Recirculating air

Re: Recirulating air

Hello jryan,
Do you have the a/c set to auto? If you do it will switch to recirculate at start up.

 

.... until the car cools down sufficiently, then it switches back to fresh.

 

Can you stop the ventlation system from automatically going to “recirculate†on a 2004 Prius?

 

Re: Recirulating air

Supposedly, you can ask a dealership to set it with a hand scantool. The question is which dealership will do it for free.

 

Re: Recirulating air

<div class='quotetop'>QUOTE(jryan\";p=\"108682)</div>

The system is smart enough to automatically close the air vent until the system has cooled the air sufficiently. The only time when this is not an effective strategy is when the car has been sitting in the sun for a while, when you want to get rid of that hot air as soon as possible. Even then, however, the most energy-efficient strategy is to ignore the vent setting and roll down the windows for the first minute or so of driving to let all the hot air out as quickly as possible. With the windows rolled down it really makes no perceptible difference whether the little fresh air vent is open or closed. Having rolled the windows back up, make sure the vent is closed for best results (better mpg and faster cooling).

In general, the recirculate setting saves a lot of watts. So unless you're using your Prius to haul steer manure, you might consider leaving it on recirc all of the time, except perhaps on a long trip, when occasionally opening the fresh air vent can help maintain air quality in the cabin.

 

<div class='quotetop'>QUOTE(jryan\";p=\"108682)</div>

What makes you consider that a problem? I think it just one more neat feature.

 

I believe if you manually toggle the recirculate, it will stay there. To bring it back to full automatic, I believe you have to turn off the AC, then hit Auto again, which will make all controls automatic.

You see, there are three states for the various controls: off, on, or automatic. However the manual buttons only allow selection of 2 of those states: on or off, though off could be Automatic.

I have my recirc on, and have to remember to reset it to on when I turn off the AC and subsequently put it back on to Auto.

 

<div class='quotetop'>QUOTE(NuShrike\";p=\"108741)</div>

I'm here to say yes!

You can have the dealer change this mode (all the available the options can be found in the knowledge base).

You can also find a dealer who'll do it for free. The first one I asked wanted $100. The second one said "no problem". They considered it warranty work.

The only time I use recirc is if there's a dust or exhaust cloud.



DGStan

 

Re: Recirulating air

has anyone had this problem...
To start, I only like re-circulate. I hate it when it brings in outside air (unless I'm on a long car trip .... maybe....) so anyway...
The problem is, that the car just switches every now and then from recirculate to fresh.... seemingly for no reason.
I had the AC in manual mode (not auto) so I don't think that it was switching because of auto....

 

Seems to me that the obvious reason to use fresh air is to minimize the "funky smell" that can build up in the air ducts when condensation is allowed to pool for multiple days in a row. Ponded water from the condensor will find the smallest low spots in the line and grow mold or bacteria over time which manifests in a funky smell. Two solutions are to run more fresh air through, or to run the fan without a/c for the last 30 secs to minute of your drive to dry out the ponding. The last ditch is a nuke-job with lysol, of course. Preferring to avoid Lysol, I try to keep the car in fresh-air mode most of the time, only going to recirc if I'm passing a [sewage treatment plant, stockyard, turkey farm, garbage truck,..., exhaust cloud-producing car]

The reason to use recirculate would be that it, supposedly, helps cool the car faster. I'm not convinced, and it seems that cracking the windows while running fresh-air blows the hot air out faster to cool the car. An added bonus of the fresh-air setting is that it probably forces more cooling volume past the battery in the back (which in 110 degrees in Arizona probably helps the mileage more than leaving the A/C off!) Are there any reasons, other than to avoid an outside odor, to use recirculate that I'm not aware of?

 

One would think that fresh air is constantly being circulated into the cabin even when recirc is on. Since the battery pulls cool air from the cabin to cool the battery then exhausts it through a side vent to the outside, new air must replace that exhausted air right?

 

Well, sure, cars aren't perfectly sealed, or else they would float!

 

Didn't the old VW Beetle float?

 

"Didn't the old VW Beetle float?"

Yes, for about 45 minutes. A little longer if you greased the door seals. Eventually it leaked through the grommets that sealed cables, tubes, hoses.

 

Re: Recirulating air

Have you ever had that smell of dirty socks when you first turn on the A/C? I have on other cars. Not on my Prius tho. A service person at a dealership told me once that it comes from mold and mildew collecting in the vents from having the car on recirculate too much. He suggested that I try to use Fresh Air as often as possible to keep this from happening. Also, if you already have the problem of the foul odor, use Fresh Air for several weeks, and it usually cleans the problem out. I always suggest using Fresh Air mode after eating at White Castles or Weinerschnitzle :lol:

 

Re: Recirulating air

Does the "fresh air" option actually leave the vents open when the engine is off?

Rather than crack the windows down on hot muggy overnights and wake up to various little buggies on the inside of my Prius, I'd like to "open the vents" as I used to manually on my previous car just to let in the nite air to keep things fresh.

On my other car, I could hear (and see) that the vents were open. On my Prius, I'm not sure -- everything is so electronic. Does selecting fresh air actually let in/exchange air through the vents if the engine is off?

Thanks!

 

Re: Recirulating air

<div class='quotetop'>QUOTE(Don-RI\";p=\"115725)</div>

As Dan said above, the Prius has 3 settings. On, off and automatic. If you have the climate system on "on", which means the yellow bar over the auto button is out, and you have the fresh air button pressed meaning the yellow bar is present over that button, then it will stay like that forever. So the vents do not close when you shut the car off.

But the refresh system gets air movement via the forward motion of the car, unless a fan speed is picked. But when the car is off, there is no fan, and no forward speed of the car. So the air movement will be extremely close to zero. Except maybe in Florida certain times of the year.

I suspect that when the auto button is pressed, it will stay in whatever settings are present at the time you shut off the car. Then when you start the car later, it will do some sensing and then change things depending on the new circumstance at that time. So I would suspect that when you shut off the car and the vents are open, they stay open until you restart the car later.

But again, don't expect much air movement from those open vents.

 

Re: Recirulating air

<div class='quotetop'>QUOTE(vitium\";p=\"114615)</div>

My observations are that automatic activation of recirculate is related to a couple of things. I think the system activates recirc when there is direct sunlight on the sun sensor on the dash, and there is a significant differential between inside setpoint and the outside temperature. It makes sense that if it is 100 out and your inside setpoint is 75 (a 25 degree differential) and there is direct sunlight hitting the cabin, the vehicle will probably consider it most efficient to switch over to recirc considering that outside air will have to be cooled down before entering the cabin more so than inside air which is already someplace near the setpoint. On top of that solar heating will cause the system to increase a/c effort and that would also cause the system to want to revert to precooled inside air.

Does that make sense to anyone else?