[Kitts32]

I can't make sense of why BMW have this on pretty much all there cars.

You have your normal air conditioning or heater/fan controls to control your temperature / power / direction etc of the air being blown out of the vents, which makes perfect sense. Even the split dual zone temperature controls makes sense, passenger and driver getting different temperatures.

Why do I need another adjuster just for that main central vent for temperature? if its a hot day and I select 17 degrees for example on my air con, why would i want the option to have hot air coming out of one central vent and cold air to come out of all the others? and if you do set it to hot / cold / in the middle or what ever it doesn't seem to have any effect on the temp of the air blowing of that vents anyways?

Dose anyone know what this is for?

Thanks

[ovekvam]

It does seem to have an effect on our car. I usually leave it centered, but some people like to have cold air in their face while the car is warm, or the other way around.

[Bob UK]

It's a blend control and allows you a little more control over the cabin air and it only operates on the centre vent.

[osvic]

I have it on my M sport, didnt have it on a Sport I was loaned this week. Its just a little more control. Mines centre in winter, cold in summer.

[matthewcornish]

I've always kept mine dead on centre because really I've not understood the point - like you - in having another control over the dual climate controls. However, reading what Bob has said kinda makes sense. I should probably play with it

[Bob UK]

Once you start using it Matthew, you won't be able to keep your hands off it.

Mine is a Sport osvic and has the control, I would think all models would as it's a pretty basic control even on non A/C equipped cars.

[matthewcornish]

Originally Posted by Bob UK

I would think all models would as it's a pretty basic control even on non A/C equipped cars.

Interestingly the 118i SE that I have as a courtesy car right now doesn't have that control so will just have to wait to get my car back

[Kitts32]

I did start playing with this again after starting this thread and reading your comments. It does actually blow out cooler / warmer air if you adjust it so ignore my comment that it doesn’t work in the OP.

I still don't entirely see the point though, however this morning I had the controls set to as hot as possible, it was a cold morning and wanted to warm up fast. After about 10 / 15 mins the car was too hot and I had to bring it down to find a comfortable sweet spot. When it did get too hot though that central adjuster did blow out cooler air instantly which was nice.

Just out of interest, do you guys tend to leave AC on all the time? I was told by the dealer to leave it on continuously - he was quite pushy about this, I’m not sure why though??

I'm too cheap to use the AC continuously and want my fuel to go as far as possible so I rarely use it. The blowers without AC are quite powerful on their own I find, but its harder to find that perfect temperature at times. I sometimes have to play about with the controls over long motorway journeys as the car heats up too much, then your bring it down, and then back up etc etc. Its better with AC on but I find the AC too powerful at times, even on the lowest fan setting it still blows out a lot of air and noisy.

Does anyone else struggle with the fans / AC like this?

[ovekvam]

It is recommended to have the A/C on at all times to ensure that the gaskets do not dry out. It doesn't use much fuel anyway, and it keeps the car nice and dry inside, so you avoid the windows misting up.

The fan buttons are not directly controlling the fan speed with the A/C set to automatic. It controls the intensity of the system. At the lowest setting, it will run low fan speeds, and not try all that hard to keep the temperature correct. I usually prefer the second lowest intensity. Higher than that, and it becomes noisy and windy at times.

[Bob UK]

I keep the A/C on all the time for the reasons ovekvam states, hardly makes a dent in consumption esp in diesels. In 2000 a friend had an e46 318i and the A/C dropped the mpg by 3 when in use, I'd expect it has far less effect these days even on the smaller petrols.

I find setting the climate sensitivity to middle and temp to 20 in the Winter gives a comfy environment without getting so hot you fall asleep.

[Kitts32]

Hmm I might turn it on for a full tank and see if it makes much difference. I tried this same experiment with it in comfort and Eco... If you drive in the same way there isn't really a noticeable difference, so long as you don't drive it harder in comfort (My 116d feels soo different in comfort compaired to Eco, it's hard not to accelerate harder when in comfort).

If your constantly using the AC... How often do you need to have it re gassed?
Thanks

[ovekvam]

Originally Posted by Kitts32

Hmm I might turn it on for a full tank and see if it makes much difference. I tried this same experiment with it in comfort and Eco... If you drive in the same way there isn't really a noticeable difference, so long as you don't drive it harder in comfort (My 116d feels soo different in comfort compaired to Eco, it's hard not to accelerate harder when in comfort).

If your constantly using the AC... How often do you need to have it re gassed?
Thanks

I have seen 10 year old cars with no need for A/C service. I guess it can last the life time of the car if you are lucky.

[Bob UK]

If you run in Eco Pro the A/C may well be forced to run at a low level as part of the Eco program. I would say at least 5 years before needing a regas and even then it's rare unless the system has been damaged.

[Kitts32]

I'm suprised it would last so long!

The Vauxhall Astra we had previously(55 plate) was taken to Vauxhall for first 6 years or so of its life for servicing and every year they said it needs re gassing. I only gassed it on the first year but ignored them afterwards as I tended not to use the ac. I just assumed re gassing was an annual thing if you use the AC a lot

The ac did eventually start to make funny noises after about 8 years, but I put this down to lack of use.. Gaskets probably damaged as mentioned above

[sandyjohny]

I have no idea what the technical workings of this dial are. I will say that I like it. It allows the climate control to make the whole car warm w/o blasting your face with hot air.

[dizx]

I live in a hot climate, and I use that switch when the car is already cooled down. I bring it to the right a bit against the center, and the air will be mixed with a little hot air, resulting in a nice air temperature.

[SteveC]

The centre vent with temperature balance lets you set the air temperature that blows on your face independent of the car's overall temperature setting

Lets say its very cold out and you want your car at 20 but you don't want hot air blowing on your face. Easy...just use the vent and mix in cold air. The rest of the car will compensate by blowing hot air to bring the overall temperature to 20 degrees while your face has a nice, cooler airflow

Lets say its hot out, your car is 40 degrees and you want it down to 18 but don't want your face frozen with frigid air. You simply set the centre vent to blow say 20 degrees while the rest of the car is getting air at 10 degrees until the interior cools down to the required 18

The point is, the centre vent is a direct airflow while the rest is indirect. You can set it at a constant temperature, while the rest of the is changing to adjust the overall car's temperature