AC ECON button

[MoonRiver]

Does anyone know the diffrence between AUTO and Econ setting in the 07 G35 ac control is?. The manual says huminity at ECON is higher than in AUTO, AUTO works engine harder. How? I don't see at ECON the circulation light lights up, meaning it's not circulating air inside. I always think that as long as AC turns on it drys air, does ECON run AC less? if so how does it reach the set temperature, takes longer?

[joe603]

With ECON (or economy) on, the AC compressor isn't running all the time. The "normal" is akin to the "max AC" setting that keeps the compressor running. You can run the system without the AC compressor, best for winter heat. Having the AC on makes the cabin air more humid.

As for the recirculating function, it has more of an affect on how quick the cabin changes temp. Using the cabin air will always be quicker then outside.

[Tampa G35 Sedan 6MT]

I see you are in tampa...

Do you have a 07 sedan or coupe?

If you have the coupe then That is the same as my 06 sedan so I can say my thoughts about how I have it working.

For cold times when I need the heat I put the vent open so that it pulls air from outside and then I turn the fan up and push the ac button so that it isn't on as it isn't needed to heat the air!

The air circulates in the heater core and comes in hot... No need to run the ac compressor as it isn't doing any good.

also you are better off having the air come in the vent with the heat. I find that the heat doesn't work to well when you have to recirculate it in the cabin.

DJ

DJ

[kmckis1029]

basic chemistry.... cold things heat faster than hot things and vice vera

[Sentientbydesign]

I want to chime in my opinion.

I'm not sure exactly what the ECON vs Auto does, but I highly doubt the A/C compressor is going to run if the thermostat is set to a warmer than interally ambient temperature.

The climate control will actually switch from A/C to just recirculating air to heat on it's own if the temperature fluctuates enough.

A good way of knowing which one it's doing is to set it on AUTO and see where it's blowing air. A/C goes up top (towards your face). Ambient blows both bottom and top. Heat goes to the bottom only (feet).

I don't believe you have to trick the system into turning the A/C off. It's driven by a clutch and relay.

[marlin29311]

With ECON (or economy) on, the AC compressor isn't running all the time. The "normal" is akin to the "max AC" setting that keeps the compressor running. You can run the system without the AC compressor, best for winter heat. Having the AC on makes the cabin air more humid.

As for the recirculating function, it has more of an affect on how quick the cabin changes temp. Using the cabin air will always be quicker then outside.

The whole point of A/C is to remove humidity from the air...the cold effect is just a by-product of the process in this particular application...

Generally speaking, in any newer model car, the A/C will automatically turn on if you have the defroster on - the point of the defroster is to remove the condensation from the windows, and you can't remove condensation with water saturated air...The A/C can turn on at any temperature

As for the ECON setting, I have no idea. But even if it's 20 degrees outside and you set your defroster for 80, the A/C will turn on.

[06x]

With ECON (or economy) on, the AC compressor isn't running all the time. The "normal" is akin to the "max AC" setting that keeps the compressor running. You can run the system without the AC compressor, best for winter heat. Having the AC on makes the cabin air more humid.

As for the recirculating function, it has more of an affect on how quick the cabin changes temp. Using the cabin air will always be quicker then outside.

That's what I've always thought. But why does the AC button/light come on when I choose to recirculate air while heating the cabin?

I don't need any of the AC apparutus running this winter (if that's what the light implies) - why can't I just have heat with recirculating air just like other cars?

[DrNick]

A/C will REMOVE humidity from the air btw...not the opposite.

http://en.wikipedia.org/wiki/A...ntrol

[joe603]

I'm no expert...but in the winter, I thought the AC system adds humidity

Econ just puts the compressor in a low use state for better fuel economy.

[tollboothwilley]

AC never adds humidity. It removes the water from the air. This is how it makes air colder (during the summer), and in winter it will increase defrost effects by halving the time to defrost.

The ECON setting like previously mentioned, allows for the AC compressor to not be fully engaged all the time, so it will save you, theoretically, some gas $$.

Now, you can run the AUTO for heat without the AC button engaged. Press the AUTO, then the AC and you have just normal heat. Additionally, you can make it recirculated heat by pressing that button.

[joe603]

AC never adds humidity. It removes the water from the air. This is how it makes air colder (during the summer), and in winter it will increase defrost effects by halving the time to defrost.

The ECON setting like previously mentioned, allows for the AC compressor to not be fully engaged all the time, so it will save you, theoretically, some gas $$.

Now, you can run the AUTO for heat without the AC button engaged. Press the AUTO, then the AC and you have just normal heat. Additionally, you can make it recirculated heat by pressing that button.

Cool! Thanks for the info...I was never into the HVAC thing

All I know is that -39's suck in the desert. You have to kick 'em to get the compressor to work...and they freeze up. (military guys may get the reference )

[C-Kwik]

The whole point of A/C is to remove humidity from the air...the cold effect is just a by-product of the process in this particular application...

This is a bit of the chicken or the egg argument, but I don't think that the cooler temperature is simply a by-product. Dry sitting in a 90 degree dry heat and tell me you don't want the air to be cooler. Both humidity and temperature go hand-in-hand, but my thought it temperature would be more important. Otherwise we would have no need for a temperature control.

Not sure if the G would run a compressor 100% of the time. I'd imagine its possible under the right conditions, but under cooler conditions, doing so could cause the evaporator to ice up which would impede the flow of air out of your vents.

My thought it that the econ button simply increases the temperature range the evaporator runs in. This would reduce the load over time on the engine by cycling the compressor less and/or for shorter durations. When I had the G, I ran it in econ mode 95% of the time, but I live in a relatively moderate to dry climate. I'd imagine it would be more of an issue for people living in more humid climates.

One could simply grab a stop watch and observe the compressor cycle intervals and duration to see what it does...

[Sentientbydesign]

I think what was meant to be said is that A/Cs were designed to remove humidity (go do some history searching for more details). Cooling was a positive side-effect of removing humidity. Now we typically use the side-effect as the primary purpose and the dehumidifying as a by-product.

[marlin29311]

I think what was meant to be said is that A/Cs were designed to remove humidity (go do some history searching for more details). Cooling was a positive side-effect of removing humidity. Now we typically use the side-effect as the primary purpose and the dehumidifying as a by-product.

Exactly

[joe603]

What about "dry heat"...how do you take moisture out of the air when its really dry to cool?

[marlin29311]

If its dry heat, there is no moisture to remove - the system just works as normal, except there is no moisture to extract.

[joe603]

got it...so the moisture removal is a side-effect, not required for cooling.

Thanks for the HVAC lesson

[marlin29311]

lol - it's the other way around actually - the cooling is the side-effect of the "conditioning" of the air. However, the system still cools the air when it is on, even if there is nothing to remove from the air. It does everything the same, except it just doesn't have to extract water

[MoonRiver]

I see you are in tampa...

Do you have a 07 sedan or coupe?

cabin.

DJ

DJ

I have a 6 MT coupe.Still puzzled by when the compressor turns on and off, I have been studing the SM, hoping can figure it out soon. It's a dual AC, which makes it more complicated. I'll report back what I found out. Thanks all for the replys.

[telcoman]

If its dry heat, there is no moisture to remove - the system just works as normal, except there is no moisture to extract.

There are two kinds of heat.

1- The kind that ignites and burns down shanties.

2- The kind that excites and brings down panties.



Telcoman

[Jacko3]

Telcoman:

That was funny

[Tampa G35 Sedan 6MT]

Good one telco..

I know you are as old as dirt but I bet you had your day with the ladies lol

DJ

[Beancooker]

The whole point of A/C is to remove humidity from the air...the cold effect is just a by-product of the process in this particular application...

Generally speaking, in any newer model car, the A/C will automatically turn on if you have the defroster on - the point of the defroster is to remove the condensation from the windows, and you can't remove condensation with water saturated air...The A/C can turn on at any temperature

As for the ECON setting, I have no idea. But even if it's 20 degrees outside and you set your defroster for 80, the A/C will turn on.

Thank you. You saved me from typing that EXACT statement.

[Beancooker]

Joe, here is a basic example; Take a can of air duster for your keyboard. Squeeze the trigger, and after a minute, the can feels cold. If you were to run a fan over the can, it would blow cold air.

The AC in your car works "kind of" the same way. That is a brief explanation.

[MoonRiver]

Done studying G35 service manual. Here's what I found.

First off when it's in AUTO, air passes evaporator then flows either heater core or direct to air outlets, depending on preset temperature. The amount of air going through or bypass heater core is controlled by gates which are microprocessor controlled, in the air duct. The more heater flow the warmer, vise verse. When air passing through the cold evaporator, the moisture in the air condensates in the evaporator, therefore the moisture got removed.

On the other hand in ECON mode the microprocessor runs the compressor, it runs or stops, again depending on the preset temp. The compressor is swash plate type, meaning its compression ratio is variable. Its compression volume can be anywhere from 13 cc to 134 cc, the more liquified R134 enters evaporator, the colder. A microprocessor controls the volume compressed. It takes more engine the compress a bigger volume.

So the ECON is economical.I am going to set it to Econ from now on.