Carrier 48HC 04-28 Controls, Start-Up, Operation And Troubleshooting page 46

alert will show you one of the below alerts. All these alerts are
generated by the OAU device and reported to the MBB. These
alerts can only occur if the Outdoor Air Unit Type (Configura-
 
tion OAU OA.TY) is not set to 0. Control action is only tak-
en on the OAU side and these alerts will reset automatically
when the OAU clears them. Refer to the EnergyX Supplemental
Installation Instructions for more information on these alarms.
• OAU Motor Failure
This alert occurs when the OAU Motor Failure Alarm (Operat-
 
ing Modes OAU ALM.1) is on. This is usually due to mo-
tor status reporting a failure on the OAU.
• OAU Dirty Filter
This alert occurs when the OAU Dirty Filter Alarm (Operating
 
Modes OAU ALM.2) is on. This is usually due to filter sta-
tus reporting a dirty filter on the OAU.
• OAU Low CFM
This alert occurs when the OAU Low CFM Alarm (Operating
 
Modes OAU ALM.3) is on. This is usually due to OAU not
capable of achieving proper CFM. If unit is equipped with a
VFD on the indoor fan, the configuration OAU Fan Boost En-
ALARM
OR
DESCRIPTION
ALERT
NUMBER
Compressor A1 Safety Trip
Service Test — Compressor A1
Safety Trip
T051
Compressor A1 Detected After
Turnoff
Service Test — Compressor A1
Detected After Turnoff
Compressor B1 Safety Trip
Service Test — Compressor B1
Safety Trip
T055
Compressor B1 Detect After Turnoff Turn off all compressors
Service Test — Compressor B1
Detected After Turnoff
Circuit A Saturated Condensing
T064
Temp Thermistor Failure
Circuit B Saturated Condensing
T065
Temp Thermistor Failure
Circuit A Saturated Suction
T066
Temperature Thermistor Failure
Circuit B Saturated Suction
T067
Temperature Thermistor Failure
Outdoor Air Temperature
T073
Thermistor Failure
Space Temperature Thermistor
T074
Failure
Supply Air Temperature Thermistor
T075
Failure
T076 Return Air Thermistor Failure
Space Relative Humidity Sensor
T077
Failure
Circuit A Suction Pressure
T092
Transducer Failure
Circuit B Suction Pressure
T093
Transducer Failure
Compressor A1 Current Sensor
T102
Failure
Compressor A1 Current Sensor
T103
Failure
Circuit A Loss of Charge
T110
Service Test — Circuit A Loss of
Charge
able is set to yes (Configuration
this alarm is active for 10 minutes, the fan will be commanded
to the next highest configured fan speed. If this alarm is still
active after another 10 minutes, the fan will again change to the
next highest configured fan speed, and so on every 10 minutes
until the maximum speed is commanded. The fan will stay at
this override commanded speed until this alarm clears and a
different function changes the commanded speed.
•
This alert occurs when the OAU Alarm (Operating Modes

tation for details.
Alert Code A420 — Supply VFD Fault
This alarm occurs when the VFD has faulted and communi-
cates it to the Main Base Board (MBB). The last VFD fault
number can be viewed as VFD1 Last Full code (Run Sta-
tus
for details on its alarms and faults. The alarm will shut down
the unit if the fan ramps down to 0%. This alarm will automat-
ically reset or can be reset through the display.
Table 14 — ComfortLink Alarm Codes
ACTION TAKEN BY
CONTROL
Add Strike for Circuit A
Turn off all compressors
Add Strike for Circuit B
Limited Diagnostic
Limited Diagnostic
No Circuit A Cooling
No Circuit B Cooling
No cooling with economizer
If U.CTL = 3, then no heating
or cooling
No cooling with economizer
and No adaptive compressor
staging
If RAT.S = Yes, then no
differential Dry Bulb control
If RH.S = Yes, then no indoor
humidity control
Lockout Circuit A
Lockout Circuit B
If CS.A1 = Enable, then no
T051 current alarm
If CS.B1 = Enable, then no
T055 current alarm
Lockout Circuit A
46
OAU General Alarm

OAU ALM.4) is on. Refer to the specific OAU documen-
 
S.VFD LFC). Refer to VFD major component section
RESET
PROBABLE CAUSE
METHOD
High-pressure switch open. Compressor internal
Automatic
protection open. Wiring error
Automatic Welded contactor
Automatic High-pressure switch open. Compressor internal
protection open. Wiring error
Automatic
Welded contactor
Faulty, shorted, or open thermistor caused by wiring
Automatic
error or loose connection.
Automatic Faulty, shorted, or open thermistor caused by wiring
error or loose connection.
Automatic Circuit A Suction transducer internally forced inactive
Automatic Circuit B Suction transducer internally forced inactive
Automatic Faulty, shorted, or open thermistor caused by wiring
error or loose connection.
Faulty, shorted, or open thermistor caused by wiring
Automatic
error or loose connection.
Automatic Faulty, shorted, or open thermistor caused by wiring
error or loose connection.
Faulty, shorted, or open thermistor caused by wiring
Automatic
error or loose connection.
Automatic Faulty, shorted, or open sensor caused by wiring error
or loose connection.
Faulty transducer, faulty 5-V power supply, or loose
Manual
connection
Faulty transducer, faulty 5-V power supply, or loose
Manual
connection
Automatic Faulty transducer, faulty 5-V power supply, or loose
connection
Faulty transducer, faulty 5-V power supply, or loose
Automatic
connection
Manual Low refrigerant or faulty suction pressure transducer
 
OAU EFBE = Yes), and