20
TROUBLESHOOTING INFORMATION: UNITARY DIAGNOSTIC CODES
D igit 3
D igit 2
D igit 1
• A ir co nditio ner/heat
pump may appear to be
o perating no rmally.
• Co mpresso r pro teco r
may be o pen (co mpresso r
and o utdo o r fan o ff).
• Integrated co ntro l
mo dule diagno stic/status
LED display sho ws the
indicated co de.
B LA NK
H
8
• High Line
Vo ltage
• High line vo ltage • Co rrect high line
vo ltage co nditio n;
co ntact lo cal utility
if needed.
• Verify unit is
co nnected to
po wer supply as
specified o n rating
plate.
• Turn po wer OFF
prio r to repair.
• Co ntro l detects
line vo ltage greater
than 255 VA C.
• Fault will clear if
line vo ltage
decreases belo w
255 VA C.
• A ir co nditio ner/heat
pump may appear to be
o perating no rmally.
• Integrated co ntro l
mo dule diagno stic/status
LED display sho ws the
indicated co de.
B LA NK
0
9
• Lo w P ilo t
Vo ltage
• Co ntro l detects
seco ndary
vo ltage less than
18 VA C.
• Transfo rmer
o verlo aded.
• Lo w line vo ltage.
• Check fuse.
• Co rrect lo w
seco ndary vo ltage
co nditio n.
• Check
transfo rmer;
replace if needed.
• Turn po wer OFF
prio r to repair.
• Fault will clear if
seco ndary vo ltage
rises abo ve 21 VA C.
• Replace with
co rrect
replacement part(s).
• Co mpresso r is o ff.
• Integrated co ntro l
mo dule diagno stic/status
LED display sho ws the
indicated co de.
B LA NK
P
0
• Co mp
pro tecto r Open
• No current
thro ugh run o r
start windings.
• Co mpresso r run
winding is o pen.
• Co mpresso r
no t pro perly wired
to co ntro l.
• Faulty
Co mpresso r
wiring.
• Failed
co mpresso r run
capacito r.
• Faulty run
capacito r wiring.
• Check
co mpresso r;
repair/replace as
needed.
• Check wiring
repair/replaced as
needed.
• Check run
capacito r; replace
as needed.
• Turn po wer OFF
prio r to repair.
• Fault will clear
after 1 no rmal cycle.
• M ust clear fault by
cycling 24 VA C to
co ntro l.
• Replace with
co rrect
replacement part(s).
• A ir co nditio ner/heat
pump may appear to be
o perating no rmally.
• Co mpresso r pro teco r
may be o pen (co mpresso r
and o utdo o r fan o ff).
• Integrated co ntro l
mo dule diagno stic/status
LED display sho ws the
indicated co de.
B LA NK
L
8
• Lo w Line
Vo ltage
• Lo w line vo ltage. • Check circuit
breakers and
fuses.
• Verify unit is
co nnected to
po wer supply as
specified o n rating
plate.
• Co rrect lo w line
vo ltage co nditio n;
co ntact lo cal utility
if needed.
• Turn po wer OFF
prio r to repair.
• Co ntro l detects
line vo ltage less
than 185 VA C.
• Fault will clear if
line vo ltage
increases abo ve
185 VA C.
• A ir co nditio ner/heat
pump may appear to be
o perating no rmally.
• Co mpresso r pro teco r
may be o pen (co mpresso r
and o utdo o r fan o ff).
• Integrated co ntro l
mo dule diagno stic/status
LED display sho ws the
indicated co de.
B LA NK
L
8
• No Line
Vo ltage
• No line vo ltage.
• Check circuit
breakers and
fuses.
• Verify unit is
co nnected to
po wer supply as
specified o n rating
plate.
• Turn po wer OFF
prio r to repair.
• Co ntro l detects
line vo ltage less
than 185 VA C.
• Fault will clear if
line vo ltage
increases abo ve
185 VA C.
UN IT A R Y D IA G N O S T IC C O D E S
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
