AERCO BMK 3.0 LN Natural Gas July 2011 - Manual (Page 66)

TROUBLESHO
OTING
8
-
8
TABLE 8-1. BOILER TRO
UBLESHOOTING – Contin
ued
FAULT INDI
CATION
PROBABL
E CAU
SES
CORRECTI
VE ACTI
O
N
INTERL
OCK
OPEN
1.
Interlock jum
per not in
stall
ed or
remove
d
2.
Energy Man
ag
ement Syste
m
does
not have boil
er ena
bled.
3.
Device provin
g swit
ch ho
oked to
interloc
ks
is
not c
losed.
1.
Che
ck for a jumpe
r pro
pe
rly
ins
talled across
the interlock
terminals
in the I/O box
2.
If there are two external wi
res on the
se t
ermin
als
che
ck a
ny
Energy Man
ag
ement sy
ste
m
to
se
e if they have the units
disa
bled (a ju
mper may be
temporarily in
stalled to see
if the
interloc
k
ci
rc
uit is
func
tioning).
3.
Che
ck that proving switch f
or
any device
hooked to the interlo
ck
circuit is
closi
ng and that th
e device i
s op
eration
al.
LINE VOLTA
G
E
OUT OF P
H
ASE
1.
Line an
d Ne
ut
ral swit
che
d in AC
Power Box.
2.
Inc
orrec
t power s
upply trans
former
wirin
g.
1.
Che
ck Line (hot) and
Neut
ral in AC Power Box to ensure they
are not reversed
2.
Che
ck tran
sforme
r wi
ring,
in AC Powe
r Box, against the po
wer
box transfo
rm
er wi
ring di
ag
ram to en
sure it is wired
correctly
LOW GAS
PRESSURE
1.
In
co
rr
ec
t s
upp
ly g
as
p
re
ssu
re
.
2.
Defe
ctive Lo
w Pre
ssure
G
as Swit
ch
1.
Measure ga
s pre
ssure up
stream
of the supply gas
regulator w
ith
the unit firing. Ensure it is at leas
t 3.5”
W.C. for FM gas
train, or
4.0” W.
C. for IR
I gas
train. Max.
allowabl
e pre
ssure is 2 psig
(se
e pa
ra. 2.7.1).
2.
Measure ga
s pre
ssure at the lo
w ga
s pr
es
su
re swit
ch.
If
it is
greate
r than 2.6” W.
C., measure
cont
in
uit
y acro
ss t
he swit
ch
and re
pla
ce if nece
ssary.
LOW WATE
R
LEVEL
1.
Ins
uffic
ient water level in sys
tem
2.
Defective wat
er level ci
rcuitry.
3.
Defe
ctive wat
er level probe
.
1.
Che
ck sy
st
em
fo
r suf
ficie
nt
wat
er lev
el
.
2.
Test water le
vel circuitry u
sing the
Cont
rol Box front panel L
O
W
WATER TES
T
and RESE
T buttons. Repla
ce water
level
ci
rc
uitry if it does
not respond.
3.
Che
ck co
ntin
uity of probe end
to the sh
ell, chan
ge probe if there
is no continuit
y.
MODB
US COMM
FAULT
1.
Boiler n
ot seeing i
nform
ation from
Modbu
s net
work
1.
Che
ck net
w
or
k co
nne
ct
ion
s.
If
fault persi
sts, co
ntact q
ualified
Service Pe
rsonnel.
PRG SWTCH CLOSED
DU
RI
N
G
IG
N
ITI
ON
1.
A/F Valve rotated ope
n to purg
e and
did not rotate
to ignition pos
ition
1.
Start the u
ni
t. The Air/Fu
el Va
lve
sh
ould rotate to the purge
(ope
n)
po
sition, then
ba
ck to ig
nition
positio
n (to
w
ard
s
clo
sed
)
during the ignition c
yc
le. If the va
lve does
not rotate
back
to the
ignition po
sit
ion, che
ck the Air/Fuel
Valve cali
bration. If
calib
ration i
s okay, the pro
blem may be
in the Air/Fuel Valve or
the Control Box. Refer faul
t to qualified servi
ce pe
rso
nnel.