L.B. White HW 120 Therma Grow - Manual (Page 21)

21
T
w
o
T
im
e
s
Flash patt
ern
begins 12 seconds af
te
r
condition occur
s.
(Patt
ern
indicat
es
lac
k of air
pr
o
ving in fan
section of unit.)
Are air
-pr
o
ving switch
contacts stuck
open? (P
er
form
continuity check
.)
Does
fan mo
tor star
t up
for prepurge
during initial call
for heat?
Is f
an wheel
binding?
Is f
a
n wheel
loose on mo
to
r
shaf
t?
Ye
s
Ye
s
Ye
s
No
Check f
o
r binding of
air
-pr
o
ving switch arm
on housing, R
e
pair or
replace as necessar
y.
Ye
s
Ye
s
Check f
o
r pr
oper clearance of
fan wheel t
o
mo
tor mount. If
good, replace f
an wheel, or
check f
o
r housing alignment.
Tight
en set scre
w(s) on f
an. Mak
e
sure set scre
w(s) are tight
ened
against flat(s) of mo
tor shaf
t.
Ye
s
Clean the f
an wheel with
com
pressed air or sof
t brush.
Ye
s
R
emo
v
e
obstruction.
Clean as necessar
y.
No
Is f
an wheel
plugged with
dir
t?
Is there an obstruction
in blo
w
er outlet pre
v
enting
air
-pr
o
v
ing switch closure?
No
Are 1
1
5 v
o
lts sent
fr
om ignition
contr
ol t
erminal
IND t
o
mo
to
r?
No
If im
pr
oper v
oltage is supplied,
contact electrician.
- OR -
If no v
o
ltage is supplied t
o
mo
to
r,
check wiring be
wtw
een mo
to
r and
ignition contr
ol. If good, replace
contr
ol.
No
Ye
s
Are 2
4
v
olts supplied
fr
om t
erminal PS1
on contr
oller t
o
the
air pr
o
v
ing switch?
Check wiring betw
een ignition contr
ol
and com
p
onent. R
epair or replace
as necessar
y.
If wiring is good,
replace ignition contr
ol module.
No
Def
ectiv
e mo
to
r.
R
eplace mo
to
r.
Ye
s
Are 2
4
v
olts returned
fr
om air pr
o
v
ing
switch t
o
t
erminal
PSO on contr
oller?
No
Def
ectiv
e ignition
contr
ol. R
eplace
ignition contr
ol.
No No
Def
e
ctiv
e air pr
o
ving switch.
R
eplace switch.