[xpro]

Originally Posted by 330XDave

You're doing it all wrong. Leave it on 19 through the summer and just move the red to blue wheel from either fully blue when it's like 21+ outside or in the middle for anything less.

Sure 19 is too hot?? even with the blue wheel on. As soonest you move from 16c, the air gets heated, while 16 is just the lowest setting and its drawing the external air which means theres no heating of matrix element. As soonest you bump up the temp, the hot coolant is introduced into matrix and temps go up..
This is with AC OFF.

[adam.b]

Originally Posted by xpro

^^^^ This man is on the numbers!!



The other scenario, if you keep the car in ECO mode, regardless of the AC being ON, the car will limit the AC usage ( as seen in live data) which is the part of eco function and reducing the ac compressor load, which can often give similar effects.

Always I'm switching off ECO aircon in ECO mode, it is useless in this set up.

[330XDave]

Originally Posted by xpro

Sure 19 is too hot?? even with the blue wheel on. As soonest you move from 16c, the air gets heated, while 16 is just the lowest setting and its drawing the external air which means theres not heating of matrix element.

You must be hot blooded. 19 on blue wheel with air con on is plenty cool enough for me. If it gets to 30+ outside I MIGHT put it down to 18 but very rarely.

[adam.b]

Originally Posted by xpro

Sure 19 is too hot?? even with the blue wheel on. As soonest you move from 16c, the air gets heated, while 16 is just the lowest setting and its drawing the external air which means theres no heating of matrix element. As soonest you bump up the temp, the hot coolant is introduced into matrix and temps go up..
This is with AC OFF.

I think one is thinking with AUTO on and the other with MANUAL set up ?

[xpro]

Originally Posted by 330XDave

You must be hot blooded. 19 on blue wheel with air con on is plenty cool enough for me. If it gets to 30+ outside I MIGHT put it down to 18 but very rarely.

I am. Hence the issue. I just want the lowest setting on climate without the AC engaging by itself..

I mean whats the point of BMW having an AC ON/OFF switch when the ecu dictates when the ac comes on or off.

Say for people that have asthma, the AC is the worst thing as it dries the air and reduces humidity.. so how do you stop it then?

Hopefully we'll find the solution on how to code out the humidity sensor so I have the full control of the AC system.

And im not the first one with the same issue. Tons of post about this

https://f30.bimmerpost.com/forums/sh....php?t=1160120

https://f30.bimmerpost.com/forums/sh....php?t=1274071

[330XDave]

Originally Posted by xpro

I am. Hence the issue. I just want the lowest setting on climate without the AC engaging by itself..

I mean whats the point of BMW having an AC ON/OFF switch when the ecu dictates when the ac comes on or off.

Say for people that have asthma, the AC is the worst thing as it dries the air and reduces humidity.. so how do you stop it then?

Hopefully we'll find the solution on how to code out the humidity sensor so I have the full control of the AC system.

And im not the first one with the same issue. Tons of post about this

https://f30.bimmerpost.com/forums/sh....php?t=1160120

https://f30.bimmerpost.com/forums/sh....php?t=1274071

I'm sorry but you're giving the wrong impression on air conditioning and asthma. I suffer with asthma as well as other allergies and the only time I know I can be free of symptoms is when I'm at work in a large open air conditioned environment. Outside and at home my allergies tend to flare up. Air conditioning MAY cause issues with skin allergies as the last thing you want is dry air so a high level of humidity is important but it is not known to cause issues with asthma that I'm aware of.

[HighlandPete]

Originally Posted by xpro

So if I turn it to 20 or 22, its fine as longest the AC is on. As soonest this auto feature turns off, the cabin then gets warm... and the vicious circle continues.

What I don't understand is what's the meaning of "the cabin then gets warm"? How does it turn off? You touch it? If not, how does it get warm, at a set temperature, like 20C? Should be constant. Any increase in temperature hints at a fault.

Originally Posted by xpro

Now every time it rains, I find my self leaving the climate off completely so this auto AC doesnt kick in..

When it rains, that is when humidity increases, you typically need heat or AC function to control humidity.

BTW why not try 16.5C and keep to a regulated temperature, see how it functions without AC.

[xpro]

Originally Posted by 330XDave

I'm sorry but you're giving the wrong impression on air conditioning and asthma. I suffer with asthma as well as other allergies and the only time I know I can be free of symptoms is when I'm at work in a large open air conditioned environment. Outside and at home my allergies tend to flare up. Air conditioning MAY cause issues with skin allergies as the last thing you want is dry air so a high level of humidity is important but it is not known to cause issues with asthma that I'm aware of.

Well my mam has Asthma, and every time shes in AC environment she starts coughing like mad,as has asthma attacks, where inhaler needs to be taken in double doses.. So Im speaking from her experience. You might have different tolerances.

Originally Posted by HighlandPete

What I don't understand is what's the meaning of "the cabin then gets warm"? How does it turn off? You touch it? If not, how does it get warm, at a set temperature, like 20C? Should be constant. Any increase in temperature hints at a fault.



When it rains, that is when humidity increases, you typically need heat or AC function to control humidity.

BTW why not try 16.5C and keep to a regulated temperature, see how it functions without AC.

I see what you mean. I will try this too.

As this is getting complicated, ( especially for those that don't have an AC humidity sensor feature and it might be hard the explain this exact phenom, I am going to make a little video tomorrow with infra red thermometer and various temp setting to show how excessive temperature changes are when the AC kicks in in humid conditions.

cheers

[HighlandPete]

Originally Posted by xpro

Sure 19 is too hot?? even with the blue wheel on. As soonest you move from 16c, the air gets heated, while 16 is just the lowest setting and its drawing the external air which means theres no heating of matrix element. As soonest you bump up the temp, the hot coolant is introduced into matrix and temps go up..
This is with AC OFF.

This is not necessarily correct. A lot of the issue with modern cars, (not just BMW) is the HVAC systems have so much content, ducting, etc., that the heat soak from around the engine bay does influence the air intake temperatures. True, incoming air is hot, but not necessarily heated by the HVAC heater matrix.

Simply put, even with ambient temperatures below say 18C, you won't keep the CC down to 18C without AC helping the cooling. I know this for fact, as I've tried with thermometers in several cars, it is impossible to have ambient temperature airflows into the cabin.

It is not like years ago where fresh air was almost straight into the cabin, likely losing less than 1C. My current BMW will be 3 - 4C higher, even after driving a few miles. If I want to hold my 20C setting without AC, ambient has to be below 16/17C. Any higher and AC is required.

[HighlandPete]

Originally Posted by xpro

As this is getting complicated, ( especially for those that don't have an AC humidity sensor feature and it might be hard the explain this exact phenom, I am going to make a little video tomorrow with infra red thermometer and various temp setting to show how excessive temperature changes are when the AC kicks in in humid conditions.

Which modern BMWs don't have a humidity sensor? We've had them for over 12 years. E9x models with (IHKA) Climate Control are all fitted with humidity sensors. F3x models have the sensors and the AC humidity/demand feature.

BTW, I'm not doubting you are experiencing temperature swings, but shouldn't be happening with AC running in Auto mode.

[xpro]

Originally Posted by HighlandPete

This is not necessarily correct. A lot of the issue with modern cars, (not just BMW) is the HVAC systems have so much content, ducting, etc., that the heat soak from around the engine bay does influence the air intake temperatures. True, incoming air is hot, but not necessarily heated by the HVAC heater matrix.

Simply put, even with ambient temperatures below say 18C, you won't keep the CC down to 18C without AC helping the cooling. I know this for fact, as I've tried with thermometers in several cars, it is impossible to have ambient temperature airflows into the cabin.

It is not like years ago where fresh air was almost straight into the cabin, likely losing less than 1C. My current BMW will be 3 - 4C higher, even after driving a few miles. If I want to hold my 20C setting without AC, ambient has to be below 16/17C. Any higher and AC is required.

Without going to much into it. A comfortable 16c ( or blue or low, whatever you want to call it) on the panel without AC ON ( not taking any variants of engine heat, duct leaks and so on) feels pretty much very comfortable, especially during our summer. I haven't had a need to change the panel setting at all. Unless it really warm outside and I feel like a small bit of AC could do to chill the cabin)

Now imagine this: ( just tested some 15min ago)

AC On, same settings and infra red reads 4c airlfow from the vents. Thats a nice cold breeze if you ask me. Now image Im driving and feeling very comfortable with my 16c on the panel and the AC kicks in and all of a sudden your getting full blown cold AC air just cause humidity sensor thinks it necessary, even tho my windows and comfort levels are fine.. I dont think thats right!

Originally Posted by HighlandPete

Which modern BMWs don't have a humidity sensor? We've had them for over 12 years. E9x models with (IHKA) Climate Control are all fitted with humidity sensors. F3x models have the sensors and the AC humidity/demand feature.

I've had e46,e90,e92,e53, e70, f10, and an early f30.. Never once had that issue.. ( my current 335d is 2017 )

[HighlandPete]

Originally Posted by xpro

Now imagine this: ( just tested some 15min ago)

AC On, same settings and infra red reads 4c airlfow from the vents. Thats a nice cold breeze if you ask me. Now image Im driving and feeling very comfortable with my 16c on the panel and the AC kicks in and all of a sudden your getting full blown cold AC air just cause humidity sensor thinks it necessary, even tho my windows and comfort levels are fine.. I dont think thats right!

F3x models work in a different way than your previous models with condensation sensors. Unless there is a fault, humidity is causing the A/C to switch on, and as you are set at 16C you will get chilling while it is trying to reduce humidity. As I see it, the more humidity the cooler the car will get (time A/C is on) as it is unregulated, (at 16C setting you won't get any heat to hold the temperature).

As I suggested, try running at 16.5C, stay in the regulated range. Even if the A/C does cut in, it shouldn't chill the car, unless your cabin is above 16.5C

[NanasBack]

I rarely have the A/C switched on.
I prefer to use the extra 5HP elsewhere

Temperature is usually set to 19 with cabin air re-circ off.
(If re-circ is on, [green light on], expect window misting on every journey).

This for me, generally works ok.
On a long journey, the system will suddenly blow cold air on the odd occasion, for a minute or so. But this seems to be quite common according to other threads on this subject with F3x. (I don’t know if this is chilled air or cold air from outside. It shouldn’t be chilled air as the aircon is switched off).

Last week however, it started blowing cold air soon after the start of a journey, and the screen misted quite badly.
The car had been parked in the sun all day. It was certainly a very humid day, but I don’t think the outside temperature was low enough to feel that cold. It went on for five minutes or more.

Maybe that’s a similar situation to the OP.

If so, mine does it as well.

(The E90 never naffs about. A/C is always switched off, set to 19c, and it works as I would expect it).

[adam.b]

Originally Posted by NanasBack

On a long journey, the system will suddenly blow cold air on the odd occasion, for a minute or so..

It is designed to do this, odd blasts of cold air to prevent getting tired/sleepy behind the wheel. Keeps you more a wake.

[HighlandPete]

Originally Posted by NanasBack

This for me, generally works ok.
On a long journey, the system will suddenly blow cold air on the odd occasion, for a minute or so. But this seems to be quite common according to other threads on this subject with F3x. (I don’t know if this is chilled air or cold air from outside. It shouldn’t be chilled air as the aircon is switched off).

Illustrates what is going on in the background, often amplified when not using the A/C function. Could be either humidity and or solar sensor input. Starts the cascade strategy, (opening flaps, adjusting air speeds, etc.), to get back to threshold figures. Using A/C usually masks those actions, as it can do it in a more comfortable unobtrusive manner.

Originally Posted by NanasBack

Last week however, it started blowing cold air soon after the start of a journey, and the screen misted quite badly.
The car had been parked in the sun all day. It was certainly a very humid day, but I don’t think the outside temperature was low enough to feel that cold. It went on for five minutes or more.

Shows how much moisture we can get in our cars, even if we don't expect it to be there. If we are relying on un dried air to clear it, we get the higher air flows. Again, A/C clears the moisture more rapidly, (if we even see it at all), and with less air flow or temperature changes.

[HighlandPete]

Originally Posted by NanasBack

(The E90 never naffs about. A/C is always switched off, set to 19c, and it works as I would expect it).

Are you sure? Or you don't get to the extremes where the E9x IHKA HVAC system can fall down.

Having owned an E91 for over 6-years, I can assure you it has its limitations, where humidity can cause all sorts of strange behaviour, if you are not using the A/C feature. I believe it is one reason why the F3x model design reverts to brief A/C use, to reduce humidity more simply and quickly.

If you think I'm exaggerating the E9x limitations, BMW put a data logger in my car, for a week, collecting data and I videoed the settings/display when the system appeared to glitch. BMW got the HVAC designers involved to analyse the data to see what was happening. Turns out I was regularly reaching the limits of the system, (Scottish Glens can be pretty humid). It was doing its job to try and reduce humidity, but couldn't cope without using the full cascade strategy, which included adding lots of air and heat to try and dry the car. Running A/C, it doesn't require those extreme measures.

I run full auto and A/C all year round. Even the F11 HVAC system still has limitations, as the temperature drops to when A/C automatically switches off. In high humidity, the AUC (sniffer) system can't cope. The HVAC has to go into humidity control and that means 'fresh' outside air takes priority over the Auto recirculation, (timed phases, all part of the control strategy). So we can get polluted outside air from dirty diesels. BMW have checked it out, nothing wrong, simply humidity control. I fitted a new sniffer sensor to ensure that wasn't degrading, but makes little difference when we hit the conditions where the system has to take over to stop fogging/misting.

[doncarlyon]

Mine works perfectly

[330XDave]

Well... just driven 260 miles down to the south coast and decided to have an experiment with the climate control. Firstly I've got no idea how anyone manages to resist using the air con at this time of the year. I managed about 30 miles on the motorway with no air con, temp set at 16 and the wheel on full blue before the warmth became too much and the air con had to go on. I then turned it to 19, air con on and half blue and red and it was perfect. For reference the outside temperature was 18-19 and it was sunny.

At no point when it was set to 16c and air con off did the temperature fluctuate or the air con kick in so I have no idea what's happening with yours xpro. Maybe you have an issue with your system?

[HighlandPete]

Originally Posted by 330XDave

Well... just driven 260 miles down to the south coast and decided to have an experiment with the climate control. Firstly I've got no idea how anyone manages to resist using the air con at this time of the year. I managed about 30 miles on the motorway with no air con, temp set at 16 and the wheel on full blue before the warmth became too much and the air con had to go on. I then turned it to 19, air con on and half blue and red and it was perfect. For reference the outside temperature was 18-19 and it was sunny.

At no point when it was set to 16c and air con off did the temperature fluctuate or the air con kick in so I have no idea what's happening with yours xpro. Maybe you have an issue with your system?

Exactly how it has been with any late model BMW I've driven. Outside ambient temperature around 18C, or above, and A/C is a must to keep the cabin at a steady temperature.

Unless there is a particular fault, I'm sure humidity is the main issue, when users have what appears to be erratic behaviour. On full Auto, A/C function sorts humidity, in the background.

[lethbridge]

I never got on with the climate control in my F34 - different reason but possibly connected with the system trying to be in too much control... I too could never conceive of driving in a modern car without A/C for all the reasons people have highlighted - namely they get too hot & mist up. However in my case it was forever blasting cold air onto my hands on long journeys (which was pretty much every journey I did) regardless of the red/blue setting on the vent knob - reported it every time it went in but they always reckoned it was fine - if it was fine then I don't want it thanks - sounds like it could have been the humidity sensor playing up or just design intent to due to long journeys (as will happily drive for hours & hours without stopping) but it was truly annoying - can't believe it would be designed to behave how it did! Only solution was to point the vents at someone else or turn them off but then I would get a hot head, so was forever having to faff about... Haven't noticed the issue on my F80 but then I don't do many long journeys now.

[xpro]

Originally Posted by 330XDave

Well... just driven 260 miles down to the south coast and decided to have an experiment with the climate control. Firstly I've got no idea how anyone manages to resist using the air con at this time of the year. I managed about 30 miles on the motorway with no air con, temp set at 16 and the wheel on full blue before the warmth became too much and the air con had to go on. I then turned it to 19, air con on and half blue and red and it was perfect. For reference the outside temperature was 18-19 and it was sunny.

At no point when it was set to 16c and air con off did the temperature fluctuate or the air con kick in so I have no idea what's happening with yours xpro. Maybe you have an issue with your system?

It will only fluctuate when theres rain outside. Otherwise the AC stays off. You can see some other members are starting to report similar problems in this thread, so it does happen.

HighlandPete

Using the AC all year round is fine, but I dont see the point in this.
I fully agree with you that by having the AC on at all times you would avoid those temperature fluctuations and I could just leave the AC on and set at 19 and call it a day.

But from my engineering prospective and with detailed idea on how AC components work in the car, I see no sense to have it on at all the times.

Increased wear on the motor, increased fuel consumption due to extra loading, the condenser fan is running at all time keeping the temps low, so even additional loading on the alternator. For me these are all the cons to persuade me not to use it all the time.

I turn the AC on here and there as I need it or maybe once a week to keep the seals lubricated and not once have I had issue with AC systems in my car.

And using the AC at all times does use the freon gas in the long run which need to be replenished and so on.. otherwise we would called them sealed units without the need for a regas or service.

To be in agreement with this, if you run your car in the ECO mode, the AC off switches off periodically when the cabin temp are reached. (a similar to humidity sensor feature), so even the BMW designed it in a way to have the AC off in auto mode should you choose eco mode and thats with the AC switch ON.

[Flyboy777]

I’m on the same page as xpro.
My previous F31 used to drive me mad for the same reason. Funnily enough my current M2 exhibits the same symptom but is far less annoying so maybe being a smaller car the A/C is less powerful so not as noticeable.
I work in a dry air conditioned environment — long haul aircraft, and prefer to leave the A/C in my car off unless its v wet/humid as the very dry atmosphere is a bit uncomfortable.
This air drying feature whilst understandable is a bit annoying unless as previously posted you leave the A/C on all the time.
It should really blend in warm air as the compressor kicks in but it definitely doesn’t. I usually have my temp set at 22 so not on full cold demand (16c) either.