a/c recirculation mode

[rikdee]

Does anyone know the position of the return air duct?

[danewilson77]

Does anyone know the position of the return air duct?

You're looking for the location...correct?

[rikdee]

You're looking for the location...correct?

Yeah, bad word choice. Want to know where its at.

[danewilson77]

Yeah, bad word choice. Want to know where its at.

Ok....ima do some research.

Can I ask....why you ask?

HTC Thunderbolt+TT

[rikdee]

Ok....ima do some research.

Can I ask....why you ask?

HTC Thunderbolt+TT

I wanna spray some Wurth A/C treatment into the system intake as I'm getting the typical summer south Florida moldy smell. It is something I've done over the years with my Bimmers and have always sprayed into the (under-hood) cabin filter tray and the interior dash outlets. Yet, I'm thinking there has to be a return air duct for re-circulation and thought this is likely the best pathway to ensure the treatment chemical gets to the consealed parts of the system. The Wurth product attacks the offending mold and mildew and is not just a deodorant athough, IMHO, it does have a pleasant smell.

[aurelius]

I wanna spray some Wurth A/C treatment into the system intake...

+ a million on that question. I have had that Wurth product sitting in the garage for years but the directions say to spray into the air return ducts, which must exist if the system has a recirc function but I never know where to look. Seemed to me they were all air outlets.

You can actually manage (and in my case get rid of) the mold stink if you disengage the compressor a minute or so prior to shut off and then also disengage recirc about 30 seconds prior to shut off. All while keeeping the fan on. This has worked for me, quite well actually and I am in a reasonably humid area, tho FL is much worse.

[billschusteriv]

Found this... did a quick read and didn't see that it says where the recirc draws from... but interesting nonetheless.

www.bmwcarx.com/web/DocumentosBMW/E46ControlClimatico.pdf

[rikdee]

After reading all I could find about a "fix" (many simply too elaborate) I am doing the following based solely on supposition.

> I purchased an additional cabin a/c filter
> every week or ten days I will saturate the extra filter with Wirth Treatment, place it in the underhood housing, and run the system dialed for outside air and max fan for perhaps 5 or 10 minutes.
> I'm reasoning a frequent injection of the Wurth will, over time, produce an environment hazardous to the noisome critters that seemingly enjoy life on my evap coil. Only time will tell.
> I do practice the compressor off / fan on after I've driven with the A/C active, but it hasn't kept the odor away.

[aurelius]

That's an interesting idea but I wonder if spraying directly into that duct with the filter removed and fan on recirc might be more effective...?

Luckily (??) it is so hot in TX this summer that nothing can live anywhere but indoors, so I guess I'm good till next spring.

[rikdee]

Well, without the filter, the outside air draw could pull anything into the duct system. I reasoned having a filter there would preclude any unwanted particles, matter, etc. that might happen in. Plus, simply spraying into the duct area beneath the dash might find its way onto something that shouldn't get wet.
I still believe the frequency of the operation will be the key provided my underlying assumption is valid.