Air Conditioner / Heat Pump Error Codes: All Brands
Air conditioner and heat pump codes, shown on the indoor unit or the remote, often concern communication between indoor and outdoor units, temperature sensors, fan motors, high or low refrigerant pressure or a condensate drain problem. Safe first checks are cleaning the air filters, clearing leaves and debris from around the outdoor unit and checking the breaker. Work on the refrigerant circuit requires an EPA Section 608 certified technician.
34Codes
3.1Average severity
24%High or critical
59%DIY-friendly
Severity distribution
ENERGY STAR certified models
| Frigidaire · Air Conditioner / Heat Pump | 27 | |
|---|---|---|
| GE Appliances · Air Conditioner / Heat Pump | 14 | |
| LG · Air Conditioner / Heat Pump | 12 | |
| Whirlpool · Air Conditioner / Heat Pump | 6 |
Source: ENERGY STAR open data (data.energystar.gov) – number of certified models currently listed.
Official safety recalls (US CPSC)
- Daikin Comfort Technologies Manufacturing Recalls Amana Through-The-Wall Air Conditioners and Heat Pumps Due to Risk of Serious Injury from Fire · The snubber circuit can emit flames if it shorts, posing a risk of serious injury due to fire hazard.
- Daikin Comfort Technologies Manufacturing Recalls Amana Air Conditioners and Heat Pumps Due to Risk of Serious Injury from Fire and Burns · The heating element can remain energized during a ground fault, despite being turned off, posing a risk of fire or burn injury to consumers.
- Daikin Comfort Technologies Manufacturing Recalls Daikin FIT, Amana Brand S-series, and Goodman SD Heat Pumps Due to Risk of Excessive Heat Exposure · A power interruption in the heat pump can result in the product providing heat when the power resumes, despite the thermostat being in cooling mode, posing a risk of excessive heat exposure to consume
- Daikin Comfort Technologies Manufacturing Recalls Amana, Daikin, Goodman-Branded Air Conditioning and Heat Pump Packaged Units Due to Fire Hazard · The unit's serial plate can have incorrect electrical ratings which can lead to incorrect wirings being used, posing a fire hazard.
- Daikin Comfort Technologies Recalls Amana Packaged Terminal Air Conditioners and Heat Pumps Due to Burn and Fire Hazards (Recall Alert) · The DigiAir module compressor can overheat, posing burn and fire hazards.
- LG Electronics Recalls Portable Air Conditioners Due to Fire Hazard · The portable air conditioners can overheat, posing a risk of fire.
- Gree Reannounces Dehumidifier Recall Following 450 Fires and $19 Million in Property Damage; Brand Names Include Frigidaire, Soleus Air, Kenmore and Others · The dehumidifiers can overheat, smoke and catch fire, posing serious fire and burn hazards to consumers.
- GE Recalls Air Conditioning and Heating Units Due to Risk of Fire · Moisture from outdoor air can accumulate near the unit's heater when the unit is operated with the vent door continuously open. This, along with two shorted electrical components, can create an electr
Source: US Consumer Product Safety Commission recalls API. Check your model and serial number on the linked recall notice.
Most viewed
U4
Daikin · Air Conditioner / Heat Pump
The indoor unit has lost its data link with the outdoor unit, so the system can't cool or heat.
Moderate
E6
Mitsubishi Electric · Air Conditioner / Heat Pump
The indoor unit isn't getting valid signals back from the outdoor unit over the S3 wire.
Moderate
13
Carrier · Air Conditioner / Heat Pump
A limit or rollout switch stayed open too long, so the furnace has locked itself out for 3…
High
31
Carrier · Air Conditioner / Heat Pump
The inducer couldn't prove a clear vent, so the pressure switch stayed open and the burners…
Moderate
33
Carrier · Air Conditioner / Heat Pump
A high-temperature safety switch opened, usually because too little air is moving through…
Moderate
A1
Daikin · Air Conditioner / Heat Pump
The indoor unit's circuit board couldn't load or apply its settings, so the head refuses to run.
Moderate
All codes (31)
11
Fujitsu · Air Conditioner / Heat Pump
Error 11: the serial data link on terminal 3 between the Fujitsu indoor and outdoor units has…
Moderate
126
Trane · Air Conditioner / Heat Pump
126 on a Trane ComfortLink II thermostat: it lost its data link to the furnace, air handler…
Moderate
13
Carrier · Air Conditioner / Heat Pump
A limit or rollout switch stayed open too long, so the furnace has locked itself out for 3…
High
31
Carrier · Air Conditioner / Heat Pump
The inducer couldn't prove a clear vent, so the pressure switch stayed open and the burners…
Moderate
33
Carrier · Air Conditioner / Heat Pump
A high-temperature safety switch opened, usually because too little air is moving through…
Moderate
434
Lennox · Air Conditioner / Heat Pump
The Lennox outdoor control can't talk to the inverter drive that runs the variable-speed…
Moderate
51
Fujitsu · Air Conditioner / Heat Pump
Error 51: the indoor fan ran far slower than commanded for about a minute, so the Fujitsu unit…
Moderate
A1
Daikin · Air Conditioner / Heat Pump
The indoor unit's circuit board couldn't load or apply its settings, so the head refuses to run.
Moderate
A3
Daikin · Air Conditioner / Heat Pump
A3 means condensate is backing up in the indoor unit's drain pan and the float switch has…
Moderate
CH05
LG · Air Conditioner / Heat Pump
CH05: the LG indoor unit hears nothing back from the outdoor unit, so the compressor…
Moderate
CH10
LG · Air Conditioner / Heat Pump
CH10: the indoor unit's fan motor isn't turning or isn't reporting its speed, so the unit shuts…
Moderate
CH21
LG · Air Conditioner / Heat Pump
CH21: the outdoor inverter's power module saw a dangerous current peak and cut power…
High
CH38
LG · Air Conditioner / Heat Pump
LG's protection stopped the system because the refrigerant level or pressure looks too low.
High
E1
Goodman · Air Conditioner / Heat Pump
E1: the low-stage pressure switch reads closed before the inducer starts, so the furnace won't…
Moderate
E1
Gree · Air Conditioner / Heat Pump
E1: refrigerant pressure on the high side got too high and the Gree unit stopped the compressor…
Moderate
E101
Samsung · Air Conditioner / Heat Pump
The indoor unit waited too long for the outdoor unit to answer on the F1/F2 link and shut…
Moderate
E201
Samsung · Air Conditioner / Heat Pump
E201: after power-up the outdoor unit couldn't find and register its indoor unit(s), so it…
Moderate
E5
Gree · Air Conditioner / Heat Pump
E5: the Gree unit drew more current than allowed – often because supply voltage sagged…
Moderate
E6
Mitsubishi Electric · Air Conditioner / Heat Pump
The indoor unit isn't getting valid signals back from the outdoor unit over the S3 wire.
Moderate
E6
Gree · Air Conditioner / Heat Pump
E6 means the Gree indoor and outdoor units have lost their data link, so cooling and heating…
Moderate
E7
Daikin · Air Conditioner / Heat Pump
The outdoor fan failed to spin up, or its speed signal went wrong, so the outdoor unit shut…
Moderate
EC
Midea · Air Conditioner / Heat Pump
EC: in cooling, the indoor coil didn't get colder after the compressor started – the unit…
High
EL01
MRCOOL · Air Conditioner / Heat Pump
The MRCOOL indoor and outdoor units have stopped exchanging data, so the compressor won't run.
Moderate
H11
Panasonic · Air Conditioner / Heat Pump
H11: the Panasonic indoor unit stopped getting valid signals from the outdoor unit after it…
Moderate
L5
Daikin · Air Conditioner / Heat Pump
L5: the outdoor inverter saw a current spike on the compressor output and shut the compressor…
High
P1
MRCOOL · Air Conditioner / Heat Pump
The outdoor unit saw supply voltage too high or too low and stopped the compressor to protect…
Moderate
P4
Midea · Air Conditioner / Heat Pump
P4 (PC 04 on newer displays): the outdoor board couldn't drive the inverter compressor…
High
P8
Mitsubishi Electric · Air Conditioner / Heat Pump
The indoor coil isn't getting colder (or warmer) than the room after the compressor starts, so…
Moderate
U0
Daikin · Air Conditioner / Heat Pump
The outdoor unit has judged the system to be low on refrigerant and stopped the compressor…
High
U4
Daikin · Air Conditioner / Heat Pump
The indoor unit has lost its data link with the outdoor unit, so the system can't cool or heat.
Moderate
Brands
Daikin Air Conditioner / Heat Pump 6Mitsubishi Electric Air Conditioner / Heat Pump 5LG Air Conditioner / Heat Pump 4Carrier Air Conditioner / Heat Pump 3Gree Air Conditioner / Heat Pump 3Fujitsu Air Conditioner / Heat Pump 2Goodman Air Conditioner / Heat Pump 2MRCOOL Air Conditioner / Heat Pump 2Midea Air Conditioner / Heat Pump 2Samsung Air Conditioner / Heat Pump 2Lennox Air Conditioner / Heat Pump 1Panasonic Air Conditioner / Heat Pump 1Trane Air Conditioner / Heat Pump 1