A02108c
25
INV
ALID MODEL SELECTION OR
SETUP ERR
OR
–
If status code 25 only
flashes 4 times on po
w
er-up the control
is missing its model plug PL4 and is
def
aulting to the model selection stored
in memor
y.
If status code 25 flashes
contin
uously it could indicate an
y of the
follo
wing:
-
Model plug PL4 is missing and there
is no v
alid model stored in per
manent
memor
y.
This will happen if y
ou f
orget
to install the model plug PL4 on a
ser
vice replacement control.
-
Ther
mostat call with SW1-1 ON.
-
Ther
mostat call with SW1-6 ON.
-
SW1-1 and SW1-6 both ON.
31
HIGH-HEA
T PRESSURE SWITCH OR
RELA
Y DID NO
T CLOSE OR
REOPENED - Chec
k f
o
r:
-
Control rela
y ma
y be def
ectiv
e
.
-
Gas v
alv
e is mis
wired.
-
See status code 32.
4
1
BLO
WER MO
T
OR F
A
UL
T
–
Indicates the
b
lo
w
er f
ailed to reach 250 RPM or the
b
lo
w
er f
ailed to comm
unicate within the
prescr
ibed time limits
.
Thir
ty seconds
after being tur
ned ON or ten seconds
dur
ing steady-state oper
ation.
T
u
rn
po
w
e
r
off and chec
k the f
ollo
wing items first
bef
ore proceeding to the ne
xt step
.
-
Rub
bing b
lo
w
er wheel.
-
Loose b
lo
w
er wheel.
-
Wir
ing from fur
nace control to b
lo
w
er
motor
.
Remo
v
e
the R ther
mostat connection
from the fur
nace control, disconnect both
connectors from the b
lo
w
er motor PL13
and PL14.
Does the b
lo
w
er wheel tur
n
freely?
Replace the b
lo
w
er control module attached
to the b
lo
w
er motor
. F
ollo
w the instr
uctions
with the b
lo
w
er control module to mak
e sure
the entire b
lo
w
er motor does not need to be
replaced.
Y
ou ha
v
e
an open wire or bad ter
minal on the
BLUE wire betw
een the fur
nace control and
the b
lo
w
er motor
.
Replace the fur
nace control.
Connect a DC v
oltmeter across PL3-4 BLUE
(+) and PL3-2 GREEN (-).
Does the v
oltage
fluctuate as descr
ibed tw
o steps bac
k?
Does the v
oltage fluctuate as descr
ibed in the
pre
vious step?
Replace the b
lo
w
er control module attached
to the b
lo
w
er motor
. F
ollo
w the instr
uctions
with the b
lo
w
er control module to mak
e sure
the entire b
lo
w
er motor does not need to be
replaced.
T
u
rn
po
w
er bac
k on.
Is there 115V
A
C
at
PL14-5 and PL14-4?
Is there 12-VDC at PL13-7 RED (+) and PL13-
1 GREEN (-)?
Is there 12-VDC at PL3-1 RED (+) and PL3-
2 GREEN (-)?
Replace the fur
nace control.
Is there 5-VDC at PL13-16
YELLO
W (+) and
PL13-1 GREEN (-)?
The v
oltage just measured should be v
e
ry
stab
le and should not fluctuate more than
.02-VDC
. If the v
oltage fluctuates more than
this get a diff
erent v
oltmeter bef
ore
proceeding.
T
u
rn
po
w
er off
, reconnect PL13 and PL14 to
the b
lo
w
er motor
, then tur
n po
w
er bac
k on.
Connect a DC v
oltmeter across PL3-3
YELLO
W (+) and PL3-2 GREEN (-).
Does
the v
oltage fluctuate more than it did in the
pre
vious step?
T
u
rn
po
w
er off
, disconnect PL13 and PL14
from the b
lo
w
er motor
, then tur
n po
w
er bac
k
on.
Connect a DC v
oltmeter across PL13-
16 BLUE (+) and PL13-1 GREEN (-).
The
v
oltage should be near 0-VDC b
ut it will
fluctuate br
iefly se
v
e
ral times a second.
If
y
o
u ha
v
e
an analog v
oltmeter the needle will
br
iefly go high se
ve
ral times a second.
If y
o
u
ha
v
e
a digital v
oltmeter with a bar g
raph it
will sho
w a large change in magnitude on
the bar g
raph se
v
e
ral times a second.
If y
o
u
ha
v
e
a standard digital v
oltmeter it will sho
w
a br
ief fluctuation in v
oltage and the
magnitude ma
y v
a
ry
depending on the
v
oltmeter used.
Y
ou ha
v
e
an open wire or bad ter
minal on
either the BLA
CK or
WHITE po
w
er leads
betw
een the fur
nace control and the b
lo
w
er
motor
. If y
ou ha
v
e
a po
w
er chok
e disconnect
it and chec
k contin
uity
.
Y
ou ha
v
e
an open wire or bad ter
minal on
either the RED or GREEN wire betw
een the
fur
nace control and the b
lo
w
er motor
.
Is there 5-VDC at PL3-3
YELLO
W (+) and
PL3-2 GREEN (-)?
Y
ou ha
v
e
an open wire or bad ter
minal on the
YELLO
W wire betw
een the fur
nace control
and the b
lo
w
er motor
.
YES
NO
NO
NO
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
YES
YES
NO
49