AERCO BMK 3.0 LN Natural Gas July 2011 - Manual (Page 61)

TROUBLESHOOTING
8
-
3
TABLE 8-1. BOILER TR
OUBLESHOOTING – Contin
ued
FAULT INDI
CATION
PROBABL
E CAU
SES
COR
R
ECTI
VE ACTI
O
N
AIRFLOW FAULT DU
RI
N
G
PU
RGE
1.
Blowe
r not ru
nning o
r ru
nni
ng too slo
w
2.
Defe
ctive Air Flow Swit
ch
3.
Blocked Air flow Switch
4.
Blocked Blo
w
er inle
t or inlet duc
twork
.
5.
No voltage to
switch from control box.
6.
PROBABL
E CAU
SES
from 3 to 12
for
AI
RF
LO
W
FAUL
T D
U
R
ING
IGNITION
al
so apply for this fault
1.
Start the unit.
If the blower doe
s not
run
che
ck the
bl
owe
r
solid
state relay for input an
d output voltage. If the relay is okay,
che
ck the blo
w
er.
2.
Start the unit
. If the blower ru
ns
, c
hec
k the airflow sw
itch for
continuity. R
eplac
e the switc
h if there is no c
ontinuity.
3.
Remove the
air flow
swit
ch and in
spe
ct for sign
s of blockag
e,
clea
n or repla
ce a
s ne
ce
ssary.
4.
Inspe
ct the
inlet to
th
e comb
ustio
n blo
w
er
i
ncludi
ng
any
duct
w
ork lea
ding up to the co
mbu
stion blo
w
er f
or si
gns
of
blocka
ge.
5.
Measure for
24 VAC d
urin
g start
seq
ue
nce from e
ach sid
e of the
swit
ch to ground. If 24VAC is
not present refer to qualified
servi
ce pe
rso
nnel.
6. See
CORRECTIVE ACTION
from 3 to 12 for
AI
RFLO
W
FAU
LT D
U
RI
NG I
G
NI
TI
O
N
AIRFLOW FAULT
DU
RI
N
G
R
U
N
1.
Blowe
r stop
pe
d run
ning d
ue to thermal
or cu
rrent overloa
d
2.
Blocked Blo
w
er inlet or inl
et ductwo
rk
3.
Blocked ai
rflo
w switch
4.
Defe
ctive airflow switch
5. Comb
ustio
n
oscillation
s
6.
PROBABL
E CAU
SES
from 3 to 12
for
AI
RF
LO
W
FAUL
T D
U
R
ING
IGNITION
applies
for this
fault
1.
Che
ck
com
bustion
blo
w
er
for
sig
ns of
exce
ssive h
eat o
r hi
gh
curre
nt dra
w
that may
trip therm
al or current overl
oad
device
s.
2.
Ins
pec
t the inlet to the co
mb
ustio
n blo
w
er
i
ncludi
ng
any
duct
w
ork lea
ding up to the co
mbu
stion blo
w
er f
or si
gns
of
blocka
ge.
3.
Remove
the
airflow switch an
d in
sp
ect for
sign
s
of blo
ckage,
clea
n or repla
ce a
s ne
ce
ssary.
4.
Measure the
airflow
switch fo
r
continuity w
ith the c
ombus
tion
blower runni
ng. If there is an e
rratic resi
stan
ce rea
ding o
r the
resi
stan
ce
re
ading i
s gre
ater than
zero ohms, repla
ce the swit
ch.
5.
Run
unit
to f
ull fire. If th
e unit
rum
bles or run
s
rou
gh, pe
rform
comb
ustio
n calibratio
n.
6.
PROBABL
E CA
USE
S
from
3 to
12 for
AI
R
F
L
O
W FA
ULT
DU
RI
N
G
IG
N
ITI
ON
applies for this
fault