Carrier 48/50AJ specifications Alert and Alarm Codes

Table 114 — Alert and Alarm Codes

ALARM OR			RESET
ALERT	DESCRIPTION	ACTION TAKEN BY CONTROL		PROBABLE CAUSE
			METHOD
NUMBER
A051	Circuit A, Compressor 1 Stuck On Failure	Turn off all compressors	Manual	Welded contact
P051	Circuit A, Compressor 1 Failure	Add strike to compressor	Automatic	High pressure switch, compressor
			(max 3)	current, wiring error
T051	Circuit A, Compressor 1 Failure	Compressor locked off	Manual	Exceeded 3 strike limit
A052	Circuit A, Compressor 2 Stuck On Failure	Turn off all compressors	Manual	Welded contact
P052	Circuit A, Compressor 2 Failure	Add strike to compressor	Automatic	High pressure switch, compressor
			(max 3)	current, wiring error
T052	Circuit A, Compressor 2 Failure	Compressor locked off	Manual	Exceeded 3 strike limit
A055	Circuit B, Compressor 1 Stuck On Failure	Turn off all compressors	Manual	Welded contact
P055	Circuit B, Compressor 1 Failure	Add strike to compressor	Automatic	High pressure switch, compressor
			(max 3)	current, wiring error
T055	Circuit B, Compressor 1 Failure	Compressor locked off	Manual	Exceeded 3 strike limit
A056	Circuit B, Compressor 2 Stuck On Failure	Turn off all compressors	Manual	Welded contact
P056	Circuit B, Compressor 2 Failure	Add strike to compressor	Automatic	High pressure switch, compressor
			(max 3)	current, wiring error
T056	Circuit B, Compressor 2 Failure	Compressor locked off	Manual	Exceeded 3 strike limit
T064	Circuit A Saturated Condensing Thermistor Failure	Use OAT for head pressure control	Automatic	Faulty thermistor or wiring error
	(48/50AJ,AK,AW,AY units only)
T065	Circuit B Saturated Condensing Thermistor Failure	Use OAT for head pressure control	Automatic	Faulty thermistor or wiring error
	(48/50AJ,AK,AW,AY units only)
T072	Evaporator Discharge Reset Sensor Failure	Unit shutdown	Automatic	Faulty remote input on CEM board
T073	Outside Air Temperature Thermistor Failure	Stop use of economizer	Automatic	Faulty thermistor or wiring error
T074	Space Temperature Thermistor Failure	Unit shutdown	Automatic	Faulty thermistor or wiring error
T075	Return Air Thermistor Failure	Continue to run unit	Automatic	Faulty thermistor or wiring error
T076	Outside Air Relative Humidity Sensor Failure	Use OAT changeover control	Automatic	Faulty sensor or wiring error
T078	Return Air Relative Humidity Sensor Failure	Use differential dry bulb changeover	Automatic	Faulty sensor or wiring error
T082	Space Temperature Offset Sensor Failure	Use Space temperature without offset	Automatic	Faulty sensor or wiring error
T090	Circuit A Discharge Pressure Transducer Failure	Stop circuit	Automatic	Faulty sensor, wiring error
T091	Circuit B Discharge Pressure Transducer Failure	Stop circuit	Automatic	Faulty sensor, wiring error
T092	Circuit A Suction Pressure Transducer Failure	Stop circuit	Automatic	Faulty sensor, wiring error
T093	Circuit B Suction Pressure Transducer Failure	Stop circuit	Automatic	Faulty sensor, wiring error
T110	Circuit A Loss of Charge	Stop circuit	Manual	Low refrigerant charge
T111	Circuit B Loss of Charge	Stop circuit	Manual	Low refrigerant charge
A120				Low refrigerant charge, low airflow,
	Circuit A Low Saturated Suction Temperature Alarm.	Stop circuit	Manual	dirty coil, broken fan belt, TXV
				problem
P120				Low refrigerant charge, low airflow,
	Circuit A Low Saturated Suction Temp-Comp A2 Shutdown	Compressor A2 shutdown	Automatic	dirty coil, broken fan belt, TXV
				problem
T120				Low refrigerant charge, low airflow,
	Circuit A Low Saturated Suction Temperature Alert.	Stop circuit	Automatic	dirty coil, broken fan belt, TXV
				problem
A121				Low refrigerant charge, low airflow,
	Circuit B Low Saturated Suction Temperature Alarm.	Stop circuit	Manual	dirty coil, broken fan belt, TXV
				problem
P121				Low refrigerant charge, low airflow,
	Circuit B Low Saturated Suction Temp-Comp B2 Shutdown	Compressor B2 shutdown	Automatic	dirty coil, broken fan belt, TXV
				problem
T121				Low refrigerant charge, low airflow,
	Circuit B Low Saturated Suction Temperature Alert.	Stop circuit	Automatic	dirty coil, broken fan belt, TXV
				problem
T122	Circuit A High Saturated Suction Temperature	Stop circuit	Manual	TXV problem, high load.
T123	Circuit B High Saturated Suction Temperature	Stop circuit	Manual	TXV problem, high load.
T126	Circuit A High Head Pressure	Stop circuit	Automatic	Dirty condenser, condenser fan
				failure, system overcharged
T127	Circuit B High Head Pressure	Stop circuit	Automatic	Dirty condenser, condenser fan
				failure, system overcharged
A140	Reverse Rotation Detected	Stop unit	Manual	Incorrect compressor wiring
A150	Unit is in Emergency Stop	Stop unit	Manual	External shutdown command
T153	Real Time Clock Hardware Failure	Stop unit	Manual	Control Board failure, check lights
A154	Serial EEPROM Hardware Failure	Stop unit	Manual	Control Board failure, check lights
T155	Serial EEPROM Storage Failure Error	Stop unit	Manual	Control Board failure, check lights
A156	Critical Serial EEPROM Storage Failure Error	Stop unit	Manual	Control Board failure, check lights
A157	A/D Hardware Failure	Stop unit	Manual	Control Board failure, check lights
A171	Staged Gas Control Board Comm Failure	Stop gas heat	Automatic	Control Board failure, check lights
A172	Controls Expansion Module Comm Failure	Stop options on CEM	Automatic	Control Board failure, check lights
A173	ECB1 Board Communication Failure	Stop economizer & power exh	Automatic	Control Board failure, check lights
A174	ECB2 Board Communication Failure	Stop unit	Automatic	Control Board failure, check lights
T177	4-20 MA Demand Limit Failure	Stop demand limiting	Automatic	Input failure, wiring error
T178	4-20 MA Static Pressure Reset/VFD Fail	Stop static pressure reset/VFD	Automatic	Input Failure, wiring error
A200	Linkage Timeout Error - Communication Failure	Stop unit	Manual	Wiring errors, board failures
T210	Building Pressure Transducer Failure	Close economizer, stop exhaust	Automatic	Sensor failure, wiring error
T211	Static Pressure Transducer Failure	Stop unit	Automatic	Sensor failure, wiring error
T220	Indoor Air Quality Sensor Failure	Stop IAQ control	Automatic	Sensor failure, wiring error
T221	Outdoor Air Quality Sensor Failure	Use a default value for IAQ	Automatic	Sensor failure, wiring error
T229	Economizer Minimum Position Override Input Failure	Use software configured	Automatic	Input failure, wiring error
		minimum

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