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Old 19-08-2019, 09:08 AM   #2936
Great Supremacy Member
Join Date: Jun 2001
Posts: 56,185

Hi gurus,

I have been sick alot recently (cough flu sore throat etc) and recently kenna sinus infection which have not recovered after a week.

I suspected it was because of a weird smell coming out from my aircon but brushed it aside for months.

Due to my infection, I bought a Xiaomi Air Purifer 2S to try out. Initially AQI was quite ok around 20+ when I first used the machine for a while.

When I turned on my aircon, the weird smell came again and the AQI shot up to 320+ (even 350+ at one point).

I carried the purifer to test out all my other rooms (reading 20+) to confirm the sensor should be working properly.

My question is, is the particle sensor accurate (to show the 300+ readings)?

Next, what could have caused such hazardous air quality?

Dunno if picture is linked correctly:
Not saying that it's 100%, but there is a high possibility that it's a mold allergy/mold infestation from your FCU.

The chronic allergy started small, then worsened, brought about inflammation that is chronic, and you then were also susceptible to secondary "normal" infections and sickness.

You might have recovered (immunity usually fluctuates due to many factors eg work, family etc), then fall ill again, then recover.......etc.

The AP with high air change hour is a good option, but since you only have the Xiaomi 2S, it is not enough. Remember, you are probably doing around 100 m2/hr airflow in reality from it during sleeping time, never mind that it's rated for 323 m3/hr coz that's on paper/theory, since 99.9% of the time in reality you are not going to be using that speed.

Say you have a 20 m2 room, the ceiling is 2.7m, the volume is 54 m3. Deduct maybe 30% coz of furnitures in the room, you are left with 38 m3.
You need to do at least 5 Air changes per hr for it to be really significant in effect, so we are talking abut 200 m3/hr.
In fact for these stuff, i'd really recommend at least 8 ACH, that is 304 m3/hr airflow.
That is a Samsung AX40 operating at full fan speed, this unit is among the quietest at full fan speed (45 dBA only at 320 m3/hr), but still those who are a bit sensitive to noise during sleeping still need to position it creatively away from the bed sleeping positions.

If you really think this is a possible source for your issue, then try to learn how to DIY clean your aircon FCU. Slowly learn.
If you do not like to DIY, then embark on cleaning it professionally with chemical washing 3X a year, at least. I'd recommend 4-5X yearly if possible.

Do not use General aircon servicing, they do not work in your case.
Do not use Chemical Wash with alkaline coil cleaners, there are Chemical Wash with detergent/solvent cleaners that are not caustic and won't harm your aluminum evaporator coils. Also, some service providers do a better and more thorough job than others, using high pressure water (just high enough pressure that won't damage your fins).

So yeah, if you do not DIY, esp if you have multiple aircon units in your home, it's going to get pretty expensive.

PS. Disregard the Xiaomi 2S sensor. If you wanna play, go to Taobao and get those laser particle counter meters. They are still are pretty good in sensitivity, go and read the past 10-20 pages, i posted some stuff.
1-hr ug/m3 + PSI
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