMuM SuPPLy PRESSuRE MAxIMuM SuPPLy PRESSuRE

NATURAl GAS PROPANE GAS NATURAl GAS PROPANE GAS NATURAl GAS PROPANE GAS

0.24 W. C. (0.056 kPa) 0.17 W. C. (0.042 kPa) 3.5 W. C. (0.87 kPa) 8 W. C. (1.20 kPa) 14 W. C. (3.49 kPa) 14 W. C. (3.49 kPa) Maifl ffset pressres will var. See the Service ntes belw.

Service Ntes:

The maifl "ffset" gas pressre is factr set a cat be ajste i the el.

The maifl ffset gas pressre a the sppl gas pressre ca be measre at tw pressre test

prts the water heaters 24 Vlt Gas Valve, see Figre 27 belw. The maifl ffset pressre testprt is clsest t the Cmbsti Blwer, see Figre 28 page 26. There is a eele valve i each testprt that is pee/clse with a small sltte screwriver. Tr the eele valve cter-clckwise tpe the test prt valve a clckwise t clse it.

Maifl ffset gas pressre will r clse t 0 W.C. r lwer (i a vacm) epeig the crretperatig state, see operatig States page 48. This pressre will be csierabl lwer, -5.00 W.C.

t -7.50 W.C. rig the Pre- Prge a Pst-Prge peratig states whe the Cmbsti Blwer isrig at high spee a the 24 Vlt Gas Valve is clse, see Vetri page 22.

Whe the 24 Vlt Gas Valve pes gas eterig the Vetri will case a rise i maifl ffset gaspressre. Maifl ffset gas pressres will tpicall be +0.24 W.C. atral gas mels a +0.17W.C. prpae gas mels rig the Heatig peratig state. Keep i mi these pressres areapprimate a will var epeig the eqivalet legth f the vet a/r itake air pipe istalle.

There is sall a rp i sppl gas pressre tice whe the water heaters 24 Vlt Gas Valve pesrig igiti. Seeig a crrespig rise i maifl ffset pressre rig igiti crms the valveis peig a gas is wig t the Brer, see Gas Flw Test page 27.

A sstaie rp i sppl gas pressre f 1.5" W.C. r mre rig igiti ma iicate the sppl

gas lie is ersize. If the water heater is eperiecig a sstaie rp i sppl gas pressre f

1.5" W.C. r mre a the water heater is eperiecig repeate Ignition Failure falt citis,itermittet lss f ame r rgh startig esre the sppl gas lie is size i accrace with thecrret eiti f natial Fel Gas Ce (AnSI Z223.1/nFPA 54) r the natral Gas a Prpae

Istallati Ce (CAn/CSA B149.1).

VENTURI

SUPPLY GAS

CONNECTION

PRESSURE

TEST PORTS

COMBUSTION

BLOWER

CONNECTION

24 VOLT GAS VALVE

COMBUSTION

AIR INLET

Figure 27


28/72


gas pressure test

1. If the water heater is i a heatig ccle lwer the operatig Set Pit t e the ccle, see Temperatres page 49.



4. ope the maifl ffset a sppl gas pressre test prts the 24 Vlt Gas Valve, see Figre 28 belw.Tr the eele valve sltte heas 1/2 t 1 fll tr cter-clckwise with a small sltte screwriver

t pe the valves.5. Attach a sesig tbe frm 2 igital mameters (see Tls Reqire page 2) t the tw gas pressre

test prts the valve b as shw i Figre 28 belw.

6. ope the mai gas shtff valve servig the water heater.

7. The mameter cecte t the sppl gas pressre test prt shl rea the "static" (gas is twig) sppl gas pressre.

8. Recr the sppl gas pressre.

9. Recr the maifl ffset pressre (shl be at r ear 0" W.C. - Cmbsti Blwer is ff).

10. Restre pwer - a raise the operatig Set Pit t iitiate a heatig ccle.

11. Recr the maifl ffset pressre whe the Cmbsti Blwer starts a ramps p t high spee

rig the Pre-Prge peratig state (shl be i a eep vacm; -5.00 W.C. t -7.50 W.C.)12. Retr the Ctrl Sstem LCd t the desktp Scree, see desktp Scree page 46.

13. Recr the maifl ffset pressre a the sppl gas pressre whe the Igiti Activati peratigstate begis; whe the aimate gas valve Stats Ic appears the desktp Scree.

The maifl ffset pressre shl rise t ear 0" W.C. as the 24 Vlt Gas Valve pes.

The sppl gas pressre will tpicall rp as the 24 Vlt Gas Valve pes.

Putting The Water Heater Back In Service

14. Lwer the operatig Set Pit t e the heatig ccle.

15. Clse the mai gas shtff valve servig the water heater.

16. discect mameter sesig tbes.

17. Clse the maifl ffset a sppl gas pressre test prts the 24 Vlt Gas Valve. Tr the eele

valve sltte heas clckwise til tight.

18. ope the mai gas shtff valve servig the water heater a check fr leaks at the gas valve test prts.

19. Restre pwer t the water heater a raise the operatig Set Pit t activate a call fr heat.

20. R the water heater thrgh a cmplete heatig ccle befre leavig t esre it is peratig prperl.

MANIFOLD OFFSET

PRESSURE TEST PORT

SUPPLY GAS

PRESSURE

TEST PORT

Figure 28


29/72


gas flow test

The fllwig illstratis shw the apprimate pressres fr the maifl ffset a sppl gas fr theStab, Pre-Prge a Heatig peratig states rig a rmal heatig seqece. ntice hw the maifl

ffset pressre starts at 0" W.C. i the Stab peratig state, falls t a eep vacm rig the Pre-Prgestate a the rises t a slight psitive pressre whe the 24 Vlt Gas Valve is eergize rig the Heatigstate. Als tice hw the sppl gas pressre remais cstat til the 24 Vlt Gas valve is eergize awhich pit it rps slightl.

Fllw the prcere t cect tw igital mameters t the 24 Vlt Gas Valve i the Gas Pressre Tes

page 26. observe the pressre chages rig the three peratig states liste i Figre 29 belw.

The rp i sppl pressre a crrespig rise i maifl ffset pressre, betwee Steps 2 a 3,

prves the 24 Vlt Gas valve is peig a that fel gas is wig thrgh the valve.

CONDITIONS:

COMBUSTION BLOWER OFF

24 VOLT GAS VALVE OFF

PRESSURE READINGS:

MANIFOLD OFFSET:

SUPPLY GAS:

0.00 W.C.

+8.41 W.C.

OPERATING STATE:

PRE-PURGE

OPERATING STATE:

STANDBY

OPERATING STATE:

HEATING

1

2

3

CONDITIONS:

COMBUSTION BLOWER ON

24 VOLT GAS VALVE OFF

PRESSURE READINGS:

MANIFOLD OFFSET:

SUPPLY GAS:

-5.33 W.C.

+8.41 W.C.

CONDITIONS:

COMBUSTION BLOWER ON

24 VOLT GAS VALVE ON

PRESSURE READINGS:

MANIFOLD OFFSET:

SUPPLY GAS:

0.07 W.C.

+7.75 W.C.

Figure 29


30/72


pressure switChes

The water heaters cvere i this maal are factr eqippe with three pressre switches. Figre 4 page 9 shws the lcati f the three pressres switches tp f the water heater. This secti f the

maal cvers pressre switch cstrcti, perati a the test prceres se t iagse peratialprblems assciate with pressre switches.

ConstruCtion & operation

Pressre switches activate i respse t chages i pressre the sese thrgh a plastic sesig tbe

cecte t sesig prts the water heater, see Sesig Tbes page 30.A iaphragm ivies the b f a pressre switch it tw chambers. The chamber the sesig prt is

attache t is seale. The ther chamber is vete t the atmsphere which allws the iaphragm t mvep a w. There is likage that attaches the switch ctacts t the iaphragm s that whe the iaphragmmves the ctacts are activate, see Figre 30 belw.

Activate meas t chage frm the rmal state. If the ctacts are rmall pe, activatig the ctactswill case them t clse. If the ctacts are rmall clse, activatig the ctacts will case them t pe.

Vent Port

Sensing PortFlexible Diaphragm

Wiring TerminalsSwitch Contacts

Normal State

(open switch contacts)

Activated State

(closed switch contacts)

Internal Linkage

Normal State Activated State

Blower Prover

Pressure Switch

Normally open contacts ,

close on a rise in pressure .

Blocked Exhaust

Pressure Switch

Normally closed contacts,

open on a rise in pressure .

Blocked Intake Air

Pressure Switch

Normally c losed contacts,open on a fall in pressure .

CONSTRUCTION

TYPES AND APPLICATION

Figure 30


31/72


Control system monitoring

The Ctrl Sstem mitrs the state f the pressre switch ctacts iiviall thrgh three separatecircits, see Wirig diagram page 44. The state f the switch refers t whether the switch ctacts are pe

r clse, see Cstrcti & operati page 28.

At the begiig f a heatig seqece, befre the Cmbsti Blwer is eergize, the Ctrl Sstem

eters the Ipt Vericati peratig state, see operatig States page 48. drig Ipt Vericati theCtrl Sstem mitrs all three pressre switches t esre their ctacts are i the crrect "rmal"state. The Blwer Prver switch ctacts mst be pe, the ctacts fr the Blcke Itake Air a Blcke

Ehast switches mst be clse, see Figre 30 page 28 a the Seqece of operati page 54.

If a f the pressre switch ctacts are t i their crrect rmal state rig Ipt Vericati the Ctr

Sstem will lck t a ispla a falt message the LCd iicatig which pressre switch case thefalt citi, see Figre 31 belw. If all sstem checks pass rig the Ipt Vericati peratig state theCtrl Sstem eters the Pre-Prge peratig state a eergizes the Cmbsti Blwer.

After the Cmbsti Blwer is eergize the Ctrl Sstem mst crm the Blwer Prver switch ctactshave clse, see the Seqece of operati Flw Chart page 55. The Blcke Itake Air a BlckeEhast switch ctacts mst remai clse at all times.

If the Blwer Prver switch ctacts are clse rig the Ipt Vericati the Ctrl Sstem will lck a ispla Blower Prover Failure the LCd. If the Blwer Prver switch ctacts t clse after the

Cmbsti Blwer is eergize the Ctrl Sstem will lck t a ispla Blower Prover Open the

LCd. If either the Blcke Itake Air r Blcke Ehast switch ctacts pe at a time rig a heatigseqece the Ctrl Sstem will lck t a ispla Blocked Air Intake rBlocked Exhaust the LCd

See Figre 31 belw.

CHANGE BACK ADVANCED

Blower Prover FailureFault occurred 2 mins ago

The blower prover switch is

closed out of sequence.

Call a service professional:

Your Company Name Here

(press [DOWN] for more....)


Blower Prover OpenFault occurred 2 mins ago

The blower prover switch remains

open after the blower has been

energized.





Blocked Air IntakeFault occurred 2 mins ago

The combustion air intake isrestricted.





Blocked ExhaustFault occurred 2 mins ago

The exhaust is blocked orrestricted. Ensure

condensate hose is draining.




PRESSURE SWITCH FAULT MESSAGES

Figure 31


32/72


Sensing Tubes

The three pressre switches mitr pressre thrgh plastic sesig tbes frm three ifferet sesigprts the water heater, see Figre 32 belw.

The Blwer Prver switch mitrs pressre frm the Cmbsti Blwer's tlet, see Figre 14 page 15.The Blcke Itake Air switch mitrs pressre frm the Cmbsti Blwers itake air cecti ttig,

see Figre 1 page 5. The Blcke Ehast switch mitrs pressre frm the ehast elbw the bttmf the water heater; there is a almim cectig tbe mte the sie f the water heater betweethe Blcke Ehast switch at the tp a the ehast elbw at the bttm. Tw shrt pieces f plastic

sesig tbe are se at either e f this almim tbe t cect t the pressre switch a the ehastelbw, see Figre 3 page 8.

These plastic sesig tbes mst be rte t the crrect sesig prts the water heater. Sesig tbertig shl alwas be checke wheeverBlower Prover Open, Blower Prover Failure, Blocked AirIntake rBlocked Exhaustis isplae the Ctrl Sstem LCd, see Figre 31 page 29. These "FaltCitis" ca be case b icrrect sesig tbe rtig.

BLOWER PROVER BLOCKED INTAKE AIR

PRESSURE SWITCH SENSING TUBE CONNECTIONS

BLOCKED EXHAUST BLOCKED EXHAUST

Figure 32


33/72


pressure switCh tests

Cmplete pressre switch testig ivlves three prceres:

Ctiit Test drig Stab belw.

Ctiit Test drig operati page 32.

Pressre Test drig operati page 32.

Continuity test during standby

This test is perfrme while the Cmbsti Blwer is t rig with the water heater tre ff. This is a"rmal state" ctiit test f the ctacts isie each pressre switch. discect the tw wires t each

pressre switch fr this test.


page 49.


3. discect bth wires at each pressre switch.

4. usig a hm meter set fr ctiit testig, check fr ctiit betwee the tw wirig termials ateach pressre switch, see Figre 33 belw.

Resuts/Actins

Passed Resuts: If the Blwer Prver switch ctacts are pe rig this test (iite hms/pe circit)the Blwer Prver switch has passe the test. If the Blcke Itake Air a Blcke Ehast switch ctactsare clse rig this test, (zer hms/irect shrt), these switches have passe the test.

Faied Resuts: If the Blwer Prver switch ctacts are clse (zer hms/irect shrt) rig this test, theBlwer Prver switch mst be replace. If the Blcke Itake Air a/r Blcke Ehast switch ctacts arepe rig this test, the switch(s) mst be replace.

Prcee t the Ctiit Test drig operati page 32.

Figure 33


34/72


Continuity test during operation

This test is perfrme while the Cmbsti Blwer is rig at high spee rig the Pre-Prge peratigstate. The test is perfrme all three pressre switches. discect the tw wires t each pressre switch

- e at a time, check ctiit a the recect the wires t that switch befre testig the et switch.

1. Esre pwer t the water heater is tre ff at the water heater's /ff switch.

2. Esre the sesig tbes frm each pressre switch are cecte t the crrect sesig prt thewater heater, see Sesig Tbes page 30.

3. discect the tw wires fr the switch t be teste.4. Whe testig the Blcke Ehast a Blcke Itake Air switches, cect a small jmper wire t the

shrt the tw wires iscecte. This will tempraril prevet the Ctrl Sstem frm lckig t rig

the test. Whe the test fr these tw switches is cmplete, remve the jmper wire a recect thepressre switch wirig befre mvig t the et switch.

5. Restre pwer t the water heater, if the water heater es t begi a heatig ccle raise the operatigSet Pit t activate a heatig ccle.

6. usig a hm meter set fr ctiit testig, check fr ctiit betwee the tw wirig termials at thepressre switch after the Cmbsti Blwer has starte a rampe p t high spee rig the Pre-Prge peratig state, see Figre 33 page 31. Recr the reslts; pe r clse.

7. Repeat this prcere fr each pressre switch.

8. Esre the wires t all pressre switches are rececte whe testig is cmplete.

Resuts/Actins

Passed Resuts: If the Blwer Prver switch ctacts activate/clse (zer hms/irect shrt) rig this testthe switch has passe this test. If the Blcke Itake Air a Blcke Ehast switch ctacts remai clse

rig this test, (zer hms/irect shrt), these switches have passe the test.

Faied Resuts: If the Blwer Prver switch ctacts t clse rig this test, the Pressre Test drig

operati belw mst be perfrme t etermie if the switch is efective. If the Blcke Itake Air rBlcke Ehast switch ctacts pe rig this test, the Pressre Test drig operati belw mst beperfrme t etermie if the switch(s) is efective.

Prcee t the Pressre Test drig operati belw.

pressure test during operation

This test will be perfrme while the Cmbsti Blwer is rig at high spee rig the Pre-Prge

peratig state. This test is ecessar whe a pressre switch has passe the Ctiit Test drig Stab page 31 bt has faile the Ctiit Test drig operati abve t etermie if the pressre switch isefective r t. This test reqires a igital mameter, see Tls Reqire page 2.

Service Ntes:

Befre perfrmig this test eamie the sesig tbe cectis the water heaters sesig prts

a the pressre switch. Check fr wear, cracks, leaks, kiks, r a ki f ebris r cesate ithe sesig tbes, repair/replace as ecessar.

T etermie if a pressre switch is peratig prperl mst rst kw the "switch acti" (whether

the switch activates a rise r a fall i pressre) a the "activati pressre" the switch will activateat. Activati pressres are prvie i Table 3 page 33. Switch actis are as fllws:

Blwer Prver switch - rmall pe ctacts, clse a rise i pressre.

Blcke Itake Air switch - rmall clse ctacts, pe a fall i pressre.

Blcke Ehast switch - rmall clse ctacts, pe a rise i pressre.

Activatin Pressures

Table 3 page 33 shws the activati pressres a tlerace fr each f the three pressre switches. A+ sig befre the pressre iicates a psitive pressre; abve atmspheric pressre. A - sig befre thepressre iicates a egative pressre (i a vacm); belw atmspheric pressre. Tleraces are specie

t allw reasable leewa fr imperfectis a iheret variabilit witht cmprmisig perfrmace.


35/72


table 3

b p bck ik a Bcked Exhaust

Activati Pressre +0.75" W.C. -2.00" W.C. +2.00" W.C.

Tlerace 0.05" W.C. 0.05" W.C. 0.05" W.C.

Thgh it is cmm, pressre switch specicatis ca be chage b the mafactrer. These activati pressres arecrret as f the (mth/ear - epresse as MM/yy) ate ce prite the frt cver f this maal i the lwer left crer.

If the accrac f these specicatis are i bt call the tll free spprt phe mber the back cver f this maal tverif.

Pressure Test:

1. Esre pwer t the water heater is tre ff at the water heater's /ff switch.

2. discect the sesig tbe frm the switch beig teste.

3. Cect a igital mameter t the sesig tbe iscecte abve r cect a lger mameter

sesig tbe t the prt the water heater if eee, see Figre 32 page 30 a Figre 34 page 34

4. Restre pwer t the water heater, if the water heater es t begi a heatig ccle raise the operatig

Set Pit t activate a heatig ccle.

5. Whe the Cmbsti Blwer cmes a ramps p t fll spee, recr the pressre reaig.

6. Repeat this test fr all three pressre switches as ecessar.

7. Cmpare the pressre reaigs take t the activati pressres i Table 3 abve.8. Esre all sesig tbes are prperl rte a rececte whe testig is cmplete, see Sesig

Tbes page 30.

Resuts/Actins

b p: If the pressre reaig take at the Blwer Prver switch sesig tbe is at r abve the

activati pressre shw i Table 3and the switch ctacts i t clse rig the Ctiit Test drigoperati page 32 - the switch is efective a mst be replace. If the pressre reaig take es reach r rise abve the activati pressre i Table 3 the pressre switch is not efective a shl be replace - call the tll free phe mber the back cver f this maal fr frther techical assistace

Have the cmplete Mel, Series a Serial mber (lcate the water heater's ratig label) fr the wateheater beig service ha befre callig.

bck ik a: nte these are egative pressres; i a vacm. If the pressre reaig take at theBlcke Itake Air switch sesig tbe es t reach r rp lwer tha the pressre shw i Table 3and the switch ctacts were peig rig the Ctiit Test drig operati page 32 - the switchis efective a mst be replace. If the pressre reaig take reaches r rps lwer tha the pressre

shw i Table 3 a the switch ctacts were peig rig the Ctiit Test drig operati page32 - the switch is not efective a shl t be replace. Check fr restrictis at the itake air cecti the water heater, check fr t small f pipe istalle, t ma eqivalet feet a/r t ma elbws i

the itake air pipig. Check fr lw pits i the itake air pipig where water ma be cllectig a blckigthe itake air pipig. Check fr a restrictis r ebris at the itake air termiati trs. Check frcesate/water i the sesig tbe/switch, if the sesig tbe has water i it, replace the Blcke Itake

Air switch a the tbe. Esre the sesig prt is riete prperl, see Itake Air Cecti page 5.

Bcked Exhaust: If the pressre reaig take at the Blcke Ehast switch sesig tbe es t reachr rise abve the activati pressre give i Table 3and the switch ctacts were peig rig the

Ctiit Test drig operati page 32 - the switch is efective a mst be replace. If the pressrereaig take reaches r ecees the pressre shw i Table 3 a the switch ctacts were peigrig the Ctiit Test drig operati page 32 - the switch is not efective a shl t be

replace. Esre the cesate rai cecte t the ehast elbw the water heater is t clggea is raiig freel. Check fr restrictis r blckage i the vet pipe, check fr t small f pipe istallet ma eqivalet feet a/r t ma elbws i the vet pipig. Check fr lw pits i the vet pipewhere water ma be cllectig a blckig the vet pipig. Check fr a restrictis r ebris at the ve

termiati trs.


36/72


BLOWER PROVER SWITCH

PRESSURE TEST

BLOCKED INTAKE AIR SWITCH

PRESSURE TEST

BLOCKED EXHAUST SWITCH

PRESSURE TEST

Figure 34


37/72


temperature probe

This secti f the maal prvies ifrmati theTemperatre Prbe, see Figre 3 page 8 fr lcati. The

Temperatre Prbe ctais the ECo (eerg ct t) aa Temperatre Sesr. The Temperatre Prbe cects tthe J7 Scket the CCB, see CCB Circit Bar Lat

page 41 a CCB Cecti Ieticati page 42

eCo high temperature limit switCh

The ECo (eerg ct t) is a high temperatre limit switchesige t prtect agaist ecessivel high water temperatres isie the water heater's strage tak. TheECo is a rmall clse switch that pes a rise i temperatre. The ECo switch is lcate isie the

Temperatre Prbe (tw re wires). The ECo temperatre settig is ajstable; the ctacts pe a201F (94C) a will clse at apprimatel 140F (60C).

The Ctrl Sstem cstatl mitrs the state f the ECo switch ctacts. If the ECo activates (ctactspe) e t abrmall high water temperatre the Ctrl Sstem will lck t a ispla Energy CuOut (ECO) the LCd.

Shl the ECo activate, the water temperatre mst rp belw 140F (60C) befre the Ctrl Sstemca be reset. oce the water temperatre has cle belw this pit the pwer sppl t the water heater

mst be tre ff a agai t reset the Ctrl Sstem.temperature sensor

The Temperatre Sesr lcate isie the Temperatre Prbe is a thermistr (tw black wires). Thermistrsare thermall sesitive resistrs. As the water temperatre rises the resistace (measre i hms) f thesesr will ecrease; as the temperatre falls the resistace will icrease - see Table 4 page 36.

The Ctrl Sstem iterprets chages i the temperatre sesr resistace as chages i water temperatrea ses this ata t activate a eactivate heatig ccles a isplas this temperatre i the Ctrl

Sstem mes, see desktp Scree page 46 a Temperatres Me page 50.

The Ctrl Sstem cstatl mitrs the Temperatre Sesr. The Ctrl Sstem is prgramme t

eclare a falt citi if the resistace f the temperatre sesr rps belw 390 hms (shrte) r abve56,000 hms (pe).

If the resistace f the Temperatre Sesr is belw 390 hms the Ctrl Sstem will lck t a isplaTemp Probe Short the LCd. If the resistace f the temperatre sesr is abve 56,000 hms theCtrl Sstem will lck t a ispla Temp Probe Open the LCd. The pwer sppl t the water

heater mst be tre ff a agai t reset the Ctrl Sstem. nte; the Ctrl Sstem will t reseless the citi has bee crrecte.

temperature sensor test


2. Remve the tp cver the water heater, see Figre 3 page 8.

3. discect the fr pi plg/scket cecti frm the Temperatre Prbe tsie the CCB eclsre the left, see Figre 35 page 36.

4. usig a hm meter: set the hm meter rage t a scale jst abve 30,000 hms.

5. Check resistace betwee the tw isie pis (black wires) f the plg e frm the Temperatre Prbe

see Figre 35 page 36. Cmpare the measre resistace t the vales give i Table 4 page 36Temperatre Prbes are ver reliable a shl l be replace whe:

The resistace is abve 56,000 hms (pe) r belw 390 hms (shrte).

The atre f the service prblem is temperatre ctrl a the resistace reaigs arecsierabl ( 25%) ifferet tha the vales i Table 4 page 36 at the give temperatre.


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TABlE 4

water temperature temperature sensor

resistanCe in ohmsCelsius fahrenheit

3 40 26,435

21 70 11,974

38 100 5,862

49 120 3,780

55 130 3,06660 140 2,503

71 160 1,698

82 180 1,177

eCo Continuity test


2. Remve the tp cver the water heater, see Figre 3 page 8.

3. discect the fr pi plg frm the Temperatre Prbe tsie the CCB eclsre the left, see

Figre 35 belw.

4. Esre tak temperatre is less tha 100F (38C) - mp water t lwer tak temperatre if ecessar.5. usig a hm meter set the rage fr ctiit testig.

6. Check ctiit betwee the tw tsie pis (re wires) f the plg e frm the Temperatre Prbe,see Figre 35 belw.

Resuts/Actins

If the hm meter shws ctiit (clse circit) betwee the tw tsie pis (re wires) the ECoswitch has reset prperl. If the Ctrl Sstem cties t lck t isplaig Energy Cut Out(ECO) the LCd with ctiit thrgh the ECo preset call the tll free spprt phe mberliste the back cver f this maal fr frther assistace.

If the hm meter shws ctiit (pe circit) betwee the tw tsie pis (re wires) a the

tak temperatre is kw t be at r belw 100F (38C) - replace the Temperatre Prbe. Fllwthe raiig a llig istrctis i the maiteace secti f the Istrcti Maal that camewith the water heater whe replacig the Temperatre Prbe.

If the Ctrl Sstem cties t lck t isplaig Energy Cut Out (ECO) the LCd a thewater temperatre isie the water heater is becmig ecessive (at r abve 201F/94C) checkwater sstem pipig; esre heat is t beig ae b a ther heatig appliaces r heat srces.If all these tests have bee perfrme a the Ctrl Sstem cties t lck t call the tll free

spprt phe mber liste the back cver f this maal fr frther assistace.

Figure 35


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Control system hardware

This secti f the maal will prvie ifrmati Ctrl Sstem harware , perati a serviceprceres. See Ctrl Sstem operati page 45 fr ifrmati Ctrl Sstem featres, avigati

mes, a ser settigs.

The water heaters cvere i this maal are eqippe with a electric Ctrl Sstem that reglateswater temperatre isie the strage tak. Heatig ccles a igiti are maage b the Ctrl SstemThe ECo (eerg ct t), Flame Sesr, pressre switches a Temperatre Prbe are mitre b theCtrl Sstem. The Cmbsti Blwer, Igiter a the 24 Vlt Gas Valve are all eergize b the Ctr

Sstem. See Featres A Cmpets page 8 fr the lcati f these cmpets.

Components

The mai cmpets f the Ctrl Sstem are a uIM (user Iterface Mle) a a CCB (Cetral CtrBar). The uIM is lcate the tp frt sie f the water heater, see Figre 3 page 8. The CCB ismte tp f the water heater isie a prtective eclsre, see Figre 4 page 9.

UIM (USER INTERFACE MoDUlE)

The uIMs majr cmpets icle a Circit Bar with LCd ispla a a Btt Pa overla whichctais the ve ser ipt btts. Figre 36 belw shws these cmpets that are lcate behi thectrl iterface cver the frt f the water heater.

UIM CIRCUIT BOARD BACK

J3 SOCKET - BUTTON

PAD COMMUNICATION

BUTTON PAD OVERLAY

J3 SOCKET - ENSURE

CABLE IS PLUGGED IN

EXACTLY AS SHOWN

UIM CIRCUIT BOARD FRONT

J2 SOCKET - CCB

COMMUNICATION

CAT V CABLE

LCD SCREEN

Figure 36


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uim ribbon Cable ConneCtion

Service Ntes:

The Ribb Cable that cects the Btt Pa overla t the uIM Circit Bar mst be plgge i eactlas shw i Figre 36 page 37. The metal crimp cectis i the Ribb Cable plg mst be facig awafrm the uIM circit bar. These metal crimp cectis are l visible e sie f the plg, see Figre37 belw. There are si at metal pis the uIM circit bar J3 scket. Esre all si pis are fll iserte

it the Ribb Cable plg wheever remvig r istallig the uIM r the Btt Pa overla.

It is pssible t cect the Ribb Cable Plg icrrectl. It ca be plgge i psie w (with the crimp

cectis facig the circit bar) r it ca be plgge i with less tha all si f the J3 scket pis iserteit the plg.

Failre t cect this Rib

Documents

A/O Smith Gas Water Heater Service Handbook