14
TROUBLESHOOTING INFORMATION: UNITARY DIAGNOSTIC CODES
D igit 3
D igit 2
D igit 1
• Integrated co ntro l mo dule
diagno stic/status LED display
sho ws the indicated co de.
B LA NK
A
2
• Outdo o r air temp
senso r fault
• Sho rted senso r.
• Open senso r.
• Senso r
disco nnected.
• Senso r o ut o f
range.
• Check senso r
co nnectio n.
• Replace o pen/
sho rted senso r.
• Turn po wer OFF prio r to
repair.
• Replace with co rrect
replacement part.
• Heat pump fails to o perate in
heating mo de.
• Integrated co ntro l mo dule
diagno stic/status LED display
sho ws the indicated co de.
B LA NK
A
3
• Outdo o r co il
temp senso r fault
• Sho rted senso r
• Open senso r.
• Senso r.
disco nnected.
• Senso r o ut o f
range.
• Check senso r
co nnectio n.
• Replace o pen/
sho rted senso r.
• Turn po wer OFF prio r to
repair.
• Replace with co rrect
replacement part.
• A ir co nditio ner/heat pump
fails to o perate.
• Integrated co ntro l mo dule
diagno stic/status LED display
sho ws the
indicated co de.
B LA NK
E
5
• Open fuse
• Sho rt in lo w vo ltage
wiring.
• Lo cate and co rrect
sho rt in lo w vo ltage
wiring.
• Turn po wer OFF prio r to
repair.
• Replace fuse with
3-amp auto mo tive type.
• A ir co nditio ner/heat pump
fails to o perate.
• Integrated co ntro l mo dule
diagno stic/status LED display
sho ws the
indicated co de.
B LA NK
E
E
• B o ard mis-
o peratio n
• Co mpresso r relay
co ntacts welded.
• Replace co ntro l.
• Turn po wer OFF prio r to
repair
• Replace with co rrect
replacement part.
• A ir co nditio ner/heat pump
fails to o perate.
• Integrated co ntro l mo dule
diagno stic/status LED display
sho ws the indicated co de.
B LA NK
b
0
• Circulato r
blo wer mo to r is
no t running when it
sho uld be running.
• Indo o r bIo wer
mo to r pro blem.
• Co mmunicatio ns
erro r between
indo o r and o utdo o r
unit.
• Check indo o r
bIo wer mo to r.
• Check indo o r
bIo wer mo to r wiring.
• Check indo o r unit
co ntro l.
• Repair/ replace any
faulty wiring.
• Repair/ replace
indo o r bIo wer mo to r
o r co ntro l.
• Turn po wer OFF prio r to
repair.
• Replace with co rrect
replacement part.
• A ir co nditio ner/heat
pump o perates at reduced
perfo rmance.
• A ir co nditio ner/heat pump
o perating at lo w stage when
expected to o perate at high
stage.
• Integrated co ntro l mo dule
diagno stic/status LED display
sho ws the indicated co de.
B LA NK
b
9
• A ir flo w is lo wer
than demanded
• Indo o r bIo wer
mo to r pro blem
• B lo cked filters .
• Restrictive/
undersized ductwo rk
• Indo o r/ o utdo o r
unit miss-match.
• Check indo o r
blo wer mo to r.
• Check Filters
clean/replace as
needed.
• Check ductwo rk,
resize as needed.
• Verify indo o r and
o utdo o r units are
pro perly matched.
• Turn po wer OFF prio r to
repair.
• Replace with co rrect
replacement part. See speci
catio n sheet s fo r air o w re
uirements and ma imum e
ter nal static pressure.
• See specificatio n sheets
fo r appro ved
system matches.
SYSTEM TROUBLESHOOTING
UNITARY DIAGNOSTIC CODES
S ym pt o m s o f A bno rm a l
O pe ra t io n
( Le ga c y & C o m f o rt N e t ™
T he rm o s t a t )
D ia gno s t ic / S t a t us
LE D D is pla y C o de s
F a ult
D e s c ript io n
P o s s ible
C a us e s
C o rre c t iv e
A c t io ns
N o t e s
&
C a ut io ns
