Whynter Portable AC E2 Error — How to Fix

What Does This Error Mean?

Whynter Portable AC E2 error means the evaporator coil temperature sensor (NTC thermistor clipped to the cold coil) has failed or is reading outside its valid range. The unit shuts down cooling to protect the compressor. Power reset first; if E2 persists, the sensor or its wiring connection has failed and the unit needs professional service.

Affected Models

Whynter ARC-14SH
Whynter ARC-14S
Whynter ARC-110WD
Whynter ARC-12SDH
Whynter ARC-131GD

Common Causes

The evaporator coil sensor has an open or short circuit internally
The sensor's wiring clip has come loose from the evaporator coil or the board connector
Heavy ice build-up on the coil is holding the sensor in an abnormal temperature range
A power surge damaged the sensor or the control board's sensor input circuit

How to Fix It

Unplug the unit for 15 minutes and allow any ice to melt

E2 can appear when the evaporator coil is heavily iced — the sensor reads below its valid range. Unplug the unit and let it sit for 15–30 minutes. If the coil was iced, you will see water drain from the unit during defrost. Once defrosted, restart and test.
Clean the air filter to restore proper airflow

The most common cause of coil icing is a clogged air filter restricting airflow. Remove and wash the filter. Let it dry completely before reinstalling. A clean filter allows warm room air to flow over the coil at the correct rate, preventing ice from forming.
Ensure room temperature is not below the minimum operating range

Running a portable AC in a room below 61°F (16°C) can cause the coil to ice up and the E2 sensor to read out of range. Portable ACs should only be used for cooling in warm conditions — they are not designed for use in cold environments.
Perform a power reset — unplug for 10 minutes, then restart

After the coil has had time to defrost, plug the unit in and restart. Power on in fan-only mode first and run for 5 minutes to confirm the coil is clear before switching to cooling mode. E2 should be gone if ice was the cause.
Contact Whynter support if E2 returns without obvious icing

If E2 appears immediately on power-on without any icing present, the sensor itself has failed internally. Sensor replacement requires disassembling the unit. Contact Whynter support for warranty service or to obtain the part if the unit is out of warranty.

Frequently Asked Questions

How do I prevent the evaporator coil from icing on my Whynter AC?

Coil icing is prevented by: keeping the filter clean, ensuring the intake vents have adequate clearance, not setting the thermostat unrealistically low, and not running the unit in a room below 65°F (18°C). If the coil ices regularly despite these precautions, have the refrigerant charge checked by an HVAC technician.

Is E2 more serious than E1 on a Whynter portable AC?

Both E1 (ambient sensor) and E2 (evaporator sensor) stop the cooling function and need to be resolved. E2 can sometimes be caused by temporary icing, which makes it slightly more likely to be self-clearing after defrost. E1 is more commonly a hardware sensor failure. Both require the same first step — power reset and defrost check.