Aircon/ventilation D2

[2 rocks]

Look...sorry to drag this up again...

Either I'm thick or can't follow advice properly...then again possibly both! :)

Now that the weather has warmed up this is really beginning to p...er, "tick" me off...

I have tried:
1) putting on "auto" lowest temp, then turning off: still seem to then get warm air through the vents
2) setting to lowest temp (16deg as LO automatically brings up "recirculate") the switching to ECON mode: still get warm air through the vents

Yes, I know lots of people will say the aircon doesn't affect power/economy and it's possibly true, but unless it's really hot, I'm a window down and fresh air kind of guy...except for the bloody warm air coming out the vents!!!!

So can someone please explain in the terms of a 5 year old (so I can understand it, lol) how I get ambient temp air to come through the cabin vents?

Mike

[Graeme]

I don't know if this is what you're looking for, but set the temps to LO then switch off recirculate and probably also slow the fan down.

[MickG]

Drives me mad too.....I have yet to work it out too even after posting a reading advice on here.

Don't want to highjack but does anyone know how to make the temp go up or down on both passenger and driver side by only pressing the drivers side temp switch. I have to press both at same time to get them both to read the same temp I want:mad:

[harlie]

I’m pretty sure you won’t get ambient temp through the vents because there is too much heat transfer in the ducting and evaporator unit when the compressor isn’t running. I like some fresh air too and if I have windows down I just shut the system down altogether. Not turn it off – just shut the air flow off. As you probably know when you turn off the power on the climate system the fresh air (which will now be warm) will open.
To shut air flow off completely - 1. set it to ‘econ’ - 2. set fan to 0 - 3 (when recirculation off) hold recirculation button down until it beeps twice (about 3 sec). There will now be no air through the vents.
The system has built in function that will switch recirculation on and off if it’s in econ mode (annoys the hell out of me), the double beep cancels this.

Hope this helps

[5teve]

i have wondered about this... and wondered if its something to do with the heat held in the ducts and tubes.. but witha 35k drive home it didnt seem to get much cooler.. i just wack the windows down and enjoy it :D

i did a test to see if the valve was knackered by turning the temp to max... and it came out even hotter! but i do wonder where it comes from.. i know it cant be from the heater matrix as the car is cold at start up (relatively)

so we all get hot air on a hot day then... glad its not just me! :angel:

Steve

[ladas]

First check the outside air temp -

Then make sure the unit is not on recirc.

Then sent the cab temp to 1 Deg above outside air, and DONT put econ on. Put on AUTO.

This will then allow outside air in, without cooling, and should work just right.

Well it does on mine.

If the outside air does rise dramatically - it will mean the compressor will start.

In terms of ecconomy of using AC - you increase drag on the vehicle and thus increase fuel consumtion - more - when you open a window - than you do when you switch the AC on.

Food for thought.



Look...sorry to drag this up again...

Either I'm thick or can't follow advice properly...then again possibly both! :)

Now that the weather has warmed up this is really beginning to p...er, "tick" me off...

I have tried:
1) putting on "auto" lowest temp, then turning off: still seem to then get warm air through the vents
2) setting to lowest temp (16deg as LO automatically brings up "recirculate") the switching to ECON mode: still get warm air through the vents

Yes, I know lots of people will say the aircon doesn't affect power/economy and it's possibly true, but unless it's really hot, I'm a window down and fresh air kind of guy...except for the bloody warm air coming out the vents!!!!

So can someone please explain in the terms of a 5 year old (so I can understand it, lol) how I get ambient temp air to come through the cabin vents?

Mike

[LandyAndy]

Hi Ladas
BUT IT DONT GO TO 42 Like it was when I left work:D:D:D:D:D:D
Mike
I set both temps to LO,make sure recyle is OFF(press the 3 arrows pointing at each other) then run the aircon.Once cold air comes out press econ.When warm air comes out later run the aircon again to cool all the bits the air flows over then revert to econ.
With the recycle off no fan is needed.
Goodluck
Andrew

[LandyAndy]

To get the best out of the aircon,Ive found you need both auto temp set to 16 and auto fan enabled(hold the fan button for a few sec)
I DONT like bellowing screaming fans,but it does settle pretty quickly and gives alot colder air than setting it to lo with speed 1 fan which I normally use.
Andrew

[2 rocks]

Cheers Andy
I'll give that a crack too!
Mike

[BMKal]

I've found it's easiest to just let it run in auto with the inside temp set points set to about what is outside ambient temp as Ladas has said.

Tried to slow the fans down manually one day when driving from Perth to Kalgoorlie in about 40 degrees outside, and ended up freezing up the whole bloody unit. Last 150 k's or so was very uncomfortable. Didn't really know what the problem was until I got home and a big puddle on the shed floor under the Disco.

Have left it on auto ever since and no further problems.

[2 rocks]

Ok first, thanks to all who replied!:BigThumb:

I have finally worked it out...well for me anyhow! And this is no doubt a combination of things you guys have said, but this is how I'd describe it:

1) ECON mode
2) set to LO
3) turn Recirculate off
4) fan on or off as you choose

and hey presto - outside air through the vents...the footwell vents seem to still suffer from heat transfer, seems to reduce a little if I just select the "face" vents...hope this helps someone

Mike

[vnx205]

....................... ......................
In terms of ecconomy of using AC - you increase drag on the vehicle and thus increase fuel consumtion - more - when you open a window - than you do when you switch the AC on.

Food for thought.
It's not quite that simple.
I'm not sure how it works in vehicles with the aerodynamics of a brick, but in vehicles shaped like a well worn bar of soap, it goes something like this.

Below about 80kph it is more economical to open the windows.
Above about 80kph it is more economical to close the windows and turn on the A/C.

The extra drag created by having the windows open doesn't exceed the extra power needed to run the compressor until you go over about 80kph.

[ladas]

Sorry but I have to disagree, whilst speed is relevant the slower you go the more drag caused by an open window

- the power required to run the compressor aproximates to 7% +/-

The compressor pulls the same relational power whether at 40 km or 90 km

The head pressure of a compressor is directionally relative to the speed of the compressor to a point.

so, in theory the faster you go the more power it needs.

............but the compressor will pull more power - relatively - at a very low speed - due to the fuild dynamics and the friction elements which are constant.

So if at 1000 rpm the head pressure is 200 psi, which will equate to approx 5 hp - the fluid dynamics - or static restistance of the refrigerant being used will add another say 0.5 hp and the friction element will add another say 0.50 hp of drag - so at 1000 rpm you have 6hp of drag.

at 2000 rpm - the head pressure will rise to 225 - so the HP draw will be 5.55 but the fixed elements (fluid dynamics and friction) remain static. so a total of 6.55 - so it argues against the direct pressure relationship. but its still relative.

The effect of a window open can reduce power greater than 12% - regardless of speed , but it is temp/humidity/density/wind direction relative

You do not reduce pressure inside the vehicle by going slower - in fact you increase it.

The faster you go the pressure outside the vehicle is reduce - and thus the inside of the vehicle is at a + pressure, and will in effect reduce drag.

Just look at basic physics X amount of air having to move over a large area, and increase speed = pressure drop

The lower the speed of the vehicle the closer the internal and external pressures are, and thus the more drag is induced.

If you smoke just do a very simple experiment - drive around at 40 km/h with the window open with a cigarette alight - or something else that gives off smoke - at 40 km/h most of the smoke remains in the vehicle, because the pressures are near equal.

When you increase speed - watch the smoke - it will start to move towards the window and out of it, because the pressure outside is being reduced by speed.

Air exiting will not increase drag, it is only the free movement of air from outside to in does this.

sorry I have rattled on about this - but I have spent weeks/months working on this type of experiments.


It's not quite that simple.
I'm not sure how it works in vehicles with the aerodynamics of a brick, but in vehicles shaped like a well worn bar of soap, it goes something like this.

Below about 80kph it is more economical to open the windows.
Above about 80kph it is more economical to close the windows and turn on the A/C.

The extra drag created by having the windows open doesn't exceed the extra power needed to run the compressor until you go over about 80kph.

[LandyAndy]

Hi Allan
Myth Busters Busted that one !!!!!
The airconed vehicle used more fuel,not substantially though.They were very thorough in their testing.
Mike thats how I do mine.Mines BLACK so it gets hot when parked and get hot air,thats why I just hit the econ button(which is compressor ON/OFF) to cool the aircon system then when I get cold air econ again to switch the compressor off.
In winter when its colder outside the vehicle climate control will keep the vent temp at your set temp with the econ set on(no compressor),ie will regulate the hot air to your temp set.
Andrew

[4bee]

On my D1 facelift, the ambient air gets heated by the fact it has to enter the trough under the screen, travel along that to the pass. side before entering the inlet duct.

The engine side of that trough is open to engine heat at the firewall,, with no insulation on its face. An ideal heat exchanger in fact.:mad:

It seems near impossible to insulate this section now & I had thought about spray on foam, but decided it could look a right mess.

It annoys the crap out of me, when on a mild day with a comfortable ambient temp, I have to put the cooling on to maintain a good temperature because it's heating up as it travels through the trough.

The stealership looked at it but did nothing & said it was fine.

I arrived at the above conclusion by having a good hard look at the components & layout.

It ain't rocket science as it turns out, but why the LR twits didn't rectify this for Australian conditions I'll never know. Probably fine for the UK.