GSZC18 Installation

14
TROUBLESHOOTING INFORMATION: UNITARY DIAGNOSTIC CODES
Digit3 Digit2 Digit 1
• In
tegrated control module
diagnostic/status LED display shows
the indicated code.
BLANK A 2 • Outdoor air temp
sensor fault
• Shorted sensor.
• Open sensor.
• Sensor disconnected.
• Sensor out of range.
• Check sensor
connection.
• Replace open/ shorted
sensor.
•
T
urn power OFF prior to repair.
•
R
eplace with correct
replacement part.
• Heat pump fails to operate in
heating mode.
• In
tegrated control module
diagnostic/status LED display shows
the indicated code.
BLANK A 3 • Outdoor coil temp
sensor fault
• Shorted sensor
• Open sensor.
• Sensor. disconnected.
• Sensor out of range.
• Check sensor
connection.
•
Re
place open/ shorted
sensor.
•
T
urn power OFF prior to repair.
•
R
eplace with correct
replacement part.
•
A
ir conditioner/heat pump fails to
operate.
• In
tegrated control module
diagnostic/status LED display shows
the
indicated code.
BLANK E 5 • Open fuse • Short in low voltage
wiring.
• Locate and correct short
in low voltage wiring.
• Turn power OFF prior to repair.
•
R
eplace fuse with
3-amp automotive type.
•
A
ir conditioner/heat pump fails to
operate.
• In
tegrated control module
diagnostic/status LED display shows
the
indicated code.
BLANK E E • Board mis- operation • Compressor relay
contacts welded.
•
R
eplace control. • Turn power OFF prior to repair
•
R
eplace with correct
replacement part.
•
A
ir conditioner/heat pump fails to
operate.
• In
tegrated control module
diagnostic/status LED display shows
the indicated code.
BLANK b0• Circulator
blower motor is not
running when it
should be running.
• In
door bIower motor
problem.
• Communications erro
r
be
tween indoor and
outdoor unit.
• Check indoor bIower
motor.
• Check indoor bIower
motor wiring.
• Check indoor unit
control.
•
Re
pair/ replace any
faulty wiring.
• R
epair/ replace
indoor bIower motor or
control.
•
T
urn power OFF prior to repair.
•
R
eplace with correct
replacement part.
• A
ir conditioner/heat
pump operates at reduced
performance.
•
A
ir conditioner/heat pump
operating at low stage when expected
to operate at high stage.
• In
tegrated control module
diagnostic/status LED display shows
the indicated code.
BLANK b9• Air flow is lower
than demanded
• In
door bIower motor
problem
•
Bl
ocked filters .
•
R
estrictive/ undersized
ductwork
•
I
ndoor/ outdoor unit
miss-match.
• Check indoor blower
motor.
• Check Filters
clean/replace as needed.
• Check ductwork, resize
as needed.
• V
erify indoor and
outdoor units are
p
roperly matched.
•
T
urn power OFF prior to repair.
•
R
eplace with correct
replacement part. See
specification sheets for airflo
w
r
equirements and maximu
m
ex
ternal static pressure.
• See specification sheets for
approved system matches.
SYSTEM TROUBLESHOOTING
UNITARY DIAGNOSTIC CODES
Symptoms of Abnormal
Operation
(Legacy & ComfortNet™
Thermostat)
Diagnostic/Status LED
Display Codes
Fault Description Possible Causes
Corrective
Actions
Notes &
Cautions