50
SERVICING
PCBJA104 AIR HANDLER DIAGNOSTIC CODES
ComfortNet™
Thermostat On
ly
Sy
mp
toms of
Ab
normal Operatio
n
(Lega
cy
&
ComfortNet™ Thermostat
)
7-Segment LED
Codes
Characters Will Alternat
e
Fault Description
Message
Code
Possible Causes
Corrective
A
ctions
Notes & Caution
s
A
ir handler blo
we
r fails to operate.
Integrated control module LED
display
prov
ides indicated error code.
ComfortNet™ thermostat “Call for
Serv
ice” icon illuminated.
ComfortNet™ thermostat scrolls
“Check Air Handler” message.
b5
C
irculator blo
we
r
motor fails to start 10
consecutiv
e times.
MT
R
LCKD
ROTOR
b5
O
bstruction in circulator
blow
er housing.
Seized circulator blo
we
r motor
bearings. Failed circulator blo
we
r motor.
Check circulator blow
er for
obstructions. Remo
ve
and
repair/replace w
heel/motor if
nec
es
sa
ry
.
Check circulator blow
er motor
shaft rotation and motor. Replace motor if necessary
.
T
urn po
we
r OFF prior to
repair Replace motor w
ith
correct replacement
part. Replace w
heel w
ith
correct replacement
part.
A
ir handler blo
we
r fails to operate.
Integrated control module LED
display
prov
ides indicated error code.
ComfortNet™ thermostat “Call for
Serv
ice” icon illuminated.
ComfortNet™ thermostat scrolls
“Check Air Handler” message.
b6
C
irculator blo
we
r
motor shuts do
wn
for
ov
er or under
vo
ltage
condition.
C
irculator blo
we
r
motor shuts do
wn
d
ue
to o
ve
r temperature
condition on pow
er
module.
MO
TOR
VOLTS
b6
H
igh AC line
vo
ltage to air
handler blow
er.
L
ow
AC line v
oltage to air
hander blow
er.
H
igh ambient temperatures.
Check pow
er to air handler
blow
er. Verif
y
line
vo
ltage to
blow
er is w
ithin the range
specified on the air handler blow
er rating plate.
S
ee "Installation Instructions" for installation requirements.
T
urn po
we
r OFF prior to
repair.
A
ir handler blo
we
r fails to operate.
I
ntegrated control module LED
display
prov
ides indicated error code.
ComfortNet™ thermostat “Call for
Serv
ice” icon illuminated.
C
omfortNet™ thermostat scrolls
“Check Air Handler” message.
b7
C
irculator blow
er
motor does not have enough information to
operate properl
y.
Motor fails to start 40
consecutiv
e times.
MO
TOR
PARA
MS
b7
Error w
ith integrated control
module. M
otor has a locked rotor
condition.
Check integrated control module. Verif
y
control is
populated w
ith correct shared
data set. See data errors abov
e for details.
Check for locked rotor condition (see error code abov
e for details).
T
urn pow
er OFF prior to
repair. R
eplace w
ith correct
replacement part(s). U
se memory
card for
the specific model.
Insert memor
y
card
BEFORE turning pow
er
ON. M
emory
card ma
y
be
remo
ve
d after data is
loaded T
urn pow
er off before
remo
vi
ng memory
car
d.
A
ir handler blo
we
r operates at reduced
performance or operates on lo
w
stage
w
hen high stage is ex
pected.
I
ntegrated control module LED
display
pro
vi
des indicated error code.
b9
A
irflo
w
is low
er than
demanded.
LO
W
ID
AIRFLO
W
b9
B
locked filters.
R
estricti
ve
ductw
ork.
Undersized ductw
ork.
Check filters for blockage. Clean filters or re
mo
ve
obstruction.
Check ductw
ork for blockage.
Remo
ve
obstr
uc
tion
. Verif
y
all registers are fully
open.
V
erif
y
ductw
ork is
appropriatel
y
sized for
sy
stem. R
es
iz
e/
repl
ac
e
duct
wo
rk if necessary
.
T
urn pow
er OFF prior to
repair.
