L.B. White AW250(building controller) - Manual (Page 21)

21
Problem
LED constant on
Red LED not on during a call for heat.
Normal Operation
Is heat
er
connect
ed t
o
its
po
w
er supply?
Connect it t
o
the
po
w
er supply
.
Ye
s
No
Ye
s
Is
pr
oper
v
oltage supplied
to
heat
er po
w
er cor
d
and thr
ough
po
w
er cor
d?
Check dataplat
e f
or electrical
supply req
uirements. Pr
o
vide
pr
oper v
oltage. Check cir
cuit
break
er
s. Check po
w
er cor
d f
o
r
continuity
.
Are 2
4
v
olts
supplied fr
om
transf
ormer?
R
eplace
transf
ormer
No
No
No
Ye
s
Are
2
4
v
olts supplied
to
ignition
module?
P
oor electrical connection or br
ok
en wire present.
R
epair or replace.
Ye
s
LED in contr
ol module is
def
ectiv
e. R
eplace ignition
module.
Is
pr
oper
v
oltage supplied
to
transf
ormer?
Check electrical connections and
po
w
er supply t
o
transf
ormer
.
R
epair as necessar
y.
No
Ye
s
Ye
s
Is
building contr
oller
calling f
or heat?
Set contr
oller t
o
call f
or heat.
No
Heater does not cycle above minimum heat output.
Is building
contr
oller
calling f
or heat?
No
Is pr
oper gas
pressure supplied
to
heat
er?
Ye
s
Pr
o
vide pr
oper
pressure t
o
heat
er and
check with a gauge.
No
Set the building
contr
oller t
o
call f
o
r
heat.
Is v
ariable rat
e
solenoid on gas contr
ol
v
alv
e receiving DC v
olts
or millam
p signal fr
om
building contr
oller?
No
Ye
s
Problem
Measure acr
oss t
erminals of
modulating gas contr
ol v
alv
e f
o
r
an
ywhere fr
om 1-1
5 v
olts DC.
If absent, check all wiring. If wiring is
good, the building contr
oller’s
settings must be check
ed.
Def
ectiv
e v
ariable rat
e gas contr
ol
solenoid v
alv
e. R
eplace gas
contr
ol.
Ye
s