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Leaving a\c on in winter and if so what setting?

Discussion in 'A3/S3/Sportback (8P Chassis)' started by cdb2, Mar 13, 2006.

  1. cdb2
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    cdb2 Member

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    It appears to be good advice to leave our climate control on all year to lubricate the seals or use it for 30 mins a week.

    If this is true, is leaving it on Auto at 22 degrees during the winter enough?

    Or should it be set to blow cold air periodically as presumably unless it is blowing cold air the compressor\chiller is not working and therefore not lubricating?

    I'm confused - anyone in the know or with the manual handy?
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  2. cosmicblue
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    cosmicblue Member

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    [ QUOTE ]
    It appears to be good advice to leave our climate control on all year to lubricate the seals or use it for 30 mins a week.

    If this is true, is leaving it on Auto at 22 degrees enough?

    Or should it be set to blow cold air as presumably unless it is blowing cold air the compressor\chiller is not working and therefore not lubricating?

    I'm confused - anyone in the know or with the manual handy?

    [/ QUOTE ]


    Auto=having the Air Conditioning compressor ON

    Auto+Econ the Air Conditioning compressor is OFF though the climate control system will still work to maintain the desired temperature. Without the compressor active the air won't be de-humidified.

    Remember that when the compressor is running it saps 10% of the engine's power with fuel economy taking a hit too.

    The advice to run the system with Econ turned off for 30 mins each week is valid.

    In the Winter I run Auto+Econ all of the time - works a treat.
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  3. h5djr
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    h5djr Well-Known Member

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    I run with my air-conditioning set on Auto and 20-21 degrees all the time, summer and winter. Sometimes if it's really cold I change the air flow direction to screen and footwells but I never turn it off.

    I've used it in the same way on all 5 of my A3 and never had any problems.
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  4. cosmicblue
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    cosmicblue Member

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    Most people do David, most are not aware that the compressor is running in Auto only mode and impacting fuel economy/performance in the process.

    If they knew however they might behave differently....but there again, maybe not.
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  5. powerplay
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    powerplay Grrrr

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    [ QUOTE ]
    Remember that when the compressor is running it saps 10% of the engine's power with fuel economy taking a hit too.

    [/ QUOTE ]

    10%, is that right? Nearly 25 horsepower to run my air con. Can't be that ineficient, surely!
    #5
  6. madvw
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    madvw Active Member

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    usually takes aroung 5hp to run the aircon, and consumes an extra 5mpg.

    the only problem when using the aircon in winter, is that it has to be above 5 degrees C outside for the compressor to work. I usually leave it on auto in winter to enable it to run when it can.
    #6
  7. god_thats_quick
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    god_thats_quick Numptie of the highest order

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    Mine stays at 22 ish all the time, the whole point in climate control is to let it sort it out, seems to work perfectly in my S3 too.

    The whole power and econemy thing is a joke surely, you don't choose when you want to be warm or listen to the stereo on the amount of power it uses - if you do I think serious help is required.

    The system in my S3 is designed to cut the compressor under full acceleration so again the argument about performace is pathetic.

    I just don't understand people that buy cars with climate control then fiddle with it the whole bloody time or don't use it - utter madness, it's also shown to be bad for the system if not used.
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  8. h5djr
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    h5djr Well-Known Member

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    I've have tried running mine with the compressor ON and with the compressor OFF and have not really noticed any difference in either power or fuel comsumption. The compressor has an electric clutch and only engages when the air is required to be cooled or dehumidified, the rest on the time it's just spinning in 'neutral'

    On my previous Audi 80 back 1988 you could feel a slight jolt in the power when the compressor clutch engaged but I've not noticed it on any of the 7 VW/Audi cars I had since and they have all been fitted with air-con.

    According to the Owner's Manual, in order to achieve maximum engine power, the air conditioning compressor is temporary switched off when pulling away from a standstill with full throttle.

    The air-con also takes out moisture from the air entering the cabin so is very useful for keeping the windows clear in winter when it's cold and damp. I cannot remember the last time I needed to switch on my heated rear screen.
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  9. Amchlolor
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    Amchlolor Active Member

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    I also run mine on 'auto' all the time.

    Anything else and the windows mist up something rotten,
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  10. The Slug
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    The Slug Active Member

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    AUTO on all the time at 21-22 and econ only in mornin, once engines warmer then depress the econ.....i can guess where this came from, lol, AudiDriver by any chance...
    #10
  11. yak
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    yak Member

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    Not really an issue here at least, since leaving it at auto or econ makes no difference, the A/C is turned off when there's enough cold outside.

    If you want to use your A/C, drive into some warm parking lot or such. It should work, unless the engine is still too cold /ubbthreads/images/graemlins/wink.gif

    But in all honesty, 30 mins every week is a bit too much, and unrealistic. It will work just fine with less using, once a month, once a winter even /ubbthreads/images/graemlins/wink.gif
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  12. cdb2
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    cdb2 Member

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    Thanks guys, seems from what u say that full Auto (=having the Air Conditioning compressor ON) is the optimum in terms of keeping your system going and safe in the winter to hopefully avoid problems later in life, but will marginally affect your mpg.

    Auto+Econ (the Air Conditioning compressor is OFF though the climate control system will still work to maintain the desired temperature. Without the compressor active the air won't be de-humidified) seems to be fine too but probably recommended to run the system with Econ turned off for 30 mins each week to keep everything lubed up. This method being marginally more fuel efficient.

    Must admit, I'm less concerned about the mpg, more concerned about making sure the climate system doesn't suffer and need expensive repairs so will probably stick with full auto.

    Presumably then if it has to be above 5 degrees C outside for the compressor to work, if you live in a colder climate your a\c compressor will do less work in the winter if any at all so could be more prone to seals drying out than it would be in a slightly warmer winter climate where the temperature ocassionally went above 5 degrees in the winter thus causing it to kick in occasionally?
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  13. marriedblonde
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    marriedblonde Moderator

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    I leave mine set to around 16.5 - 17.5 and on Auto all the time.

    Yes I know it saps some engein power and will effect the MPG... But I would rather the car was comfortable to drive in

    J.
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  14. madvw
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    madvw Active Member

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    Yak, the reason why it doesn't work below 5 degrees centigrade is to protect the air-con from freezing itself up and breaking, not because the air it's drawing is cold enough already.
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  15. Amchlolor
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    Amchlolor Active Member

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    Out of curiosity,how come my car mists up somehing terrible if I switch off the A/C,yet my wife's car demists quite happily without the A/C ?

    Her A/C's never on in the winter,yet mine is never off.

    Not a big deal,I'm just curious.
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  16. jdp1962
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    jdp1962 Grumpy Old Moderator Staff Member Moderator

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    [ QUOTE ]

    I leave mine set to around 16.5 - 17.5 and on Auto all the time.

    Yes I know it saps some engein power and will effect the MPG... But I would rather the car was comfortable to drive in

    J.

    [/ QUOTE ]

    16.5-17.5!! What're you trying to do, freeze-dry yourself?!

    I keep mine at about 19 or 20 in winter, & 21 in summer.

    A propos original question, I leave mine on Auto permanently. If I was worried about the effect of fuel consumption, I wouldn't have bought an climate-controlled car with a V6 engine, automatic transmission & permanent four-wheel drive.
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  17. wilko
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    wilko Top Gear

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    I'm sure I read somewhere before buying the car that the Aircon doesn't run direct from the engine power it runs from a different power source/supply (can't remember exactly). And therefor doesn't effect the MPG or performance.

    But if you turn you aircon off and then turn in on again you don't notice a drop in RPM so I think this could be right.... correct me if I'm wrong (i'm sure you will anyway)!! /ubbthreads/images/graemlins/froggie_red.gif
    #17
  18. h5djr
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    h5djr Well-Known Member

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    Cannot think of another power source available on a car to run the compressor other than the engine.

    On the A3 the compressor is driven off the engine using a wide ribbed belt. The reason you don't notice any drop in revs is down to the electric clutch on the compressor. Unless cold air is required the pulley on the compressor is basically just spinning. Only when cold air is required does the clutch engage and the compressor starts working. When this happens the ECU adjusts the idle speed to compensate for the extra load. All clever stuff.
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  19. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    the fuel economy hit with the compressor engaged is only noticeable when sitting in traffic and the engine has to work harder than it normally would to drive the a/c system. For normal driving it is just not a factor.
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  20. cosmicblue
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    cosmicblue Member

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    [ QUOTE ]
    Out of curiosity,how come my car mists up somehing terrible if I switch off the A/C,yet my wife's car demists quite happily without the A/C ?

    Her A/C's never on in the winter,yet mine is never off.

    Not a big deal,I'm just curious.

    [/ QUOTE ]

    Your car mists up because there is moisture in the car, usually you can fix this by driving with a window partially open for a few minutes - just replace the air with some drier stuff.

    Make sure the re-circ button is off or the car will recycle the moist air inside the car.

    If you have more moisture and perhaps a damp piece of carpet or such it will mist up again.
    #20
  21. bacardi
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    bacardi Active Member

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    missus car doesnt mist up either bowfer, though she rarely uses air con, perhaps thats why? ours are moisture free coz we use air con all the time so mist up quicker if we dont turn it on?
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  22. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    Climate control has a dryer which takes the moisture out of the air, which is why on humid summer days if you leave it running on the drive it p1sses water all over the place and you think you've got a leak.
    I think on conventional aircon you still have outside air coming through the vents without the blower on so it's probably a more direct route than with climate control = less steamy.
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  23. jdp1962
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    jdp1962 Grumpy Old Moderator Staff Member Moderator

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    [ QUOTE ]
    Climate control has a dryer which takes the moisture out of the air, which is why on humid summer days if you leave it running on the drive it p1sses water all over the place and you think you've got a leak.


    [/ QUOTE ]

    Yeah, I got caught out by that when I first had a car with CC. I still get people telling me I've got a leak after I've parked it on a hot day.
    #23
  24. h5djr
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    h5djr Well-Known Member

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    I think you will find the the water on the drive is caused by condensation dripping of the cold evaporator in warm weather.

    As the Owner's manual says...

    "If the humidity and temperature outside the vehicle are high, condensation can drip off the evaporator in the air conditioning system and form a pool underneath the vehicle. This is normal and does not indicate a leak"
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  25. jdp1962
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    jdp1962 Grumpy Old Moderator Staff Member Moderator

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    [ QUOTE ]
    I think you will find the the water on the drive is caused by condensation dripping of the cold evaporator in warm weather.

    As the Owner's manual says...

    "If the humidity and temperature outside the vehicle are high, condensation can drip off the evaporator in the air conditioning system and form a pool underneath the vehicle. This is normal and does not indicate a leak"

    [/ QUOTE ]

    Indeed it does, & I first read it about ten minutes after getting out of my first CC-equipped car on the day I bought it
    #25
  26. h5djr
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    h5djr Well-Known Member

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    Yes it's always I little worrying if you not aware of the situation. I've had several people comment to me a my car 'leaking' water in the past.

    If you purchase a new car in the winter it can be several months before you notice the 'pool' when you park.
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  27. jdp1962
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    jdp1962 Grumpy Old Moderator Staff Member Moderator

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    The dumb part is that although I've CC-equipped cars for nearly ten years, it still unnerves me a fraction the first time each year that it happens, cos it always looks like a scuzzy mixture of coolant & other oily fluids, instead of just water.

    It's usually round about this time of year that it makes its first appearance, but this year it's still so frickin' cold!
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  28. h5djr
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    h5djr Well-Known Member

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    It's more likely to be melted snow or frost at the moment !
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  29. synthdood
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    It is good practice to turn off the airco (ECO on) a few minutes before you reach your destination to allow the condensation in the system to evaporate. If you leave the airco running until you stop driving the airo and ventilation system will constantly be wet and that's what causes the infamous "wet cat" smell after a while.
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  30. cdb2
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    cdb2 Member

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    1) Do you mean turn it off completely by pressing the - button until it goes off totally or by turning on Econ mode?

    2) Is the only way to turn the a\c and ventilation off completely by repeatedly pressing the - button? There is no OFF button to turn it all off completely!
    #30
  31. h5djr
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    h5djr Well-Known Member

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    My current A3 is my 8th car with air-conditioning and I've never turned it off on any of them and never had any unwanted smells from the system. At least 3 of then I kept for over 3 years and one for over 4 years.

    My car is parked in a garage every night so perhaps the cats cannot get at it !
    #31
  32. imported_ANNANBHOY
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    imported_ANNANBHOY Guest

    as i said on another thread my heating system is a bit funny at the minute, even when on high it sometimes goes cold !
    #32
  33. jdp1962
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    jdp1962 Grumpy Old Moderator Staff Member Moderator

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    [ QUOTE ]
    1) There is no OFF button to turn it all off completely!

    [/ QUOTE ]

    There is on mine.
    #33
  34. Amchlolor
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    Amchlolor Active Member

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    Anyone else noticed how much quieter a drive it is if you take it off auto and switch it to the 'down/feet' mode instead ?

    Try it.

    It's the same in my A3 as it was in my A4.

    You instantly get less 'air/wind' noise and it makes the car seem much quieter.A very marked difference.
    #34
  35. Amchlolor
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    Amchlolor Active Member

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    [ QUOTE ]
    [ QUOTE ]
    1) There is no OFF button to turn it all off completely!

    [/ QUOTE ]

    There is on mine.

    [/ QUOTE ]

    There is an OFF button on the A4.
    No OFF button on the A3.
    #35
  36. h5djr
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    h5djr Well-Known Member

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    There is no OFF button on my a/c either. But I do agree with Bowfer (suprise, suprise) that the a/c is quieter if you change from Auto and select the footwell/down air distribution. In the winter I often run with the Auto off and the down (footwells) and up (screen) selected. It does seem quieter and also stops warm air blow into you face from the vents. I know you can close the vents but this way just seems easier and does still allow a very small amount of air through them.
    #36
  37. wilko
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    wilko Top Gear

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    And you can turn it off... keep pressing minus until everthing goes blank!
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  38. cdb2
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    cdb2 Member

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    Presumably then if you change from Auto and select the footwell/down air distribution that it still satisfies the 'requirement' of keeping the compressor running to keep the system lubed? Presumably you are just shifting to footwell vents rather than automatic temp regulation everywhere - but whichever the compressor is still running so everything stays lubed?
    #38
  39. imported_S_Line
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    imported_S_Line Guest

    turn it all off by lowing the fan speed down..down...........down.......
    then OFF /ubbthreads/images/graemlins/smile.gif
    #39
  40. h5djr
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    h5djr Well-Known Member

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    The compressor is always 'running'. At least the pulley on the end of the compressor is always going round driven by the ribbed belt from the engine pulley. The compressor itself only moves when the electric clutch engages. This clutch only engages when the a/c system requests cold air. If the outside air temperature is already cold, then the system will not ask for cold air to be produced. Thats the way it's been designed to work so I'm sure the compressor will not give problems just because it not actually producing any cold air for a few months. None of mine, on various VW/Audis over the last 18 years have given any problems at all.

    The compressor will still at times during cold weather inorder to provide the dehumifying during wet weather. Just leaving it switched on and let it look after itself. By all means change the air distribution, but leave it switched on.
    #40

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