Junghole
Junghole SuperDork
8/26/21 11:17 a.m.

I drive a vehicle that doesn't have the recirculated air feature. Would it be better to run the air conditioning? My thought is that the AC evaporator would possibly filter out some of the smoke? Completely hypothetical of course, I have zero Science to go off of this. 

Cactus
Cactus HalfDork
8/26/21 11:23 a.m.

I assume your vehicle is also old enough to not to have a cabin filter. Yeah, the condensation on the outside of the chilly bits will suck some of them microparticles and either stick them to the exchanger or drip them away.

 

It's better than having the windows open, at least.

asphalt_gundam
asphalt_gundam Reader
8/26/21 11:59 a.m.

I'm just dieing of smoke and the allergies its triggering. Happy whenever the wind switches direction. Been thick as fog in the mornings lately

Junghole
Junghole SuperDork
8/26/21 12:04 p.m.

In reply to Cactus :

That is the real catch here. The vehicle is a 2020 GMC van. Has air-conditioning, but I don't see a recirculation setting. And when I turn on the air I definitely still get smoke in the cabin. I think I need to check for a cabin filter. It would be strange for a vehicle this new to not have one, then again, perhaps GMC did not deem it necessary on a Passenger van

02Pilot
02Pilot UltraDork
8/26/21 12:06 p.m.

Even if there's no Recirc switch, I wonder if the system includes the functionality. Check the manual to see if it says anything about automatically going into recirculated air in some modes. If there's no cabin filter, is it possible to fabricate something to include one?

Edit: Yup, p.146 of the manual - "Max AC - Cools the air inside the vehicle faster, by recirculating the inside air."

Junghole
Junghole SuperDork
8/26/21 12:14 p.m.

In reply to 02Pilot :

Hey thanks man. This thing only has 14k mi On it, but never came with any manuals

CAinCA
CAinCA HalfDork
8/26/21 12:20 p.m.

Is there a MAX AC mode? That's another term for recirc.

Junghole
Junghole SuperDork
8/26/21 12:27 p.m.

In reply to CAinCA :

Yeah there is. And apperently page 146 of the manual tells us

DeadSkunk  (Warren)
DeadSkunk (Warren) UltimaDork
8/26/21 12:29 p.m.

Does it have a snowflake icon and a max-snowflake one? I think on max it recircs, but I'm not positive.

Edit: Online owners manual (pg 146) says the max setting is the recirc.

2020 GMC Savana Owners Manual

DeadSkunk  (Warren)
DeadSkunk (Warren) UltimaDork
8/26/21 12:35 p.m.

Slow off the mark again I am.....

Junghole
Junghole SuperDork
8/26/21 12:59 p.m.

In reply to DeadSkunk (Warren) :

But still appreciate it!

Marjorie Suddard
Marjorie Suddard General Manager
8/26/21 1:25 p.m.

Wow. Less than 45 minutes, multiple answers complete with link. Honestly, with you guys around, I'm not sure why I ever Google anything.

Margie

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
8/26/21 6:11 p.m.

Yup... on GMs, the "max" setting is the recirc.  The "norm" or "AC" setting is outside air.

The air you get in the cabin is always flowing over the evaporator.  The only thing the A/C does is make the evaporator cold.  Any filtering (which may actually be significant) would be from the condensation on the evaporator.

Your van also likely has a cabin air filter.  Swap it out for a good swanky filter and it should help.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
8/26/21 6:18 p.m.

This is somewhat typical of how the airflow goes in your GM.  Most of them after the early 80s have a bypass valve for the heater core so it's not getting hot and fighting the A/C in the summer, but this is pretty typical.

See the source image

Some stack the heater core right in front of the evap coil which often results in slightly slower transitioning from heat to cooling, but how often do you have a day where it instantly goes from 40 degrees to 80 degrees outside and you need a fast transition?

Well, maybe in South Dakota.

rustomatic
rustomatic Reader
8/29/21 6:58 a.m.

If you're anywhere near the Sierras, the particulate matter (lots of ash in the air) will build up very quickly in filters.  This has of course been a thing for years now, but as the fires get more huge (and create more of their own super-fun "fire weather"), the ash quantity (and quality) gets more volcanic in nature.  Just ask someone who was around when Mt. Saint Helens blew . . .

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