Odd HVAC ISsue

lo_cheng · 09-13-2019, 02:07 PM

I have a odd AC/HVAC issue, that I need to schedule an appointment, may be do it with the oil change next month. Here is my issue, see anyone here have same issue before?

First, I don't use Auto mode. I always turn the AC ON or OFF myself.
In weather like now, I usually want just fan on with outside air coming in.

What happen is the HVAC system seem to have life of its own.
I set the FAN to 3, AC off, Temp at 16c (Lowest setting), and Air Re-circulation off.
So it should be just a fan with outside air coming in.

However, sometime it will have the AC running (AC light still off but it blowing COLD air).

Sometime it turn the heat on. Like today, outside is 17c and it keep blowing hot air at me, when I set the temp of the system to lowest setting 16c.

When it was summer, I got some random issue of I turned the AC on (the AC light turned on), but after 10min of driving, it will turn the AC off (Light off, and no cold air come out).

Anyone have issue like I having now??

M40iG01 · 09-13-2019, 03:47 PM

ac is controlled by some type of enthalpy sensor. it will cycle the compressor regardless of if you have ac on. I am like you and like to have control over the compressor running however I learned when I got this BMW that these climate system are more advanced and its objective is to keep the cabin at an optimal humidity level regardless of what we want. only option if you want the compressor disabled is shut the climate system off. flow through for free air doesnt work well with this system design

guess we are supposed to use auto and keep the windows shut lol.

lo_cheng · 09-13-2019, 03:57 PM

Quote:

Originally Posted by M40iG01

ac is controlled by some type of enthalpy sensor. it will cycle the compressor regardless of if you have ac on. I am like you and like to have control over the compressor running however I learned when I got this BMW that these climate system are more advanced and its objective is to keep the cabin at an optimal humidity level regardless of what we want. only option if you want the compressor disabled is shut the climate system off. flow through for free air doesnt work well with this system design

guess we are supposed to use auto and keep the windows shut lol.

What I want is very simple. When temp is nice, I just want FAN, No heating, No cooling, just FAN.

M40iG01 · 09-13-2019, 06:15 PM

Haha. you wont get it. it annoys me to but it is how the system is designed.

Tchgrif · 09-14-2019, 07:36 AM

I set mine to auto then manually turn off the AC, seems to work just fine.

09-13-2019, 02:07 PM	#1
lo_cheng First Lieutenant 101 Rep 361 Posts Drives: BMW X3 M40i Join Date: Apr 2019 Location: Toronto iTrader: (0)	Odd HVAC ISsue I have a odd AC/HVAC issue, that I need to schedule an appointment, may be do it with the oil change next month. Here is my issue, see anyone here have same issue before? First, I don't use Auto mode. I always turn the AC ON or OFF myself. In weather like now, I usually want just fan on with outside air coming in. What happen is the HVAC system seem to have life of its own. I set the FAN to 3, AC off, Temp at 16c (Lowest setting), and Air Re-circulation off. So it should be just a fan with outside air coming in. However, sometime it will have the AC running (AC light still off but it blowing COLD air). Sometime it turn the heat on. Like today, outside is 17c and it keep blowing hot air at me, when I set the temp of the system to lowest setting 16c. When it was summer, I got some random issue of I turned the AC on (the AC light turned on), but after 10min of driving, it will turn the AC off (Light off, and no cold air come out). Anyone have issue like I having now?? __________________ 2019 X3 M40i - Phytonic Blue, Black Vernasca Leather, 21" 718M Wheels, Premium Essential
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09-13-2019, 03:47 PM	#2
M40iG01 Private First Class 79 Rep 117 Posts Drives: 2018-X3 M40i Join Date: Oct 2018 Location: Toronto, Canada iTrader: (0)	ac is controlled by some type of enthalpy sensor. it will cycle the compressor regardless of if you have ac on. I am like you and like to have control over the compressor running however I learned when I got this BMW that these climate system are more advanced and its objective is to keep the cabin at an optimal humidity level regardless of what we want. only option if you want the compressor disabled is shut the climate system off. flow through for free air doesnt work well with this system design guess we are supposed to use auto and keep the windows shut lol.
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09-13-2019, 06:15 PM	#4
M40iG01 Private First Class 79 Rep 117 Posts Drives: 2018-X3 M40i Join Date: Oct 2018 Location: Toronto, Canada iTrader: (0)	Haha. you wont get it. it annoys me to but it is how the system is designed.
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09-14-2019, 07:36 AM	#5
Tchgrif Lieutenant 254 Rep 453 Posts Drives: X4 M40i Join Date: Sep 2014 Location: pgh pa, USA iTrader: (0)	I set mine to auto then manually turn off the AC, seems to work just fine.
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