How to check your own air purifier Xiaomi: a complete guide with tests and tips

Xiaomi air purifiers are some of the most popular devices in the brand's smart home lineup, but even they require regular inspection. Over time, filters get clogged, sensors get polluted, and performance drops. How do you know if the appliance is working correctly? Should I change it? HEPA-filter if the indicator is still green, and why can the device show a high level? PM2.5, when the room is clean?

In this article, we will discuss 7 practical ways to test Xiaomi air purifier – from basic diagnostics through the Mi Home app to professional tests with a laser particle counter. You'll learn how to measure the actual efficiency of cleaning, detect sensor malfunctions, and extend the life of the device. PM2.5 In the application can differ from the data of third-party devices by 30-50% and what to do about it.

1.Verification through the Mi Home app: What sensors show

The easiest way to evaluate the cleaner is to use the official Mi Home app (or Mi Home Lite for the simplified version). PM2.5, temperature, humidity and filter condition, but how do you interpret these data?

Open the app and select your cleaner. On the home screen, you'll see:

• 📊 Current level PM2.5 — the norm up to 35 μg / m3 (green zone), 35-75 (yellow), above 75 (red).
• 🌡️ Temperature and humidity – indirectly affect the operation of sensors (with humidity above 70% of the reading) PM2.5 may overstate).
• 🔄 Automatic, night or manual (e.g. Favorite in Xiaomi Air Purifier models) 3/4).
• ⚠️ Condition of filters - percent of wear HEPA and carbon filter (updated every 24 hours).

Note: If the cleaner shows a high level of PM2.5, And there's no visible sources of pollution in the room, dust, smoke, and the problem could be a contaminated sensor, and in Xiaomi Air Purifier Pro and the newer, the sensor is located under the front panel, and you can clean it neatly with a cotton swab dipped in alcohol.

⚠️ Note: If the level of the cleaner is turned on PM2.5 not falling 10–15 Just a minute, check the density of the filter. 3H/4 Often there is a problem with improper installation of the carbon filter - it can block the air flow.

Visual inspection: filters, fan and body

Even if the app is doing well, a physical inspection of the device can reveal hidden problems, starting with disconnecting the cleaner from the network — that's a must for security.

What to check:

• 🔍 HEPA-The filter should be uniformly gray. Dark spots or black plaque indicate a lot of pollution (replacement is needed). In Xiaomi 4 Pro models, the filter is antibacterial coated - it can not be washed!
• ⚫ Coal filter – if it crumbles or has a sharp chemical smell, it is time to change it (lifetime – 3-6 months).
• 🌀 Fan blades -- they shouldn't be dusty or hairy, clogged fans can reduce performance by 20 to 40 percent%.
• 🔌 Contacts and connectors – oxidation or contamination can cause power errors (e.g. code) E1 Xiaomi Air Purifier 2).

Pay special attention to the sealing gum between the body and the lid. If it deforms or loses elasticity, the slits will pass through the untreated air. 3H and newer removable rubber band - it can be replaced separately (article) DJF-Z01).

3. Performance Test: How to Measure Real Cleanup

Cleaner sensors can lie, especially if they are contaminated or uncalibrated, and to evaluate the device objectively, conduct a test with the source of the contamination:

You'll need:

• 🕯️ Candle or match (smoke source).
• 📏 Line or roulette (measure distance).
• ⏱️ Stopwatch (on a smartphone).

Instructions:

1. Place the cleaner in the center of the room (up to 20 m2).
2. Light a candle 1 meter away from the device and let it burn for 30 seconds.
3. Turn off the candle and turn on the cleaner at maximum power.
4. Find out the time at which the level PM2.5 In the app, it will fall from red to green".

Normal results:

If the cleaning time is much longer than normal, the problem may be:

• 🔋 Scored. HEPA-filter (replace it).
• 🌀 Faulty fan (check the blades for damage).
• 📡 Incorrect settings in the application (for example, Sleep Mode is enabled, which limits power).

Checking the sensor PM2.5: calibration and comparison with other instruments

Sensors. PM2.5 in Xiaomi cleaners (e.g. Sharp) DN7C3CA06Y model 3/4) They lie over time, especially if the device has been working in a dusty room for a long time?

Method 1: Comparison with a third-party device

If you have another air quality meter (e.g. Xiaomi Mi Air Quality Monitor or Netatmo Weather Station), place it next to the purifier.

• 🟢 Up to 15% - Normal error.
• 🟡 15–30% – The sensor needs calibration (see below).
• 🔴 More than 30% – sensor malfunction or severe pollution.

Method 2: Manual calibration

In some models (for example, Xiaomi Air Purifier) 3H) You can reset the sensor calibration via Mi Home:

1. Open the app and select a cleaner.
2. Go to Settings. → Additionally. → Sensor calibration.
3. Press Reset and leave the device for 10 minutes in a clean room (for example, after airing).

Method 3: The salt test

If you do not have a second device at hand, use table salt:

1. Sprinkle 1 tablespoon of salt on a plate and put next to the cleaner.
2. Turn the device on at maximum power.
3. In 5 minutes, level. PM2.5 should rise to 50–100 μg/m3 (due to small salt particles).
4. If the readings do not change, the sensor is defective.

⚠️ Note: Xiaomi Air Purifier 4 Pro and later uses a laser sensor Sharp GP2Y1051AU0F, It's sensitive to direct light, and don't do tests in the sun or near light bulbs, and it'll distort the results.

Diagnostics of errors and fault codes

Xiaomi air purifiers display errors through indicators on the case or in the application.

If the cleaner makes a mistake E4 (It is found in Xiaomi Air Purifier 4 Pro, it indicates the engine overheating:

• 🔥 Clogging of ventilation holes (clean them with a vacuum cleaner).
• 🔌 Working at maximum power for more than 8 hours in a row (let the device rest).
• 🌡️ High temperature in the room (more than 35)°C).

In models with a display (for example, Xiaomi Smart Air Purifier 4), errors are displayed in the form of text. If the screen shows "Check Filter" but the filters are new, the problem may be in the contacts of the sensor - carefully remove and install the filter again.

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If the cleaner suddenly stops responding to commands from the app, try resetting it to factory settings. To do this, hold the power button 5-10 seconds before the beep. In touch-controlled models (for example, Xiaomi 4 Pro), the reset is performed through Settings. → Resetting in annex.

Verification of noise and vibration levels

Xiaomi air purifiers normally operate almost silently (20-30 dB), but over time, foreign sounds may appear.

• 🔊 Honking or whistling - speaks of problems with the fan (possibly a foreign object hit).
• 💥 Clicking or knocking – weakened fastening of the blades or engine.
• 🌀 Vibration of the body - improper installation of the filter or wear of bearings.

How to check:

1. Turn the cleaner on at maximum power.
2. Bring your ear to the top of the body (where the fan is located).
3. If you hear a metal clang, most likely, the blades touch the body - you need disassembly and centering.

Xiaomi Air Purifier models 3H And the newer one is a brushless engine, which doesn't wear out very much. If it comes out suddenly, it's usually two reasons:

1. Getting hair or threads into the fan (remove them with tweezers).
2. Disbalance of the blades due to deformation (replacement is needed).

For objective noise assessment, use a noise-meter application (for example, Decibel X for the soundtrack). iOS/Android). Normal values:

• 🌙 Sleep Mode: 20-25 dB.
• 🔄 Auto Mode: 30-40 dB.
• ⚡ Turbo Mode: 50–60 dB (short-term).

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If the cleaner began to make more noise than usual, first check the filters - clogged HEPA-filter increases the load on the fan, which leads to increased wear and noise.

7. Air leak test: how to check leakiness

Even if the filters are new and the sensors are good, the cleaning efficiency can be reduced by air leaks.

Method 1: Smoke test

1. Turn the cleaner on at maximum power.
2. Bring a lit cigarette or candle to the joints of the case (especially around the filter).
3. If smoke seeps in without passing through the filter, the sealing gum is worn out.

Method 2: Paper test

1. Take a thin sheet of paper (such as a napkin).
2. Apply it to the edges of the cleaner cover when the device is working.
3. If the paper is attracted to the case - there is a leak (air is sucked past the filter).

Xiaomi Air Purifier 4 Pro and Smart Air Purifier 4 models use 360 system° It's a problem, because you're not getting enough air, so you're less likely to leak:

• 🔧 Pull up the mounting screws on the bottom panel (in Xiaomi models) 2/3).
• 🛠️ Replace the sealing gum (the article depends on the model, for example, DJF-Z02 Xiaomi 3H).
• 🧴 Apply a thin layer of silicone lubricant to the rubber band for a better fit.

⚠️ Note: In Xiaomi cleaners with Air Duo function (e.g. Xiaomi Air Purifier) 3H) Air leakage through the top panel can lead to false readings of the sensor PM2.5. If after replacing the filters, the level of contamination does not fall, check the tightness at the top of the device.

FAQ: Frequent questions about checking Xiaomi cleaners