L.B. White FA-MCS-D - Manual (Page 18)

Green LED on programmable controller is steady ON Green LED on programmable controller is OFF. No display at touch pad, all indicator lights are off. Heaters do not operate.
Is main po
w
er supply
fuse in
Smar
t Bo
x
™
deliv
ering 120 V
A
C t
o
transf
ormer
s?
No
Is 120 V
A
C
deliv
ered t
o
Smar
t Bo
x
™
?
Ye
s
Check break
er
s in building.
Check po
w
er cor
d f
or tight
connections and continuity
.
Check po
w
er outlet f
o
r
def
ects, corr
osion, etc.
No
R
eplace the fuse. V
erify
b
y checking v
oltage t
o
and fr
om fuse or check continuity
.
Is upper
transf
ormer
receiving 120 V
A
C fr
om main
po
w
er fuse?
No
Ye
s
Problem 2
Def
ectiv
e electrical wire or
connection. R
epair or replace as
needed.
V
erify 2
4
V
A
C fr
om transf
ormer
betw
een the tw
o y
ello
w leads,
(T
erminals 1 and 2) of the
pr
ogrammable contr
oller
. If absent,
replace the transf
ormer
.
Ye
s
Is
upper transf
ormer
deliv
ering 2
4
V
A
C t
o
pr
ogrammable contr
oller?
No
Ye
s
18
Cy
cle the po
w
er t
o
the
Smar
t Bo
x
™
OFF and then
ON. If the LED remains st
eady ON, replace the
contr
oller
.
Problem 1
Is t
ouch pad receiving
1
8
VDC fr
om
contr
oller?
No
Check acr
oss br
o
wn wires at t
ouch
pad. If 1
8
VDC is absent, trace the
wires back t
o
the contr
oller
.
Check f
or 1
8VDC at the contr
oller
terminals 5 and 6 (br
o
wn). If present
at contr
oller
, repair or replace wiring
betw
een t
ouch pad and
pr
ogrammable contr
oller
. If absent,
replace pr
ogrammable contr
oller
.