What do the error codes on a portable air conditioner mean?

Most portable air conditioner error codes point to one of four conditions: a full internal water tank (FL, P1, P2, CH04), a coil freeze-up or sensor fault (E5, CH05), a sealed-system or compressor issue (E1, E2, E6), or a power or communication fault (E3, E4, CH01). The first step in nearly every case is to power cycle the unit and clean the air filter.

Why does my portable AC show both FL and P1 at the same time?

FL and P1 both mean the internal tank is full, but they come from two different sensors. FL is from the electronic water level sensor near the top of the tank, and P1 is from the mechanical float switch near the bottom. When the tank is genuinely full, both sensors trip and the display shows both codes or alternates between them.

What is the most common portable AC error code?

FL and P1 are the two most common because they are triggered by the internal water tank, which fills during normal cooling. E5 is also common because it is triggered by the evaporator coil, which can ice up in humid rooms with a dirty filter or restricted airflow.

Can I keep using my portable AC while an error code is showing?

Most portable ACs shut the compressor off while an error code is displayed. The fan may keep running but cooling will not resume until the underlying condition is resolved and the code is cleared with a full power cycle.

How do I reset a portable AC error code?

Turn the unit off, unplug it for at least 60 seconds, plug it back in, and restart in Cool mode. This clears the float counter and most sensor latches. If the code returns within minutes, the underlying condition has not been resolved and needs the troubleshooting steps that match the specific code.

Portable Air Conditioner Error Codes: Complete List and What They Mean

Quick Answer

Portable air conditioner error codes follow a few common patterns across brands. The most frequent codes are FL and P1 for a full internal water tank, E5 for evaporator freeze-up or a coil sensor fault, E1 and E2 for sealed-system or compressor issues, and the CH series on LG units for similar conditions. The first step in nearly every case is to power cycle the unit, clean the air filter, and confirm the room is at least 65 F. If the code returns within minutes, the fix depends on the specific code and is usually covered in our per-code guides.

Common Portable AC Error Code Chart

The chart below covers the codes you will see most often on Hisense, LG, Midea, Frigidaire, GE, Whirlpool, Danby, and Electrolux portable air conditioners. Brand-specific quirks are listed after the chart.

Code	Meaning	Most Common Trigger	First DIY Step
FL	Internal tank is full (electronic sensor)	Tank has reached capacity	Drain the tank, level the unit, reset
P1	Internal tank is full (float switch)	Tank has reached capacity or float is stuck	Drain, free the float by hand, reset
P2	Tank full (secondary sensor) or pump fault	Midea units: condensate pump failure	Drain, check the pump if model has one
P4	Tank sensor fault	Danby portable ACs: sensor wiring or board	Power cycle, then service if it returns
E1	Compressor high-pressure cut	Blocked exhaust hose or hot ambient	Clear exhaust hose, lower room temp
E2	Compressor low-pressure cut	Low refrigerant or iced coil	Thaw the coil, clean the filter
E3	Communication fault between boards	Loose ribbon cable or power glitch	Power cycle, reseat connectors if accessible
E4	Ambient temperature sensor fault	Sensor open or shorted	Power cycle, then service if it returns
E5	Evaporator freeze-up or coil sensor	Dirty filter, blocked exhaust, cold room	Clean filter, clear exhaust, warm the room
E6	Communication or sensor fault	Internal wiring issue	Power cycle, then service if it returns
CH01	Communication fault (LG)	Loose cable or power surge	Power cycle for 5 minutes
CH02	Indoor coil sensor fault (LG)	Sensor short or open	Power cycle, then service if it returns
CH04	Internal tank full (LG formal code)	Tank reached capacity	Drain, level the unit, reset
CH05	Evaporator freeze-up (LG formal code)	Dirty filter or restricted airflow	Clean filter, clear exhaust, warm the room
CH06	Outdoor coil sensor fault (LG dual-hose units)	Sensor short or open	Power cycle, then service if it returns

Most brands follow the same general logic. The code that is displayed is the symptom, and the fix is usually one of four actions: drain the tank, clean the filter, clear the exhaust hose, or wait for the coil to thaw.

Before You Start Any Troubleshooting

A few setup and safety checks apply to nearly every error code and will save you time:

Unplug the unit before opening the drain port, removing the air filter, or opening any panel.
Place the unit on a hard, level surface. An unlevel cabinet can keep the float switch triggered even after a real drain.
Have a shallow pan, a few towels, and a floor drain or sink nearby if you plan to drain the tank.
Confirm the room temperature is at least 65 F (18 C) before starting Cool mode. A cold room can trigger E5 even on a healthy unit.
If the unit has been running for less than 30 minutes, give it time to cool down before opening anything.
Do not bypass any safety switch or pull the housing apart while the unit is plugged in.
If the unit is still under warranty, call the manufacturer before opening the sealed case.

Step-by-Step: First-Line Troubleshooting for Any Code

Most portable AC error codes clear with the same first-line sequence. Try these steps in order before moving to a code-specific guide.

Step 1: Power Cycle the Unit

A full power cycle resets the float counter and most sensor latches. Just pressing the power button is often not enough.

Turn the unit off using the control panel or remote.
Unplug the power cord from the wall outlet. Wait at least 60 seconds.
Plug the cord back in and start the unit in Fan Only mode for 2 to 3 minutes.
Switch to Cool mode and set the thermostat at least 5 F below the current room temperature.
Wait 10 minutes. If the code does not return, the original trigger was a transient sensor reading and you are done.

Step 2: Clean the Air Filter and Check the Exhaust Hose

A dirty filter and a kinked exhaust hose cause more error codes than anything else.

Open the front grille and slide the air filter out.
Rinse the filter under warm water and let it air dry completely.
While the filter is drying, vacuum the inside of the grille opening with a brush attachment.
Move the unit away from the wall and inspect the full exhaust hose run for kinks, low spots, or crushed sections.
Confirm the window kit seal is tight. Hot air leaking back into the room raises the cabinet temperature and confuses the coil sensor.

Step 3: Check Room Temperature and Mode Settings

A room below about 65 F (18 C) can trigger E5 even on a perfectly healthy unit. The Cool mode on most portable ACs is designed for rooms at or above that threshold.

Confirm the room temperature with a separate thermometer.
If the room is below 65 F, switch the unit to Fan Only or Dehumidify mode instead of Cool.
Avoid running Cool mode in a room that is being actively cooled by another air conditioner or by open windows in cold weather.
Set the thermostat to a realistic target. Asking the unit to cool a 60 F room to 68 F will keep tripping E5.

Step 4: Drain the Tank If FL, P1, P2, CH04, or a Tank Code Is Showing

If the error code relates to a full tank, drain the tank, level the unit, and reset.

Place a shallow pan under the drain port.
Open the drain plug or valve and let the water flow out.
Once the visible flow stops, leave the plug off for 30 seconds so any pooled water can drain.
Lift and release the float inside the tank by hand if you can reach it. The float should move freely with a soft click.
Refit the drain plug firmly and stand the unit level.
Power cycle the unit and start it in Cool mode.

Brand-by-Brand Code Reference

Most portable AC brands share the same OEM base design, but the code display and naming vary. Use the table below to find the code that matches your brand.

Brand	Tank-Full Code	Freeze-Up Code	Compressor/System Code	Sensor Code
Hisense	FL or P1	E5	E1 or E2	E3 or E4
LG	P1 (with CH04 as formal)	E5 (with CH05 as formal)	E1 or E2	E3 or E4
Midea	P1 (with P2 for pump)	E5	E1 or E2	E3 or E4
Frigidaire	P1 (with tank indicator)	E5	E1 or E2	E3 or E4
GE	P1	E5	E1 or E2	E3 or E4
Whirlpool	P1	E5	E1 or E2	E3 or E4
Danby	P1 (with P4 as sensor)	E5	E1 or E2	E3 or E4
Electrolux	P1	E5	E1 or E2	E3 or E4

If your brand is not listed, the LG and Midea behavior is the most common OEM baseline. Hisense and Frigidaire tend to use the same codes with slightly different display labels.

How to Find the Right Per-Code Guide

For deeper troubleshooting on a specific code, use the index below. Each link goes to a per-code guide that covers the brand-specific behavior, the common causes, and the DIY fix steps.

FL and P1 (tank full): see Portable Air Conditioner FL P1 Error Code and Portable Air Conditioner P1 Code After Draining.
E5 (evaporator freeze-up): see Portable Air Conditioner E5 Error Code.
Tank full but no water visible: see Portable Air Conditioner Water Full but No Water.
Unit is on but not cooling: see Portable Air Conditioner Not Cooling.
Unit keeps shutting off: see Portable Air Conditioner Keeps Shutting Off.
Brand-specific E5 guides: Hisense Portable Air Conditioner E5 and LG Portable Air Conditioner E5.
Filter and airflow maintenance: see Portable Air Conditioner Filter Cleaning.

When to Call a Technician

Stop DIY work and contact the manufacturer or a qualified service technician if any of the following is true:

The code returns within minutes of a full power cycle, a clean filter, a clear exhaust hose, and a room above 65 F.
You hear a hissing or bubbling sound anywhere in the cabinet, which can indicate a refrigerant leak.
The unit trips the breaker as soon as you restart it.
The compressor is running but the unit is not cooling at all.
You see oily residue on the copper lines or around the evaporator coil.
The display shows two or more codes at once that are not part of the same sensor family (for example, E1 and E5 together).
The unit is still under warranty. Opening the housing can void coverage on most brands.

If the unit is out of warranty and you have ruled out the filter, the exhaust hose, the room temperature, and the drain, the most likely remaining cause is a sensor fault, a sealed-system fault, or a control board fault. All three are parts-level repairs that need a qualified technician.

Safety Notes for Working on a Portable AC

Appliance repair can involve electrical, water, and refrigerant hazards. A few rules apply to any troubleshooting on a portable air conditioner:

Always disconnect power before opening the drain port, removing the air filter, or opening any panel.
Wear appropriate protective equipment, especially if the unit has been running and the coil area is icy or wet.
Do not attempt repairs beyond your skill level, especially anything involving refrigerant or sealed-system work.
Stop using the unit immediately if you notice smoke, sparks, burning smells, exposed wiring, water near electrical parts, repeated breaker trips, suspected refrigerant leaks, or severe overheating.
For the deeper safety context, see our disclaimer.

Safety First

Always disconnect power before inspecting your appliance. If you're not comfortable handling electrical components, compressor issues, or refrigerant, contact a professional technician.

Frequently Asked Questions

What do the error codes on a portable air conditioner mean?: Most portable air conditioner error codes point to one of four conditions: a full internal water tank (FL, P1, P2, CH04), a coil freeze-up or sensor fault (E5, CH05), a sealed-system or compressor issue (E1, E2, E6), or a power or communication fault (E3, E4, CH01). The first step in nearly every case is to power cycle the unit and clean the air filter.
Why does my portable AC show both FL and P1 at the same time?: FL and P1 both mean the internal tank is full, but they come from two different sensors. FL is from the electronic water level sensor near the top of the tank, and P1 is from the mechanical float switch near the bottom. When the tank is genuinely full, both sensors trip and the display shows both codes or alternates between them.
What is the most common portable AC error code?: FL and P1 are the two most common because they are triggered by the internal water tank, which fills during normal cooling. E5 is also common because it is triggered by the evaporator coil, which can ice up in humid rooms with a dirty filter or restricted airflow.
Can I keep using my portable AC while an error code is showing?: Most portable ACs shut the compressor off while an error code is displayed. The fan may keep running but cooling will not resume until the underlying condition is resolved and the code is cleared with a full power cycle.
How do I reset a portable AC error code?: Turn the unit off, unplug it for at least 60 seconds, plug it back in, and restart in Cool mode. This clears the float counter and most sensor latches. If the code returns within minutes, the underlying condition has not been resolved and needs the troubleshooting steps that match the specific code.