www.white-rodgers.com278

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Line VoltageLow Voltage

MV

MV

TR

TH

FP

GND

FlameSensorProbe Silicon

CarbideIgnitor

Black

Transformer25 VAC, 60 Hz

Thermostat

Hot NeutralGND

Line Voltage

50E47/50F47

Lim

it

Bla

ck

Whi

te

W R Common (“C”)

RedundantValve

MainValve

L

IGN

TYPICAL SYSTEM WIRING DIAGRAM

Terminal LegendMV – Main ValveTR – TransformerTH – ThermostatFP – Flame ProbeGND – Burner GroundL – LineIGN – Ignitor

HOT SURFACE IGNITIONSYSTEM (HSI)

TROUBLESHOOTINGGUIDE

50E47-1XX OR 50F47-1XXIGNITION/DETECTION CONTROL MODULEQualified Serviceman’s ALL HSI Troubleshooting GuideTROUBLESHOOTING PROCEDUREMODELS WITH DIAGNOSTIC LIGHT have self diagnostic capabilities. If the light on the module is on continuously, the fault is likely to be internal to the module. To make sure, interrupt line or 25 volt thermostat power for a few seconds and then restore. If internal fault is indicated again, and flame sensor is not shorted to ground, replace control. A flashing light indicates the problem is most likely in the external components or wiring. Proceed as follows:FOR ALL 50E47 OR 50F47 CONTROL MODULESThree Visual Checks�) The ignitor will warm up and glow red (see Chart �)2) The main burner flame will ignite (see Chart 2)3) The main burner flame will continue to burn after the ignitor is turned off (see Chart 3)

Troubleshooting the system consists of checking for these three visual indications. The following charts define the proper action if any of these indications do not occur.

!

-NOT FIELD REPAIRABLE-

REPLACE ONLY WITH

EXACT MODEL NUMBER.

EXPLOSION AND SERIOUS

INJURY COULD RESULT

WARNING

DISCONNECT POWER

BEFORE SERVICING

WARNING!Failure to read and follow all instructions carefully before in-stalling or operating this control, could cause personal injury and/or property damage.

WARNING!50E47 and 50F47 controls contain no serviceable parts – replace with exact model and type number to prevent a possible flame rollout and resulting injury.

WARNING!Turn power off before servicing.

Line voltage (�20 VAC) could be present on the surface of the ignitor, if the system is not correctly wired. Such voltage can cause serious injury or death.

The following 4 steps must be performed first before any troubleshooting begins.�) Disconnect electric power to system at main fuse or circuit breaker.2) Remove draft shield (if necessary to gain access to the ignitor.3) Visually inspect equipment for apparent damage. Check wiring for loose connections.4) Check for Reversed Polarity. (HSI models with diagnostic light are polarity sensitive and may lock out if �20 volt service wiring is reversed.) A. Disconnect the ignitor socket from the wiring harness. Connect an AC voltmeter across the terminal connected to the white wire and chassis ground. B. Re-connect electric power to system. If no voltage exists, polarity is correct; proceed to step 4D. C. If voltage exists between the terminal connected to the white wire and the chassis ground, the main power supply lines are improperly connected to the furnace (Reversed Polarity). Again disconnect electric power to the system; then reverse incoming line voltage leads and repeat step 4B. D. Re-connect the ignitor socket to the wiring harness. Re-check the system for proper operation.

If neither apparent damage, loose connection nor reversed polarity is the problem, proceed to the visual check chart (�st, 2nd or 3rd) that is suggested by the actual condition.

SYSTEMCOMPONENTS50E47/50F47-XXX Ignition Detection Control36EXX-XXX Redundant Gas Valve767A-XXX Silicon Carbide Ignitor760-XXX Sense ElectrodeF115-XXXX Harness

www.white-rodgers.com 279

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CH

AR

T 1

50E

47/5

0F47

FIR

ST

VIS

UA

L C

HE

CK

(Do

es ig

nit

or

glo

w b

rig

ht

red

?)

Doe

s si

licon

igni

tor w

arm

up

and

glow

brig

ht re

d af

ter p

repu

rge

dura

tion?

(see

mod

ule

labe

l)

Cal

l for

hea

t. The

rmos

tat

cont

acts

clo

se.

Go

to C

hart

2.

No

Yes

Is 2

5 vo

ltspr

esen

t acr

oss

seco

ndar

yof

tran

sfor

mer

?

Rep

lace

ope

n 25

vol

t lim

its o

rth

erm

osta

t. En

ergi

ze s

yste

man

d ch

eck

for p

rope

r ope

ratio

n.

Rep

lace

igni

tor.

Con

nect

ele

ctric

pow

er to

sys

tem

at m

ain

fuse

or

circ

uit b

reak

er.

Cor

rect

dis

cont

inui

ties

inig

nito

r har

ness

or c

onne

ctio

ns.

Ener

gize

sys

tem

and

che

ck fo

rpr

oper

ope

ratio

n.

NOTE

: All

volta

ge re

adin

gs +

10%

- 15

%

Con

nect

ohm

met

er a

cros

s IG

N&

L te

rmin

als

of m

odul

e.

Syst

em is

func

tioni

ng p

rope

rly.

Rep

lace

tran

sfor

mer

. Ene

rgize

syst

em a

nd c

heck

for p

rope

rop

erat

ion.

Rep

lace

ope

n lim

its o

r fus

es in

120

volt

supp

ly. E

nerg

izesy

stem

and

che

ck fo

r pro

per

oper

atio

n.

Is 1

20 v

olts

pres

ent a

cros

s pr

imar

y of

trans

form

er?

No

Yes

No

Yes

Ener

gize

sys

tem

.D

oes

igni

tor

deen

ergi

ze a

fter t

rial f

or ig

nitio

npe

riod?

(see

mod

ule

labe

l)

Doe

s co

ntin

uity

exis

t bet

wee

n IG

N &

Laf

ter p

repu

rge

dura

tion?

(see

mod

ule

labe

l)

Yes

No

No

Yes

Is 2

5 vo

ltspr

esen

t acr

oss

mod

ule

term

inal

s TH

& T

R?

No

Yes

Unp

lug

igni

tor f

rom

wire

harn

ess

and

conn

ect

ohm

met

er a

cros

s ig

nito

r lea

ds. I

sre

sist

ance

with

in e

quip

men

tm

anuf

actu

rer’s

spec

ifica

tions

?

Rep

lace

mod

ule.

Ene

rgize

syst

em a

nd c

heck

for p

rope

rop

erat

ion.

Con

nect

ele

ctric

pow

er to

syst

em a

t mai

n fu

se o

r circ

uit

brea

ker.

Ener

gize

sys

tem

.

Rep

lace

mod

ule.

Ene

rgize

syst

em a

nd c

heck

for p

rope

rop

erat

ion.

No

Yes

DIS

CO

NN

ECT

ELEC

TRIC

POW

ER T

O S

YSTE

M A

TM

AIN

FU

SE O

R C

IRC

UIT

BREA

KER

!

HOT SURFACE IGNITIONSYSTEM (HSI)

TROUBLESHOOTINGGUIDE

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HOT SURFACE IGNITIONSYSTEM (HSI)

TROUBLESHOOTINGGUIDE

CH

AR

T 2

50E

47/5

0F47

SE

CO

ND

VIS

UA

L C

HE

CK

(Do

es m

ain

bu

rner

ign

ite?

)

Doe

s m

ain

burn

er ig

nite

?

Go

to C

hart

3

No

Yes

Turn

man

ual k

nob

on g

as v

alve

to “O

N”

posi

tion.

Ene

rgize

sys

tem

.Is

out

let p

ress

ure

dete

cted

?

Turn

man

ual k

nob

on g

as v

alve

to “O

FF” p

ositi

on. C

onne

ctm

anom

eter

to o

utle

t pre

ssur

eta

p.

Purg

e sy

stem

of a

ir. En

ergi

zesy

stem

and

che

ck fo

r pro

per

oper

atio

n.

Is o

utle

tpr

essu

re a

t nam

epla

tera

ting?

Yes

No

Yes

Yes

No

Is m

anua

l kno

bon

gas

val

ve in

“ON

”po

sitio

n?

Yes

Turn

man

ual k

nob

on g

as v

alve

to “O

N” p

ositi

on. E

nerg

izesy

stem

and

che

ck fo

r pro

per

oper

atio

n.

No

Cor

rect

sup

ply

pres

sure

.En

ergi

ze s

yste

m a

nd c

heck

for

prop

er o

pera

tion.

With

sys

tem

ener

gize

d, is

25

volts

pres

ent a

cros

s M

V &

MV

term

inal

s of

mod

ule

afte

rig

nito

r war

m u

pdu

ratio

n? No

Rep

lace

mod

ule.

Ene

rgize

syst

em a

nd c

heck

for p

rope

rop

erat

ion.

Is g

asav

aila

ble

at s

ourc

e?R

esto

re g

as s

uppl

y at

sou

rce.

Ener

gize

sys

tem

and

che

ck fo

rpr

oper

ope

ratio

n.

Rep

lace

gas

val

ve. E

nerg

izesy

stem

and

che

ck fo

r pro

per

oper

atio

n.

Yes

No

Yes

No

Rep

lace

lead

s. En

ergi

ze s

yste

man

d ch

eck

for p

rope

r ope

ratio

n.

Yes

NOTE

: All

volta

ge re

adin

gs +

10%

- 15

%

Dis

conn

ect

lead

s at

gas

val

ve.

Ener

gize

sys

tem

. Is

25 v

olts

pres

ent a

cros

s le

ads

afte

rig

nito

r war

m u

p du

ratio

n?(s

ee m

odul

ela

bel)

www.white-rodgers.com 28�

TE

CH

NIC

AL

HE

LP

CH

AR

T 3

50E

47/5

0F47

TH

IRD

VIS

UA

L C

HE

CK

(Do

es m

ain

bu

rner

rem

ain

lit?

)

Doe

s m

ain

burn

erre

mai

n lit

afte

r tria

l for

igni

tion

perio

d? (s

ee m

odul

ela

bel)

Ther

mos

tat s

atis

fied.

No

Yes

Con

nect

ohm

met

erac

ross

sen

sor l

ead

term

inal

and

sens

or p

robe

. Doe

sco

ntin

uity

exi

st?

Cor

rect

gro

und

wiri

ng.

Is c

ontro

lbo

x G

ND

term

inal

wire

d to

bur

ner

grou

nd?

Yes

No

Yes

No

Yes

Doe

s fla

me

sens

or p

robe

hav

eca

rbon

or d

ust

build

-up?

No

No

HSI

sys

tem

cyc

le c

ompl

ete.

Rem

ove

flam

e se

nsor

. Cle

ansu

rface

of f

lam

e se

nse

rod

with

fine

stee

l woo

l or e

mer

y cl

oth,

then

rein

stal

l.

Yes

Yes

Rep

lace

50E

47/5

0F47

-XXX

cont

rol.

Igni

tor r

emai

ns h

eate

d (b

right

red)

with

mai

n bu

rner

flam

epr

esen

t.

Rep

lace

50E

47/5

0F47

-XXX

cont

rol.

Doe

s ig

nito

r tur

nof

f with

mai

n bu

rner

flam

est

ill pr

esen

t?

No

Yes

Yes

Rep

lace

sen

sor.

Ener

gize

sys

tem

and

chec

k fo

r pro

per o

pera

tion.

Rep

lace

sen

sor.

Ener

gize

sys

tem

and

chec

k fo

r pro

per o

pera

tion.

Rep

ositi

on fl

ame

sens

e pr

obe

toac

hiev

e 1µ

a or

gre

ater

sen

secu

rrent

, or,

if un

atta

inab

le,

repl

ace

760-

XXX

sens

or.

No

Yes

NOTE

: All

volta

ge re

adin

gs +

10%

- 15

%

Is fl

ame

sens

epr

obe

loca

ted

prop

erly

in fl

ame?

Pro

per l

ocat

ion

wou

ld p

rovi

de a

dequ

ate

flam

e cu

rrent

yet n

ot e

xcee

d m

axim

um ro

dte

mpe

ratu

re. M

icro

amm

eter

read

s1µa

or g

reat

er.

Dee

nerg

izesy

stem

and

dis

conn

ect

sens

or le

ad fr

om m

odul

e.C

onne

ct o

hmm

eter

acr

oss

sens

orle

ad te

rmin

al a

nd b

urne

r gro

und.

Is re

sist

ance

less

than

50 m

eg o

hms?

HOT SURFACE IGNITIONSYSTEM (HSI)

TROUBLESHOOTINGGUIDE