17
TROUBLESHOOTING INFORMATION: UNITARY DIAGNOSTIC CODES
D igit 3
D igit 2
D igit 1
• Co mpresso r and o utdo o r fan are
o ff.
• Lo w pressure switch trip 3 times
within same thermo stat demand.
• Thermo stat demand is present.
• Intergrated co ntro l mo dule
diagno stic/status LED display
sho ws the indicated co de.
B LA NK
L
1
• Lo w P ressure Cut
Out Lo cko ut (3 Trips)
• Lo w refrigerant
charge.
• Restrictio n in
liquid line.
• Indo o r blo wer
mo to r failure.
• Indo o r
thermo stat set
extremely lo w.
• Verify refrigerant
charge; adjust as
needed.
• Check fo r
restricted liquid
line; repair/replace
as needed.
• Check indo o r
blo wer mo to r;
repair/replace as
needed.
• Check lo w
pressure switch;
repair/replace as
needed.
• Check indo o r
thermo stat setting.
• Turn po wer OFF prio r
to repair.
• M ust clear fault by
cycling 24 VA C to
co ntro l.
• Replace with co rrect
replacement part(s).
•
Fo ur co nsecutive co mpresso r
pro tecto r trips with average run
time between trips greater than 1
minute and less than 15 minutes.
• Lo w pressure and high pressure
switches are clo sed.
• Intergrated co ntro l mo dule
diagno stic/status LED display
sho ws the indicated co de.
B LA NK
0
2
• High Side Fault
• B lo cked
co ndenser co il.
• Outdo o r fan no t
running.
• Check and clean
co ndenser co il.
• Check o utdo o r
fan mo to r;
repair/replace as
needed.
• Check o utdo o r
fan mo to r wiring;
repair/replace as
needed.
• Check o utdo o r
fan mo to r
capacito r; replace
as needed.
• Turn po wer OFF prio r
to repair.
• Fault will clear after 4
co nsecutive no rmal
cycles.
• Fault may be cleared
by cycling 24 VA C to
co ntro l.
• Replace with co rrect
replacement part(s)
• Co mpresso r and o utdo o r fan are
o ff.
• Thermo stat demand is present.
• Intergrated co ntro l mo dule
diagno stic/status LED display
sho ws the indicated co de.
B LA NK
0
2
• High P ressure Cut
Out Trip
• B lo cked
co ndenser co il.
• Outdo o r fan no t
running.
• Check and clean
co ndenser co il.
• Check o utdo o r
fan mo to r;
repair/replace as
needed.
• Check o utdo o r
fan mo to r wiring;
repair/replace as
needed.
• Check o utdo o r
fan mo to r
capacito r; replace
as needed.
• Turn po wer OFF prio r
to repair.
• Replace with co rrect
replacement part(s).
• Co mpresso r and o utdo o r fan
are o ff.
• Lo w pressure switch trip 3 times
within same thermo stat demand.
• Thermo stat demand is present.
• Intergrated co ntro l mo dule
diagno stic/status LED display
sho ws the indicated co de.
B LA NK
L
2
• High P ressure Cut
Out Lo cko ut (3 Trips)
• B lo cked
co ndenser co il.
• Outdo o r fan no t
running.
• Check and clean
co ndenser co il.
• Check o utdo o r
fan mo to r;
repair/replace as
needed.
• Check o utdo o r
fan mo to r wiring;
repair/replace as
needed.
• Check o utdo o r
fan mo to r
capacito r; replace
as needed.
•Turn po wer OFF prio r
to repair.
•M ust clear fault by
cycling 24 VA C to
co ntro l.
•Replace with co rrect
replacement part(s).
Sym ptom s of Abnorm al
Operation (Legacy &
Com fortNet™
Therm ostat)
Fault
Description
Possible
Causes
Corrective
Actions
Notes & Cautions
UNITARY DIAGNOSTIC CODES
Diagnostic/Status
LED Display Codes