Carrier 58MCB - Manual (Page 17)

17
Is LED status light on? Is LED status light b
linking rapidly without a
pause? Is LED status light b
linking ON/OFF
slo
wly
with a combination of shor
t and long flashes?
Deter
mine status code
.
The status code is a
2 digit number with the first digit deter
mined
by
the number
of shor
t flashes
and the second
digit b
y the number of long flashes?
Go to section belo
w f
or the status code that
w
as flashed.
Is there 115V at L1 and L2? Is there 24V at SEC
-1 and SEC
-2?
Replace fur
nace control.
Chec
k f
or correct line v
oltage polarity and ground-
ing. If units are twinned, check for proper low- voltage (24V) transformer phasing. To
recall status code briefly remo
ve
and reconnect one RED wire from the Limi
t
Switch or Flame Rollout s
witch to displa
y stored status code
. On RED LED
control do not remo
ve po
wer or b
lo
wer access panel bef
ore initiating status
code recall.
Y
ou can also recall the pre
vious status code b
y momentar
ily shor
ting
the
TEST/TWIN ter
minal to Com24V ter
minal until the LED goes out.
LED will
flash the pre
vious status code or status code #11 (1 shor
t and 1 long flash) if
there w
as no pre
vious code
. After the control repeats the code 4 times
, the
control will go through
a br
ief component test sequenc
e.
The inducer will star
t
and r
un f
or the entire component test.
The HSI, b
lo
wer motor F
AN speed
(AMBER LED boards only) HEA
T speed, and COOL speed will r
un f
or 10 – 15
seconds each.
Gas v
alv
e and humidifier will no
t be tur
ned on.
W
as there a pre
vious status code
other than #11?
Is door s
witch closed?
Is there 115V going to s
witch?
Replace door s
witch.
Replace transf
or
mer
.
Does the control
respond to
W
, Y1
(if present),
Y/Y2, and G (24V) ther
mostat signals?
R
un system
through
a
heating
or
cooling
cycle
to chec
k operation.
Status codes are erase
d
after 72 hours
. On RED LED boards stored
status codes can also be erased whene
ve
r
(115V or 24V) is interr
upted.
Replace fur
nace control.
Close door s
witch and go bac
k to ST
A
R
T.
Is circuit break
er closed?
Chec
k f
or continuity
in wire from c
ircuit break
er
to fur
nace
.
Close circuit break
er and go bac
k to ST
A
R
T.
Chec
k room ther
mostat or
interconnecting cab
le
.
Is 24V present at
W,
Y
1 (if present),
Y/Y2 or
G ther
mostat ter
m
inals on
the
fur
nace
control?
Disconnect all the the
rmostat wires from the
fur
nace control.
Does the prob
lem repeat when using
a jumper wire? The ther
mostat is not compatib
le with the
fur
nace
control.
Either i
nstall a
ballast resistor
,
connect the Com24V ther
mostat ter
minal to
the ther
mostat, or replace the ther
mostat.
NO
YES
YES
NO
NO
YES
YES
YES YES
NO
YES YES
NO
YES
NO
YES
NO
NO NO
YES
NO YES NO
ST
AR
T
TR
OUBLESHOO
TING GUIDE
NO
A05107
58MC
B