L.B. White AD250 - Manual (Page 24)

Three Times Ignition failure. The module has gone int
o saf
e
ty
loc
k
out.
Is
LP tank
full and pr
operly
sized and are all gas
supply v
alv
es t
o
heat
er open?
Fill tank or resize if
necessar
y.
Open all
gas supply v
alv
es
Ye
s
No
Is pr
oper gas
pressure supplied
to
heat
er?
Ye
s
Ha
v
e
the burner
orif
ice, burner
casting and manif
old
been check
ed f
o
r
block
age?
Ye
s
Does ignit
er
spark?
Is flame
sensor clean?
Is ignit
er
pr
operly
connect
ed?
Is ignit
er
pr
operly gapped?
Ye
s
Ye
s
Ye
s
Close gas supply valve to heater. Disconnect ignit
or cable fr
om ignition contr
ol.
Place the tip of a scre
wdriv
er about 1/8 in. fr
om
where ignit
er cable w
as connect
ed t
o
contr
ol.
Turn heat
er on.
If spark does no
t jum
p fr
om ignition contr
ol t
o
scre
wdriv
er
, replace ignition contr
ol.
If spark is seen, replace the ignit
er/sensor assembly
Clean flame sensor with emer
y clo
th or
st
eel w
ool.
Connect ignit
er t
o
ignit
er high
v
oltage cable.
Check gap betw
een ignit
er
electr
ode and burner
casting. Gap should be 1/8 - 3/1
6 In. R
epair or
replace as necessar
y.
Pr
o
vide pr
oper
pressure t
o
heat
er
and check with a
gauge.
No
R
emo
v
e
orif
ice and
burner casting. Blo
w
out with com
pressed
air or clean with a
sof
t brush.
No
No
No
No
No
Is
flame sensor
insulat
or
crack
ed?
No
Is
flame sensor
pr
operly
positioned?
Ye
s
P
osition flame
sensor so 1/2 -
3/4 in. of tip is in
burner flame.
No
Is heat
er
pr
operly
gr
ounded?
Contact electrician.
Syst
em must be
gr
ounded f
o
r
pr
oper operation.
No
24
Ye
s
Is t
op of
burner casting
corr
oded?
No
Ye
s
R
emo
v
e
corr
osion.
Clean t
op of
casting with emer
y clo
th.
R
eplace ignit
er
and sensor assembly
.
Ye
s
Is
burner manif
old
pressure read at
outlet of gas
v
alv
e?
Ye
s
Are high limit
switch contacts
closed?
If contacts are open,
reset the switch.
Det
ermine cause of
high limit tripping. See f
o
o
tno
te
at the
end of the
tr
oubleshoo
ting
section.
If pressure is no
t read,
check ohm reading betw
een wires of recitif
ier
plug as connect
ed t
o
gas
contr
ol. R
eading should be
3 meg ohm. If reading sho
ws o
v
erload or 0 ohms,
replace the rectif
ier plug
and recy
cle the heat
er
. If
pr
oblem still e
xists, replace
the gas contr
ol v
alv
e.
No
No
Is high limit
receiving 2
4
v
olts
fr
om ignition
contr
ol?
A
. Check f
or def
ectiv
e
wires, repair or replace. B. If wires are good and v
oltage is no
t deliv
ered,
replace ignition contr
ol.
No
Ye
s
Ye
s