Two random HVAC questions

[gpking]

First of all, cabin air filters.
I have the part number for the filters from the OS and I have an '03 to put them in, but before I buy, I want to know if they will solve my problem:
Whenever I run the a/c dust/debris is blown out of the vents. I keep my phone in the "big gulp" cup holder and after just 5 minutes of driving, the screen will be covered in said dust with a fan setting of 2 or higher.
This never happened in the winter running the heat, just the a/c. Will the filters cut down or eliminate this dust?


Second, what is the purpose of the recirculate button? Note, I have the manual HVAC controller with the temperature sliders.
I was under the impression it caused the HVAC to pull cabin air as opposed to exterior air and that was it.
After my a/c got fixed, I noticed the recirculate button turns on the a/c and blows cold air without the snowflake coming on.
Whether the snowflake is on or off, recirculate turns on the a/c (as long as the sliders are in the blue).
Is this the intended function? Why can't I just cycle the cabin air?

In the winter the recirculate button is able to come on, what does it do when the heat is on? Cycle and heat the cabin air?
Also, why can't recirculate be activated on the digital HVAC controllers with the heat on? I've tried this in numerous GM vehicles and recirculate just flashes then goes off on the fancy digital controllers.
Is this an easter egg of the manual controller or does it not do anything?


Thanks for any insight!

 

[AtlWrk]

If the dust is coming from the coils themselves or the ductwork the filter won't do a whole lot (until all of the dust works itself out of the system). You may want to get under there and take a look at the A/C coils (through the filter door) for mold/mildew/gunk. I would also pull the blower motor and poke around. Deteriorating foam seals crumble and turn to dust. If you were always running recirc mode in the winter with heat then it may just be dust being pulled in from the outside now that the recirc is usually off. Do you live in a dusty/rural area?

The recirculate button activates the A/C compressor to dehumidify the cabin to keep occupants from fogging up the windows. This happens in the winter too with defrost/defog modes. You can raise the temperature sliders to offset the cooling.

 

[gpking]

If the dust is coming from the coils themselves or the ductwork the filter won't do a whole lot (until all of the dust works itself out of the system). You may want to get under there and take a look at the A/C coils (through the filter door) for mold/mildew/gunk. I would also pull the blower motor and poke around. Deteriorating foam seals crumble and turn to dust.

The thing is the previous owner absolutely never cleaned the interior, nor ran the a/c. The interior didn't even see a vacuum for 9 years.
The day I brought it home, I spent about 4 hours cleaning the inside. My guess is it's just residual dust inside the vents, but I'll be sure to check deeper in the system.

If you were always running recirc mode in the winter with heat then it may just be dust being pulled in from the outside now that the recirc is usually off. Do you live in a dusty/rural area?

I use recirculate year-round, and yes, I live in the boonies.
The dust is only really bad in the summer (corresponding with the dry weather when the dirt/gravel starts kicking up lots of dust).

The recirculate button activates the A/C compressor to dehumidify the cabin to keep occupants from fogging up the windows. This happens in the winter too with defrost/defog modes. You can raise the temperature sliders to offset the cooling.

So essentially recirculate activates the compressor year-round to keep the humidity down?

 

[The_Roadie]

So essentially recirculate activates the compressor year-round to keep the humidity down?

Yes, because you used to see a lot of Hondas and Toyotas in cold rain with totally fogged up INSIDE windows and it was a severe driving safety hazard. Clueless moron owners couldn't be trusted to understand they had a humidity build-up problem, so the industry started forcing the AC on for dehumidification in defrost and recirculate modes.