Author Topic: Ecowitt WH41 Air Quality Sensor (PM2.5) only reading low  (Read 435 times)

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Offline theslydog

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Ecowitt WH41 Air Quality Sensor (PM2.5) only reading low
« on: April 26, 2021, 06:41:50 PM »
Has anyone run into this problem?

I have a Ecowitt WH41 and it is just sitting on 3-4ug/m3 no matter what the actual AQI is.

IE there is currently a fire in our area and a hand held is reading 100ug/m3 similar to the offical AQI website but the Ecowitt is reading 3ug/m3.

Is there any reset or a part than can be replaced?

Or is the unit now US?

The Unit was purchased in the middle of 2019 and seems to have started this behavior b4 Christmas.


Offline davidefa

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Re: Ecowitt WH41 Air Quality Sensor (PM2.5) only reading low
« Reply #1 on: April 27, 2021, 10:23:43 AM »
I don't know if this is your case but I stumbled in this video ( as I was searching how to mount my PMS7003 to prevent dust build up on the sensor )
Even tough the WH41 sensor is different, these low cost sensors are similar, so the problem could be dust build up, a malfunctioning fan...

P.S. I don't know how to trust a sensor after such a cleaning...
P.P.S. Here a small comparison of a few sensor, the oldest sensors show sign of 'fatigue'
So this is to be expected with time...
« Last Edit: April 27, 2021, 10:34:57 AM by davidefa »

Offline theslydog

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Re: Ecowitt WH41 Air Quality Sensor (PM2.5) only reading low
« Reply #2 on: June 04, 2021, 08:43:11 PM »
I don't know if this is your case but

The Ecowitt uses a Honeywell sensor.
Anyway it stays on 3-4ug/m3 even with the sensor disconnected.

So definitely a problem somewhere.

Just to let everyone know Lucy sent me a replacement for this faulty one at no charge.

I thought the new one was also not working, but it is fine.
It was sitting on 0ug/m3 for a bit, but it was just that the original I had never ever went to 0.
So the original may have been faulty from the beginning.


Offline kc2kzz

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Re: Ecowitt WH41 Air Quality Sensor (PM2.5) only reading low
« Reply #3 on: June 07, 2021, 08:12:46 AM »
I will say that Ecowitt has been good at replacing these.  My original one, which worked fine for 6 months,  started to report only 11 ug/m3 regardless of what the actual reading was.  The first replacement was bad also due to a bad antenna/board.  The 2nd replacement appears to be working great.