SERVICE AND TECHNICAL SUPPORT MANUAL
Gas Furnace: N9MSE
Specifications subject to change without notice.
440 04 4402 03
23
Figure 16
Troubleshooting
−
Flow Chart
Is
LE
D s
tat
us lig
ht
ON s
o
lid,
alt
e
rn
atel
y
flashi
ng bri
ght
-d
im
-b
rig
h
t-
dim
lik
e a
h
ea
rtb
e
a
t, o
r fl
ashi
ng
ON a
n
d
O
F
F
?
Is
th
er
e 2
4
V
at
2
4
V
A
C
a
nd C
O
M?
Is
th
er
e 1
15V
at
L1
an
d
NE
UT
RA
L?
Is
th
e 2
4
V
f
u
se
op
en
?
Is
do
or
s
w
itc
h
clo
s
ed
?
Rep
la
ce t
ra
n
sf
orm
e
r.
Rep
la
ce do
or
s
w
it
ch
.
Is
th
er
e 1
1
5V
goi
ng t
o
s
w
it
ch
?
Cl
ose
the
d
oor
s
w
itc
h
.
Is
circ
uit
bre
a
k
e
r cl
ose
d
?
Che
ck
fo
r co
nti
n
uit
y
i
n
w
ir
e
fr
om
ci
rc
ui
t
b
rea
ke
r to
fu
rn
a
c
e.
Cl
ose
circ
uit b
re
a
k
e
r a
n
d
go
ba
ck
to
ST
ART
.
Is
LE
D s
tat
us li
g
h
t
alte
rn
atel
y
fla
s
hin
g
brig
ht
-d
im
-b
rig
h
t-
dim
lik
e a h
e
a
rtb
eat
?
Dete
rm
ine
s
ta
tus c
o
d
e
. T
h
e st
atu
s
co
d
e
is a
si
ngle
or
t
w
o
di
git
n
u
m
b
e
r
w
it
h
t
he
fir
s
t
num
b
e
r
det
erm
in
ed b
y
t
he num
b
e
r of
shor
t fl
ash
e
s a
nd
th
e se
con
d
num
b
e
r
afte
r
the plus (+)
sig
n
,
the num
b
e
r
of l
o
ng
flash
e
s.
T
o
r
e
c
a
ll a
sta
tu
s
cod
e
: B
riefl
y
(2
–
3
seco
nds
) c
onn
ect
th
e
T
EST
/T
W
IN te
rm
ina
l
to
t
h
e
“C
”
th
e
rm
o
st
at t
e
rm
in
al
w
it
h
a
j
u
m
p
er
wi
re
t
o
b
egi
n st
atu
s
co
de
re
cov
e
ry
an
d
com
p
o
nen
t t
e
st.
If a
p
revio
us s
ta
tus c
o
de is
pres
en
t, t
he c
o
d
e
w
ill
re
pea
t 4
tim
e
s t
h
en
go
on t
o
c
o
m
p
o
nen
t t
e
st.
If n
o
pre
v
iou
s
cod
e
is p
re
s
en
t, a
co
m
p
on
ent
tes
t
w
ill
begi
n w
it
h
o
u
t
fl
ashi
ng an
y
sta
tus cod
e
s
.
C
o
mpon
en
t T
e
s
t
S
e
qu
enc
e
: Ga
s
va
lv
e
and
h
u
m
idi
fier
w
ill n
o
t
be t
u
rn
e
d
on
.
In
d
u
ce
r
m
o
to
r w
ill sta
rt
a
n
d
r
e
m
a
in
on until
the
en
d o
f th
e bl
o
w
e
r t
e
st,
th
en
off.
T
he
foll
o
w
ing c
o
m
p
o
n
e
n
ts
ar
e o
n
f
o
r
10
–
15
seco
nds
ea
ch i
n
divi
duall
y
: h
o
t s
u
rf
a
c
e
ign
ite
r,
blo
wer spe
e
ds
: FA
N
(if
pr
es
ent
),
HE
AT
, COOL
.
W
a
s there
a p
revi
ous
stat
us c
o
d
e
?
Go t
o
s
e
ctio
n b
e
lo
w fo
r t
he fl
ash
ed
sta
tus
cod
e
.
Doe
s
th
e
co
ntr
o
l r
e
sp
on
d t
o
W
, Y
1
,
Y
/Y2,
and
G
(24V
) t
h
e
rm
o
sta
t sig
nals
?
Run s
y
stem
t
h
ro
u
g
h
a
h
eat
, o
r c
ooli
n
g
c
y
cle t
o
c
heck
op
er
atio
n. S
tat
us c
o
d
e
s
are
er
ase
d
afte
r 7
2
hou
rs.
Is
2
4
V
p
res
ent
at
W
, Y
1
,
Y/
Y
2
or
G
th
e
rm
o
sta
t te
rm
ina
ls
o
n
th
e f
u
rnac
e
cont
rol
?
Check
ro
om
th
erm
o
s
tat
or
inter
co
nne
ctin
g ca
ble
.
Di
scon
nec
t all
the
th
erm
o
s
tat
wi
re
s fr
o
m
the fur
n
ac
e
c
ont
rol.
Does
the
p
robl
em
r
epe
at
whe
n u
s
ing
a
jum
per
w
ire
?
Repla
ce f
u
rnac
e c
ont
rol.
T
he th
erm
o
s
tat
is n
o
t c
o
m
pati
b
le
w
ith
th
e
fur
nac
e co
ntr
o
l.
E
ithe
r i
n
stall
a
ball
a
st
resist
o
r,
co
nn
ect t
h
e
C
fu
rn
ace
co
ntr
o
l
th
e
rm
o
sta
t te
rm
ina
l
to
th
e
th
er
m
o
s
ta
t,
o
r
repl
ace
th
e t
herm
o
stat
.
YE
S
NO
YE
S
YE
S
YE
S
YE
S
YE
S
YE
S
YE
S
STAR
T
YE
S
YE
S
NO
NO
NO
NO
NO
NO
NO
NO
YE
S
NO
NO
Troubles
h
ooting Guide
Repla
ce f
u
rnac
e c
ont
rol.
YE
S
Insp
ect
s
e
c
ond
ar
y
volt
ag
e
(24V
) w
iri
ng,
includi
ng
th
erm
o
st
at l
e
a
d
s f
o
r s
h
o
rt
circuit
.
Rep
la
ce f
u
s
e
NO
Is
L
E
D s
ta
tus lig
ht
ON s
o
lid?
NO
YE
S
T
he co
ntr
o
l is l
o
ck
ed
out
an
d
w
ill
aut
o
-
rese
t
a
fte
r
1 ho
ur.
L
o
ck
out coul
d be du
e
to
a
n
y
of
the foll
o
w
in
g
:
-
Flam
e s
e
n
s
e ci
rcui
t fail
ur
e.
-
G
a
s
va
lv
e r
e
lay
st
u
c
k op
e
n
.
- S
o
ft
w
a
re
che
c
k
err
o
r.
Rese
t p
o
wer
to
cle
a
r l
o
ck
out.
Re
plac
e
cont
rol if
co
de
re
pe
ats.
