48
SERVICING
ComfortNet™
Thermostat Onl
y
Sy
mp
toms of
Ab
normal Operation
(Legac
y
& ComfortNet™ Thermostat)
7-Segment LED
Codes
Characters Will Alternate
Fault Description
Message
Code
Possible Causes
Corrective
A
ctions
Notes & Cautions
A
ir handler blow
er fails to operate
I
ntegrated control module LED
displa
y
prov
ides no signal.
C
omfortNet™ thermostat “Call for
Serv
ice” icon illuminated
C
omfortNet™ thermostat scrolls
“Check Air Handler” message
No Display
N
o 208/230 v
olt pow
er
to air handler blow
er
or no 24
vo
lt pow
er to
integrated control
module
Blo
wn
fus
e
or circuit
breaker Integrated control module has an internal fault.
INTERNAL
FAULT
EE
Manual disconnect sw
itch OFF
or 24 v
olt w
ire improperl
y
connected or loose
B
lo
wn
fuse or circuit breaker
Integrated control module has
an internal fault
Assure 208/230 v
olt and 24
vo
lt pow
er to air handler
blow
er and integrated control
module.
Check integrated control module fuse (3A). Replace if nece
ss
ar
y.
C
heck for possible shorts in
208/230 v
olt and 24 v
olt
circuits. Repair as necessary
.
Replace bad integrated
control module.
T
urn pow
er OFF prior to
repair. R
eplace integrated
control module fuse w
ith
3A automoti
ve
fus
e.
R
eplace integrated
control module w
ith
correct replacement part R
ead precautions in
“Electrostatic Discharge”
section of manual.
A
ir handler blow
er fails to operate.
Integrated control module LED
displa
y
prov
ides indicated error code.
C
omfortNet™ thermostat “Call for
Serv
ice” icon illuminated.
C
omfortNet™ thermostat scrolls
“Check Air Handler” message.
d0
D
ata not
ye
t on
netw
ork.
NO NET
DATA
d0
Air handler blo
we
r does not
contain any
shared
data.
Populate shared data set using memory
car
d.
T
urn pow
er OFF prior to
repair Use memory
car
d for
the specific model. Insert memor
y
card
BEFORE turning pow
er
ON. Memor
y
car
d may
be remov
ed after data is
loaded. Error code
wi
ll be
cleared once data is
loaded. Turn pow
er off before
remov
ing memor
y
card
A
ir handler blow
er fails to operate.
Integrated control module LED
displa
y
prov
ides indicated error code.
C
omfortNet™ thermostat “Call for
Serv
ice” icon illuminated.
C
omfortNet™ thermostat scrolls
“Check Air Handler” message.
d1
I
nv
alid data on
netw
ork.
INVALI
D
DATA
d1
Air handler blo
we
r does not
contain an appropriate shared
data set.
Populate correct shared data
set using memory
card.
T
urn pow
er OFF prior to
repair Use memor
y
card for
the specific model. Insert memor
y
card
BEFORE turning pow
er
ON. Memor
y
card
may
be remov
ed after data is
loaded.
E
rror code
wi
ll be
cleared once data is
loaded.
Operation different than ex
pected or no
operation. Integrated control module LED
displa
y
prov
ides indicated error code.
C
omfortNet™ thermostat “Call for
Serv
ice” icon illuminated.
C
omfortNet™ thermostat scrolls
“Check Air Handler” message.
d4
Inv
alid memor
y
card
data.
INVALI
D
MC
DATA
d4
Shared data set on memory
card has been rejected by
integrated control module
V
erify
shared data set is
correct for the specific model. Re-populate data using
correct memor
y
card if
required.
Turn pow
er OFF prior to
repair
Use memory
card
for
the specific model.
I
nsert memory
card
BEFORE turning pow
er
ON. Memor
y
card may
be remov
ed after data is
loaded. E
rror code w
ill be
cleared once data is
loaded. Turn pow
er off before
remo
vi
ng memor
y
card
PCBJA104 AIR HANDLER DIAGNOSTIC CODES