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Navien Air Conditioner Error Codes: Meanings & Safe Checks
Choose the code exactly as shown. Meanings and reset procedures can change across model families, display formats and markets.
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ATL The official NAA Air Conditioner Installation and Operation Manual identifies ATL as overtemperature protection. Search/display variants: ATL stop-use d0 The official NAA Air Conditioner Installation and Operation Manual identifies d0 as running indication during oil-return mode. Search/display variants: d0 caution dC The official NAA Air Conditioner Installation and Operation Manual identifies dC as running indication during forced-cooling mode. Search/display variants: dC caution F0 The official NAA Air Conditioner Installation and Operation Manual identifies F0 as communication failure (outdoor unit). Search/display variants: F0 caution F1 The official NAA Air Conditioner Installation and Operation Manual identifies F1 as low pressure switch error. Search/display variants: F1 caution F4 The official NAA Air Conditioner Installation and Operation Manual identifies F4 as t4 outdoor ambient temperature sensor error. Search/display variants: F4 caution F5 The official NAA Air Conditioner Installation and Operation Manual identifies F5 as t5 compressor discharge temperature sensor error. Search/display variants: F5 caution F6 The official NAA Air Conditioner Installation and Operation Manual identifies F6 as t3 condensing temperature sensor error. Search/display variants: F6 caution F7 The official NAA Air Conditioner Installation and Operation Manual identifies F7 as t7 temperature sensor error. Search/display variants: F7 caution F8 The official NAA Air Conditioner Installation and Operation Manual identifies F8 as t7 temperature sensor error in detecting condensate risks. Search/display variants: F8 caution F9 The official NAA Air Conditioner Installation and Operation Manual identifies F9 as ac overvoltage or undervoltage protection. Search/display variants: F9 caution FA The official NAA Air Conditioner Installation and Operation Manual identifies FA as outdoor-unit eeprom failure. Search/display variants: FA caution FB The official NAA Air Conditioner Installation and Operation Manual identifies FB as driver-chip eeprom failure. Search/display variants: FB caution FC The official NAA Air Conditioner Installation and Operation Manual identifies FC as ipm module sensor error. Search/display variants: FC caution FD The official NAA Air Conditioner Installation and Operation Manual identifies FD as hlp pressure sensor failure. Search/display variants: FD caution FE The official NAA Air Conditioner Installation and Operation Manual identifies FE as t3 or t5 sensor disconnected. Search/display variants: FE caution FF The official NAA Air Conditioner Installation and Operation Manual identifies FF as hps condenser sensor disconnected. Search/display variants: FF caution H0 The official NAA Air Conditioner Installation and Operation Manual identifies H0 as communication fault between the master board and driver chip. Search/display variants: H0 caution H1 The official NAA Air Conditioner Installation and Operation Manual identifies H1 as t3 sensor high temperature error after three p5 events within 180 minutes. Search/display variants: H1 caution H2 The official NAA Air Conditioner Installation and Operation Manual identifies H2 as high pressure switch error after three p1 events within 150 minutes. Search/display variants: H2 stop-use H4 The official NAA Air Conditioner Installation and Operation Manual identifies H4 as ipm module high temperature error after three p8 events within 120… Search/display variants: H4 caution H5 The official NAA Air Conditioner Installation and Operation Manual identifies H5 as low pressure error after five p2 events within 240 minutes. Search/display variants: H5 caution H6 The official NAA Air Conditioner Installation and Operation Manual identifies H6 as abnormal discharge temperature after three p4 events within 100 minutes. Search/display variants: H6 caution H7 The official NAA Air Conditioner Installation and Operation Manual identifies H7 as moisture exposure operation error after three pc events within 200… Search/display variants: H7 caution H8 The official NAA Air Conditioner Installation and Operation Manual identifies H8 as t3 condenser sensor disconnection after three fe events within 120… Search/display variants: H8 caution HC The official NAA Air Conditioner Installation and Operation Manual identifies HC as discharge temperature sensor disconnection after three fe events within… Search/display variants: HC caution HE The official NAA Air Conditioner Installation and Operation Manual identifies HE as condensate error after three events within 60 minutes. Search/display variants: HE caution L0 The official NAA Air Conditioner Installation and Operation Manual identifies L0 as low dc bus voltage protection. Search/display variants: L0 caution L1 The official NAA Air Conditioner Installation and Operation Manual identifies L1 as high dc bus voltage protection. Search/display variants: L1 caution LA The official NAA Air Conditioner Installation and Operation Manual identifies LA as frequency limited by voltage. Search/display variants: LA caution LB The official NAA Air Conditioner Installation and Operation Manual identifies LB as frequency limited or reduced by high pressure. Search/display variants: LB stop-use LC The official NAA Air Conditioner Installation and Operation Manual identifies LC as frequency limited by condenser temperature. Search/display variants: LC caution LD The official NAA Air Conditioner Installation and Operation Manual identifies LD as frequency limited by discharge temperature. Search/display variants: LD caution LE The official NAA Air Conditioner Installation and Operation Manual identifies LE as frequency limited by high ipm module temperature. Search/display variants: LE caution LF The official NAA Air Conditioner Installation and Operation Manual identifies LF as frequency limited by current. Search/display variants: LF caution P1 The official NAA Air Conditioner Installation and Operation Manual identifies P1 as high pressure switch error. Search/display variants: P1 stop-use P2 The official NAA Air Conditioner Installation and Operation Manual identifies P2 as low pressure protection. Search/display variants: P2 caution P3 The official NAA Air Conditioner Installation and Operation Manual identifies P3 as inverter overcurrent protection. Search/display variants: P3 caution P4 The official NAA Air Conditioner Installation and Operation Manual identifies P4 as high compressor discharge temperature protection at the t5 sensor. Search/display variants: P4 caution P5 The official NAA Air Conditioner Installation and Operation Manual identifies P5 as high condenser temperature protection at the t3 sensor. Search/display variants: P5 caution P6 The official NAA Air Conditioner Installation and Operation Manual identifies P6 as ipm protection. Search/display variants: P6 caution P8 The official NAA Air Conditioner Installation and Operation Manual identifies P8 as ipm high temperature protection (ft). Search/display variants: P8 caution P9 The official NAA Air Conditioner Installation and Operation Manual identifies P9 as dc fan motor error. Search/display variants: P9 caution PC The official NAA Air Conditioner Installation and Operation Manual identifies PC as wet operation error. Search/display variants: PC caution PRH The official NAA Air Conditioner Installation and Operation Manual identifies PRH as crankcase heater in progress; start-up is inhibited. Search/display variants: PRH caution