To clean the WH41 PM2.5 Plantower sensor, use the following instructions:
1. Remove the unit from the mounting, pinching the white tabs to make this happen
2. Remove the batteries
3. Pinch the black tabs on both sides, and gently slide the sensor away from the case. Be careful there is a wire connected to the solar cell, so do this gently and leave the wire intact. It has enough length to allow you work on the unit.
4. Now you’ll see the metal casing of the sensor itself. You cannot take this out from the other part of the sensor. So you’ll have to mess around a bit to get the metal casing off.
5. Gently pull out the white connector from the upper half part of the sensor. Do not clean it, it is made greasy to prevent any rust.
6. The next part is the hardest: You can peel off the sticker with the brand and type information, or cut through it. Use a knife or a flat screw drawer to get under the metal outside of the sensor. The goal is to get under the metal casing and bend the metal up slightly to lift it off the black slide clips the metal is attached to. I used wooden toothpicks to keep it lifted.
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7. Once you can get it off on three sides, the fourth side will release also. Take the metal casing off the sensor.
There are 2 springs under the metal casing and they will jump out once you take it off. Don’t let them fall on the floor and get lost
8. Take a very tiny Philips screwdriver (I used a jeweler's screwdriver) to remove the three screws.
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9. Take off the plastic cover to see the sensor board
10. Disconnect the fan plug by pulling the red-black-yellow wire until it dislodges from the back of the board
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11. Take off the sensor board. Again, be careful of two other springs that are under the board.
12. You will now be able to see the interior of the sensor. You can blow it out or use a cotton swab (q-tips) to clean the inside. E.g. remove some spider webs or some dust. Try to avoid water or high pressure compressor to not damage the inside.
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13. On the other side of the sensor board, there is the lens and the receiver. If necessary, you can clean this using distilled water and a cotton swab. Take a small amount of distilled water and dip one end of a swab in. Carefully go over the lens of the sensor with the damp swab and the IR receiver. Use the other end of the swab to gently dry off the sensor and wait a few minutes for it to air dry. Make sure to not to touch the tips of the swab with your hands, as the oils from your hands could get on the swab and may affect the sensor. Also make sure no ‘hairs’ of the swab remain on the sensor. This can result in false readings.
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14. Reverse procedure and assemble the unit.
A tip is to first plug in the white connector and insert batteries and check if the sensor is working correctly and measurements are normal, before you’ll put back the metal casing.
Happy cleaning!
