Aircon Auto-Mode causes external air intake

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Post Reply
aneesh84
Posts: 366
Joined: 31 Jul 2011, 22:29
Location: Lisbon, Portugal
My Cars:
x 28

Aircon Auto-Mode causes external air intake

Post by aneesh84 »

Whenever I run my C5 AC on Auto Mode, it is taking external air into the cabin. Which means all the road pollutants and smoke from other cars are sucked inside making the Auto Mode unusable. Is this how its supposed to be? I would have found it more logical for Auto mode to engage cabin internal air circulation.
Xantia Estate 1999 2.0 HDI 110
C5 2005 2.0 HDI 138
Nissan Leaf 2018 40Kwh
User avatar
GiveMeABreak
Forum Admin Team
Posts: 37005
Joined: 15 Sep 2015, 19:38
Location: West Wales
My Cars: C3 Aircross SUV HDi Flair Peperoncino Red (The Chili Hornet)
C5 X7 2.0 HDi Exclusive Mativoire Beige (The Golden Hornet)
C3 1.6 HDi Exclusive Aluminium Grey (The Silver Hornet)
C5 MK II 2.0 HDi Exclusive Obsidian Black
C5 MK I 2.0 HDi SX Wicked Red
Xantia S2 2.0 HDi SX Hermes Red
C15 Romahome White
XM 2.0 Turbo Prestige Emerald Green Pearlescent
XM 2.0 Turbo Prestige Polar White
XM 2.0 SX Polar White
CX 20 Polar White
GS 1220 Geranium Red
CX 2.4 Prestige C-Matic Nevada Beige
GS 1000 Cedreat Yellow
x 5646

Re: Aircon Auto-Mode causes external air intake

Post by GiveMeABreak »

No that wouldn't work and you'd probably die from carbon dioxide poisoning from the passengers if it was designed that way (if you've ever seen the Apollo 13 film - you'll know the problem they had).

The system is designed to allow partial or full air recycling depending on the outside temperature, the inside temperature and the temperature requested by the passengers. The system will cut off this function if there is a risk of misting (via the hygrometry sensor).

There is a pollution sensor to detect Nitric Oxide or Carbon Monoxide from the exterior and this will determine the level of air recirculation. Bear in mind this does nothing for the smell of the pollutants - but it can inhibit exterior air intake to the cabin if it detects high levels of pollutants.

Om my C5 X7, the system often switched to internal air only whenever I hit reverse to prevent the exhaust fumes from being sucked up into the cabin as I reversed, so yes, the system is designed to work like that for good reason.
Please Don't PM Me For Technical Help

Marc
Post Reply