28
Dual 7-Segment
LEDs Display
Code
Diagnostic Description
Status/Possible Cause – Troubleshooting
Information
2
9 – High Pressure Control Open
The ICC detects the HPC is open
•
Outdoor coil is dirty (cooling mode)
•
Outdoor fan is not running (cooling mode)
•
Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
12
2
1 – Low Pressure Control Open
The ICC detects the LPC is open.
N
ote: The low pressure control is ignored
f
or the first 90 seconds of compressor
operation
• Unit has low refrigerant charge
• Indoor coil is frozen (cooling mode)
• Dirty indoor coil or filter (cooling mode)
• Indoor blower is not running (cooling mode)
• Outdoor coil is frozen (heating mode)
• Outdoor fan is not running (heating mode)
• Expansion valve is not operating correctly
FLASHING
L21 – Active Protection
Low Pressure
Control Trip
T
he ICC has locked out the compressor due to
three (3) consecutive LPC trips on the same
command for unit operation
2
7 – Low Line Voltage or No Line Voltage
Fault
• Check incoming line voltage to the disconnect
and unit
• Check wiring connections
28 – High Line Voltage Fault
•
Check line voltage
2
9 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.
L29 – Active Protection High Pressure
Control Trip
LPC has opened 3 times in the same cooling
operation, the ICC has locked out the com-
pressor to protect it. ICC alternately flashes L
and 29
(see 29 above)
LPC has opened 3 times in the same cooling
operation, the ICC has locked out the compressor
to protect it. ICC alternately flashes L and 29
12
2
1 – Low Pressure Control Open
The ICC detects the LPC is open.
N
ote: The low pressure control is ignored
f
or the first 90 seconds of compressor
operation
• Unit has low refrigerant charge
• Indoor coil is frozen (cooling mode)
• Dirty indoor coil or filter (cooling mode)
• Indoor blower is not running (cooling mode)
• Outdoor coil is frozen (heating mode)
• Outdoor fan is not running (heating mode)
• Expansion valve is not operating correctly
FLASHING
L21 – Active Protection
Low Pressure
Control Trip
T
he ICC has locked out the compressor due to
three (3) consecutive LPC trips on the same
command for unit operation
2
7 – Low Line Voltage or No Line Voltage
Fault
• Check incoming line voltage to the disconnect
and unit
• Check wiring connections
28 – High Line Voltage Fault
•
Check line voltage
29 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.
80 – Low Air Flow
The ICC detects that the indoor unit is
not providing the minimum airflow
requirements.
• Misapplied/wrong indoor air mover –
replace with properly sized unit.
12
21 – Low Pressure Control Open
The ICC detects the LPC is open.
Note: The low pressure control is ignored
for the first 90 seconds of compressor
o
peration
•
Unit has low refrigerant charge
• Indoor coil is frozen (cooling mode)
•
Dirty indoor coil or filter (cooling mode)
•
Indoor blower is not running (cooling mode)
• Outdoor coil is frozen (heating mode)
• Outdoor fan is not running (heating mode)
•
Expansion valve is not operating correctly
FLASHING
L
21 – Active Protection
Low Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive LPC trips on the same
command for unit operation
27 – Low Line Voltage or No Line Voltage
Fault
• Check incoming line voltage to the disconnect
a
nd unit
•
Check wiring connections
28 – High Line Voltage Fault
• Check line voltage
29 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.
12
21 – Low Pressure Control Open
The ICC detects the LPC is open.
Note: The low pressure control is ignored
for the first 90 seconds of compressor
operation
• Unit has low refrigerant charge
• Indoor coil is frozen (cooling mode)
• Dirty indoor coil or filter (cooling mode)
• Indoor blower is not running (cooling mode)
• Outdoor coil is frozen (heating mode)
• Outdoor fan is not running (heating mode)
• Expansion valve is not operating correctly
FLASHING
L21 – Active Protection
Low Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive LPC trips on the same
command for unit operation
27 – Low Line Voltage or No Line Voltage
Fault
• Check incoming line voltage to the disconnect
and unit
• Check wiring connections
28 – High Line Voltage Fault
• Check line voltage
29 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
• Check sensor is installed correctly on control
12
2
1 – Low Pressure Control Open
T
he ICC detects the LPC is open.
Note: The low pressure control is ignored
f
or the first 90 seconds of compressor
operation
• Unit has low refrigerant charge
• Indoor coil is frozen (cooling mode)
• Dirty indoor coil or filter (cooling mode)
• Indoor blower is not running (cooling mode)
•
Outdoor coil is frozen (heating mode)
•
Outdoor fan is not running (heating mode)
• Expansion valve is not operating correctly
F
LASHING
L21 – Active Protection
Low Pressure
Control Trip
T
he ICC has locked out the compressor due to
three (3) consecutive LPC trips on the same
c
ommand for unit operation
27 – Low Line Voltage or No Line Voltage
Fault
• Check incoming line voltage to the disconnect
and unit
• Check wiring connections
28 – High Line Voltage Fault
•
Check line voltage
29 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
• Check sensor is installed correctly on control
12
21 – Low Pressure Control Open
The ICC detects the LPC is open.
Note: The low pressure control is ignored
for the first 90 seconds of compressor
o
peration
•
Unit has low refrigerant charge
• Indoor coil is frozen (cooling mode)
• Dirty indoor coil or filter (cooling mode)
•
Indoor blower is not running (cooling mode)
• Outdoor coil is frozen (heating mode)
• Outdoor fan is not running (heating mode)
•
Expansion valve is not operating correctly
FLASHING
L21 – Active Protection
Low Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive LPC trips on the same
command for unit operation
27 – Low Line Voltage or No Line Voltage
F
ault
•
Check incoming line voltage to the disconnect
and unit
•
Check wiring connections
28 – High Line Voltage Fault
• Check line voltage
29 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.
93 – Internal Control Fault
The control is not functioning
properly.
• Check control for proper system
operation.
• Replace control
12
21 – Low Pressure Control Open
The ICC detects the LPC is open.
Note: The low pressure control is ignored
for the first 90 seconds of compressor
o
peration
•
Unit has low refrigerant charge
•
Indoor coil is frozen (cooling mode)
• Dirty indoor coil or filter (cooling mode)
• Indoor blower is not running (cooling mode)
• Outdoor coil is frozen (heating mode)
• Outdoor fan is not running (heating mode)
• Expansion valve is not operating correctly
FLASHING
L21 – Active Protection
Low Pressure
C
ontrol Trip
The ICC has locked out the compressor due to
t
hree (3) consecutive LPC trips on the same
command for unit operation
27 – Low Line Voltage or No Line Voltage
F
ault
•
Check incoming line voltage to the disconnect
and unit
• Check wiring connections
28 – High Line Voltage Fault
• Check line voltage
29 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.
12
2
1 – Low Pressure Control Open
The ICC detects the LPC is open.
N
ote: The low pressure control is ignored
f
or the first 90 seconds of compressor
operation
• Unit has low refrigerant charge
• Indoor coil is frozen (cooling mode)
• Dirty indoor coil or filter (cooling mode)
• Indoor blower is not running (cooling mode)
• Outdoor coil is frozen (heating mode)
• Outdoor fan is not running (heating mode)
• Expansion valve is not operating correctly
FLASHING
L21 – Active Protection
Low Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive LPC trips on the same
command for unit operation
27 – Low Line Voltage or No Line Voltage
Fault
• Check incoming line voltage to the disconnect
and unit
• Check wiring connections
28 – High Line Voltage Fault
• Check line voltage
29 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
12
2
1 – Low Pressure Control Open
T
he ICC detects the LPC is open.
Note: The low pressure control is ignored
f
or the first 90 seconds of compressor
operation
• Unit has low refrigerant charge
• Indoor coil is frozen (cooling mode)
• Dirty indoor coil or filter (cooling mode)
• Indoor blower is not running (cooling mode)
•
Outdoor coil is frozen (heating mode)
•
Outdoor fan is not running (heating mode)
• Expansion valve is not operating correctly
F
LASHING
L21 – Active Protection
Low Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive LPC trips on the same
c
ommand for unit operation
27 – Low Line Voltage or No Line Voltage
Fault
• Check incoming line voltage to the disconnect
and unit
• Check wiring connections
28 – High Line Voltage Fault
•
Check line voltage
29 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.
d1 – No Shared Data • Replace memory card with correct system
information.
11
d1 – No Shared Data
ELECTRONICS GROUP TO
DESCRIBE
d3 – Airflow CFM Mismatch
The indoor air mover (air handler/furnace)
cannot supply the required airflow for
proper system operation
• Misapplied/wrong indoor air mover – replace
with properly sized air handler/furnace.
P – Protector Trip
A command for compressor operation is
present but no current is measured to the
compressor
• Motor protector open
• Line voltage disconnected
01 – Long Run Time (Compressor)
The compressor has continuously run for
more than 18 hours in the cooling mode.
• Low refrigerant charge
• Air ducts have substantial leakage
• Dirty indoor air filter
• Dirty outdoor coil
02 – High Pressure Control Open
The ICC detects the HPC is open.
Reference ICC codes:
• 21
• L21
• 29
• L29
03 – Short Cycling
The ICC detects the run time for the past
four (4) compressor cycles is less than three
(3) minutes each.
• Check thermostat wire connections (R, C, 1, &
2)
• Check thermostat location in zone (too close to
discharge grill)
L4 – Locked Rotor
The ICC detects four (4) consecutive
protector trips have occurred and the
average run time for each trip is less than 15
seconds
• Bad run capacitor
• Low line voltage
• Excessive refrigerant in compressor
• Seized bearings in compressor
05 – Open Circuit (Compressor will not
Run)
• The ICC has received a command for
unit operation but no current is present in
the start and run circuits.
• The ICC will attempt to restart the unit
every five (5) minutes for four (4)
attempts. After that, the ICC will attempt
a restart every twenty (20) minutes for up
to four (4) hours.
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
• Check for open compressor internal protector
06 – Compressor Open Start Circuit
The ICC detects current in the Run circuit
but not in the Start circuit of the compressor
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
07 – Compressor Open Run Circuit
The ICC detects current in the Start circuit
but not in the Run circuit of the compressor
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
09 – Low Secondary Volts
The secondary voltage at R and C is below
18VAC
• Control transformer overloaded
• Low line voltage
d3 – Airflow CFM Mismatch
The indoor air mover (air
handler/furnace) cannot supply the
required airflow for proper system
operation
• Misapplied/wrong indoor air mover –
replace with properly sized air
handler/furnace.
11
d1 – No Shared Data
ELECTRONICS GROUP TO
DESCRIBE
d3 – Airflow CFM Mismatch
The indoor air mover (air handler/furnace)
cannot supply the required airflow for
proper system operation
• Misapplied/wrong indoor air mover – replace
with properly sized air handler/furnace.
P – Protector Trip
A command for compressor operation is
present but no current is measured to the
compressor
• Motor protector open
• Line voltage disconnected
01 – Long Run Time (Compressor)
The compressor has continuously run for
more than 18 hours in the cooling mode.
• Low refrigerant charge
• Air ducts have substantial leakage
• Dirty indoor air filter
• Dirty outdoor coil
02 – High Pressure Control Open
The ICC detects the HPC is open.
Reference ICC codes:
• 21
• L21
• 29
• L29
03 – Short Cycling
The ICC detects the run time for the past
four (4) compressor cycles is less than three
(3) minutes each.
• Check thermostat wire connections (R, C, 1, &
2)
• Check thermostat location in zone (too close to
discharge grill)
L4 – Locked Rotor
The ICC detects four (4) consecutive
protector trips have occurred and the
average run time for each trip is less than 15
seconds
• Bad run capacitor
• Low line voltage
• Excessive refrigerant in compressor
• Seized bearings in compressor
05 – Open Circuit (Compressor will not
Run)
• The ICC has received a command for
unit operation but no current is present in
the start and run circuits.
• The ICC will attempt to restart the unit
every five (5) minutes for four (4)
attempts. After that, the ICC will attempt
a restart every twenty (20) minutes for up
to four (4) hours.
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
• Check for open compressor internal protector
06 – Compressor Open Start Circuit
The ICC detects current in the Run circuit
but not in the Start circuit of the compressor
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
07 – Compressor Open Run Circuit
The ICC detects current in the Start circuit
but not in the Run circuit of the compressor
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
09 – Low Secondary Volts
The secondary voltage at R and C is below
18VAC
• Control transformer overloaded
• Low line voltage
d4 – (Device) Memory Card Invalid for
Device
The data in the memory card inserted
into the control board does not match
the data in the control.
• Check memory card to ensure it matches
device
• Check if memory card is present
11
d1 – No Shared Data
ELECTRONICS GROUP TO
DESCRIBE
d3 – Airflow CFM Mismatch
The indoor air mover (air handler/furnace)
cannot supply the required airflow for
proper system operation
• Misapplied/wrong indoor air mover – replace
with properly sized air handler/furnace.
P – Protector Trip
A command for compressor operation is
present but no current is measured to the
compressor
• Motor protector open
• Line voltage disconnected
01 – Long Run Time (Compressor)
The compressor has continuously run for
more than 18 hours in the cooling mode.
• Low refrigerant charge
• Air ducts have substantial leakage
• Dirty indoor air filter
• Dirty outdoor coil
02 – High Pressure Control Open
The ICC detects the HPC is open.
Reference ICC codes:
• 21
• L21
• 29
• L29
03 – Short Cycling
The ICC detects the run time for the past
four (4) compressor cycles is less than three
(3) minutes each.
• Check thermostat wire connections (R, C, 1, &
2)
• Check thermostat location in zone (too close to
discharge grill)
L4 – Locked Rotor
The ICC detects four (4) consecutive
protector trips have occurred and the
average run time for each trip is less than 15
seconds
• Bad run capacitor
• Low line voltage
• Excessive refrigerant in compressor
• Seized bearings in compressor
05 – Open Circuit (Compressor will not
Run)
• The ICC has received a command for
unit operation but no current is present in
the start and run circuits.
• The ICC will attempt to restart the unit
every five (5) minutes for four (4)
attempts. After that, the ICC will attempt
a restart every twenty (20) minutes for up
to four (4) hours.
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
• Check for open compressor internal protector
06 – Compressor Open Start Circuit
The ICC detects current in the Run circuit
but not in the Start circuit of the compressor
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
07 – Compressor Open Run Circuit
The ICC detects current in the Start circuit
but not in the Run circuit of the compressor
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
09 – Low Secondary Volts
The secondary voltage at R and C is below
18VAC
• Control transformer overloaded
• Low line voltage
11
d1 – No Shared Data
ELECTRONICS GROUP TO
DESCRIBE
d3 – Airflow CFM Mismatch
The indoor air mover (air handler/furnace)
cannot supply the required airflow for
proper system operation
• Misapplied/wrong indoor air mover – replace
with properly sized air handler/furnace.
P – Protector Trip
A command for compressor operation is
present but no current is measured to the
compressor
• Motor protector open
• Line voltage disconnected
01 – Long Run Time (Compressor)
The compressor has continuously run for
more than 18 hours in the cooling mode.
• Low refrigerant charge
• Air ducts have substantial leakage
• Dirty indoor air filter
• Dirty outdoor coil
02 – High Pressure Control Open
The ICC detects the HPC is open.
Reference ICC codes:
• 21
• L21
• 29
• L29
03 – Short Cycling
The ICC detects the run time for the past
four (4) compressor cycles is less than three
(3) minutes each.
• Check thermostat wire connections (R, C, 1, &
2)
• Check thermostat location in zone (too close to
discharge grill)
L4 – Locked Rotor
The ICC detects four (4) consecutive
protector trips have occurred and the
average run time for each trip is less than 15
seconds
• Bad run capacitor
• Low line voltage
• Excessive refrigerant in compressor
• Seized bearings in compressor
05 – Open Circuit (Compressor will not
Run)
• The ICC has received a command for
unit operation but no current is present in
the start and run circuits.
• The ICC will attempt to restart the unit
every five (5) minutes for four (4)
attempts. After that, the ICC will attempt
a restart every twenty (20) minutes for up
to four (4) hours.
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
• Check for open compressor internal protector
06 – Compressor Open Start Circuit
The ICC detects current in the Run circuit
but not in the Start circuit of the compressor
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
07 – Compressor Open Run Circuit
The ICC detects current in the Start circuit
but not in the Run circuit of the compressor
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
09 – Low Secondary Volts
The secondary voltage at R and C is below
18VAC
• Control transformer overloaded
• Low line voltage
d8 – Old Shared Data
System data is obsolete
• If system will not operate, order new
memory card to update system
information.
12
21 – Low Pressure Control Open
The ICC detects the LPC is open.
Note: The low pressure control is ignored
for the first 90 seconds of compressor
operation
• Unit has low refrigerant charge
• Indoor coil is frozen (cooling mode)
• Dirty indoor coil or filter (cooling mode)
• Indoor blower is not running (cooling mode)
• Outdoor coil is frozen (heating mode)
• Outdoor fan is not running (heating mode)
• Expansion valve is not operating correctly
FLASHING
L21 – Active Protection
Low Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive LPC trips on the same
command for unit operation
27 – Low Line Voltage or No Line Voltage
Fault
• Check incoming line voltage to the disconnect
and unit
• Check wiring connections
28 – High Line Voltage Fault
• Check line voltage
29 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.
11
d1 – No Shared Data
ELECTRONICS GROUP TO
DESCRIBE
d3 – Airflow CFM Mismatch
The indoor air mover (air handler/furnace)
cannot supply the required airflow for
proper system operation
• Misapplied/wrong indoor air mover – replace
with properly sized air handler/furnace.
P – Protector Trip
A command for compressor operation is
present but no current is measured to the
compressor
• Motor protector open
• Line voltage disconnected
01 – Long Run Time (Compressor)
The compressor has continuously run for
more than 18 hours in the cooling mode.
• Low refrigerant charge
• Air ducts have substantial leakage
• Dirty indoor air filter
• Dirty outdoor coil
02 – High Pressure Control Open
The ICC detects the HPC is open.
Reference ICC codes:
• 21
• L21
• 29
• L29
03 – Short Cycling
The ICC detects the run time for the past
four (4) compressor cycles is less than three
(3) minutes each.
• Check thermostat wire connections (R, C, 1, &
2)
• Check thermostat location in zone (too close to
discharge grill)
L4 – Locked Rotor
The ICC detects four (4) consecutive
protector trips have occurred and the
average run time for each trip is less than 15
seconds
• Bad run capacitor
• Low line voltage
• Excessive refrigerant in compressor
• Seized bearings in compressor
05 – Open Circuit (Compressor will not
Run)
• The ICC has received a command for
unit operation but no current is present in
the start and run circuits.
• The ICC will attempt to restart the unit
every five (5) minutes for four (4)
attempts. After that, the ICC will attempt
a restart every twenty (20) minutes for up
to four (4) hours.
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
• Check for open compressor internal protector
06 – Compressor Open Start Circuit
The ICC detects current in the Run circuit
but not in the Start circuit of the compressor
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
07 – Compressor Open Run Circuit
The ICC detects current in the Start circuit
but not in the Run circuit of the compressor
• Check for damaged, miswired, or wrong run
capacitor
• Check for broken wires, loose connectors, or
miswired compressor
• Check compressor windings for continuity
09 – Low Secondary Volts
The secondary voltage at R and C is below
18VAC
• Control transformer overloaded
• Low line voltage
28 – High Line Voltage Fault • Check line voltage
12
2
1 – Low Pressure Control Open
The ICC detects the LPC is open.
N
ote: The low pressure control is ignored
f
or the first 90 seconds of compressor
operation
• Unit has low refrigerant charge
•
Indoor coil is frozen (cooling mode)
• Dirty indoor coil or filter (cooling mode)
• Indoor blower is not running (cooling mode)
• Outdoor coil is frozen (heating mode)
• Outdoor fan is not running (heating mode)
• Expansion valve is not operating correctly
F
LASHING
L21 – Active Protection
Low Pressure
C
ontrol Trip
The ICC has locked out the compressor due to
t
hree (3) consecutive LPC trips on the same
command for unit operation
27 – Low Line Voltage or No Line Voltage
Fault
• Check incoming line voltage to the disconnect
and unit
• Check wiring connections
28 – High Line Voltage Fault
• Check line voltage
29 – High Pressure Control Open
The ICC detects the HPC is open
• Outdoor coil is dirty (cooling mode)
• Outdoor fan is not running (cooling mode)
• Dirty indoor coil or filter (heating mode)
• Indoor blower is not running (heating mode)
• Liquid line restriction
• Excessive refrigerant charge
FLASHING
L29 – Active Protection High Pressure
Control Trip
The ICC has locked out the compressor due to
three (3) consecutive HPC trips on the same
command for unit operation
30 – Fuse Open
The ICC detects the on-board fuse is open
• The 3-amp fuse on the ICC is open.
• Low voltage wiring at R and C is damaged or
miswired.
83 – Condenser Coil Temperature Fault
The sensor detects an abnormally low or
high coil temperature
• Replace the sensor
84 – Outdoor Ambient Temperature Fault
The sensor detects an abnormally low or
high outdoor ambient temperature
• Check unit placement – If the outdoor unit is in
a high temperature area, wait until the ambient
temperature drops and check sensor reading.
• Replace the sensor.
90 – Communication Fault
The ICC detects and internal fault condition
• Replace the ICC.