AERCO BMK 3.0 LN Natural Gas July 2011 - Manual (Page 60)

TROUBLESHO
OTING
8-2
TABLE 8-1. BOIL
ER TROUBLESHOOTING
FAULT INDI
CATION
PROBABL
E CAU
SES
COR
R
ECTI
VE ACTI
O
N
AIRFLOW FAULT
DU
RI
N
G
IG
N
ITI
ON
1.
Blo
w
er
s
to
ppe
d r
unn
in
g due
to
thermal o
r cu
rre
nt overloa
d
2.
Blocked Blo
w
er inlet or inl
et ductwo
rk
3.
Blocked Blo
w
er proof switch
4.
Blocked blo
cked
-ai
r inlet switch
5.
Defe
ctive Blower p
ro
of swi
tch
6.
Defe
ctive blo
cked-air inl
et swit
ch
7.
Loo
se tempe
rature to AUX
con
ne
ction
in I/O Box
8. Defe
ctive
temperatu
re
sen
sor
9.
Loo
se wi
re conne
ction b
etwee
n the
0-10V
si
gnal from I/O box to the
Blower Motor input
10. Defe
ctive
I/O
box
11.
Wrong 0
-10V
output sele
ct
ion on the
control box
12. Defe
ctive
Air-Fuel
Valve
potentiomete
r
1.
Che
ck com
bu
st
ion blo
w
er
fo
r sig
ns of
ex
ce
ssiv
e h
eat
or high
cu
rre
nt
drain that ma
y trip thermal
or cu
rrent overloa
d device
s.
2.
Ins
pec
t the inlet to the c
ombus
tion
b
low
er
in
cl
ud
in
g any d
uc
tw
or
k
leadin
g up to the comb
usti
on blo
w
er fo
r sign
s of blo
ckage.
3.
Remove the Blowe
r pro
of swit
ch an
d in
spe
ct for si
gn
s of blocka
ge
,
clea
n or repla
ce a
s ne
ce
ssary.
4.
Remove the
blocke
d-ai
r in
let switch an
d insp
ect for
sign
s of
blocka
ge, cle
an or repla
ce
as ne
ce
ssary
.
5.
Measure the Blowe
r pro
of swit
ch
for
co
ntinuity w
ith the c
ombus
tion
blower runnin
g. If
there is a
n erratic re
si
stance readi
ng
or the
resi
stan
ce
re
ading i
s gre
ater than
zero ohms, repla
ce the swit
ch.
6.
Measure the blocke
d-ai
r in
let sw
itch for c
ontinuity w
ith the
co
mbus
tion blower running. If
ther
e is an
errati
c re
sist
ance rea
ding
or the re
si
sta
nce readi
ng i
s gre
a
ter than z
ero ohms
, replac
e the
swit
ch.
7.
Che
ck the act
ual inlet air te
mp
erature a
nd m
easure voltage at AUX
input in the I/O Box. Verify
that
the volta
ge c
onforms
to the values
sho
w
n in the
tabular li
sting
provided in A
ppen
dix C.
8.
Refer to
CORRECTIVE ACTION
7 an
d verify that the voltage
confo
rm
s to the value
s sh
own in App
en
dix C.
9.
Check
w
ire connec
tion from I/O
Box 0-
10V sign
al to the Blowe
r
Motor.
10.
Measure voltage at the I/O box
0-10V o
utput. A volta
ge of 8.2V
equate
s to a 100% ope
n ai
r/fuel valve position.
11. Check
the
Analog Out
opti
on on the C-More
Config
ur
ation Me
nu.
Valve Position
0-10V
sho
ul
d be sel
ect
ed
.
12.
Che
ck Air/F
uel Valve po
sit
ion at 0%, 50% and 100% open
positio
ns. Th
e positio
n on
the VALVE POSITION bar graph
sho
uld
match the rea
ding on the Ai
r/Fuel Valve dial.