Code index · 16 entries
Carrier AC / heat pump error codes
What does your Carrier AC / heat pump error code mean? 16 codes from official Carrier AC / heat pump documentation. Select a code for causes, how to fix it safely and when to call a pro. Carrier manufacturer manual (PDF) (opens in a new tab) ↗.
16 of these 16 Carrier AC / heat pump pages are marked call-a-pro because the source document points at gas, venting, refrigerant, high voltage or a control the manual does not leave to a homeowner. The other 0 start with a check the document describes, then say when to stop.
Related guides: AC High and Low Pressure Codes · AC Voltage and Power Codes: Brownout, L8, H8, E5 · Heat Pump Not Heating in the Cold · How to Read a Bryant Evolution Outdoor Status Light.
Invalid model plug / inverter size: the control does not accept the model plug for this inverter.
High pressure switch open: the unit steps down capacity for each occurrence and elevates to fault 84 if it happens on the lowest stage. Reset time is 6 minutes.
Low pressure trip: the control elevates to fault 83 (low pressure lockout) after 3 occurrences. Reset time is 6 minutes.
Lost inverter communications, the local fault. It is logged after 2 minutes with no communication between the outdoor control (AOC) and the inverter (MOC). It elevates to fault 48 after 3 consecutive failures within 20 minutes, or after 20 minutes of continuous loss of connection. The manual says to refer to fault code 48.
Brownout event: low line voltage reaching the unit. Reset time is 6 minutes.
Lost inverter communications (system malfunction): the outdoor control (AOC) and the inverter (MOC) have stopped communicating. Fault 33 is logged after 2 minutes with no communication and is elevated to 48 after 3 consecutive failures within 20 minutes, or 20 minutes of continuous loss of connection.
Compressor overcurrent fault. The control elevates this to fault 95 after 5 occurrences. Reset time is 6 minutes.
Outdoor air temperature sensor fault.
Coil temperature sensor fault.
Outdoor air temperature and outdoor coil temperature thermistors are out of range. The manual lists this as an event, not a lockout.
Suction pressure sensor fault. The suction pressure transducer reading cannot be trusted. There is no reset time on this row.
DC volts low, speed limiting. Supply voltage is under 197 V, or a loose wire or the inverter is limiting compressor speed. The table does not list a reset time.
Low pressure lockout for 4 hours, elevated from fault 32 after 3 occurrences.
High pressure lockout for 4 hours, elevated from fault 31 when the stage (speed) can no longer be lowered.
Compressor and inverter lockout for 2 hours, elevated from fault 79 after 5 occurrences. The compressor failed to start often enough that the control stopped the retries.
Compressor overcurrent lockout for 2 hours, elevated from fault 49 after 5 occurrences.
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Source: Carrier manufacturer manual (PDF) (opens in a new tab) ↗ · Last updated