Is the A/C really on when it's pumping heat

mtsarpilot · 08-27-2006, 10:15 AM

Today is the first day since getting my Prius 3 weeks ago that the outside temp has been low enough that the A/C Auto has needed to put out a little heat instead of air conditioning. Heat definately coming out of the vents, yet on the Climate screen, both Auto and A/C have their yellow bar illuminated. I manually turned off the A/C button on the screen and of course no change in the heat coming out.

Is the car really running the A/C compressor when it's putting out heat? Or is this indicator really just an "A/C is enabled" indicator and not an indicator that it's truly using the A/C?

I notice that if you turn off the A/C button, the "A/C Auto" indicator up on the panel stays on. But if you leave the A/C button on and turn of the "Auto" button, that indicator goes off. That to is therefore a misnomer. It's really just an "Auto" indicator not an "A/C" indicator. Why'd they do that?

tumbleweed · 08-27-2006, 10:46 AM

If you have it in AUTO AC the system will heat or cool as needed to keep the temprature where you have set it. The AC does not run all the time and due to the variable speed compressor motor it is quite efficient when it is cooling. The problem is there is very little hystereses, it needs to have a cool setting and a heat setting like the ones in most houses. I try to get around it by setting the temp to 78 or 80 when I want AC, when I want heat I set it to 70 and turn the AC off with the MDF.

richard schumacher · 08-27-2006, 11:38 AM

A/C means air conditioner, not air cooler. The A/C does what is needed to maintain the desired cabin condition. The compressor runs only when needed for cooling or dehumidifying.

8AA · 08-27-2006, 11:41 AM

To the Japanese (and maybe other parts of the world) "air conditioning" means that the air is being heated, cooled, or dehumidified. On the Prius, "A/C Auto" indicates that the climate control will try to maintain the adjustable temperature and the non-adjustable relative humidity. The "A/C" button on the "Climate" screen is an override for the cooling compressor. If the button is illuminated, it means that the climate control has permission to use the compressor when it sees fit.

seasalsa · 08-27-2006, 06:17 PM

<div class='quotetop'>QUOTE(mtsarpilot @ Aug 27 2006, 07:15 AM) [snapback]310097[/snapback]</div>

Quote:

Is the car really running the A/C compressor when it's putting out heat?
[/b]

The A/C compressor has nothing to do with providing heat to the cabin. Heat comes from either electrical resistance or hot water.

08-27-2006, 10:15 AM	#1
mtsarpilot Join Date: Jun 2006 Posts: 87 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Today is the first day since getting my Prius 3 weeks ago that the outside temp has been low enough that the A/C Auto has needed to put out a little heat instead of air conditioning. Heat definately coming out of the vents, yet on the Climate screen, both Auto and A/C have their yellow bar illuminated. I manually turned off the A/C button on the screen and of course no change in the heat coming out. Is the car really running the A/C compressor when it's putting out heat? Or is this indicator really just an "A/C is enabled" indicator and not an indicator that it's truly using the A/C? I notice that if you turn off the A/C button, the "A/C Auto" indicator up on the panel stays on. But if you leave the A/C button on and turn of the "Auto" button, that indicator goes off. That to is therefore a misnomer. It's really just an "Auto" indicator not an "A/C" indicator. Why'd they do that? __________________ Seaside '06 Package #6 Leather added Full Clear Bra package Mud Flaps, Side moldings, and Coastal receiver hitch Purple Wire switch and Sirius Here2Anywhere Receiver installed behind smoked window door

08-27-2006, 10:46 AM	#2
tumbleweed Senior Member Join Date: Oct 2005 Location: Eastern Oregon Posts: 1,006 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	If you have it in AUTO AC the system will heat or cool as needed to keep the temprature where you have set it. The AC does not run all the time and due to the variable speed compressor motor it is quite efficient when it is cooling. The problem is there is very little hystereses, it needs to have a cool setting and a heat setting like the ones in most houses. I try to get around it by setting the temp to 78 or 80 when I want AC, when I want heat I set it to 70 and turn the AC off with the MDF. __________________ former Prius owner, waiting for a G III present car BMW 3 series

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08-27-2006, 11:38 AM	#3
richard schumacher nacreous lacquer Join Date: Mar 2004 Location: United States Posts: 4,131 My Car: 2004 Prius Package: #6 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	A/C means air conditioner, not air cooler. The A/C does what is needed to maintain the desired cabin condition. The compressor runs only when needed for cooling or dehumidifying.

08-27-2006, 11:41 AM	#4
8AA Senior Member Join Date: Feb 2004 Location: Maryland Posts: 492 My Car: 2004 Prius Package: #9 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	To the Japanese (and maybe other parts of the world) "air conditioning" means that the air is being heated, cooled, or dehumidified. On the Prius, "A/C Auto" indicates that the climate control will try to maintain the adjustable temperature and the non-adjustable relative humidity. The "A/C" button on the "Climate" screen is an override for the cooling compressor. If the button is illuminated, it means that the climate control has permission to use the compressor when it sees fit.