- Appliances
- Dehumidifiers
AS
Midea AS on dehumidifier: indoor humidity sensor error
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
Code AS on a Midea dehumidifier signals a humidity sensor error. Turn the unit off, check that the air grilles are unobstructed, unplug the power cord and plug it back in; if AS returns, disconnect power and contact Midea Customer Service or a qualified technician.
Safety first
Stop and check this first
- If code AS persists after unplugging and plugging back in, turn the dehumidifier off and disconnect the power cord before calling service; do not open the cabinet yourself.
- Bear in mind that any error code cancels an active Timer setting, and after stopping the unit you must wait 3 minutes before the compressor can restart.
Safe checks you can perform
- Unplug the dehumidifier and respect the 3-minute restart delay
- Check for airflow obstructions and clean the air filter
- Tell AS apart from ES or EH60/EH61 and check room temperature
Leave these tasks to a qualified professional
- Do not attempt this professional task: Humidity sensor and harness inspection by a qualified technician
- Do not attempt this professional task: Verification of 30% to 90% RH readout on the control panel
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Humidity sensor and harness inspection by a qualified technician
What they doWhen AS persists after a power reset and airflow check, Midea Customer Service or a qualified technician inspects the humidity sensor and its internal wiring connection to the control board.
They must show youthe test of the humidity sensor and its plug before any part is replaced.
In writingthe recorded AS fault, the sensor check results and whether the sensor or harness was replaced.
Verification of 30% to 90% RH readout on the control panel
What they doAfter servicing the humidity sensor, the technician confirms that the LED display reads actual room humidity in the 30% to 90% RH range (+/- 5% accuracy) and responds to 35% to 85% RH setpoints.
They must show youthe LED panel displaying a steady room humidity percentage without AS returning.
In writingthe verified humidity reading after repair and the warranty coverage on the service work.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Unplug the dehumidifier and respect the 3-minute restart delay
- Who:
- you, at the wall outlet for your Midea unit.
- How:
- turn the dehumidifier off with the POWER button, unplug the power cord from the wall socket, wait a couple of minutes and plug it back in. Keep in mind that compressor protection prevents the unit from restarting until 3 minutes have passed after stopping.
- Result that matters:
- the LED display returning to a room humidity reading between 30% and 90% RH without code AS.
- If AS clears and you can set target humidity between 35% and 85% RH in 5% steps:
- reset your Timer if needed, since any error code cancels active Timer settings.
- If code AS comes right back on the display:
- move on to checking airflow and room conditions.
- Evidence to keep:
- a photo of code AS on the display and a note of whether it returns immediately after power-up.
Evidence: Midea dehumidifier user manual MAD22C1AWS / MAD35C1AWS / MAD50C1AWS / MAD50P1AWS / MAD50PS1WS · Midea Cube Dehumidifier User Manual MAD20S1QWT / MAD35S1QWT / MAD50S1QWT (EN/ES) · Midea MDDN-12DEN7-QA3 manual de usuario de deshumidificador
Check for airflow obstructions and clean the air filter
- Who:
- you, with the Midea dehumidifier switched off and unplugged.
- How:
- following the MDDN-12DEN7-QA3 fault note, check that curtains or furniture are at least 20 cm away from the sides (and 40 cm above the air outlet), then remove the rear air filter and wash it with warm water and a mild detergent before drying it thoroughly.
- Result that matters:
- clean, unobstructed air reaching the internal humidity sensor.
- If removing a blockage or cleaning a dusty filter clears AS on restart:
- clean the filter every two weeks.
- If vents and filter are clean but AS remains:
- check the ambient room temperature.
- Evidence to keep:
- photos of the filter condition and the clearance around the dehumidifier.
Evidence: Midea MDDN-12DEN7-QA3 manual de usuario de deshumidificador
Tell AS apart from ES or EH60/EH61 and check room temperature
- Who:
- you, checking the Midea display and a room thermometer.
- How:
- make sure the code shown is AS (humidity sensor error) rather than ES (evaporator tube temperature sensor error) or EH60/EH61/Eh0b on the European Cube MDDM-20DEN7-QA3, and confirm the room sits between 5 °C (41 °F) and 32 °C (90 °F) (or 35 °C / 95 °F on Cube).
- Result that matters:
- ruling out extreme room temperatures and giving support the exact sensor code.
- If the room was colder than 5 °C or warmer than 32 °C/35 °C:
- let the room return to the rated range and retry once.
- If within normal room temperature AS still persists:
- turn off the unit, unplug the power cord and contact Midea service.
- Evidence to keep:
- model number from the rating label, exact code displayed and ambient temperature.
Evidence: Midea dehumidifier user manual MAD22C1AWS / MAD35C1AWS / MAD50C1AWS / MAD50P1AWS / MAD50PS1WS · Midea Cube Dehumidifier User Manual MAD20S1QWT / MAD35S1QWT / MAD50S1QWT (EN/ES) · Midea MDDN-12DEN7-QA3 manual de usuario de deshumidificador · Midea Cube MDDM-20DEN7-QA3 manual de usuario de deshumidificador
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Appliances
- Brand
- Midea
- Product type
- Dehumidifiers
Known code variants
- A S
- A-S
- AS
- deshumidificador Midea AS
- Midea AS
- Midea Cube AS
- Midea dehumidifier AS
- Midea MAD50 AS
- Midea MDDN AS
What it means
Across Midea's official user manuals for the EasyDry MAD series (MAD22C1AWS to MAD50PS1WS), the Midea Cube series (MAD20S1QWT, MAD35S1QWT, MAD50S1QWT) and the European MDDN-12DEN7-QA3 model, display code AS means a humidity sensor error, whereas ES points to the evaporator tube temperature sensor (and on the European Cube MDDM-20DEN7-QA3 equivalent sensor faults appear as EH60 and EH61). Under normal operation the LED display reads actual room humidity from 30% to 90% RH within +/- 5% accuracy. Other models may differ, and code AS alone never proves that the sensor or control board has failed.
Warnings and stop conditions
- Mediumsource verified
If code AS persists after unplugging and plugging back in, turn the dehumidifier off and disconnect the power cord before calling service; do not open the cabinet yourself.
Evidence: Midea Cube Dehumidifier User Manual MAD20S1QWT / MAD35S1QWT / MAD50S1QWT (EN/ES) · Midea MDDN-12DEN7-QA3 manual de usuario de deshumidificador
- Lowsource verified
Bear in mind that any error code cancels an active Timer setting, and after stopping the unit you must wait 3 minutes before the compressor can restart.
Evidence: Midea Cube Dehumidifier User Manual MAD20S1QWT / MAD35S1QWT / MAD50S1QWT (EN/ES) · Midea MDDN-12DEN7-QA3 manual de usuario de deshumidificador
Symptoms and causes
Probable causes · in order
- Temporary sensor reading glitch cleared by a power resetCommon
Midea's primary remedy for code AS in the MAD, Cube and MDDN-12DEN7-QA3 manuals is to unplug the dehumidifier and plug it back in to clear a transient control fault.
Evidence: Midea dehumidifier user manual MAD22C1AWS / MAD35C1AWS / MAD50C1AWS / MAD50P1AWS / MAD50PS1WS · Midea Cube Dehumidifier User Manual MAD20S1QWT / MAD35S1QWT / MAD50S1QWT (EN/ES) · Midea MDDN-12DEN7-QA3 manual de usuario de deshumidificador
- Blocked air intake or a dirty filter restricting airflowPossible
The MDDN-12DEN7-QA3 fault note instructs turning off the unit and checking for any obstruction whenever an error code appears, alongside cleaning the air filter every two weeks.
Evidence: Midea MDDN-12DEN7-QA3 manual de usuario de deshumidificador
- Room temperature or humidity outside the operating rangePossible
Midea specifies a working environment of 5 °C (41 °F) to 32 °C (90 °F) on MAD and MDDN models (up to 35 °C / 95 °F on Cube) and 30% to 80% RH; conditions outside those limits can trigger abnormal readings.
Evidence: Midea dehumidifier user manual MAD22C1AWS / MAD35C1AWS / MAD50C1AWS / MAD50P1AWS / MAD50PS1WS · Midea Cube Dehumidifier User Manual MAD20S1QWT / MAD35S1QWT / MAD50S1QWT (EN/ES) · Midea MDDN-12DEN7-QA3 manual de usuario de deshumidificador
- Faulty humidity sensor or internal wiring connectionLess common
When code AS repeats after unplugging and checking for obstructions, Midea directs you to shut off the appliance, unplug the power cord and contact Customer Service or a qualified technician.
Evidence: Midea dehumidifier user manual MAD22C1AWS / MAD35C1AWS / MAD50C1AWS / MAD50P1AWS / MAD50PS1WS · Midea Cube Dehumidifier User Manual MAD20S1QWT / MAD35S1QWT / MAD50S1QWT (EN/ES) · Midea MDDN-12DEN7-QA3 manual de usuario de deshumidificador
Virtual technician
Does AS still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 2
Midea Cube Dehumidifier User Manual MAD20S1QWT / MAD35S1QWT / MAD50S1QWT (EN/ES)
Midea · 2026 · official_doc
- 3
Midea MDDN-12DEN7-QA3 manual de usuario de deshumidificador
Midea · 2023 · official_doc
- 4
Midea Cube MDDM-20DEN7-QA3 manual de usuario de deshumidificador
Midea · 2022 · official_doc
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